Transitioning from conventional radiotherapy to intensity-modulated radiotherapy for localized prostate cancer: changing focus from rectal bleeding to detailed quality of life analysis

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.

Patient-reported persistent symptoms after radiotherapy and association with quality of life for prostate cancer survivors

PURPOSE

To evaluate the persistence of symptoms after radiotherapy (RT) for localised prostate cancer (PCa) and the association with quality of life (QOL).

MATERIALS AND METHODS

Prospective patient-reported outcome (PRO) from a multi-institutional study on PCa treated with radical RT (2010-2014) was analysed. Data was collected at baseline (BL) and follow-ups (FUPs) up to 5 years. Patients with BL and ≥3 late FUPs (≥6 months) were analysed. PRO was scored by means of the IPSS and ICIQ-SF (urinary), LENT-SOMA (gastrointestinal [GI]), and EORTC-C30 (pain, insomnia, fatigue, and QOL) questionnaires. Symptoms were defined 'persistent' if the median score over FUPs was ≥3 (urinary) or ≥2 (GI, pain, insomnia, and fatigue), and worse than BL. Different thresholds were chosen to have enough events for each symptom. QOL was linearly transformed on a continuous scale (0-100). Linear-mixed models were used to identify significant differences between groups with and without persistent symptoms including age, smoking status, previous abdominal surgery, and diabetes as confounders. Mean QOL differences between groups were evaluated longitudinally over FUPs.

RESULTS

The analysis included 293 patients. Persistent urinary symptoms ranged from 2% (straining) to 12% (weak stream, and nocturia). Gastrointestinal symptoms ranged from 7% (rectal pain, and incontinence) to 30% (urgency). Proportions of pain, insomnia, and fatigue were 6, 13, and 18%. Significant QOL differences of small-to-medium clinical relevance were found for urinary incontinence, frequency, urgency, and nocturia. Among GI symptoms, rectal pain and incontinence showed small-to-medium differences. Fatigue was associated with the largest differences.

CONCLUSIONS

The analysis showed that symptoms after RT for PCa occur with different persistence and their association with QOL varies in magnitude. A number of persistent urinary and GI symptoms showed differences in a comparable range. Urinary incontinence and frequency, rectal pain, and faecal incontinence more often had significant associations. Fatigue was also prevalent and associated with largely deteriorated QOL.

Late Toxicity After 3-Dimensional External Beam Radiotherapy Among Children With Cancer: A Systematic Review

Radiotherapy has evolved from 2-dimensional conventional radiotherapy (2D-RT) to 3-dimensional planned radiotherapy (3D-RT). Because 3D-RT improves conformity, an altered late health outcomes risk profile is anticipated. Here, we systematically reviewed the current literature on late toxicity after 3D-RT in children treated for cancer. PubMed was searched for studies describing late toxicity after 3D-RT for childhood cancer (below 21 y). Late toxicity was defined as somatic health outcomes occurring ≥90 days after treatment. We identified 13 eligible studies, describing most frequently head/neck area tumors. Included studies reported on crude frequencies of late toxicities including subsequent tumors and conditions of organ systems. Three studies offered a global assessment of the full spectrum of late toxicity; one study compared toxicities after 2D-RT and 3D-RT. Incidence rates were typically not provided. Heterogeneity in study characteristics, small study sizes and short follow-up times precluded multivariable modeling and pooling of data. In conclusion, among the first pediatric cohorts treated with 3D-RT, a broad variety of late toxicity is reported; precise estimates of incidence, and contributions of risk factors are unclear. Continued systematic evaluation of well-defined health outcomes in survivors treated with 3D-RT, including proton therapy, is needed to optimize evidence-based care for children with cancer and survivors.

Clinical predictors of severe late urinary toxicity after curative intensity-modulated radiation therapy for localized prostate cancer

Intractable late urinary toxicity is a serious complication after radiotherapy for patients with localized prostate cancer (LPC). We assessed clinical factors correlated with severe late urinary toxicity in LPC treated with curative image-guided intensity-modulated radiation therapy (IMRT). A total of 452 patients with LPC treated with IMRT between 2002 and 2016 were retrospectively analyzed. Among them, 432 patients received androgen deprivation therapy (ADT). The median total irradiated doses were 80 (range, 76-80) Gy. Each daily dose was 2 Gy per fraction. The median follow-up was 83 (range, 4-210) months. Late urinary toxicity was scored according to the National Cancer Institute Common Terminology Criteria for Adverse Events, Version 4.03. Grade 3 late urinary toxicity was observed in 27 patients. No cases with grade ≥ 4 late urinary toxicity were observed. The 5-, 10-, and 12.5-year grade 3 late urinary toxicity-free survival rates were 97%, 91.8% and 88.1%, respectively. Age, risk classification, total irradiated dose, ADT duration, antithrombotic therapy (AT), cardiovascular disease, hypertension (HT), diabetes mellitus (DM), dyslipidemia (DL), prior transurethral resection of the prostate (TURP) and prior high-intensity focused ultrasound (HIFU) were investigated for correlations with grade 3 late urinary toxicity. In univariate analysis, AT and prior HIFU and no other studied factors, were correlated with grade 3 late urinary toxicity. AT and prior HIFU appear to be predictive of grade 3 late urinary toxicity. Patients with LPC with these relevant clinical factors should be carefully followed up by sharing detailed information with the urology department.

Radiotherapy for Clinically Localized T3b or T4 Very-High-Risk Prostate Cancer-Role of Dose Escalation Using High-Dose-Rate Brachytherapy Boost or High Dose Intensity Modulated Radiotherapy

Simple Summary

Recently, high-risk prostate cancer was subdivided to a very-high-risk group considered to have the worst prognosis, including clinical stage T3b–T4, primary Gleason pattern 5, or more than four biopsy cores with Gleason score 8–10. Among these, T3b–T4 stage is a special interest in radiotherapy because of their wider target volume outside the prostate. We examined this subgroup and found that dose escalation in radiotherapy both with brachytherapy or intensity modulated radiotherapy (IMRT) improved biochemical free survival rate but not in prostate cancer specific survival rate and overall survival rate.

Abstract

To examine the efficacy of dose escalating radiotherapy into patients with cT3b or T4 localized prostate cancer, we compared Group A (86 conventional dose external beam radiotherapy: EBRT group, treated with 70–72 Gy) and group B (39 high dose EBRT group (HDEBRT group, 74–80 Gy) and 124 high-dose-rate brachytherapy (HDR) + EBRT (HDR boost)) using multi-institutional retrospective data. The actuarial 5-year biochemical disease-free survival (bDFS) rate, prostate cancer specific survival rate (PSS), and overall survival rate (OS) were 75.8%, 96.8%, and 93.5%. Group B showed superior 5-year bDFS rate (81.2%) as compared to the group A (66.5%) (p < 0.0001) with a hazard ratio of 0.397. Equivocal 5-year PSS (98.3% and 94.8% in group B and group A) and OS (both 93.7%) were found between those groups. Accumulated late grade ≥ 2 toxicities in gastrointestinal and genitourinary tracts were similar among those three groups. Therefore, both HDEBRT and HDR boost could be good options for improving the bDFS rate in cT3–T4 localized prostate cancer without affecting PSS and OS.

High-dose-rate brachytherapy with external beam radiotherapy versus low-dose-rate brachytherapy with or without external beam radiotherapy for clinically localized prostate cancer

To compare the outcomes of localized prostate cancer treatment with high-dose-rate brachytherapy (HDR-BT) and low-dose-rate brachytherapy (LDR-BT), we examined 924 patients treated with HDR-BT + external beam radiotherapy (EBRT) and 500 patients treated with LDR-BT ± EBRT using multi-institutional retrospective data. The HDR-BT treated advanced disease with more hormonal therapy than LDR-BT. To reduce background selection bias, we performed inverse probability of treatment weighting (IPTW) analysis using propensity scores and excluded patients with T3b-4 disease/ initial prostate-specific antigen (PSA) levels > 50 ng/ml. The actuarial 5-year biochemical control rates (5y-bNED) were 96.3% and 95.7% in the HDR-BT and LDR-BT groups, respectively. The corresponding values were 100% and 96.5% in the low-risk group; 97.4% and 97.1% in the intermediate-risk group (97.2% and 97% in the higher titer group and 97.5% and 94.6% in the lower titer group, respectively); and 95.7% and 94.9% in the selected high-risk group, respectively. IPTW correction indicated no significant difference among the groups. The 5y-bNED in the HDR-BT + EBRT, LDR-BT + EBRT, and LDR-BT alone groups were 96.3%, 95.5%, and 97%, respectively (P = 0.3011). The corresponding values were 97.4%, 94.7%, and 96.6% (P = 0.1004) in the intermediate-risk group (97.5%, 100%, and 94.5% in the lower titer group [P = 0.122] and 97.2%, 96.2%, and 100% [P = 0.664] in the higher titer group, respectively) and 95.7%, 95.5%, and 100% (P = 0.859) in the high-risk group, respectively. The HDR-BT group showed a lower incidence of acute grade ≥ 2 genitourinary toxicities; the incidence of other early and late grade ≥ 2 toxicities were similar between the HDR-BT and LDR-BT groups. Acute genitourinary toxicity predicted the occurrence of late genitourinary toxicity. EBRT increased the risk of grade ≥ 2 gastrointestinal toxicity. HDR-BT + EBRT is a good alternative to LDR-BT ± EBRT for low-, intermediate-, and selected high-risk patients.

Dose-volume Histogram-based Predictors for Hematuria and Rectal Hemorrhage in Patients Receiving Radiotherapy After Radical Prostatectomy

AIM

The aim of this study was to evaluate the dose-volume histogram parameters for late hematuria and rectal hemorrhage in patients receiving radiotherapy after radical prostatectomy.

PATIENTS AND METHODS

Data of 86 patients treated between January 2006 and June 2019 were retrospectively evaluated. The median radiation dose was 64 Gy in 32 fractions. Receiver operating characteristic (ROC) curves were used to identify optimal cut-off values for late adverse events.

RESULTS

Eleven patients experienced hematuria, and the 5-year cumulative rate was 18%. Four patients experienced rectal hemorrhage, and the 5-year cumulative rate was 7%. ROC curve analysis demonstrated the following significant cut-off values: bladder V50 Gy: 43% (p=0.02) and V40 Gy: 50% (p=0.03) for hematuria, and rectum V60 Gy: 13% (p=0.04) and V50 Gy: 33% (p=0.03) for rectal hemorrhage.

CONCLUSION

This is the first study to identify dose constraints that may reduce hematuria and rectal hemorrhage in patients receiving radiotherapy in the postoperative setting.

Early and late side effects, dosimetric parameters and quality of life after proton beam therapy and IMRT for prostate cancer: a matched-pair analysis

Purpose: To compare early and late toxicities, dosimetric parameters and quality of life (QoL) between conventionally fractionated proton beam therapy (PBT) and intensity-modulated radiation therapy (IMRT) in prostate cancer (PCA) patients. Methods: Eighty-eight patients with localized PCA treated between 2013 and 2017 with either definitive PBT (31) or IMRT (57) were matched using propensity score matching on PCA risk group, transurethral resection of the prostate, prostate volume, diabetes mellitus and administration of anticoagulants resulting in 29 matched pairs. Early and late genitourinary (GU) and gastrointestinal (GI) toxicities according to Common Terminology Criteria for Adverse Events (CTCAE) and QoL based on EORTC-QLQ-C30/PR25 questionnaires were collected prospectively until 12 months after radiotherapy (RT). Associations between toxicities and dose-volume parameters in corresponding organs at risk (OARs) were modeled by logistic regression. Results: There were no significant differences in GI and GU toxicities between both treatment groups except for late urinary urgency, which was significantly lower after PBT (IMRT: 25.0%, PBT: 0%, p = .047). Late GU toxicities and obstruction grade ≥2 were significantly associated with the relative volume of the anterior bladder wall receiving 70 Gy and the entire bladder receiving 60 Gy, respectively. The majority of patients in both groups reported high functioning and low symptom scores for the QoL questionnaires before and after RT. No or little changes were observed for most items between baseline and 3 or 12 months after RT, respectively. Global health status increased more at 12 months after IMRT (p = .040) compared to PBT, while the change of constipation was significantly better at 3 months after PBT compared to IMRT (p = .034). Conclusions: Overall, IMRT and PBT were well tolerated. Despite the superiority of PBT in early constipation and IMRT in late global health status compared to baseline, overall QoL and the risks of early and late GU and GI toxicities were similar for conventionally fractionated IMRT and PBT.

Effect of Androgen Deprivation Therapy on Other-Cause of Mortality in Elderly Patients with Clinically Localized Prostate Cancer Treated with Modern Radiotherapy: Is There a Negative Impact?

The influence of androgen deprivation therapy (ADT) on other-cause of mortality (OCM) was investigated in patients with localized prostate cancer treated with modern high-dose radiotherapy. A retrospective review was conducted on 1125 patients with localized prostate cancer treated with high-dose radiotherapy, including image-guided, intensity-modulated radiotherapy or brachytherapy with a median follow-up of 80.7 months. Overall survival rate was no different between ADT (+) and ADT (−) group in high-, intermediate-, and low-risk groups. OCM was found in 71 patients, consisting of 4% (10/258) in the ADT (−) group and 7% (61/858) in the ADT (+) group (p = 0.0422). The 10-year OCM-free survival rate (OCMFS), if divided by the duration of ADT (ADT naïve (ADT (−)), ADT <2-year, and ADT ≥2-year groups), showed statistical significance, and was 90.7%, 88.2%, and 78.6% (p = 0.0039) for the ADT (−), ADT <2-year, and ADT ≥2-year groups, respectively. In patients aged ≥75 years, 10-year OCMFS for ADT (−), ADT <2-, and ADT ≥2-year groups was 93.5% (at 115.6 months), 85.6%, and 60.7% (p = 0.0189), respectively, whereas it was 90.7%, 89.9%, and 89.0% (p = 0.4716), respectively, in their younger counterparts. In localized prostate cancer patients, treatment with longer ADT for ≥2 years potentially increases the risk of OCM, especially in patients aged ≥75 years.

Intensity-modulated radiation therapy for elderly patients (aged ≥75 years) with localized prostate cancer: Comparison with younger patients (aged <75 years)

The aim of the present study was to evaluate the efficacy and safety of intensity-modulated radiation therapy (IMRT) for elderly patients with prostate cancer (age ≥75 years) compared with younger patients (<75 years). The numbers of patients enrolled into the elderly and younger groups were 238 and 853, respectively. More than half of the patients in the elderly group were high-risk, and the total risk of the elderly group was higher than that of younger group. The median follow-up periods for the elderly and younger groups were 42 (range, 2-108) and 49 (range, 2-120) months, respectively. All patients were treated with IMRT at a dose of 74-78 Gy with or without androgen-deprivation therapy. The biochemical failure-free rates (BFFRs) at 3-year follow-up for the elderly and younger groups were 93.3 and 95.7%, respectively; there was no significant difference between the 2 groups in regard to the BFFR. The clinical failure-free rates (CFFR) at 3-year follow-up for the elderly and younger groups was 95.8 and 98.5%, respectively; the 2 groups did not differ significantly in regard to the CFFR. The cumulative incidence rates of gastrointestinal toxicity (grade ≥2) and genitourinary toxicity (grade ≥2) at 3-year follow-up were 10.5 and 1.3%, respectively; there was no significant difference between the elderly and younger groups. It was concluded that in prostate cancer patients aged 75 years or older, IMRT has a treatment effect equivalent to that in patients <75 years old; adverse events are also comparable.

High-Dose-Rate Brachytherapy Monotherapy versus Image-Guided Intensity-Modulated Radiotherapy with Helical Tomotherapy for Patients with Localized Prostate Cancer

The aim of this paper is to compare outcomes between high-dose-rate interstitial brachytherapy (HDR-BT) monotherapy and image-guided intensity-modulated radiotherapy (IG-IMRT) for localized prostate cancer. We examined 353 HDR-BT and 270 IG-IMRT patients. To reduce background selection bias, we used the method of inverse probability treatment weighting (IPTW) with propensity scores. The actuarial five-year biochemical failure-free survival rates were 92.9% and 96.7% (p = 0.1847; p = 0.077 in IPTW) for HDR-BT and IG-IMRT, respectively; they were 100% and 95.8% (p = 0.286) for the low-risk group, 95.6% and 92% (p = 0.42) for the intermediate-risk group, 90.4% and 84.9% (p = 0.1059; p = 0.04 in IPTW) for the high-risk group, and 87.1% and 89.2% (p = 0.3816) for the very-high-risk group. In the assessment of accumulated incidences of grade ≥ 2 toxicity (Common Terminology Criteria for Adverse Events version 4.0) at five years, HDR-BT monotherapy showed higher genitourinary toxicity (11.9%) than IG-IMRT (3.3%) (p < 0.0001). The gastrointestinal toxicity was equivalent for HDR-BT (2.3%) and IG-IMRT (5.5%) (p = 0.063). No Grade 4 or 5 toxicity was detected in either modality. HDR-BT showed higher genitourinary toxicity than IG-IMRT. HDR-BT and IG-IMRT showed equivalent outcomes in low-, intermediate-, and very-high-risk groups. For high-risk patients, HDR-BT showed potential to improve prostate-specific antigen (PSA) control rate compared to IG-IMRT.

Comparison of Image-Guided Intensity-Modulated Radiotherapy and Low-dose Rate Brachytherapy with or without External Beam Radiotherapy in Patients with Localized Prostate Cancer

To compare the outcome of low-dose rate brachytherapy (LDR-BT) and image-guided intensity-modulated radiotherapy (IG-IMRT) for localized prostate cancer, we examined 488 LDR-BT and 269 IG-IMRT patients. IG-IMRT treated older and advanced disease with more hormonal therapy than LDR-BT, which excluded T3b–T4 tumor and initial PSA > 50 ng/ml. The actuarial five-year biochemical failure-free survival rate was 88.7% and 96.7% (p = 0.0003) in IG-IMRT and LDR-BT, respectively; it was 88.2% (85.1% for IG-IMRT and 94.9% for LDR-BT, p = 0.0578) for the high-risk group, 95.2% (91.6% and 97.0%, p = 0.3361) for the intermediate IG-IMRT and 96.8% (95.7% and 97%, p = 0.8625) for the low-risk group. Inverse probability of treatment weighting (IPTW) involving propensity scores was used to reduce background selection bias. IPTW showed a statistically significant difference between LDR-BT and IG-IMRT in high risk (p = 0.0009) and high risk excluding T3-4/initial PSA > 50 ng/ml group (p = 0.0073). IG-IMRT showed more gastrointestinal toxicity (p = 0.0023) and less genitourinary toxicity (p < 0.0001) than LDR-BT. LDR-BT and IG-IMRT showed equivocal outcome in low- and intermediate-risk groups. For selected high-risk patients, LDR-BT showed more potential to improve PSA control rate than IG-IMRT.

Intensity-modulated radiotherapy for prostate cancer

Radiation therapy (RT) is a curative treatment modality for localized prostate cancer. Over the past two decades, advances in technology and imaging have considerably changed RT in prostate cancer treatment. Treatment has evolved from 2-dimensional (2D) planning using X-ray fields based on pelvic bony landmarks to 3-dimensional (3D) conformal RT (CRT) which uses computed tomography (CT) based planning. Despite improvements with 3D-CRT, dose distributions often remained suboptimal with portions of the rectum and bladder receiving unacceptably high doses. In more recent years, intensity-modulated radiation therapy (IMRT) has become the standard of care to deliver external beam RT. IMRT uses multiple radiation beams of different shapes and intensities delivered from a wide range of angles to ‘paint’ the radiation dose onto the tumor. IMRT allows for a higher dose of radiation to be delivered to the prostate while reducing dose to surrounding organs. Multiple clinical trials have demonstrated improved cancer outcomes with dose escalation, but toxicities using 3D-CRT and escalated doses have been problematic. IMRT is a method to deliver dose escalated RT with more conformal dose distributions than 3D-CRT and has been associated with improved toxicity profiles. IMRT also appears to be the safest method to deliver hypofractionated RT and pelvic lymph node radiation. The purpose of this review is to summarize the technical aspects of IMRT planning and delivery, and to review the literature supporting the use of IMRT for prostate cancer.

Radiotherapy for prostate cancer - Does daily image guidance with tighter margins improve patient reported outcomes compared to weekly orthogonal verified irradiation? Results from a randomized controlled trial

BACKGROUND

Novel cancer drugs are subject to strict scientific evaluation of safety and efficacy and usually undergo a cost effectiveness analysis before approval for use in clinical practice. For new techniques in radiotherapy (RT) such as image-guided radiotherapy (IGRT), this is often not the case. We performed a randomized controlled trial to compare daily cone beam computer tomography (CBCT) IGRT with reduced planning target volume (PTV) margins vs weekly orthogonal portal imaging with conventional PTV margins. The primary aim of the study was to investigate the effect of two different image guidance techniques on patient reported outcome (PRO) using early side effects as proxy outcome of late rectal side effects in patients receiving curative RT for prostate cancer.

METHODS

This open label, phase 3 trial conducted at two RT centers in Norway enrolled men aged 18 years or older with previously untreated histologically proven intermediate or high-risk adenocarcinoma of the prostate. Patients eligible for radical RT received it after 3 months of total androgen blockage and were randomly assigned to 78 Gy in 39 fractions guided either by weekly offline orthogonal portal imaging (15 mm margins to PTV) or by daily online CBCT IGRT (7 mm margins to PTV). Based on previous results indicating that acute rectal side effects are a valid proxy outcome for late rectal side effects, the primary outcome was acute rectal toxicity at end of RT as evaluated by rectal bother scale (five of the items from PRO's QUFW94). The RIC-trial is registered with ClinicalTrials.gov, number NCT01550237.

FINDINGS

Between October 2012 and June 2015, 257 patients were randomly assigned to weekly offline portal imaging (n = 129) or daily online CBCT IGRT (n = 128). Out of 250 evaluable patients, 96% completed PROs at baseline and 97% at end of RT. Baseline analyses demonstrated balance between groups for baseline characteristics as well as for PROs. In general, patients reported a small degree of side effects at end of RT, and there was no difference between groups for primary outcome (rectal bother scale of QUFW94 1.871 vs 1.884, p = 0.804). In addition, there were no significant differences between groups for any other gastrointestinal or urinary symptom as reported by QUFW94. Health related quality of life analyses (EORTC QLQ 30) demonstrated no differences between groups.

INTERPRETATION

In radical RT for prostate cancer, daily CBCT IGRT with reduced PTV margins demonstrated no advantage with respect to patient reported side effects at end of RT as compared to weekly orthogonal offline portal imaging with standard PTV margins.

Treatment outcomes and late toxicities of intensity-modulated radiation therapy for 1091 Japanese patients with localized prostate cancer

AIM

This study aimed to evaluate the treatment result of intensity-modulated radiation therapy (IMRT) in a large number of Japanese patients with prostate cancer.

BACKGROUND

A total of 1091 patients with localized prostate cancer were recruited between March 2006 and July 2014. The patients were stratified into low- (n = 205 [18.8%]), intermediate- (n = 450 [41.2%]), high- (n = 345 [31.6%]), and very high-risk (n = 91 [8.3%]) groups according to the National Comprehensive Cancer Network classification. All patients were irradiated via IMRT at a dose of 74-78 Gy with or without androgen-deprivation therapy. The mean follow-up period was 50 months (range, 2-120 months).

RESULTS

The biochemical failure-free rate (BFFR), the clinical failure-free rate, and the overall survival rate at the 5-year follow-up for all patients was 91.3%, 96.2%, and 99.1%, respectively. In univariate analysis, the prostate-specific antigen (PSA) levels (≤20 vs. >20 ng/ml) were significantly correlated with BFFR. A trend toward higher BFFR was noted in patients with a Gleason score (GS) of ≤7 than in patients with GS ≥8. In multivariate analysis, only PSA (≤20 vs. >20 ng/ml) was significantly correlated with BFFR. The cumulative incidence rate of gastrointestinal and genitourinary toxicity (≥grade 2) at the 5-year follow-up was 11.4% and 4.3%, respectively.

CONCLUSIONS

The findings of this study indicate that IMRT is well tolerated and is associated with both good long-term tumor control and excellent outcomes in patients with localized prostate cancer.

Managing an Older Adult with Cancer: Considerations for Radiation Oncologists

Older adults with cancer present a unique set of management complexities for oncologists and radiation oncologists. Prognosis and resilience to cancer treatments are notably dependent on the presence or risk of "geriatric syndromes," in addition to cancer stage and histology. Recognition, proper evaluation, and management of these conditions in conjunction with management of the cancer itself are critical and can be accomplished by utilization of various geriatric assessment tools. Here we review principles of the geriatric assessment, common geriatric syndromes, and application of these concepts to multidisciplinary oncologic treatment. Older patients may experience toxicities related to treatments that impact treatment effectiveness, quality of life, treatment-related mortality, and treatment compliance. Treatment-related burdens from radiotherapy are increasingly important considerations and include procedural demands, travel, costs, and temporary or permanent loss of functional independence. An overall approach to delivering radiotherapy to an older cancer patient requires a comprehensive assessment of both physical and nonphysical factors that may impact treatment outcome. Patient and family-centered communication is also an important part of developing a shared understanding of illness and reasonable expectations of treatment.

Does intensity-modulated radiation therapy (IMRT) alter prostate size? Magnetic resonance imaging evaluation of patients undergoing IMRT alone

AIM

To assess the changes in prostate size in patients with prostate cancer undergoing intensity-modulated radiation therapy (IMRT).

BACKGROUND

The effect of size change produced by IMRT is not well known.

MATERIALS AND METHODS

We enrolled 72 patients who received IMRT alone without androgen-deprivation therapy and underwent magnetic resonance imaging (MRI) examination before and after IMRT. The diameter of the entire prostate in the anterior-posterior (P-AP) and left-right (P-LR) directions was measured. The transitional zone diameter in the anterior-posterior (T-AP) and left-right (T-LR) directions was also measured.

RESULTS

The average relative P-AP values at 3, 6, 12, 24, and 36 months after IMRT compared to the pre-IMRT value were 0.94, 0.90, 0.89, 0.89, and 0.90, respectively; the average relative P-LR values were 0.93, 0.92, 0.91, 0.91, and 0.90, respectively. The average P-AP and P-LR decreased by approximately 10% during the 12 months post-IMRT, and remained unchanged thereafter. The average relative T-AP values at 3, 6, 12, 24, and 36 months after IMRT compared to the pre-IMRT value were 0.93, 0.88, 0.91, 0.87, and 0.89, respectively; the average relative T-LR values were 0.96, 0.90, 0.91, 0.87, and 0.88, respectively. The average T-AP and T-LR also decreased by approximately 10% during the 12 months post-IMRT, and remained unchanged thereafter. At 12 months after IMRT, the average relative T-AP was significantly lower in patients with recurrence than in those without recurrence.

CONCLUSIONS

The average prostate diameter decreased by approximately 10% during the 12 months after IMRT; thereafter remained unchanged.

Local tumor control and DNA-PK activity of peripheral blood lymphocytes in prostate cancer patients receiving radiotherapy

Repair of DNA damage is critical for genomic stability, and DNA-dependent protein kinase (DNA-PK) has an important role in repairing double-strand breaks. We examined whether the DNA-PK activity of peripheral blood lymphocytes (PBLs) was related to biochemical (prostate-specific antigen: PSA) relapse and radiation toxicity in prostate cancer patients who have received radiotherapy. A total of 69 patients with localized adenocarcinoma of the prostate participated in this study. Peripheral blood was collected 2 years or later after radiotherapy and centrifuged, then DNA-PK activity was measured by a filter binding assay. The high DNA-PK activity group had a significantly higher PSA relapse-free survival rate than the low DNA-PK activity group. The 10-year PSA relapse-free survival was 87.0% in the high DNA-PK activity group, whereas it was 52.7% in the low DNA-PK activity group. Multivariate analysis showed the Gleason score and the level of DNA-PK activity were significant predictors of PSA relapse after radiotherapy. In addition, the low DNA-PK activity group tended to have a higher incidence of Grade 1-2 urinary toxicity than the high DNA-PK activity group. Prostate cancer patients with low DNA-PK activity had a higher rate of PSA relapse and a higher incidence of urinary toxicity. DNA-PK activity in PBLs might be a useful marker for predicting PSA relapse and urinary toxicity, possibly contributing to personalized treatment of prostate cancer.

Statistical-learning strategies generate only modestly performing predictive models for urinary symptoms following external beam radiotherapy of the prostate: A comparison of conventional and machine-learning methods

PURPOSE

Given the paucity of available data concerning radiotherapy-induced urinary toxicity, it is important to ensure derivation of the most robust models with superior predictive performance. This work explores multiple statistical-learning strategies for prediction of urinary symptoms following external beam radiotherapy of the prostate.

METHODS

The performance of logistic regression, elastic-net, support-vector machine, random forest, neural network, and multivariate adaptive regression splines (MARS) to predict urinary symptoms was analyzed using data from 754 participants accrued by TROG03.04-RADAR. Predictive features included dose-surface data, comorbidities, and medication-intake. Four symptoms were analyzed: dysuria, haematuria, incontinence, and frequency, each with three definitions (grade ≥ 1, grade ≥ 2 and longitudinal) with event rate between 2.3% and 76.1%. Repeated cross-validations producing matched models were implemented. A synthetic minority oversampling technique was utilized in endpoints with rare events. Parameter optimization was performed on the training data. Area under the receiver operating characteristic curve (AUROC) was used to compare performance using sample size to detect differences of ≥0.05 at the 95% confidence level.

RESULTS

Logistic regression, elastic-net, random forest, MARS, and support-vector machine were the highest-performing statistical-learning strategies in 3, 3, 3, 2, and 1 endpoints, respectively. Logistic regression, MARS, elastic-net, random forest, neural network, and support-vector machine were the best, or were not significantly worse than the best, in 7, 7, 5, 5, 3, and 1 endpoints. The best-performing statistical model was for dysuria grade ≥ 1 with AUROC ± standard deviation of 0.649 ± 0.074 using MARS. For longitudinal frequency and dysuria grade ≥ 1, all strategies produced AUROC>0.6 while all haematuria endpoints and longitudinal incontinence models produced AUROC<0.6.

CONCLUSIONS

Logistic regression and MARS were most likely to be the best-performing strategy for the prediction of urinary symptoms with elastic-net and random forest producing competitive results. The predictive power of the models was modest and endpoint-dependent. New features, including spatial dose maps, may be necessary to achieve better models.

Late Side Effects After Image Guided Intensity Modulated Radiation Therapy Compared to 3D-Conformal Radiation Therapy for Prostate Cancer: Results From 2 Prospective Cohorts

PURPOSE

Technical developments in the field of external beam radiation therapy (RT) enabled the clinical introduction of image guided intensity modulated radiation therapy (IG-IMRT), which improved target conformity and allowed reduction of safety margins. Whether this had an impact on late toxicity levels compared to previously applied three-dimensional conformal radiation therapy (3D-CRT) is currently unknown. We analyzed late side effects after treatment with IG-IMRT or 3D-CRT, evaluating 2 prospective cohorts of men treated for localized prostate cancer to investigate the hypothesized reductions in toxicity.

METHODS AND MATERIALS

Patients treated with 3D-CRT (n=189) or IG-IMRT (n=242) to 78 Gy in 39 fractions were recruited from 2 Dutch randomized trials with identical toxicity scoring protocols. Late toxicity (>90 days after treatment) was derived from self-assessment questionnaires and case report forms, according to Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer (RTOG-EORTC) scoring criteria. Grade ≥2 endpoints included gastrointestinal (GI) rectal bleeding, increased stool frequency, discomfort, rectal incontinence, proctitis, and genitourinary (GU) obstruction, increased urinary frequency, nocturia, urinary incontinence, and dysuria. The Cox proportional hazards regression model was used to compare grade ≥2 toxicities between both techniques, adjusting for other modifying factors.

RESULTS

The 5-year cumulative incidence of grade ≥2 GI toxicity was 24.9% for IG-IMRT and 37.6% following 3D-CRT (adjusted hazard ratio [HR]: 0.59, P=.005), with significant reductions in proctitis (HR: 0.37, P=.047) and increased stool frequency (HR: 0.23, P<.001). GU grade ≥2 toxicity levels at 5 years were comparable with 46.2% and 36.4% following IG-IMRT and 3D-CRT, respectively (adjusted HR: 1.19, P=.33). Other strong predictors (P<.01) of grade ≥2 late toxicity were baseline complaints, acute toxicity, and age.

CONCLUSIONS

Treatment with IG-IMRT reduced the risk of late grade ≥2 complications, whereas GU toxicities remained comparable. This clinically relevant observation demonstrates that IMRT and image-guidance should therefore be the preferred treatment option, provided that margin reduction is implemented with caution.

International prostate symptom score (IPSS) change and changing factor in intensity-modulated radiotherapy combined with androgen deprivation therapy for prostate cancer

The purposes of this study on prostate cancer are to demonstrate the time course of International Prostate Symptom Score (IPSS) after intensity-modulated radiation therapy (IMRT) combined with androgen deprivation therapy (ADT) and to examine the factor associated with the IPSS change. This study included 216 patients treated with IMRT between 2006 and 2010. Patients were evaluated in three groups according to baseline IPSS as defined by the American Urological Association classification, where IPSSs of 0 to 7, 8 to 19, and 20 to 35 represent mild (n = 124), moderate (n = 70), and severe (n = 22) symptom groups, respectively. The average IPSSs ± standard deviation at baseline vs. those at 24 months after IMRT were 3.5 ± 2.1 vs. 5.1 ± 3.6 in the mild group (P < 0.001), 12.6 ± 3.4 vs. 10.0 ± 6.0 in the moderate group (P = 0.0015), and 23.8 ± 2.9 vs. 14.4 ± 9.1 in the severe group (P < 0.001). Among factors of patient and treatment characteristics, age, IPSS classification, pretreatment GU medications, and positive biopsy rates were associated with the IPSS difference between baseline and 24 months (P = 0.023, < 0.001, 0.044, and 0.028, respectively). In conclusion, patients with moderate to severe urinary symptoms can exhibit improvement in urinary function after IMRT, whereas patients with mild symptoms may have slightly worsened functions. Age, baseline IPSS, GU medications, and tumor burden in the prostate can have an effect on the IPSS changes.

Clinical outcomes of helical tomotherapy for super-elderly patients with localized and locally advanced prostate cancer: comparison with patients under 80 years of age

We investigated the clinical outcomes of helical tomotherapy in 23 patients aged ≥80 years with localized and locally advanced prostate cancer and compared the results with data from 171 patients under 80 years. All patients received helical tomotherapy in our hospital between September 2009 and October 2012. The median follow-up periods were 35 months in the aged group and 34 months in the younger group. The median prescribed dose in helical tomotherapy was 78 Gy in 39 fractions (range, 72-78 Gy). The 3-year overall survival and biochemical relapse-free rates were 92% and 96% in the aged group and 99.4% and 97.3% in the younger group, respectively. There was no significant difference between the two groups in the biochemical relapse-free rates. The 3-year cumulative incidences of late Grade 2 or higher rectal toxicity and urinary toxicity were 13% and 4.8% in the aged group and 7.0% and 1.2% in the younger group, respectively. There was no significant difference between the aged group and the younger group in the cumulative incidence rates of rectal toxicity or urinary toxicity. No patients exhibited Grade 4 or higher toxicity, and all patients improved with conservative therapy. Helical tomotherapy in super-elderly patients with localized and locally advanced prostate cancer had good biochemical control rates without severe late toxicity. Definitive helical tomotherapy may be the treatment of choice for patients with localized and locally advanced prostate cancer, even in those older than 80 years of age.

Prediction of gastrointestinal toxicity after external beam radiotherapy for localized prostate cancer

Background

Gastrointestinal (GI) toxicity is a common effect following radiation therapy (RT) for prostate cancer. Purpose of the present work is to compare two Normal Tissue Complication Probability (NTCP) modelling approaches for prediction of late radio-induced GI toxicity after prostate external beam radiotherapy.

Methods

The study includes 84 prostate cancer patients evaluated for late rectal toxicity after 3D conformal radiotherapy. Median age was 72 years (range 53-85). All patients received a total dose of 76 Gy to the prostate gland with daily fractions of 2 Gy. The acute and late radio-induced GI complications were classified according to the RTOG/EORTC scoring system. Rectum dose-volume histograms were extracted for Lyman-Kutcher-Burman (LKB) NTCP model fitting using Maximum Likelihood Estimation. The bootstrap method was employed to test the fit robustness. The area under the receiver operating characteristic curve (AUC) was used to evaluate the predictive power of the LKB and to compare it with a multivariate logistic NTCP model previously determined.

Results

At a median follow-up of 36 months, 42% (35/84) of patients experienced grade 1-2 (G1-2) acute GI events while 25% (21/84) of patients developed G1-2 late GI events. The best-estimate of fitting parameters for LKB NTCP model for mild\moderate GI toxicity resulted to be: D₅₀ = 87.3 Gy, m = 0.37 and n = 0.10. Bootstrap result showed that the parameter fit was robust. The AUC values for the LKB and for the multivariate logistic models were 0.60 and 0.75, respectively.

Conclusions

We derived the parameters of the LKB model for mild\moderate GI toxicity prediction and we compared its performance with that of a data-driven multivariate model. Compared to LKB, the multivariate model confirmed a higher predictive power as showed by the AUC values.