Long-term results of the M. D. Anderson randomized dose-escalation trial for prostate cancer

Five-Year Outcomes of Moderately Hypofractionated Proton Therapy Incorporating Elective Pelvic Nodal Irradiation for High-Risk Prostate Cancer

PURPOSE

To assess the efficacy of moderately hypofractionated intensity modulated proton therapy (IMPT) targeting the prostate/seminal vesicles and pelvic lymph nodes for high-risk (HR) or unfavorable intermediate-risk (UIR) prostate cancer (PCa).

MATERIALS AND METHODS

A prospective study (ClinicalTrials.gov: NCT02874014) of moderately hypofractionated IMPT accrued a target sample size of 56 patients with HR or UIR-PCa. The prostate/seminal vesicles and pelvic lymph nodes were treated simultaneously with 67.5 and 45 Gy, respectively, in 25 daily fractions. All received androgen deprivation therapy. Its primary objective was late gastrointestinal (GI) and genitourinary (GU) adverse events (AEs), and secondary objectives were a recurrence-free rate (RFR), including freedom from prostate-specific antigen (PSA) relapse and disease-free survival (DFS) at 5 years. PSA and AEs were evaluated at 3, 6, and 12 months post-IMPT, then every 6 months for 5 years, and then yearly thereafter. The actuarial rates of late GI and GU AEs, RFR, and DFS were estimated with the Kaplan-Meier method.

RESULTS

Median age was 75 years. Median PSA was 10.5 ng/mL. Fifty-three patients had HR-PCa; 2 had UIR-PCa. Median androgen deprivation therapy duration was 18 months. Median follow-up was 62 months. Late grade ≥2 and 3 GI AEs at 5 years were 16% and 4%, respectively. Late grade ≥2 and 3 GU AEs at 5 years were 41% and 0%, respectively. None had a grade ≥4 late AE. At 5 years, RFR and DFS were 90% and 89%, respectively. Seven patients had PCa recurrence, all detected by PSA relapse initially. Three patients died with PSA <0.1 ng/mL at last follow-up. None died of PCa or treatment-related AEs.

CONCLUSIONS

This regimen of moderately hypofractionated IMPT for HR or UIR-PCa yielded encouraging 5-year RFR, DFS, and late AE outcomes. A phase III study is needed to assess any therapeutic gain of IMPT compared with photon-based radiation therapy.

PIM kinase inhibition counters resistance to radiotherapy and chemotherapy in human prostate cancer

PURPOSE

PIM kinases are associated with treatment resistance and poor prognosis in prostate cancer through roles in DNA damage response, cellular metabolism, proliferation, and survival. We hypothesized PIM inhibition addresses treatment resistance to radiotherapy and docetaxel in prostate cancer.

METHODS

PIM inhibition in prostate cancer cell lines was examined by phosphorylated H2AX and colony formations assays. In normal and castrated mice with prostate tumor xenografts, tumor growth was monitored with daily oral PIM inhibition +/- fractionated radiotherapy (RT) or docetaxel. Radiotherapy was given 30 Gy in 15 treatments, mimicking clinical conventional daily treatment over 3 weeks in a translational murine model system.

RESULTS

PIM inhibition decreased radiotherapy-induced DNA-damage repair and decreased cell proliferation and survival. In mice, PIM inhibition increased the efficacy of both radiation and docetaxel to reduce tumor size in hormone-dependent and -independent xenografts. Xenografts showed altered gene expression changes, including downregulation of ribosomal pathways and upregulation of cardiomyocyte signaling pathways, due to PIM inhibition as analyzed by RNA-Seq. Immunostaining of multiple proteins, including COX-2 and MDM2, was altered by PIM inhibition.

CONCLUSIONS

PIM inhibition addresses treatment resistance to docetaxel and radiotherapy in multiple prostate cancer models. Our data provide a strong rationale for testing PIM inhibitors in combination with standard therapies for treatment-resistant high-risk localized or metastatic prostate cancer in clinical trials.

Primary Analysis of (NCT03380806) a Phase II Randomized Trial of Stereotactic Body Radiotherapy Boost Versus Conventional Fractionation External Beam Radiotherapy Boost in Unfavorable-Intermediate and High-Risk Prostate Cancer

BACKGROUND

Standard treatment for unfavorable-intermediate and high-risk prostate cancer involves androgen deprivation therapy (ADT) in combination with pelvic conventional fractionation (CF) external beam radiotherapy (EBRT) and a CF-EBRT or brachytherapy boost to the prostate. This trial compared CF-EBRT boost with stereotactic body radiotherapy (SBRT) boost after pelvic CF-EBRT.

METHODS

Patients were randomized to receive a boost using either CF-EBRT (32-34 Gy in 15-17 fractions) or SBRT (19.5-21 Gy in three weekly fractions) following pelvic CF-EBRT (45-46 Gy in 23-25 fractions). The primary objective was to assess early (3-month post-radiotherapy) gastrointestinal (GI) and genitourinary (GU) quality of life (QoL), using the expanded prostate index composite (EPIC) score. Secondary objectives included long-term QoL, International Prostate Symptom Score (IPSS) changes, toxicity assessments, and long-term disease control outcomes. Linear regression and Fisher's exact test were used for analysis.

RESULTS

Of the 100 patients randomized, 53 received CF-EBRT, and 47 received SBRT. After a mean follow-up of 18.5 months, no significant differences were observed in EPIC score changes between CF-EBRT and SBRT at 3 months posttreatment for urinary (11.5 vs. 8.6, p = 0.23), bowel (5.2 vs. 6.4, p = 0.57), and overall QoL (8.3 vs. 7.5, p = 0.61). IPSS scores were similar (p = 0.11), and CTCAE v.5.0 toxicity rates were comparable, with an odds ratio of 0.90 (p > 0.99). Biochemical failure rates were under 5% for both groups.

CONCLUSIONS

This is the first randomized trial to report QoL outcomes after SBRT boost radiotherapy in patients with unfavorable-intermediate and high-risk prostate cancer. SBRT boost after pelvic CF-EBRT is well-tolerated and demonstrates comparable outcomes in QoL and toxicity to the CF-EBRT boost. Further follow-up is needed to assess the long-term effects on QoL, toxicity, and disease control.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03380806.

Intensity modulated radiation therapy in prostate cancer-Better survival with higher total dose?

BACKGROUND AND PURPOSE

For patients with intermediate and high-risk prostate cancer, radiation treatment is a well-established alternative to surgery. Modern techniques, such as intensity-modulated radiation therapy and volumetric modulated arc therapy, allow for precise dose escalation to the tumor while minimizing exposure to surrounding healthy tissues. The purpose of this analysis was to assess the safety and efficacy of two different radiation treatment protocols (high dose vs low dose) in prostate cancer patients across all risk categories.

PATIENTS AND METHODS

Between 2015 and 2021, a total of 300 consecutive patients with localized adenocarcinoma of the prostate underwent intensity-modulated radiation therapy and volumetric modulated arc therapy at this institution. The study's endpoints were overall survival, prostate cancer specific overall survival, metastases-free survival, biochemically no evidence of disease survival rates as well as acute and long-term toxic effects. Influence of patient- and treatment-related parameters, including risk stratification (low and medium vs. high risk), radiation therapy dose levels (< 76 Gy vs. ≥ 76 Gy), radiation therapy duration (≤ 51 days vs. > 51 days), treatment with or without elective node irradiation, and the use of concurrent androgen deprivation therapy was evaluated by the log-rank-test and using multivariate Cox-analysis.

RESULTS

Overall survival, prostate cancer specific overall survival, metastases-free survival and biochemically no evidence of disease survival rates were 88%, 96%, 94%, 92% and 56%, 76%, 90%, 75% at 5 and 10 years, respectively. Univariate analysis identified a significant impact of total dose and androgen deprivation therapy. Overall survival rates for patients with a total radiation dose ≥ 76 Gy were 92% and 59% at 5 and 10 years, respectively, in comparison with patients receiving a total dose of < 76 Gy having a 5-year overall survival of 82% and a 10-year of overall survival 52% (p=0.012). Androgen deprivation therapy had an impact on overall survival with a 5-year of 90% and a 10-year of 57% survival rates, in comparison to a group without androgen deprivation therapy that had a significantly lower 5-year overall survival of 79.8% and a 10-year overall survival of 23.8% (p=0.041). In multivariate analysis, total radiation dose remained of significant impact on overall survival (p=0.022) and risk grouping (p=0.026) on biochemically no evidence of disease survival. Regarding toxicity, Grade II and III late genitourinary toxicity was observed in 13 patients (4.3%), and late gastrointestinal toxicity of similar grade affected 12 patients (4%) in the cohort.

CONCLUSION

Data from this retrospective analysis underscore the highly relevant influence of total dose in contemporary radiation treatment of patients with prostate cancer.

A Randomized Comparison of High Dose Rate and Low Dose Rate Prostate Brachytherapy Combined with External Beam Radiotherapy for Unfavourable Prostate Cancer: Efficacy Results after Median Follow-up 74 Months

PURPOSE

This single center randomized trial compared health-related QOL for men with unfavorable localized prostate cancer treated with combined pelvic external beam radiation (EBRT) and prostate brachytherapy (BT), randomly assigned to High Dose Rate (HDR) or Low Dose Rate (LDR). We now report efficacy outcomes with minimum 5 year follow up.

MATERIALS AND METHODS

Consenting patients receiving pelvic EBRT combined with prostate BT were randomized to either LDR (110Gy) or HDR (15Gy). Androgen deprivation was used in 76%. EBRT delivered 46 Gy/23 using IMRT or VMAT (68%) or 3DcRT (32%). Followup up was 1-, 3-, and 6-mo, then every 6 mo to 3 years, then annually. PSA ≤ 0.2ng/ml at 4 years defined cure. Biochemical failure-free survival (bFFS), and overall survival (OS) were calculated by Kaplan Meier methods. All failures were investigated by imaging (CT, bone scan and/or PSMA PET) ± biopsy if PET not available.

RESULTS

From 01/2014 to 12/2019, 195 men (42% IR/ 58% HR) were randomly assigned: 108 to HDR and 87 to LDR. Median age was 71 years. Median PSA was 11.6 ng/ml (mean 27.0 ng/ml). Median follow up was 74 months (43m - 116m). Median PSA nadirs were 0.07 and 0.08 in HDR and LDR (p=0.16), and time to nadir was 13.8 and 14.1 mo respectively (p=0.87). 4-year PSA ≤ 0.2 was maintained in 81% and 83% of HDR and LDR (p=0.91). 8-year bFFS (nadir+2) was 86% and 85% respectively. 18 of 22 BF have been identified: 3 are isolated LF while 14 are distant (isolated 11; 3 combined).

CONCLUSIONS

In this small, randomized comparison, efficacy analysis shows no difference between LDR and HDR boost in biochemical FFS at 5 and 8 years and confirms the excellent efficacy of dose escalation using prostate brachytherapy as documented in Ascende-RT for unfavorable localized prostate cancer.

Predictive Model of Acute Rectal Toxicity in Prostate Cancer Treated With Radiotherapy

PURPOSE

To aid personalized treatment selection, we developed a predictive model for acute rectal toxicity in patients with prostate cancer undergoing radiotherapy with photons and protons.

MATERIALS AND METHODS

We analyzed a prospective multi-institutional cohort of 278 patients treated from 2012 to 2023 across 10 centers. Dosimetric and nondosimetric variables were collected, and key predictors were identified using purposeful feature selection. The cohort was split into discovery (n = 227) and validation (n = 51) data sets. The dose along the rectum surface was transformed into a two-dimensional surface, and dose-area histograms (DAHs) were quantified. A convolutional neural network (CNN) was developed to extract dosimetric features from the DAH and integrate them with nondosimetric predictors. Model performance was benchmarked against logistic regression (LR) using the AUC.

RESULTS

Key predictors included rectum length, race, age, and hydrogel spacer use. The CNN model demonstrated stability in the discovery data set (AUC = 0.81 ± 0.11) and outperformed LR in the validation data set (AUC = 0.81 v 0.54). Separate analysis of photon and proton subsets yielded consistent AUCs of 0.7 and 0.92, respectively. In the photon high-risk group, the model achieved 83% sensitivity, and in proton subsets, it achieved 100% sensitivity and specificity, indicating the potential to be used for treatment selection in these patients.

CONCLUSION

Our novel approach effectively predicts rectal toxicity across photon and proton subsets, demonstrating the utility of integrating dosimetric and nondosimetric features. The model's strong performance across modalities suggests potential for guiding treatment decisions, warranting prospective validation.

Direct minimization of normal-tissue toxicity via an NTCP-based IMPT planning method

BACKGROUND

Intensity-modulated proton therapy (IMPT) planning often relies on physical dose constraints to balance tumor control and sparing of organs at risk (OARs). However, focusing solely on these dose objectives does not always minimize the normal-tissue toxicity, which is quantified as normal tissue complication probability (NTCP). NTCP is also a quantitative criterion for patient selection between proton and photon treatments.

PURPOSE

This study introduces an NTCP-based IMPT planning (NTCP-IMPT) method designed to directly minimize normal-tissue toxicity while maintaining tumor coverage.

METHODS

NTCP-IMPT simultaneously optimizes NTCP and dose-volume histogram (DVH)-based physical dose objectives while adhering to the minimum-monitor-unit (MMU) constraint for plan deliverability. The optimization problem is solved by the interior-point method. To assess its efficacy in reducing normal-tissue toxicity, NTCP-IMPT is compared with standard IMPT (without NTCP optimization) for four head-and-neck (HN) cancer patients in terms of physical dose quality and NTCP of xerostomia and dysphagia.

RESULTS

Across all four patients, NTCP-IMPT plans met target dose criteria (D95% ≥ 100% and D2% ≤ 110%) while maintaining maximum doses to the spinal cord and brainstem comparable to standard IMPT. NTCP-IMPT also reduced mean doses to parotid glands, submandibular glands, oral cavity, and pharyngeal constrictor muscles (PCMs). Compared to the standard IMPT, NTCP-IMPT achieved average reductions in NTCP for xerostomia (grade ≥ 2: 3.67%; grade ≥3: 1.07%) and dysphagia (grade ≥ 2: 7.54%; grade ≥ 3: 3.72%).

CONCLUSIONS

NTCP-IMPT effectively minimizes normal-tissue toxicity and improves the sparing of OARs associated with side effects while maintaining comparable tumor coverage compared to standard IMPT.

Hypofractionated Dose Escalation Radiotherapy for High-Risk Prostate Cancer: the survival analysis of the Prostate Cancer Study-5 (PCS-5), a GROUQ-led phase III trial

BACKGROUND AND OBJECTIVE

Prostate Cancer Study 5 (PCS5) compared conventional fractionated radiotherapy (CFRT) with hypofractionated radiotherapy (HFRT) in high-risk prostate cancer (PCa) patients, hypothesizing similar toxicity and survival outcomes. This report presents the efficacy analysis.

METHODS

PCS5 is a Canadian multicenter, open-label, phase 3 randomized control trial. Men with histologically proven, clinically localized PCa with one or more high-risk features (T3/T4, Gleason score ≥8, and prostate-specific antigen >20) were eligible. Patients were randomized 1:1 to CFRT (76 Gy/38 fractions [Fx] to the prostate and 46 Gy/23 Fx to the pelvic lymph nodes [PLNs]) or HFRT (68 Gy/25 Fx to the prostate and 45 Gy/25 Fx to the PLNs) and 28 mo of androgen suppression. The primary endpoint was toxicity; secondary endpoints included survival outcomes.

KEY FINDINGS AND LIMITATIONS

Of 329 patients, 164 were randomized to HFRT and 165 to CFRT, with 159 in the HFRT arm and 160 in the CFRT arm included in survival analyses. At the 5-yr median follow-up, there were no significant differences in overall survival (OS; 90.3% vs 89.7%; risk ratio [RR]: 1.01; 95% confidence interval [CI]: 0.93-1.09), PCa-specific survival (PCSS; 97.4% vs 97.5%; RR: 1.00; 95% CI: 0.93-1.07), biochemical recurrence-free survival (BCRFS; 85.2% vs 85.2%; RR: 1.00; 95% CI: 0.91-1.10), or distant metastasis-free survival (DMFS; 87.1% vs 87.1%; RR: 1.00; 95% CI: 0.92-1.09). Hazard ratios were 0.92 (95% CI: 0.56-1.53) for OS, 1.31 (95% CI: 0.46-3.78) for PCSS, 0.85 (95% CI: 0.56-1.30) for BCRFS, and 0.90 (95% CI: 0.56-1.43) for DMFS. Sample size was a limiting factor.

CONCLUSIONS AND CLINICAL IMPLICATIONS

There were no differences in survival outcomes between HFRT (68 Gy/25 Fx) and CFRT (76 Gy/38 Fx). HFRT, including PLN radiotherapy and long-term androgen deprivation therapy, should be considered a new standard of care for high-risk PCa patients undergoing external beam radiotherapy.

HDR brachytherapy combined with external beam radiotherapy for unfavorable localized prostate cancer: A single center experience from inception to standard of care

PURPOSE

High dose rate (HDR) brachytherapy is increasingly adopted for dose escalation in prostate cancer treatment. We report the clinical efficacy and toxicity of HDR prostate brachytherapy combined with external beam radiotherapy (EBRT) and evaluate the predictability of the biochemical definition of cure of 4-year PSA ≤0.2 ng/mL for failure free survival (FFS).

METHODS

A single centre retrospective study was conducted, including all patients with high-tier intermediate risk and high-risk prostate cancer treated with HDR brachytherapy combined with EBRT from 2011 to 2019. Patient and prostate cancer characteristics, treatment, clinical endpoints, and follow up were collected.

RESULTS

Total 319 patients were analyzed. The median age was 68 with median follow up of 77.1 months. Total 142 had high-tier intermediate and 177 had high-risk disease. Brachytherapy doses were initially 20 Gy/2 fractions, and subsequently 15 Gy/1 fraction. All patients received 46 Gy/23 fractions of EBRT. Overall survival at 5 and 9 years was 92.2% and 77.0%, respectively. Failure-free survival (FFS) was 86.0% at 5 years and 76.1% at 9 years. PSA ≤ 0.2 ng/mL at 4 years was seen in 79.3% of patients and was associated with FFS of 94.1% at 9 years. Grade 3 urethral stricture, hematuria, or proctitis occurred in 2.8%, 0%, and 0%, respectively.

CONCLUSION

HDR brachytherapy in addition to EBRT is effective treatment for unfavourable localized prostate cancer with a very acceptable toxicity profile. The biochemical definition of cure of PSA < 0.2 ng/mL at 4 years was predictive for FFS at 9 years.

Biochemical response to neoadjuvant hormonal therapy predicts long-term prostate cancer survival outcomes after high-dose-rate brachytherapy with external beam radiotherapy

We evaluated the long-term treatment outcomes and toxicities in patients with clinically localized and locally advanced prostate cancer (PC) who underwent high-dose-rate brachytherapy (HDR-BT) with external beam radiotherapy (EBRT). We retrospectively analyzed 417 patients with PC who underwent HDR-BT with EBRT. The treatment dose was 19- and 13-Gy HDR-BT in two and single fractions, respectively, both combined with external irradiation of 46 Gy in 23 fractions, and hormonal therapy (HT). The median observation period was 7.2 (range, 2.0-17.6) years. The 7-year recurrence-free, PC-specific, and overall survival rates were 93.3%, 99.1%, and 94.8%, respectively, with only six PC mortalities. Multivariable analysis showed that pre-radiotherapy prostate-specific antigen (PSA) of > 0.05 ng/mL after neoadjuvant HT was an independent poor prognostic factor of recurrence (HR, 4.44; 95% CI 1.56-12.63; p = 0.005) and overall mortality (HR, 2.20; 95% CI 1.11-4.39; p = 0.025). The 7-year cumulative incidence rate of grade ≥ 2 toxicities in genitourinary and gastrointestinal tracts were 15.7% and 2.0%, respectively. HDR-BT combined with EBRT shows promising disease control and tolerant toxicities for PC. Poor PSA response to neoadjuvant androgen deprivation predicts worse survival measures. These patients may require more intensive multidisciplinary treatment in combination with radiotherapy.

Salvage radiotherapy with volumetric modulated arc therapy (VMAT) for recurrent prostate cancer after high-intensity focused ultrasound (HIFU): A large French retrospective series and literature review

BACKGROUND AND PURPOSE

Although not validated as a standard treatment, high-intensity focused ultrasound (HIFU) is increasingly used in the management of localised prostate cancer (PCa). In case of recurrence after HIFU, treatment is currently not standardised. Our aim was to evaluate normofractionated (NFRT) and hypofractionated (HFRT) salvage radiotherapy (RT) using volumetric modulated arc therapy (s-VMAT) with doses used in first-line management of localised PCa.

MATERIAL AND METHODS

We identified all patients with local or locoregional recurrence after HIFU treated with s-VMAT in 3 RT centres between 2014 and 2023. We evaluated acute and late toxicity and oncological outcomes.

RESULTS

Fifty-six patients were identified. Median age at recurrence was 75 (70-80) years. Median time between HIFU and s-VMAT was 26.5 months (13.9-47.2). S-VMAT was delivered to the prostate only in 35 (62.5 %) patients and to the prostate and pelvis in 21 (37.5 %) patients. NFRT and HFRT were delivered in 46 (82.1 %) and 10 (17.9 %) patients, respectively. Androgen deprivation therapy (ADT) was given to 27 (48.2 %) patients. Eighteen (32 %) and four (7 %) patients reported an acute grade 2 genitourinary (GU) and gastrointestinal (GI) adverse event (AE), respectively. Two patients presented with a late grade 2 GU AE, and one with a late grade 2 GI AE. No grade 3+ toxicity was reported. With a median follow-up of 19.5 months (12 - 47), no patient had a biochemical, local or distant relapse.

CONCLUSIONS

This is the largest series of salvage RT after HIFU using VMAT and escalated doses (78-80 Gy/39-40Fr., or 60 Gy/20Fr.). Acute toxicity was acceptable and late AEs were few. Longer follow-up is required to assess efficacy. Overall, available series suggest that salvage RT could represent a valuable option in the treatment of relapses after HIFU.

Prostate-specific antigen kinetics after stereotactic body radiotherapy for localized prostate cancer: A scoping review and meta-analysis

PURPOSE

Stereotactic body radiotherapy (SBRT) is emerging as a valuable treatment modality for localized prostate cancer, with promising biochemical progression-free survival rates. Longitudinal assessment of prostate-specific antigen (PSA) is the mainstay of follow-up after treatment. PSA kinetics and dynamics are well-established in the context of brachytherapy and conventionally fractionated radiotherapy, yet little is known in the context of prostate SBRT.

METHODS

A review of available literature in MEDLINE, Scopus, and Embase was performed, focusing on studies reporting PSA slope, nadir, bounce, and biochemical failure after prostate SBRT.

RESULTS

Thirty-three records (45 % prospective) encompassing 9949 patients were included. SBRT dose ranged from 32-50 Gy in 4-5 fractions and overall median follow-up time (range) was 41 (15-74) months. Use of androgen deprivation therapy ranged from 0-38 %. SBRT was characterized by a steep initial decline of PSA, slowing down over time and ultimately yielding a lower nadir in comparison with conventional radiotherapy, with a median value (range) of 0.24 (0.1-0.6) ng/mL after a median time (range) of 33.1 (6-54) months. There was an inverse correlation between the highest SBRT dose in a trial and PSA nadir (r = - 0.59; p < 0.001). Benign PSA bounce occurred in 30 % of patients across all studies, after a median time (range) of 14.8 (9-36) months and with a median size (range) of 0.5 (0.3-1.1) ng/mL. There was no significant correlation between bounce and dose, nadir nor biochemical failure. There was, however, a significant inverse correlation between ADT use and PSA bounce frequency (r = -0.49; p = 0.046).

CONCLUSION

PSA kinetics and dynamics after SBRT for localized prostate cancer are different from those in other established radiotherapy modalities. Benign PSA bounce is very common. Clinicians should be aware of these factors and patients should be counseled accordingly, preventing unnecessary distress or salvage treatment.

Comparison prediction models of bladder toxicity based on radiomic features of CT and MRI in patients with prostate cancer undergoing radiotherapy

PURPOSE

This study aimed to assess the radiomic features of computed tomography (CT) and magnetic resonance imaging (MRI) of the bladder wall before radiotherapy using machine learning (ML) methods to predict bladder radiotoxicity in patients with prostate cancer.

METHODS

This study enrolled 70 patients with pathologically confirmed prostate cancer who were candidates for radiation therapy (RT). CT and MRI of the bladder wall before radiotherapy were used to extract radiomic features. The least absolute shrinkage and selection operator (LASSO) was used for feature selection. Algorithms such as Random Forest (RF), Decision Tree (DT), Logistic Regression (LR), and K-Nearest Neighbors (KNN) have been used to develop models based on radiomic, dosimetry, and clinical parameters. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve and accuracy were used to analyze the predictive power of all models.

RESULTS

The RF and LR models based on the radiomic features of MRI and clinical/dosimetry parameters with an AUC of 0.95 and 0.93, and an accuracy of 86% and 86%, respectively, had the highest performance in the prediction of bladder radiation toxicity.

CONCLUSIONS

This study showed that, firstly, CT and MRI radiomic features of the bladder wall before treatment could be used to predict bladder radiotoxicity. Second, MRI is better than CT in predicting bladder toxicity caused by radiation. And thirdly, the performance of the predictive models based on the combination of radiomic, clinical, and dosimetry characteristics was improved.

Factors of interobserver variability in prostate tumor MRI delineation: impact of PI-QUAL score

BACKGROUND

Prostate cancer ranks as the second most common cancer in men worldwide. Dose escalation to the tumor and/or the prostate improves biochemical recurrence-free survival. However, interobserver variability in lesion contouring poses a significant limitation to such therapeutic approaches. Therefore, a study of factors influencing this variability is necessary.

MATERIALS AND METHODS

Three independent readers delineated the index prostate lesion (DIL) using T2w and ADC sequences for each patient. Clinical data were retrospectively collected for all participants. Logistic regression analysis was employed to examine the correlation between clinical features and a mean DICE coefficient > 0.7. Features exhibiting a p value < 0.05 on univariate analysis were subjected to multivariate analysis.

RESULTS

The study comprised 68 patients, with a median DICE coefficient of 0.69 (95% CI 0.65-0.71), wherein 42.6% (29/68) attained a mean DICE > 0.7. Univariate analysis identified the PI-QUAL score, maximum diameter of DIL, and mean DIL volume as significant (p < 0.05) predictors. In multivariate analysis, only the PI-QUAL score (p = 0.008) remained statistically associated with a DICE coefficient > 0.7.

CONCLUSION

The PI-QUAL score emerges as the primary predictive factor for minimizing inter-reader variability in intraprostatic dominant lesion segmentation. These findings underscore the importance of considering PI-QUAL scores when devising focal treatment plans. Adoption of a multi-reader approach involving diverse medical specialists (radiologists, radiotherapists, urologists) is advocated, particularly for MRIs with low PI-QUAL scores.

CLINICAL RELEVANCE STATEMENT

Radiotherapy is a major treatment for patients with localized prostate cancer. Dose escalation to the tumor leads to improved cancer control. Precise delineation of the dominant intraprostatic lesion (DIL) remains a limitation to focal treatments. Features influencing inter-reader variability were never evaluated. In this study, we identified that the PI-QUAL score was the sole predictor of the inter-reader delineation variability of the DIL.

Helical Tomotherapy Versus 3-Dimensional Conformal Radiation Therapy in High-Risk Prostate Cancer: A Phase 3 Randomized Controlled Trial

PURPOSE

We present long-term outcomes from a phase 3 randomized controlled trial that compared helical tomotherapy with 3-dimensional conformal radiation therapy (3D-CRT) in the treatment of high-risk prostate cancer.

METHODS AND MATERIALS

Newly diagnosed patients with high-risk prostate cancer were randomly allocated to receive radical radiation therapy (RT) using 3D-CRT or helical tomotherapy. In both arms, patients received an initial dose of 46 Gy in 23 fractions to the prostate and pelvic lymph nodes, followed by an additional boost to the prostate of 32 Gy in 16 fractions. RT was combined with 3 years of adjuvant androgen deprivation. The primary endpoint was late (>90 days since RT initiation) rectal toxicity.

RESULTS

Overall,123 patients were randomly assigned to either the 3D-CRT (n = 60) or tomotherapy (n = 63) arms. The median follow-up was 161 months. Overall, the proportion of patients with grade ≥ 2 late rectal toxicity was 8.3% (95% CI, 3.1-19.1; n = 5) in the 3D-CRT arm and 11.1% (95% CI, 5.0-22.2; n = 7) in the tomotherapy arm with no significant between-arm difference (P = .83). There was no significant difference (P = .17) in the proportion of patients with late grade ≥ 2 genitourinary toxicity:10.0% (95% CI, 4.1-21.2) in the 3D-CRT arm and 20.6% (95% CI, 11.9-33.0) in the tomotherapy arm. There was no significant difference in the hazard of biochemical progression or death between the 2 groups (hazard ratio for the tomotherapy arm: 0.72; 95% CI, 0.46-1.15; P = .17).

CONCLUSIONS

In this phase 3 trial, the overall incidence of grade ≥ 2 rectal toxicity was low and was not significantly different between the 2 arms. There was no significant evidence of improved biochemical progression-free survival in patients treated with tomotherapy. These findings should be interpreted considering the possibility of type II errors due to limited sample size and low event rates.

Efficiency and safety of androgen deprivation therapy combined with stereotactic body radiation therapy for localized prostate cancer: A Moroccan experience

PURPOSE

This study aims to evaluate the efficacy and safety of combining androgen deprivation therapy (ADT) with stereotactic body radiation therapy (SBRT) in the treatment of localized prostate cancer.

METHODS

A retrospective analysis was conducted on 30 patients treated with SBRT for localized prostate cancer at Cheikh Khalifa Hospital between 2017 and 2022. All patients presented with intermediate prognostic risk prostate cancer, as classified by the D'Amico criteria. Each patient received a total dose of 36.25Gy in five fractions using the TrueBeam STX system, along with six months of ADT. Patient outcomes were assessed based on relapse-free survival, biochemical recurrence, overall survival, and adverse effects, including gastrointestinal (GI) and genitourinary (GU) toxicities. Quality of life was evaluated using the EPIC-26 questionnaire.

RESULTS

Over a median follow-up period of 33months, the relapse-free survival rate was 96.7%, with a biochemical recurrence rate of 3.3%. The overall survival rate at four years was 100%. Acute GI toxicities were minimal and transient, while GU toxicities were primarily grades 1 and 2, with no grade 3 or higher events reported. Erectile dysfunction was noted in 87% of patients. Quality of life assessments indicated low levels of urinary and bowel side effects but moderate impact on sexual function.

CONCLUSION

These findings suggest that the combination of ADT with SBRT approach offers favorable relapse-free and overall survival rates with manageable toxicity profiles. Further long-term studies are needed to confirm these results and better understand the impact on patient quality of life.

French AFU Cancer Committee Guidelines - Update 2024-2026: Prostate cancer - Diagnosis and management of localised disease

OBJECTIVE

The aim of the Oncology Committee of the French Urology Association is to propose updated recommendations for the diagnosis and management of localized prostate cancer (PCa).

METHODS

A systematic review of the literature from 2022 to 2024 was conducted by the CCAFU on the elements of diagnosis and therapeutic management of localized PCa, evaluating references with their level of evidence.

RESULTS

The recommendations set out the genetics, epidemiology and diagnostic methods of PCa, as well as the concepts of screening and early detection. MRI, the reference imaging test for localized cancer, is recommended before prostate biopsies are performed. Molecular imaging is an option for disease staging. Performing biopsies via the transperineal route reduces the risk of infection. Active surveillance is the standard treatment for tumours with a low risk of progression. Therapeutic methods are described in detail, and recommended according to the clinical situation.

CONCLUSION

This update of French recommendations should help to improve the management of localized PCa.

Overall Survival and Cancer-Specific Mortality in Patients with Prostate Cancer Undergoing Definitive Therapies: A Narrative Review

The overall survival (OS) of patients with prostate cancer (PCa) who receive locally definitive therapy is generally better than that of patients who do not receive definitive therapy. There is no difference in the incidence of local recurrence or distant metastasis between treatment modalities. Because the prognosis of PCa is relatively good, many studies have focused on quality of life after treatment as an endpoint. However, a limited number of patients develop biochemical recurrence after definitive treatment for PCa and subsequently develop distant metastasis or die from PCa. Therefore, we believe that preventing local recurrence and distant metastasis and prolonging the OS should be emphasized when selecting a treatment modality for PCa. In this review, the significance and usefulness of radical prostatectomy and radiation therapy as the main modalities of definitive therapies for local PCa and locally advanced PCa were evaluated, as well as the outcomes of OS and PCa-specific mortality and the treatment options after biochemical recurrence to improve the oncological outcomes.

Proton therapy toxicity outcomes for localized prostate cancer: Long-term results at a comprehensive cancer center

Background

Proton therapy (PT) has unique biologic properties with excellent clinical outcomes for the management of localized prostate cancer. Here, we aim to characterize the toxicity of PT for patients with localized prostate cancer and propose mitigation strategies using a large institutional database.

Methods

We reviewed medical records of 2772 patients with localized prostate cancer treated with definitive PT between May 2006 through January 2020. Disease risk was stratified according to National Comprehensive Cancer Network guidelines as low [LR, n = 640]; favorable-intermediate [F-IR, n = 849]; unfavorable-intermediate [U-IR, n = 851]; high [HR, n = 315]; or very high [VHR, n = 117]. Descriptive statistics and Kaplan-Meier estimates assessed toxicity and freedom from biochemical relapse (FFBR).

Results

Median follow-up was 7.0 years. The median dose was 78 Gy(RBE)(range: 72-79.2 Gy) in 2.0 Gy(RBE) fractions; 63 % of patients received 78 Gy(RBE) in 39 fractions, and 29 % received 76 Gy(RBE) in 38 fractions. Overall rates of late grade ≥3 GU and GI toxicity were 0.87 % and 1.01 %, respectively. Two patients developed grade 4 late GU toxicity and seven patients with grade 4 late GI toxicity. All patients experiencing severe late grade 4 toxicities were treated to 78 Gy(RBE) in 39 fractions with 80 Gy(RBE) dose to the anterior rectal wall and/or bladder neck. The 10-year FFBR rates for patients with LR to U-IR disease were compared between those treated with 76 and 78 Gy(RBE); the rates were 94.5 % (95 % confidence interval [CI] 92.4-96.0 %) and 93.2 % (95 % CI 91.3-95.7 %), respectively (log-rank p = 0.22).

Conclusions

Proton therapy is associated with low rates of late grade ≥3 GU and GI toxicity. While rare, late grade 4 toxicities occurred in nine (0.3 %) patients. De-escalation to a total dose of 76 Gy(RBE) yields excellent clinical outcomes for patients with LR to U-IR disease with the potential for significant reductions in grade ≥3 late toxicity.

Re-irradiation to the prostate using stereotactic body radiotherapy (SBRT) after initial definitive radiotherapy - A systematic review and meta-analysis of recent trials

Background

There is increasing data on re-irradiation to the prostate using stereotactic body radiotherapy (SBRT) after definitive radiotherapy for prostate cancer, with increasing evidence on prostate re-irradiation using a C-arm LINAC or an MR LINAC in recent years. We therefore conducted this systematic review and meta-analysis on prostate re-irradiation including studies published from 2020 to 2023, to serve as an update on existing meta-analysis.

Methods

We searched the PubMed and Embase databases in October 2023 with queries including combinations of "repeat", "radiotherapy", "prostate", "re-irradiation", "reirradiation", "re treatment", "SBRT", "retreatment". Publication date was set to be from 2020 to 2023. There was no limitation regarding language. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. After data extraction, heterogeneity testing was done by calculating the I2. A random effects model with a restricted maximum likelihood estimator was used to estimate the combined effect. Funnel plot asymmetry was assessed visually and using Egger's test to estimate the presence of publication and/or small study bias.

Results

14 publications were included in the systematic review. The rates of acute ≥ grade 2 (G2) genitourinary (GU) and gastrointestinal (GI) toxicities reported in the included studies ranged from 0.0-30.0 % and 0.0-25.0 % respectively. For late ≥ G2 GU and GI toxicity, the ranges are 4.0-51.8 % and 0.0-25.0 %. The pooled rate of acute GU and GI toxicity ≥ G2 were 13 % (95 % CI: 7-18 %) and 2 % (95 % CI: 0-4 %). For late GU and GI toxicity ≥ G2 the pooled rates were 25 % (95 % CI: 14-35 %) and 5 % (95 % CI: 1-9 %). The pooled 2-year biochemical recurrence-free survival was 72 % (95 % CI: 64-92 %).

Conclusions

SBRT in the re-irradiation of radiorecurrent prostate cancer is safe and effective. Further prospective data are warranted.

Efficacy of a hydrogel spacer for improving quality of life in patients with prostate cancer undergoing low-dose-rate brachytherapy alone or in combination with intensity-modulated radiotherapy: An observational study using propensity score matching

BACKGROUND

It is unclear whether a hydrogel spacer can improve quality of life (QOL) in patients undergoing low-dose-rate brachytherapy (LDR-BT) alone or in combination with intensity-modulated radiotherapy (IMRT).

METHODS

We enrolled patients with prostate cancer who underwent LDR-BT alone with (n = 186) or without (n = 348) a hydrogel spacer, or underwent LDR-BT in combination with IMRT with (n = 70) or without (n = 217) a hydrogel spacer. QOL was evaluated using Expanded Prostate Cancer Index Composite (EPIC) questionnaires at baseline and 1, 3, 6, 12, and 24 months after implantation. The groups were compared using propensity score matching analysis.

RESULTS

Among patients who underwent LDR-BT alone, there were no differences regarding changes in urinary, bowel, sexual, or hormonal domain scores between the spacer and no-spacer groups; however, the dose at the bowel was significantly lower in the spacer group than in the no-spacer group. Among patients who underwent LDR-BT in combination with IMRT, there were no differences regarding changes in urinary, sexual, or hormonal domain scores between the spacer and no-spacer groups. However, the changes in the bowel domain score were significantly lower in the spacer group than in the no-spacer group (p < 0.001).

CONCLUSIONS

A hydrogel spacer may not improve impaired urinary, bowel, or sexual QOL in patients undergoing LDR-BT alone. However, in patients undergoing LDR-BT in combination with IMRT, a hydrogel spacer can improve impaired bowel QOL but not sexual or urinary QOL.

Volumetric Modulated Arc Therapy for High-Risk and Very High-Risk Locoregional Prostate Cancer in the Modern Era: Real-World Experience from an Asian Cohort

This study retrospectively evaluates the clinical outcomes of definitive volumetric modulated arc therapy (VMAT) for high-risk or very high-risk locoregional prostate cancer patients from an Asian institution. Consecutive patients who received VMAT (76 Gy in 38 fractions) between January 2017 and June 2022 were included. Whole pelvic radiotherapy (WPRT) (46 Gy in 23 fractions) was employed for clinically node-negative disease (cN0) and a Roach estimated risk of ≥15%, as well as simultaneous integrated boost (SIB) of 55-57.5 Gy to node-positive (cN1) disease. The primary endpoint was biochemical relapse-free survival (BRFS). Secondary endpoints included radiographic relapse-free survival (RRFS), metastasis-free survival (MFS) and prostate cancer-specific survival (PCSS). A total of 209 patients were identified. After a median follow-up of 47.5 months, the 4-year actuarial BRFS, RRFS, MFS and PCSS were 85.2%, 96.8%, 96.8% and 100%, respectively. The incidence of late grade ≥ 2 genitourinary (GU) and gastrointestinal (GI) toxicity were 15.8% and 11.0%, respectively. No significant difference in cancer outcomes or toxicity was observed between WPRT and prostate-only radiotherapy for cN0 patients. SIB to the involved nodes did not result in increased toxicity. International Society of Urological Pathology (ISUP) group 5 and cN1 stage were associated with worse RRFS (p < 0.05). PSMA PET-CT compared to conventional imaging staging was associated with better BRFS in patients with ISUP grade group 5 (p = 0.039). Five-year local experience demonstrates excellent clinical outcomes. PSMA PET-CT staging for high-grade disease and tailored pelvic irradiation based on nodal risk should be considered to maximize clinical benefit.

[Short- and medium-term tolerance of hypofractionated prostate radiotherapy with simultaneous integrated boost]

PURPOSE

This retrospective study was conducted to ensure that irradiation of the pelvic lymph node areas associated with simultaneous hypofractionated boost to the prostate according to the protocol implemented at the university hospital of Tours (France) does not result in excess urinary and digestive toxicity in the short and medium term.

MATERIALS AND METHODS

The study population included patients with localized unfavourable intermediate or high-risk prostate cancer. The dose delivered was 65Gy in 25 fractions of 2.6Gy to the prostate and seminal vesicles, and 50Gy in 25 fractions of 2Gy to the pelvic lymph nodes. Acute toxicity events (between the start of radiotherapy and the first follow-up consultation) and medium-term toxicity events (after the first follow-up consultation) were assessed using the CTCAE version 5.0 classification.

RESULTS

Sixty-three patients were treated according to the protocol between January 1st, 2020, and October 31st, 2022. The majority of them had high-risk prostate cancer (79%). The median follow-up was 15 months. Very few patients reported grade 3-4 toxicity acutely (6% urinary and 0% digestive toxicity) or in the medium term (7% urinary and 0% and digestive toxicity).

CONCLUSION

Radiotherapy of pelvic lymph node areas with simultaneous hypofractionated boost to the prostate is feasible, with low rates of severe acute and medium-term toxicity.

The expanding role of radiation oncology across the prostate cancer continuum

Radiotherapy is used in the treatment of prostate cancer in a variety of disease states with significant reliance on imaging to guide clinical decision-making and radiation delivery. In the definitive setting, the choice of radiotherapy treatment modality, dose, and fractionation for localized prostate cancer is determined by the patient's initial risk stratification and other clinical considerations. Radiation is also an option as salvage therapy in patients with locoregionally recurrent disease after prior definitive radiation or surgery. In recent years, the role of radiation has expanded for patients with metastatic disease, including prostate-directed radiotherapy in de novo low volume metastatic disease, metastasis-directed therapy for oligorecurrent disease, and palliative management of symptomatic metastases in the advanced setting. Here we review the expanding role of radiation in the treatment of prostate cancer in the definitive, locoregionally recurrent, and metastatic settings, as well as highlight the role of imaging in clinical reasoning, radiation planning, and treatment delivery.

Treatment outcome of localized prostate cancer using transperineal ultrasound image-guided radiotherapy

BACKGROUND

We report the results of a retrospective analysis of localized prostate cancer (LPCa) treated with transperineal ultrasound image-guided radiotherapy (TPUS-IGRT).

METHODS

A total of 124 patients (median age: 74 y, 46-84 y) with LPCa who underwent TPUS-IGRT (Clarity Autoscan system; CAS, Elekta; Stockholm, Sweden) between April 2016 and October 2021 for curative/after hormone induction were enrolled. The number of patients by risk (National Comprehensive Cancer Network 2019) was 7, 25, 42, and 50 for low (LR), good intermediate (good IR), poor intermediate (poor IR), and high (HR)/very high (VHR), respectively. Ninety-five patients were given neoadjuvant hormonal therapy. The planning target volume margin setting was 3 mm for rectal in most cases, 5-7 mm for superior/inferior, and 5 mm for anterior/right/left. The principle prescribed dose is 74 Gy (LR), 76 Gy (good IR), and 76-78 Gy (poor IR or above). CAS was equipped with a real-time prostate intrafraction monitoring (RTPIFM) system. When a displacement of 2-3 mm or more was detected, irradiation was paused, and the patients were placed on standby for prostate reinstatement/recorrection. Of the 3135 fractions in 85 patients for whom RTPIFM was performed, 1008 fractions (32.1%) were recorrected at least once after starting irradiation.

RESULTS

A total of 123 patients completed the radiotherapy course. The 5-year overall survival rate was 95.9%. The 5-year biological prostate-specific antigen relapse-free survival rate (bPFS) was 100% for LR, 92.9% for intermediate IR, and 93.2% for HR/VHR (Phoenix method). The 5-year late toxicity rate of Grade 2+ was 7.4% for genitourinary (GU) and 6.5% for gastrointestinal (GI) organs. Comparing the ≤ 76 Gy group to the 78 Gy group for both GU and GI organs, the incidence was higher in the 78 Gy group for both groups.

CONCLUSION

These results suggest that TPUS-IGRT is well tolerated, as the bPFS and incidence of late toxicity are almost comparable to those reported by other sources of image-guided radiotherapy.

In Silico Comparison of Three Different Beam Arrangements for Intensity-Modulated Proton Therapy for Postoperative Whole Pelvic Irradiation of Prostate Cancer

Background and purpose: Proton therapy has been shown to provide dosimetric benefits in comparison with IMRT when treating prostate cancer with whole pelvis radiation; however, the optimal proton beam arrangement has yet to be established. The aim of this study was to evaluate three different intensity-modulated proton therapy (IMPT) beam arrangements when treating the prostate bed and pelvis in the postoperative setting. Materials and Methods: Twenty-three post-prostatectomy patients were planned using three different beam arrangements: two-field (IMPT2B) (opposed laterals), three-field (IMPT3B) (opposed laterals inferiorly matched to a posterior-anterior beam superiorly), and four-field (IMPT4B) (opposed laterals inferiorly matched to two posterior oblique beams superiorly) arrangements. The prescription was 50 Gy radiobiological equivalent (GyE) to the pelvis and 70 GyE to the prostate bed. Comparisons were made using paired two-sided Wilcoxon signed-rank tests. Results: CTV coverages were met for all IMPT plans, with 99% of CTVs receiving ≥ 100% of prescription doses. All organ at risk (OAR) objectives were met with IMPT3B and IMPT4B plans, while several rectum objectives were exceeded by IMPT2B plans. IMPT4B provided the lowest doses to OARs for the majority of analyzed outcomes, with significantly lower doses than IMPT2B +/- IMPT3B for bladder V30-V50 and mean dose; bowel V15-V45 and mean dose; sigmoid maximum dose; rectum V40-V72.1, maximum dose, and mean dose; femoral head V37-40 and maximum dose; bone V40 and mean dose; penile bulb mean dose; and skin maximum dose. Conclusion: This study is the first to compare proton beam arrangements when treating the prostate bed and pelvis. four-field plans provided better sparing of the bladder, bowel, and rectum than 2- and three-field plans. The data presented herein may help inform the future delivery of whole pelvis IMPT for prostate cancer.

The effect of dose-escalation radiotherapy with simultaneous-integrated-boost on the use of short-term androgen deprivation therapy in patients with intermediate risk prostate cancer

PURPOSE

To compare the biochemical failure (FFBF) and prostate cancer specific survival (PCSS) rates of patients with intermediate-risk prostate cancer (IR-PC) who were treated with 6 months of androgen deprivation therapy (ADT) with 78 Gy to the prostate, those treated with ADT and focal boost (FB) of 86 Gy to intraprostatic lesion (IPL) using the simultaneous-integrated boost (SIB) technique, and those treated with SIB alone.

MATERIALS AND METHODS

A retrospective analysis of 320 IR-PC patients treated between January 2012 and April 2021 was performed. Patients were divided into three groups based on their treatment arm: 78 + ADT (109 patients, 34.1%), 78/86 (102 patients, 31.8%), and 78/86 + ADT. Univariable and multivariable analyses were used to determine prognostic factors for FFBF and PCSS.

RESULTS

Median follow-up was 8.8 years. The 8-year FFBF and PCSS rates were 88.6% and 99.0%. Patients who received ADT had significantly higher pretreatment PSA levels and clinical tumor stage. Disease progression occurred in 45 patients (7.3%) at a median of 41.9 months after definitive radiotherapy (RT). Younger age, positive core biopsy (PCB) ≥ 50%, and the absence of ADT were all independent predictors of poor FFBF in multivariate analysis, whereas patients with PCB < 50% who were also given ADT had better PCSS. Patients treated with 78/86 Gy alone had worse FFBF than those treated with 78 Gy and ADT (Hazard ratio [HR] = 3.39 [95% CI = 1.46-7.88]; p = 0.005), as well as than those treated with 78/86 Gy and ADT (HR = 3.21 [95% CI = 1.23-6.46]; p = 0.009). However, FB to IPL has no effect on PCSS in multivariable analysis. There was no significant difference between treatment groups in terms of acute and late Grade ≥2 genitourinary or gastrointestinal toxicity.

CONCLUSIONS

Our findings demonstrated that patients who received 78/86 alone did worse than patients who received ADT with either 78 or 78/86 Gy. However, because IR-PC patients are so diverse, additional prospective trials are needed to validate our findings.

MRI-guided radiotherapy in twenty fractions for localised prostate cancer; results from the MOMENTUM study

Background and purpose

MRI-guided radiotherapy (MRIgRT) offers multiple potential advantages over CT-guidance. This study examines the potential clinical benefits of MRIgRT for men with localised prostate cancer, in the setting of moderately hypofractionated radiotherapy. We evaluate two-year toxicity outcomes, early biochemical response and patient-reported outcomes (PRO), using data obtained from a multicentre international registry study, for the first group of patients with prostate cancer who underwent treatment on a 1.5 T MR-Linac.

Materials and methods

Patients who were enrolled within the MOMENTUM study and received radical treatment with 60 Gy in 20 fractions were identified. PSA levels and CTCAE version 5.0 toxicity data were measured at follow-up visits. Those patients who consented to PRO data collection also completed EQ-5D-5L, EORTC QLQ-C30 and EORTC QLQ-PR25 questionnaires.

Results

Between November 2018 and June 2022, 146 patients who had MRIgRT for localised prostate cancer on the 1.5 T MR-Linac were eligible for this study. Grade 2 and worse gastro-intestinal (GI) toxicity was reported in 3 % of patients at three months whilst grade 2 and worse genitourinary (GU) toxicity was 7 % at three months. There was a significant decrease in the median PSA at 12 months. The results from both the EQ-5D-5L data and EORTC global health status scale indicate a decline in the quality of life (QoL) during the first six months. The mean change in score for the EORTC scale showed a decrease of 11.4 points, which is considered clinically important. QoL improved back to baseline by 24 months. Worsening of hormonal symptoms in the first six months was reported with a return to baseline by 24 months and sexual activity in all men worsened in the first three months and returned to baseline at 12 months.

Conclusion

This study establishes the feasibility of online-MRIgRT for localised prostate on a 1.5 T MR-Linac with low rates of toxicity, similar to that published in the literature. However, the clinical benefits of MRIgRT over conventional radiotherapy in the setting of moderate hypofractionation is not evident. Further research will focus on the delivery of ultrahypofractionated regimens, where the potential advantages of MRIgRT for prostate cancer may become more discernible.

Towards optimal heterogeneous prostate radiotherapy dose prescriptions based on patient-specific or population-based biological features

BACKGROUND

Escalation of prescribed dose in prostate cancer (PCa) radiotherapy enables improvement in tumor control at the expense of increased toxicity. Opportunities for reduction of treatment toxicity may emerge if more efficient dose escalation can be achieved by redistributing the prescribed dose distribution according to the known heterogeneous, spatially-varying characteristics of the disease.

PURPOSE

To examine the potential benefits, limitations and characteristics of heterogeneous boost dose redistribution in PCa radiotherapy based on patient-specific and population-based spatial maps of tumor biological features.

METHOD

High-resolution prostate histology images, from a cohort of 63 patients, annotated with tumor location and grade, provided patient-specific "maps" and a population-based "atlas" of cell density and tumor probability. Dose prescriptions were derived for each patient based on a heterogeneous redistribution of the boost dose to the intraprostatic lesions, with the prescription maximizing patient tumor control probability (TCP). The impact on TCP was assessed under scenarios where the distribution of population-based biological data was ignored, partially included, or fully included in prescription generation. Heterogeneous dose prescriptions were generated for three combinations of maps and atlas, and for conventional fractionation (CF), extreme hypo-fractionation (EH), moderate hypo-fractionation (MH), and whole Pelvic RT + SBRT Boost (WPRT + SBRT). The predicted efficacy of the heterogeneous prescriptions was compared with equivalent homogeneous dose prescriptions.

RESULTS

TCPs for heterogeneous dose prescriptions were generally higher than those for homogeneous dose prescriptions. TCP escalation by heterogeneous dose prescription was the largest for CF. When only using population-based atlas data, the generated heterogeneous dose prescriptions of 55 to 58 patients (out of 63) had a higher TCP than for the corresponding homogeneous dose prescriptions. The TCPs of the heterogeneous dose prescriptions generated with the population-based atlas and tumor probability maps did not differ significantly from those using patient-specific biological information. The generated heterogeneous dose prescriptions achieved significantly higher TCP than homogeneous dose prescriptions in the posterior section of the prostate.

CONCLUSION

Heterogeneous dose prescriptions generated via biologically-optimized dose redistribution can produce higher TCP than the homogeneous dose prescriptions for the majority of the patients in the studied cohort. For scenarios where patient-specific biological information was unavailable or partially available, the generated heterogeneous dose prescriptions can still achieve TCP improvement relative to homogeneous dose prescriptions.

Rectal deformation management with IGRT in prostate radiotherapy: Can it be managed with rigid alignment alone?

PURPOSE

It is challenging to achieve appropriate target coverage of the prostate with Image Guided Radiation Therapy (IGRT) while simultaneously constraining rectal doses within planned values when there is significant variability in rectal filling and shape. We investigated if rectum planning goals can be fulfilled using rigid CBCT-based on-board alignment to account for interfraction rectal deformations.

METHODS

Delivered rectal doses corresponding to prostate alignment ("PR") and anterior rectum alignment ("AR") for 239 daily treatments from 13 patients are reported. Rectal doses were estimated by rigidly mapping the planned dose on the daily CT derived from the daily CBCT according to respective alignment shifts. Rectum V95% (rV95%) was used for analyses.

RESULTS

Compared to "PR", "AR" alignment increased rV95% for an average of 34.4% across all patients. rV95% (cc) averaged over all fractions was significant from planning values for 10/13 patients for "PR" and for 9/13 for "AR". 3/13 patients had reproducible anatomy. Of patients with non-reproducible anatomy, three had dosimetrically more favorable, while seven had less favorable anatomies. Most shift differences (82.3%) between the "PR" and "AR" alignments larger than 2 mm resulted in rV95% changes larger than 2 cc. Most shift differences (82.2%) of 2 mm or less between the "PR" and "AR" alignments resulted in rV95% changes less than 2 cc. The average percentage of fractions among patients in which anterior or posterior shifts for "AR" and "PR" alignment was larger than the PTV margins was 9.1% (0.0%-37.5%) and 1.3% (0%-10%).

CONCLUSION

Rectal deformation and subsequent inconsistent interfraction separation between prostate and rectal wall translate into anatomical changes that cannot always be mitigated with rigid alignment. If systematic differences exist due to a non-reproducible planning anatomy, attempts to restore the planned rectal doses through anterior rectum alignment produce rather small improvements and may result in unacceptable target underdosage.

Multiparametric Magnetic Resonance Imaging- Guided Dose-Escalated Radiation Therapy for Localized Prostate Cancer: A Prospective Phase 2 Trial

PURPOSE

This trial's purpose was to determine the late toxicity associated with dose escalation to Prostate Imaging Reporting and Data System (PI-RADS) III-V lesions on multiparametric magnetic resonance imaging (MRI) with an image guided combined IMRT-stereotactic body radiation therapy (SBRT) approach in men with localized prostate cancer.

METHODS AND MATERIALS

In this phase 2 trial patients with localized prostate cancer with clinical tumor stage T1-T3bN0 and at least one PIRADS III-V lesion were recruited to receive 45 Gy in 25 fractions to the prostate and seminal vesicles followed by a boost of 18 Gy in 3 fractions to the prostate with a simultaneous integrated boost 21 Gy in 3 fractions to the PI-RADS lesion(s). The primary endpoint was the cumulative incidence of late grade ≥3 genitourinary and gastrointestinal toxicity by 18 months (National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0).

RESULTS

Overall, 50 patients were enrolled in this study, and 43 patients completed at least 18 months of follow-up. The cumulative incidence of grade 1, 2, and 3 late genitourinary toxicity at 18 months was 18%, 53%, and 2%. One patient was noted to have grade 3 hematuria and needed cystoscopy-guided cauterization. No acute grade 3 gastrointestinal or genitourinary toxicities were observed. The cumulative incidence of grade 1, 2, and 3 late gastrointestinal toxicity at 18 months was 31%, 4%, and 0%, respectively. At a median follow-up of 43.5 months, 3 patients developed biochemical recurrence, each with distant bone metastases without local or nodal recurrence. At 3 years, freedom from biochemical failure rate was 95.3% (95% CI, 89.2%-100%).

CONCLUSIONS

Multiparametric MRI-guided dose escalation to PI-RADS III-V lesions using a combined image guided IMRT-SBRT approach is associated with an acceptable risk of late gastrointestinal and genitourinary toxicity. The results should be interpreted with caution considering their single institutional nature, small sample size, and short follow-up and should be validated in a larger study.

Hypofractionated versus conventional fractionation external beam radiotherapy in intermediate and high risk localized prostate cancer

BACKGROUND

Prostate cancer is the second most common malignancy in men, and its incidence is increasing which is attributed to increased screening programs. The treatment options of intermediate and high risk prostate cancer include radical prostatectomy, radiotherapy and androgen deprivation therapy. Hypofractionated radiotherapy is becoming more popular lately due to better understanding of the radiobiology of prostate cancer and favorable logistics.

OBJECTIVE

To compare the toxicity and efficacy of hypofractionated versus conventional fractionation external beam radiotherapy in patients with intermediate and high risk localized prostate cancer treated in Shaukat Khanum Memorial Hospital and Research Center, Lahore (SKMCH & RC).

METHODOLOGY

We retrospectively conducted this study on histopathologically confirmed 114 patients with prostate adenocarcinoma who underwent treatment from January 2013 till December 2018. These patients were treated with radical radiotherapy along with hormonal therapy as per indication. Data was collected from electronic hospital system and analyzed by SPSS version 23.

RESULTS

114 patients were selected according to the inclusion criteria. Mean age was 68 years (61-75). 88% of patients had stage III-IVA disease at the time of diagnosis. Mean PSA and GS was 33 ± 39 SD and 7 ± 0.9 SD respectively. 89% (n = 102) received radiotherapy with 69% of patients receiving dose of 60 Gy in 20 fractions. Among patients who received hypofractionated dose, 86% (n = 61) of them were categorized as high risk and 14% (n = 10) were intermediate risk, whereas among conventional group 90% (n = 28) were high risk patients and 10% (n = 3) were of intermediate risk. In hypofractionated dose group, 14% (n = 10) developed grade 2 proctitis and 8% (n = 6) developed grade 2 cystitis, in contrast to conventional dose group in which only 3 patients (5%) developed grade 2 GI toxicity and 2 patients (2.9%) had grade 2 GU toxicity. However, these toxicities and their grade were clinically insignificant when compared with the dose groups (p = 0.11). 5 year overall survival for hypofractionated radiotherapy versus conventional dose was 100% and 90% respectively with 95% Cl and p value of 0.3 (clinically insignificant), whereas 5 year disease free survival was 100% and 75% for hypofractionation versus conventional EBRT respectively with 95% CI and p value of 0.04 (clinically significant).

CONCLUSION

Hypofractionated radiotherapy in patients with intermediate and high risk localized prostate cancer has better disease free survival at the expense of higher risk for proctitis and cystitis but no difference in overall survival as compared to conventional dose of radiation.

Optimizing Clinical Implementation of Hypofractionation: Comprehensive Evidence Synthesis and Practical Guidelines for Low- and Middle-Income Settings

The global cancer burden, especially in low- and middle-income countries (LMICs), worsens existing disparities, amplified by the rising costs of advanced treatments. The shortage of radiation therapy (RT) services is a significant issue in LMICs. Extended conventional treatment regimens pose significant challenges, especially in resource-limited settings. Hypofractionated radiotherapy (HRT) and ultra-hypofractionated/stereotactic body radiation therapy (SBRT) offer promising alternatives by shortening treatment durations. This approach optimizes the utilization of radiotherapy machines, making them more effective in meeting the growing demand for cancer care. Adopting HRT/SBRT holds significant potential, especially in LMICs. This review provides the latest clinical evidence and guideline recommendations for the application of HRT/SBRT in the treatment of breast, prostate, and lung cancers. It emphasizes the critical importance of rigorous training, technology, stringent quality assurance, and safety protocols to ensure precise and secure treatments. Additionally, it addresses practical considerations for implementing these treatments in LMICs, highlighting the need for comprehensive support and collaboration to enhance patient access to advanced cancer care.

Dosiomics for intensity-modulated radiotherapy in patients with prostate cancer: survival analysis stratified by baseline prostate-specific antigen and Gleason grade group in a 2-institutional retrospective study

OBJECTIVE

This study evaluated the prognostic impact of the quality of dose distribution using dosiomics in patients with prostate cancer, stratified by pretreatment prostate-specific antigen (PSA) levels and Gleason grade (GG) group.

METHODS

A total of 721 patients (Japanese Foundation for Cancer Research [JFCR] cohort: N = 489 and Tokyo Radiation Oncology Clinic [TROC] cohort: N = 232) with localized prostate cancer treated by intensity-modulated radiation therapy were enrolled. Two predictive dosiomic features for biochemical recurrence (BCR) were selected and patients were divided into certain groups stratified by pretreatment PSA levels and GG. Freedom from biochemical failure (FFBF) was estimated using the Kaplan-Meier method based on each dosiomic feature and univariate discrimination was evaluated using the log-rank test. As an exploratory analysis, a dosiomics hazard (DH) score was developed and its prognostic power for BCR was examined.

RESULTS

The dosiomic feature extracted from planning target volume (PTV) significantly distinguished the high- and low-risk groups in patients with PSA levels >10 ng/mL (7-year FFBF: 86.7% vs 76.1%, P < .01), GG 4 (92.2% vs 76.9%, P < .01), and GG 5 (83.1% vs 77.8%, P = .04). The DH score showed significant association with BCR (hazard score: 2.04; 95% confidence interval: 1.38-3.01; P < .001).

CONCLUSION

The quality of planned dose distribution on PTV may affect the prognosis of patients with poor prognostic factors, such as PSA levels >10 ng/mL and higher GGs.

ADVANCES IN KNOWLEDGE

The effects of planned dose distribution on prognosis differ depending on the patient's clinical background.

Impact of Prostate Cancer-related Genitourinary Radiation Injury on Mental Health Diagnosis and Treatment: Assessment of 55,425 Men

OBJECTIVE

To investigate the association of low-grade radiation injury (LGRI) and high-grade radiation injury (HGRI) following prostate cancer treatment with mental health diagnoses and therapy.

METHODS

A retrospective study of men diagnosed with prostate cancer who were treated with radiotherapy. Men were followed to assess for LGRI or HGRI using IBM MarketScan. Cohorts included: no injury (no-RI), LGRI, HGRI, and controls. Mental health diagnoses and related treatment (medication/therapy) were identified using ICD-10 codes, CPT codes, and national drug codes. A multivariable Cox proportional hazards model from time of radiation to first instance of mental health diagnosis was modeled against injury group, age, and comorbidities.

RESULTS

Between 2011 and 2020 we identified 55,425 men who received radiotherapy for prostate cancer. 22,879 (41.3%) experienced a LGRI while 4128 (7.4%) experienced a HGRI. Prior to radiation therapy, mental health diagnoses were equally distributed across cohorts (P > .05). Every marker of mental health showed a step-wise increase in incidence from no-RI to LGRI to HGRI except for alcohol abuse. Use of mental health medications and therapy visits were slightly more likely in the LGRI and HGRI groups prior to radiation, however, this difference was greatly increased postradiation therapy. LGRI (HR 1.38; P < .001) and HGRI (HR 2.1; P < .001) were independently associated with an increased likelihood of mental health diagnoses.

CONCLUSION

LGRI and HGRI following prostate cancer radiotherapy are associated with increased risk of mental health diagnosis, medication use, and therapy need compared to men who do not develop injuries. The most common mental health diagnoses were depression and anxiety.

Prospective results for 5-year survival and toxicity of moderately hypofractionated radiotherapy with simultaneous integrated boost (SIB) in (very) high-risk prostate cancer

Purpose

High-risk (HR) prostate cancer patients usually receive high-dose radiotherapy (RT) using a two-phase sequential technique, but data on a simultaneous integrated boost (SIB) technique are lacking. We prospectively evaluated the long-term results of urinary (GU) and digestive (GI) toxicity and survival data for high-dose RT using a SIB technique in HR and very high-risk (VHR) prostate cancer.

Methods

Patients were treated using an SIB technique in 34 fractions, at a dose of 54.4 Gy to the pelvis and seminal vesicles and 74.8 Gy to the prostate, combined with 36 months of androgen-depriving therapy in a prospective multicenter study. Acute and late GU and GI toxicity data were collected. Overall survival (OS), biochemical-relapse-free survival (bRFS), loco-regional-relapse-free survival (LRRFS), metastasis-free-survival (MFS) and disease-free-survival (DFS) were assessed.

Results

We recruited 114 patients. After a median follow-up of 62 months, very few patients experienced acute (M0-M3) (G3-4 GU = 3.7 %; G3-4 GI = 0.9 %) or late (M6-M60) severe toxicity (G3-4 GU = 5.6 %; G3-4 GI = 2.8 %). The occurrence of acute G2 + GU or GI toxicity was significantly related to the consequential late G2 + toxicity (p < 0.01 for both GU and GI). Medians of OS, bRFS, LRRFS, MFS and DFS were not reached. At 60 months, OS, bRFS, LRRFS, MFS and DFS were 88.2 % [82.1; 94.7], 86.0 % [79.4 %;93.2 %], 95.8 % [91.8 %;99.9 %], 87.2 % [80.9 %;94.0 %] and 84.1 % [77.2 %;91.6 %] respectively.

Conclusion

SIB RT at a dose of 54.4 Gy to the pelvis and 74.8 Gy to the prostate is feasible, leading to satisfying tumor control and reasonable toxicity in HR and VHR prostate cancer.

Inter-Rater Variability of Prostate Lesion Segmentation on Multiparametric Prostate MRI

INTRODUCTION

External radiotherapy is a major treatment for localized prostate cancer (PCa). Dose escalation to the whole prostate gland increases biochemical relapse-free survival but also acute and late toxicities. Dose escalation to the dominant index lesion (DIL) only is of growing interest. It requires a robust delineation of the DIL. In this context, we aimed to evaluate the inter-observer variability of DIL delineation.

MATERIAL AND METHODS

Two junior radiologists and a senior radiation oncologist delineated DILs on 64 mpMRIs of patients with histologically confirmed PCa. For each mpMRI and each reader, eight individual DIL segmentations were delineated. These delineations were blindly performed from one another and resulted from the individual analysis of the T2, apparent diffusion coefficient (ADC), b2000, and dynamic contrast enhanced (DCE) sequences, as well as the analysis of combined sequences (T2ADC, T2ADCb2000, T2ADCDCE, and T2ADCb2000DCE). Delineation variability was assessed using the DICE coefficient, Jaccard index, Hausdorff distance measure, and mean distance to agreement.

RESULTS

T2, ADC, T2ADC, b2000, T2 + ADC + b2000, T2 + ADC + DCE, and T2 + ADC + b2000 + DCE sequences obtained DICE coefficients of 0.51, 0.50, 0.54, 0.52, 0.54, 0.55, 0.53, respectively, which are significantly higher than the perfusion sequence alone (0.35, p < 0.001). The analysis of other similarity metrics lead to similar results. The tumor volume and PI-RADS classification were positively correlated with the DICE scores.

CONCLUSION

Our study showed that the contours of prostatic lesions were more reproducible on certain sequences but confirmed the great variability of prostatic contours with a maximum DICE coefficient calculated at 0.55 (joint analysis of T2, ADC, and perfusion sequences).

Intensity modulated radiation therapy with stereotactic body radiation therapy boost for unfavorable prostate cancer: five-year outcomes

PURPOSE

Intensity-modulated radiation therapy (IMRT) with brachytherapy boost for unfavorable prostate cancer has been shown to improve biochemical relapse-free survival compared to IMRT alone. Stereotactic body radiation therapy (SBRT) is a less-invasive alternative to brachytherapy. Early outcomes utilizing SBRT boost suggest low rates of high-grade toxicity with a maintained patient-reported quality of life. Here, we report the 5-year progression-free survival (PFS) and prostate cancer-specific survival (PCSS) of patients treated with IMRT plus SBRT boost.

MATERIALS AND METHODS

Between 2008 and 2020, 255 patients with unfavorable prostate cancer were treated with robotic SBRT (19.5 Gy in three fractions) followed by fiducial-guided IMRT (45-50.4 Gy) according to an institutional protocol. For the first year, the patient's PSA level was monitored every 3 months, biannually for 2 years, and annually thereafter. Failure was defined as nadir + 2 ng/mL or a rising PSA with imaging suggestive of recurrence. Detection of recurrence also included digital rectal examination and imaging studies, such as MRI, CT, PET/CT, and/or bone scans. PFS and PCSS were calculated using the Kaplan-Meier method.

RESULTS

The median follow-up period was 71 months. According to the NCCN risk classification, 5% (13/255) of the patients had favorable intermediate-risk disease, 23% (57/255) had unfavorable intermediate-risk disease, 40% (102/255) had high-risk disease, and 32% (83/255) had very high-risk disease. Androgen deprivation therapy was administered to 80% (204/255) of the patients. Elective pelvic lymph node IMRT was performed in 28 (10%) patients. The PFS for all patients at 5 years was 81% (favorable intermediate risk, 91%; unfavorable intermediate risk, 89%; high-risk, 78%; and very-high risk, 72%). The PCSS for all patients at 5 years was 97% (favorable intermediate risk, 100%; unfavorable intermediate risk, 100%; high risk, 100%; and very high risk, 89%).

CONCLUSION

The incidence of failure following IMRT plus SBRT for unfavorable prostate cancer remains low at 5 years.

Salvage Cryoablation for Recurrent Prostate Cancer Following Primary External Beam Radiotherapy or Primary Cryotherapy: A Propensity Score Matched Analysis of Mid-term Oncologic and Functional Outcomes

INTRODUCTION

Local prostate cancer recurrence following radiotherapy (XRT) or cryoablation (CRYO) may be addressed with salvage cryotherapy (SCT), although little is known about how the primary treatment modality affects SCT results. Oncologic and functional outcomes of patients who underwent SCT after primary XRT (XRT-SCT) or cryoablation (CRYO-SCT) were studied.

METHODS

Data was collected using the Duke Prostate Cancer database and the Cryo On-Line Data (COLD) registry. The primary outcome was biochemical progression-free survival (BPFS).  Urinary incontinence, rectourethral fistula, and erectile dysfunction were secondary outcomes. The Kaplan-Meier log-rank test and univariable/multivariable Cox proportional hazards (CPH) models were utilized to evaluate BPFS between groups.

RESULTS

419 XRT-SCT and 63 CRYO-SCT patients met inclusion criteria, that was reduced to 63 patients in each cohort after propensity matching. There was no difference in BPFS at 2 and 5 years both before (P = .5 and P = .7) and after matching (P = .6 and P = .3). On multivariable CPH, BPFS was comparable between treatment groups (CRYO-SCT, HR=1.1, [0.2-2.2]).  On the same analysis, BPFS was lower in D'Amico high-risk (HR 3.2, P < .01) and intermediate-risk (HR 1.95, P < .05) categories compared to low-risk. There was no significant difference in functional outcomes between cohorts.

CONCLUSION

Following primary cryotherapy, salvage cryoablation provides comparable intermediate oncological outcomes and functional outcomes compared to primary radiotherapy.

Prostate Stereotactic Body Radiation Therapy With a Focal Simultaneous Integrated Boost: 5-Year Toxicity and Biochemical Recurrence Results From a Prospective Trial

PURPOSE

Stereotactic body radiation therapy (SBRT) is increasingly used as a definitive treatment option for patients with prostate adenocarcinoma. The aim of this study was to assess the late toxicity, patient-reported quality of life outcomes, and biochemical recurrence rates after prostate SBRT with simultaneous integrated boost (SIB) targeting lesions defined by magnetic resonance imaging (MRI).

METHODS AND MATERIALS

Patients were eligible if they had biopsy-proven low- or intermediate-risk prostate adenocarcinoma, one or more focal lesions on MRI, and an MRI-defined total prostate volume of <120 mL. All patients received SBRT delivered to the entire prostate to a dose of 36.25 Gy in 5 fractions with an SIB to the lesions seen on MRI to 40 Gy in 5 fractions. Late toxicity was defined as any possible treatment-related adverse event occurring after 3 months from the completion of SBRT. Patient-reported quality of life was ascertained using standardized patient surveys.

RESULTS

A total of 26 patients were enrolled. Six patients (23.1%) had low-risk disease and 20 patients had intermediate-risk disease (76.9%). Seven patients (26.9%) received androgen deprivation therapy. Median follow-up was 59.5 months. No biochemical failures were observed. Three patients (11.5%) experienced late grade 2 genitourinary (GU) toxicity requiring cystoscopy, and 7 patients (26.9%) had late grade 2 GU toxicity requiring oral medications. Three patients (11.5%) had late grade 2 gastrointestinal toxicity characterized by hematochezia requiring colonoscopy and steroids per rectum. There were no grade 3 or higher toxicity events observed. The patient-reported quality-of-life metrics at the time of last follow-up were not significantly different than the pre-treatment baseline.

CONCLUSIONS

The results of this study support that SBRT to the entire prostate to a dose of 36.25 Gy in 5 fractions with focal SIB to 40 Gy in 5 fractions has excellent biochemical control and is not associated with undue late gastrointestinal or GU toxicity or long-term quality of life decrement. Focal dose escalation with an SIB planning approach may be an opportunity to improve biochemical control while limiting dose to nearby organs at risk.

Treatment outcomes of simultaneous integrated boost to intraprostatic lesions with external beam radiotherapy in localized prostate cancer patients

BACKGROUND

To evaluate the treatment outcomes and toxicity of definitive radiotherapy (RT) for prostate cancer (PC) patients using the simultaneous integrated boost (SIB) technique, which delivered 78 Gy to the entire prostate and 86 Gy to the intraprostatic lesion (IPL) in 39 fractions.

MATERIALS AND METHODS

Univariable and multivariable analyses were conducted of the prognostic factors for freedom from biochemical failure (FFBF), progression-free survival (PFS), and PC-specific survival (PCSS) of 619 PC patients who received definitive RT between September 2012 and August 2021. Predictors of late Grade ≥2 genitourinary (GU) and gastrointestinal (GI) toxicities were also identified using logistic regression.

RESULTS

The median follow-up for entire cohort was 68.5 months. The 5-year FFBF, PFS, and PCSS rates were 93.2%, 83.2%, and 98.6%, respectively. They were predicted by the serum prostate-specific antigen, Gleason score (GS), clinical nodal stage, and D'Amico risk group. Only 45 patients (7.3%) developed disease recurrence 41.9 months after RT. The 5-year FFBF rates for low-, intermediate-, and high-risk disease were 98.0%, 93.1%, and 88.5%, respectively (p < 0.001). The 5-year PFS and PCSS rates according to risk groups were 91.0%, 82.1%, and 77.4% (p < 0.001), and 99.2%, 96.4%, and 95.9% (p = 0.03), and, respectively. GS > 7 and lymph node metastasis negatively predicted FFBF and PCSS in multivariable analysis. Ninety (14.6%) and 44 (7.1%) patients had acute Grade ≥2 GU and GI toxicities, respectively, and 42 (6.8%) and 27 (4.4%) patients had late Grade ≥2 GU and GI toxicities, respectively. Diabetes and transurethral resection independently predicted late Grade 2 GU toxicity, but no significant predictor of late Grade ≥2 GI toxicity was found.

CONCLUSIONS

Localized PC was effectively and safely treated with definitive RT using the SIB technique to deliver 86 Gy to the IPL in 39 fractions without severe late toxicity. This finding must be validated with long-term results.

Five-Year Patient-Reported Outcomes in NRG Oncology RTOG 0938, Evaluating Two Ultrahypofractionated Regimens for Prostate Cancer

PURPOSE

There is considerable interest in very short (ultrahypofractionated) radiation therapy regimens to treat prostate cancer based on potential radiobiological advantages, patient convenience, and resource allocation benefits. Our objective is to demonstrate that detectable changes in health-related quality of life measured by the bowel and urinary domains of the Expanded Prostate Cancer Index Composite (EPIC-50) were not substantially worse than baseline scores.

METHODS AND MATERIALS

NRG Oncology's RTOG 0938 is a nonblinded randomized phase 2 study of National Comprehensive Cancer Network low-risk prostate cancer in which each arm is compared with a historical control. Patients were randomized to 5 fractions (7.25 Gy in 2 week and a day [twice a week]) or 12 fractions (4.3Gy in 2.5 weeks [5 times a week]). Secondary objectives assessed patient-reported toxicity at 5 years using the EPIC. Chi-square tests were used to assess the proportion of patients with a deterioration from baseline of >5 points for bowel, >2 points for urinary, and >11 points for sexual score.

RESULTS

The study enrolled 127 patients to 5 fractions (121 eligible) and 128 patients to 12 fractions (125 eligible). The median follow-up for all patients at the time of analysis was 5.38 years. The 5-year frequency for >5 point change in bowel score were 38.4% (P = .27) and 23.4% (P = 0.98) for 5 and 12 fractions, respectively. The 5-year frequencies for >2 point change in urinary score were 46.6% (P = .15) and 36.4% (P = .70) for 5 and 12 fractions, respectively. For 5 fractions, 49.3% (P = .007) of patients had a drop in 5-year EPIC-50 sexual score of ≥11 points; for 12 fractions, 54% (P < .001) of patients had a drop in 5-year EPIC-50 sexual score of ≥11 points. Disease-free survival at 5 years is 89.6% (95% CI: 84.0-95.2) in the 5-fraction arm and 92.3% (95% CI: 87.4-97.1) in the 12-fraction arm. There was no late grade 4 or 5 treatment-related urinary or bowel toxicity.

CONCLUSIONS

This study confirms that, based on long-term changes in bowel and urinary domains and toxicity, the 5- and 12-fraction regimens are well tolerated. These ultrahypofractionated approaches need to be compared with current standard radiation therapy regimens.

Dose evaluation of inter- and intra-fraction prostate motion in extremely hypofractionated intensity-modulated proton therapy for prostate cancer

Inter- and intra-fractional prostate motion can deteriorate the dose distribution in extremely hypofractionated intensity-modulated proton therapy. We used verification CTs and prostate motion data calculated from 1024 intra-fractional prostate motion records to develop a voxel-wise based 4-dimensional method, which had a time resolution of 1 s, to assess the dose impact of prostate motion. An example of 100 fractional simulations revealed that motion had minimal impact on planning dose, the accumulated dose in 95 % of the scenarios fulfilled the clinical goals for target coverage (D95 > 37.5 Gy). This method can serve as a complementary measure in clinical setting to guarantee plan quality.

Hypofractionated Radiotherapy in Localized, Low-Intermediate-Risk Prostate Cancer: Current and Future Prospectives

At the time of diagnosis, the vast majority of prostate carcinoma patients have a clinically localized form of the disease, with most of them presenting with low- or intermediate-risk prostate cancer. In this setting, various curative-intent alternatives are available, including surgery, external beam radiotherapy and brachytherapy. Randomized clinical trials have demonstrated that moderate hypofractionated radiotherapy can be considered as a valid alternative strategy for localized prostate cancer. High-dose-rate brachytherapy can be administered according to different schedules. Proton beam radiotherapy represents a promising strategy, but further studies are needed to make it more affordable and accessible. At the moment, new technologies such as MRI-guided radiotherapy remain in early stages, but their potential abilities are very promising.

Case-Matched Outcomes of Proton Beam and Intensity-Modulated Radiation Therapy for Localized Prostate Cancer

Purpose

Although both intensity-modulated radiation therapy (IMRT) and proton beam therapy (PBT) offer effective long-term disease control for localized prostate cancer (PCa), there are limited data directly comparing the 2 modalities.

Methods

The data from 334 patients treated with conventionally fractionated (79.2 GyRBE in 44 fractions) PBT or IMRT were retrospectively analyzed. Propensity score matching was used to balance factors associated with biochemical failure-free survival (BFFS). Age, race, and comorbidities (not BFFS associates) remained imbalanced after matching. Univariable and covariate-adjusted multivariable (MVA) Cox regression models were used to determine if modality affected BFFS.

Results

Of 334 patients, 176 (52.7%) were included in the matched cohort with exact matching to National Comprehensive Cancer Network (NCCN) risk group. With a median follow-up time of 9.0 years (interquartile range [IQR]: 7.8-10.2 years), long-term BFFS was similar between the IMRT and PBT matched arms with 8-year estimates of 85% (95% CI: 76%-91%) and 91% (95% CI: 82%-96%, P = .39), respectively. On MVA, modality was not significantly associated with BFFS in both the unmatched (hazard ratio [HR] = 0.75, 95% CI: 0.35-1.63, P = .47) and matched (HR = 0.87, 95% CI: 0.33-2.33, P = .78) cohorts. Prostate cancer-specific survival (PCSS) and overall survival (OS) were also similar (P > .05). However, in an unmatched analysis, the PBT arm had significantly fewer incidences of secondary cancers within the irradiated field (0.6%, 95% CI: 0.0%-3.1% versus 4.5%, 95% CI: 1.8%-9.0%, P = .028).

Conclusions

Both PBT and IMRT offer excellent long-term disease control for PCa, with no significant differences between the 2 modalities in BFFS, PCSS, and OS in matched patients. In the unmatched cohort, fewer incidences of secondary malignancy were noted in the PBT group; however, owing to overall low incidence of secondary cancer and imbalanced patient characteristics between the 2 groups, these data are strictly hypothesis generating and require further investigation.

Late Toxicity of Moderately Hypofractionated Intensity-Modulated Proton Therapy Treating the Prostate and Pelvic Lymph Nodes for High-Risk Prostate Cancer

PURPOSE

To evaluate late gastrointestinal (GI) and genitourinary (GU) toxicity of moderately hypofractionated intensity modulated proton therapy (IMPT) targeting the prostate and pelvic lymph nodes.

METHODS AND MATERIALS

A target accrual of 56 patients with high-risk or unfavorable intermediate risk prostate cancer were enrolled into a prospective study (ClinicalTrials.gov: NCT02874014) of moderately hypofractionated IMPT. IMPT with pencil beam scanning was used to deliver 6750 and 4500 cGy relative biological effectiveness in 25 daily fractions simultaneously to the prostate and pelvic lymph nodes, respectively. All received androgen deprivation therapy. Late GI and GU toxicity was prospectively assessed using Common Terminology Criteria for Adverse Events version 4.0, at baseline, weekly during radiation therapy, 3-month postradiation therapy, and then every 6 months. Actuarial rates of late GI and GU toxicity were estimated using Kaplan-Meier method.

RESULTS

Median age was 75.5 years. Fifty-four patients were available for late toxicity evaluation. Median follow-up was 43.9 months (range, 16-66). The actuarial rate of late grade ≥2 GI toxicity at both 2 and 3 years was 7.4% (95% confidence interval [CI], 0.2%-14.2%). The actuarial rate of late grade 3 GI toxicity at both 2 and 3 years was 1.9% (95% CI, 0%-5.4%). One patient experienced grade 3 GI toxicity with proctitis. The actuarial rate of late grade ≥2 GU toxicity was 20.5% (95% CI, 8.9%-30.6%) at 2 years, and 29.2 % (95% CI, 15.5%-40.7%) at 3 years. None had grade 3 GU toxicity. The presence of baseline GU symptoms was associated with a higher likelihood of experiencing late grade 2 GU toxicity.

CONCLUSIONS

A moderately hypofractionated IMPT targeting the prostate and regional pelvic lymph nodes was generally well tolerated. Patients with pre-existing GU symptoms had a higher rate of late grade 2 GU toxicity. A phase 3 study is needed to assess any therapeutic gain of IMPT, in comparison with photon-based radiation therapy.

Dosimetric analysis of patients receiving radiotherapy with VMAT technique in localized prostate cancer and its correlation with side effects

Aim

The aim was to study the relationship between dosimetric data of localized prostate cancer patients who have been treated with curative radiotherapy (RT) and gastrointestinal (GIS), genitourinary (GUS), anal and sexual side effects, and whether there was a difference between dosimetric data and clinical findings between risk groups.

Methods

Eighty-seven patients who received curative radiotherapy for localized prostate cancer between 2014 and 2019 were included in the study. Dosimetrically; whether there was a relationship between V30, V40, V50, V60, V65, V70, V75 for rectum and bladder; D90 for the penile bulb, V72, V74, V76 for the bulbomembranous urethra, V30, V45, V53, Dmax for the anus, and V45 (cc) for the intestine data and the side effects were analyzed. It was evaluated whether there was a relationship between testosterone values and sexual side effects. The Kolmogorov-Smirnov test, one-way analysis of variance (ANOVA) (F-test), and paired-sample t-test were used as statistical methods. For statistical significance, P < 0.05 was accepted.

Results

: The mean age of the patients was 69 (50-86), the mean Prostat specific antigen (PSA) (ng/dL) before RT was 25.1 (0.9-339), the median RT dose was 76 Gy (74-78 Gy), and the mean follow-up period was 38.2 months. PTVmax, PTVmean, PTVmin, bladder V40, bladder V50, rectum V30, rectum V40, rectum V50, and intestinal V45 (cc) were determined as dosimetric data showing differences between risk groups. A statistically significant relationship was found between rectum V30 (P = 0.017), V60 (P = 0.019), V65 (P = 0.008), V70 (P = 0.007), and V75 (P = 0.034) and chronic GIS side effects. G2 GIS side effects were observed in four patients (4.6%) in the entire patient group during the acute period. A statistically significant relationship was found between the patients receiving hormonotherapy (P = 0.021) and testosterone values at the last control (P ≤ 0.001) and chronic sexual side effects.

Conclusion

Attention should be paid to the rectum V30, V60, V65, V70, and V75 values to minimize the long-term GIS side effects in patients who have undergone RT. Testosterone level and ADT status affect chronic sexual toxicity.

Toxicity of dose-escalated radiotherapy up to 84 Gy for prostate cancer

PURPOSE

The outcome of radiotherapy (RT) for prostate cancer (PCA) depends on the delivered dose. While the evidence for dose-escalated RT up to 80 gray (Gy) is well established, there have been only few studies examining dose escalation above 80 Gy. We initiated the present study to assess the safety of dose escalation up to 84 Gy.

METHODS

In our retrospective analysis, we included patients who received dose-escalated RT for PCA at our institution between 2016 and 2021. We evaluated acute genitourinary (GU) and gastrointestinal (GI) toxicity as well as late GU and GI toxicity.

RESULTS

A total of 86 patients could be evaluated, of whom 24 patients had received 80 Gy and 62 patients 84 Gy (35 without pelvic and 27 with pelvic radiotherapy). Regarding acute toxicities, no > grade 2 adverse events occurred. Acute GU/GI toxicity of grade 2 occurred in 12.5%/12.5% of patients treated with 80 Gy, in 25.7%/14.3% of patients treated with 84 Gy to the prostate only, and in 51.9%/12.9% of patients treated with 84 Gy and the pelvis included. Late GU/GI toxicity of grade ≥ 2 occurred in 4.2%/8.3% of patients treated with 80 Gy, in 7.1%/3.6% of patients treated with 84 Gy prostate only, and in 18.2%/0% of patients treated with 84 Gy pelvis included (log-rank test p = 0.358).

CONCLUSION

We demonstrated that dose-escalated RT for PCA up to 84 Gy is feasible and safe without a significant increase in acute toxicity. Further follow-up is needed to assess late toxicity and survival.

Dose-escalated radiotherapy for clinically localized and locally advanced prostate cancer

BACKGROUND

Treatments for clinically localized prostate cancer include radical prostatectomy, external beam radiation therapy, brachytherapy, active surveillance, hormonal therapy, and watchful waiting. For external beam radiation therapy, oncological outcomes may be expected to improve as the dose of radiotherapy (RT) increases. However, radiation-mediated side effects on surrounding critical organs may also increase.

OBJECTIVES

To assess the effects of dose-escalated RT in comparison with conventional dose RT for curative treatment of clinically localized and locally advanced prostate cancer.

SEARCH METHODS

We performed a comprehensive search using multiple databases including trial registries and other sources of grey literature, up until 20 July 2022. We applied no restrictions on publication language or status.

SELECTION CRITERIA

We included parallel-arm randomized controlled trials (RCTs) of definitive RT in men with clinically localized and locally advanced prostate adenocarcinoma. RT was dose-escalated RT (equivalent dose in 2 Gy [EQD2] ≥ 74 Gy, lesser than 2.5 Gy per fraction) versus conventional RT (EQD2 < 74 Gy, 1.8 Gy or 2.0 Gy per fraction). Two review authors independently classified studies for inclusion or exclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently abstracted data from the included studies. We performed statistical analyses by using a random-effects model and interpreted them according to the Cochrane Handbook for Systematic Reviews of Interventions. We used GRADE guidance to rate the certainty of the evidence of RCTs.

MAIN RESULTS

We included nine studies with 5437 men in an analysis comparing dose-escalated RT versus conventional dose RT for the treatment of prostate cancer. The mean participant age ranged from 67 to 71 years. Almost all men had localized prostate cancer (cT1-3N0M0). Primary outcomes Dose-escalated RT probably results in little to no difference in time to death from prostate cancer (hazard ratio [HR] 0.83, 95% CI 0.66 to 1.04; I2 = 0%; 8 studies; 5231 participants; moderate-certainty evidence). Assuming a risk of death from prostate cancer of 4 per 1000 at 10 years in the conventional dose RT group, this corresponds to 1 fewer men per 1000 (1 fewer to 0 more) dying of prostate cancer in the dose-escalated RT group. Dose-escalated RT probably results in little to no difference in severe RT toxicity of grade 3 or higher late gastrointestinal (GI) toxicity (RR 1.72, 95% CI 1.32 to 2.25; I2 = 0%; 8 studies; 4992 participants; moderate-certainty evidence); 23 more men per 1000 (10 more to 40 more) in the dose-escalated RT group assuming severe late GI toxicity as 32 per 1000 in the conventional dose RT group. Dose-escalated RT probably results in little to no difference in severe late genitourinary (GU) toxicity (RR 1.25, 95% CI 0.95 to 1.63; I2 = 0%; 8 studies; 4962 participants; moderate-certainty evidence); 9 more men per 1000 (2 fewer to 23 more) in the dose-escalated RT group assuming severe late GU toxicity as 37 per 1000 in the conventional dose RT group. Secondary outcomes Dose-escalated RT probably results in little to no difference in time to death from any cause (HR 0.98, 95% CI 0.89 to 1.09; I2 = 0%; 9 studies; 5437 participants; moderate-certainty evidence). Assuming a risk of death from any cause of 101 per 1000 at 10 years in the conventional dose RT group, this corresponds to 2 fewer men per 1000 (11 fewer to 9 more) in the dose-escalated RT group dying of any cause. Dose-escalated RT probably results in little to no difference in time to distant metastasis (HR 0.83, 95% CI 0.57 to 1.22; I2 = 45%; 7 studies; 3499 participants; moderate-certainty evidence). Assuming a risk of distant metastasis of 29 per 1000 in the conventional dose RT group at 10 years, this corresponds to 5 fewer men per 1000 (12 fewer to 6 more) in the dose-escalated RT group developing distant metastases. Dose-escalated RT may increase overall late GI toxicity (RR 1.27, 95% CI 1.04 to 1.55; I2 = 85%; 7 studies; 4328 participants; low-certainty evidence); 92 more men per 1000 (14 more to 188 more) in the dose-escalated RT group assuming overall late GI toxicity as 342 per 1000 in the conventional dose RT group. However, dose-escalated RT may result in little to no difference in overall late GU toxicity (RR 1.12, 95% CI 0.97 to 1.29; I2 = 51%; 7 studies; 4298 participants; low-certainty evidence); 34 more men per 1000 (9 fewer to 82 more) in the dose-escalated RT group assuming overall late GU toxicity as 283 per 1000 in the conventional dose RT group. Based on long-term follow-up (up to 36 months), dose-escalated RT may result or probably results in little to no difference in the quality of life using 36-Item Short Form Survey; physical health (MD -3.9, 95% CI -12.78 to 4.98; 1 study; 300 participants; moderate-certainty evidence) and mental health (MD -3.6, 95% CI -83.85 to 76.65; 1 study; 300 participants; low-certainty evidence), respectively.

AUTHORS' CONCLUSIONS

Compared to conventional dose RT, dose-escalated RT probably results in little to no difference in time to death from prostate cancer, time to death from any cause, time to distant metastasis, and RT toxicities (except overall late GI toxicity). While dose-escalated RT may increase overall late GI toxicity, it may result, or probably results, in little to no difference in physical and mental quality of life, respectively.