High biologically effective dose radiation therapy using brachytherapy in combination with external beam radiotherapy for high-risk prostate cancer

ACR-ABS-ASTRO Practice Parameter for Transperineal Permanent Brachytherapy of Prostate Cancer

AIM/OBJECTIVES/BACKGROUND

The American College of Radiology (ACR), American Brachytherapy Society (ABS), and American Society for Radiation Oncology (ASTRO) have jointly developed the following practice parameter for transperineal permanent brachytherapy of prostate cancer. Transperineal permanent brachytherapy of prostate cancer is the interstitial implantation of low-dose rate radioactive seeds into the prostate gland for the purpose of treating localized prostate cancer.

METHODS

This practice parameter was developed according to the process described under the heading The Process for Developing ACR Practice Parameters and Technical Standards on the ACR website (https://www.acr.org/Clinical-Resources/Practice-Parameters-and-Technical-Standards) by the Committee on Practice Parameters-Radiation Oncology of the Commission on Radiation Oncology, in collaboration with ABS and ASTRO.

RESULTS

This practice parameter provides a framework for the appropriate use of low-dose rate brachytherapy in the treatment of prostate cancer either as monotherapy or as part of a treatment regimen combined with external-beam radiation therapy. The practice parameter defines the qualifications and responsibilities of all involved radiation oncology personnel, including the radiation oncologist, medical physicist, dosimetrist, radiation therapist, and nursing staff. Patient selection criteria and the utilization of supplemental therapies such as external-beam radiation therapy and androgen deprivation therapy are discussed. The logistics of the implant procedure, postimplant dosimetry assessment, and best practices with regard to safety and quality control are presented.

CONCLUSIONS

Adherence to established standards can help to ensure that permanent prostate brachytherapy is delivered in a safe and efficacious manner.

Tri‐modality therapy with i‐125 brachytherapy, external beam radiation therapy, and short‐term hormone therapy for high‐risk prostate cancer after holmium laser enucleation of the prostate

Introduction

We present tri‐modality therapy with i‐125 brachytherapy for high‐risk prostate cancer after holmium laser enucleation of the prostate.

Case presentation

A 75‐year‐old man had visited our hospital with complaints of dysuria. Holmium laser enucleation of the prostate was performed for benign prostatic hyperplasia. The resected histopathological prostate tissue showed malignancy (Gleason score: 3 + 3 = 6). Two years thereafter, Gleason score progressed (4 + 5 = 9) concomitantly with increased prostate‐specific antigen levels. Therefore, tri‐modality therapy, including brachytherapy, was applied. Combined androgen blockade therapy was conducted over a 9‐month period. One month after brachytherapy, external beam radiation was performed.

Conclusion

Brachytherapy following transurethral prostate surgery is relatively contraindicated because of increased adverse urethral event frequency and seed placement difficulties. A tri‐modality therapy, including brachytherapy, was implemented without any major problems in this patient with high‐risk prostate cancer after holmium laser enucleation of the prostate, following which he had a favorable prognosis without recurrence for 6 years.

Treatment Strategies for High-Risk Localized and Locally Advanced and Oligometastatic Prostate Cancer

Simple Summary

The definitions of locally advanced and oligometastatic prostate cancer are ambiguous, and there are no standard treatments for these. Although multidisciplinary treatment combining systemic and local treatment may be effective, there are many unresolved issues such as the choice of local treatment, use of new endocrine agents and chemotherapy, and selection of optimal patients. The present article discusses the definitions, diagnoses, and treatment of very high-risk prostate cancer and oligometastatic prostate cancer.

Abstract

Despite the significant advances in the treatment of high-risk prostate cancer, patients with very high-risk features such as being locally advanced (clinical stage T3–4 or minimal nodal involvement), having a high Gleason pattern, or with oligometastasis may still have a poor prognosis despite aggressive treatment. Multidisciplinary treatment with both local and systemic therapies is thought to be effective, however, unfortunately, there is still no standard treatment. However, in recent years, local definitive therapy using a combination of radiotherapy and androgen deprivation is being supported by several randomized clinical trials. This study reviews the current literature with a focus on the definition of very high-risk prostate cancer, the role of modern imaging, and its treatment options.

Ten-step method of high-dose LDR 125 I brachytherapy for intermediate-risk prostate cancer

Dose escalation is key for improved outcomes in intermediate‐risk prostate cancer, including unfavorable intermediate‐risk (UIR) cases. This educational report is designed to provide information about our quality high‐dose ¹²⁵I seed implantation monotherapy technique in which a biologically effective dose (BED) ≧ 200 Gy is applied for treatment of intermediate‐risk prostate cancer. This protocol is named the “Ten‐step Method,” where the rationale and principle of the method are based on the following four goals: (1) The entire prostate should be covered by the prescription isodose distribution with a sufficient margin from the prostatic capsule, achieving high D90 and V100 values by ¹²⁵I seed implantation. (2) The high‐dose cloud (240 Gy) should not invade the urethra or rectum. (3) In order to achieve goals (1) and (2), make the high‐dose cloud intentionally along the periphery (bilateral wall to anterior wall) away from the urethra and rectum. (4) In order to achieve goal (3), seeds at the periphery, except those anterior to the rectal wall, should be placed just 1mm inside the capsule. The data obtained from a total of 137 patients with intermediate‐risk prostate cancer treated with low‐dose‐rate (LDR) monotherapy are shown. The dosimetry parameters were monitored at 1 month after seed implantation by using CT and MRI fusion guidance. The data at 1 month after LDR were: Average D90, BED, and V100 of ¹²⁵I LDR monotherapy were 194.1 Gy, 207.3 Gy, and 99%, respectively. This ten‐step method was reproducible in 137 patients with intermediate‐risk prostate cancer, allowing administration of high‐dose monotherapy with excellent clinical outcomes.

Radiation treatment planning study to investigate feasibility of delivering Immunotherapy in Combination with Ablative Radiosurgery to Ultra-High DoSes (ICARUS)

PURPOSE

Immune checkpoint inhibitors improve survival in metastatic diseases for some cancers. Multisite SBRT with pembrolizumab (SBRT + Pembro) was shown to be safe with promising local control using biologically effective doses (BEDs) = 95-120 Gy. Increased BED may improve response rate; however, SBRT doses are limited by surrounding organs at risk (OARs). The purpose of this work was to develop and validate methods for safe delivery of ultra-high doses of radiation (BED₁₀  > 300) to be used in future clinical trials.

METHODS AND MATERIALS

The radiation plans from 15 patients enrolled on a phase I trial of SBRT + pembro were reanalyzed. Metastatic disease sites included liver (8/15), inguinal region (1/15), pelvis (2/15), lung (1/15), abdomen (1/15), spleen (1/15), and groin (1/15). Gross tumor volumes (GTVs) ranged from 80 to 708 cc. Following the same methodology used in the Phase I trial on which these patients were treated, GTVs > 65 cc were contracted to a 65 cc subvolume (SubGTV) resulting in only a portion of the GTV receiving prescription dose. Volumetric modulated arc therapy (VMAT) was used to plan treatments BED₁₀  = 360 Gy. Plans utilizing both 6FFF and 10FFF beams were compared to clinical plans delivering BED₁₀  = 112.50 Gy. The target primary goal was V100% > 95% with a secondary goal of V70% > 99% and OAR objectives per the trial. To demonstrate feasibility, plans were delivered to a diode array phantom and evaluated for fidelity using gamma analysis.

RESULTS

All 30 plans met the secondary coverage goal and satisfied all OAR constraints. The primary goal was achieved in 12/15 of the 6FFF plans and 13/15 of the 10FFF plans. Average gamma analysis passing rate using criteria of 3% dose difference and 3, 2, and 1 mm were 99.1  ±  1.0%, 98.5  ±  1.6%, and 95.1  ±  3.8%, respectively.

CONCLUSION

Novel VMAT planning approaches with clinical treatment planning software and linear accelerators prove capable of delivering radiation doses in excess of 360 Gy BED₁₀ to tumor subvolumes, while maintaining safe OAR doses.

Prostate cancer with nodular bladder invasion (stage T4N1) cured by low-dose-rate brachytherapy with seminal vesicle implantation in combination with external beam radiotherapy of biologically effective dose ≥ 220 Gy: a case report

Purpose

Prostate cancer with nodular bladder invasion (stage T4 prostate cancer) is an extremely difficult clinical entity to achieve complete cure. So far, there has been no clear report demonstrating complete cure of prostate cancer with nodular bladder invasion, stage T4 prostate cancer.

Case presentation

In this case report, the author presents a 55-year-old man with a diagnosis of advanced prostate cancer invading into the bladder wall with pelvic lymph node metastasis (T4N1M0 disease). The patient was treated with biologically effective dose (BED) ≥ 220 Gy of high-dose radiotherapy, using low-dose-rate (LDR) brachytherapy in combination with whole pelvis (WP) external beam radiotherapy (EBRT) and short-term androgen deprivation therapy (ADT): neo-adjuvant six months plus adjuvant six months ADT. There was no grade 2 genitourinary (GU) and gastrointestinal (GI) toxicity during follow-up. There was no evidence of hematuria, nor rectal bleeding in the follow-up. The patient stays healthy without biochemical failure and without bowel and urinary troubles at six years.

Conclusions

Along with previous outstanding data of BED ≥ 220 Gy LDR-based radiotherapy for high-risk and very high-risk prostate cancer patents, including pelvic lymph node metastasis, the present report, in which the patient was treated with BED ≥ 220 Gy of high-dose radiotherapy, LDR brachytherapy in combination with WP EBRT may be an optimal treatment for prostate cancer with nodular bladder invasion with lymph node metastasis (T4N1disease).

Clinical outcomes of low-dose-rate brachytherapy based radiotherapy for intermediate risk prostate cancer

Purpose

To monitor the outcomes for intermediate-risk prostate cancer patients treated with biologically effective dose (BED) ≥ 200 Gy radiotherapy using low-dose-rate (LDR) brachytherapy.

Material and methods

Between 2005 and 2016, a total of 397 patients with intermediate-risk prostate cancer were treated by LDR-based radiotherapy with a BED ≥ 200 Gy. Treatments consisted of LDR brachytherapy alone (177 cases) or LDR and external beam radiotherapy (EBRT) (220 cases). Short-term androgen deprivation therapy (ADT) was used in 186 patients (46.9%). The median follow-up period was 72 months (range 29-165 months). Dosimetric parameters and BED were studied in each case. The numbers of intermediate-risk features were: 163 patients with 1 intermediate-risk feature (41%), 169 patients with 2 intermediate-risk features (43%), and 65 patients with 3 intermediate-risk features (16%). A total of 145 cases were diagnosed as having primary Gleason pattern 4: Gleason score 4 + 3 (36.5%).

Results

Three patients developed biochemical failure, thus providing a 7-year actual biochemical failure-free survival (BFFS) rate of 99.1%. Biochemical failure was observed exclusively in cases with distant metastasis: two cases with lymph node metastasis and one case with bone metastasis, thus yielding a 7-year freedom from clinical failure (FFCF) rate of 99.1%. We observed eight deaths, but there was no death from prostate cancer, thus yielding a 7-year cause-specific survival (CSS) rate of 100%, and an overall survival (OS) rate of 98.4%.

Conclusions

This study highlights excellent outcomes for intermediate-risk prostate cancer patients, including unfavorable intermediate-risk cases, treated with BED ≥ 200 Gy radiotherapy using LDR brachytherapy. LDR alone with a BED of 200 Gy may be an optimal treatment for both favorable and unfavorable intermediate-risk prostate cancer patients, although a longer follow-up is mandatory to confirm the present findings.

Biochemical outcomes and predictive factors by risk group after permanent iodine-125 seed implantation: Prospective cohort study in 2,316 patients

PURPOSE

To evaluate the biochemical freedom from failure (bFFF) by risk group and treatment modality and the predictive factors of bFFF by risk group in patients with prostate cancer undergoing permanent seed implantation (PI) with or without external beam radiation therapy (EBRT) in a nationwide prospective cohort study (Japanese Prostate Cancer Outcome Study of Permanent Iodine-125 [I-125] Seed Implantation) in Japan during the first 2 years.

METHODS AND MATERIALS

The analyses included 2,316 participants in 42 institutions; bFFF was evaluated using the Phoenix definition and calculated using the Kaplan-Meier method, and the Cox proportional hazards model was used to identify the factors associated with bFFF.

RESULTS

Median followup period was 60.0 months. The 5-year bFFF rates in all patients, 1,028 low-risk patients, 1,114 intermediate-risk patients, and 133 high-risk patients were 93.6%, 94.9%, 92.7%, and 91.1%, respectively. The 5-year bFFF rates in the PI group and EBRT combination therapy group were 93.7% and 93.3%, respectively. In a multivariate analysis, younger age, higher Gleason score (GS), higher percent positive biopsies (%PB), and lower prostate V₁₀₀ (p = 0.0012, 0.0030, 0.0026, and 0.0368) in all patients; younger age, higher pretreatment prostate-specific antigen, and lower prostate V₁₀₀ (p = 0.0002, 0.0048, and 0.0012) in low-risk patients; higher GS, higher %PB, and no hormonal treatment (p = 0.0005, 0.0120, and 0.0022) in intermediate-risk patients; and higher GS and higher %PB (p = 0.0329 and 0.0120) in high-risk patients were significantly associated with bFFF.

CONCLUSIONS

PI with or without EBRT resulted in excellent short-term biochemical outcomes in all risk groups, especially in high-risk patients. Age, pretreatment prostate-specific antigen, and prostate V₁₀₀ in low-risk patients; GS, %PB, and hormonal treatment in intermediate-risk patients; and GS and %PB in high-risk patients were independently affected bFFF.

Plan reproducibility of intraoperatively custom-built linked seeds compared to loose seeds for prostate brachytherapy

Purpose

Few studies have compared the implant quality of linked and loose seeds for prostate brachytherapy. This study aimed to evaluate and compare plan reproducibility of intraoperatively built custom linked seeds and loose seeds for prostate brachytherapy.

Material and methods

Between December 2010 and March 2014, 76 localized prostate cancer patients received Iodine-125 brachytherapy with external beam radiotherapy. Linked and loose seeds were implanted in 39 and 37 patients, respectively. The primary endpoint was the mean (± standard deviation) of the absolute change in the minimum dose received by 90% of the prostate volume between intraoperative and post-operative planning (ΔD₉₀) to confirm plan reproducibility. Comparisons between the groups were evaluated using 2-sample t tests.

Results

The ΔD₉₀ values were 6.95 ± 11.6% and –0.41 ± 8.5% for the loose and linked seed groups, respectively (p < 0.01). The linked seed group showed decreased post-operative D₉₀ (118.8% vs. 127.2%), V₁₅₀ (51.7% vs. 66.7%), and RV₁₀₀ (0.44 ml vs. 0.61 ml) compared to the loose seed group (p < 0.01), whereas lung migration tended to be reduced (0% vs. 8%).

Conclusions

The plan reproducibility of the linked seed group was better than that of the loose seed group. Moreover, the linked seed group showed less migration and lower rectal dose.

Five-year effectiveness of low-dose-rate brachytherapy: comparisons with nomogram predictions in patients with non-metastatic prostate cancer presenting significant control of intra- and periprostatic disease

PURPOSE

To assess the effectiveness of low-dose-rate (LDR) brachytherapy in patients with localized prostate cancer and to compare the outcome with predictions from Kattan and Partin nomograms at 60 months after seed implantation.

MATERIAL AND METHODS

One thousand, one hundred and eighty-seven patients with localized prostate cancer at low-, intermediate-, or high-risk of progression received LDR brachytherapy using iodine-125 seeds with curative intent, applied as monotherapy or in combination with external beam radiation therapy (EBRT), and/or androgen deprivation therapy (ADT). At 60 months after seed implantation, data of 1,064 patients (1,058 alive + 6 who died of prostate cancer) were analyzed for biochemical progression-free survival (bPFS) based on prostate-specific antigen (PSA) levels using the Phoenix definition. Five-year bPFS probabilities were determined for various risk group classifications (d'Amico, Mt. Sinai, MSKCC/Seattle, NCCN). Outcomes were also compared to patient-individualized nomogram predictions of 5-year bPFS (Kattan 2002) and probability of organ-confined disease (Kattan 2002, Partin 2007).

RESULTS

Overall, 93.3% (993/1,064) of the patients were free of biochemical progression within 5 years, while the average 5-year bPFS probability according to the Kattan nomogram was significantly lower (85%, p < 0.001). Outcomes were significantly better than Kattan nomogram predictions in the subgroup of patients with monotherapy as well as in patients additionally treated with EBRT. Comparison of the overall outcome with nomogram predictions for organ-confined disease (Kattan nomogram: 50%; Partin nomogram: 65%) revealed a significant probability of LDR brachytherapy to destroy periprostatic tumor spread (p < 0.001) in all risk group constellations, even in high-risk patients.

CONCLUSIONS

The results indicate high effectiveness of LDR brachytherapy in all risk groups, significantly better than predicted with the Kattan nomogram in most subgroups. The significant superiority of LDR brachytherapy compared to nomogram predictions of organ-confined disease suggests that LDR brachytherapy effectively controls both intra- and periprostatic disease.

Hypofractionated external beam radiation therapy in combination with HDR boost for localized prostate cancer: patient reported quality of life outcomes

Purpose

There is limited data to support the use of hypofractionated external beam radiation (HypoF) in combination with high-dose-rate brachytherapy (HDR). We report our quality of life (QOL) outcomes when treating intermediate and high-risk prostate cancer patients with external beam radiation (EBRT) plus HDR.

Material and methods

The charts of 54 patients with localized adenocarcinoma of the prostate treated with standard fractionation (SF) or HypoF EBRT plus HDR boost at a single institution between 2012 and 2015 were reviewed. All patients completed the American Urological Association Symptom Score (AUASS) and Expanded Prostate Index for Prostate Cancer - Clinical Practice (EPIC-CP) quality of life assessments prior to treatment and completed at least one follow-up survey. Linear mixed models were performed to test for significant changes and differences in each outcome over time.

Results

There was no significant difference in AUA score (p = 0.98), incontinence (urge) and urinary irritation/obstruction scores (p = 0.81 and p = 0.62, respectively), and bowel QOL (p = 0.97) between the two dosing groups over time or at any discrete time point. For both groups, AUA scores peaked at 0-2 months before improving. Likewise, sexual function, vitality score, and QOL scores were also not significantly different between the dose groups over time (p = 0.59, p = 0.37, and p = 0.71, respectively). All QOL categories, except sexual function, trended toward baseline with increasing time from intervention.

Conclusions

Our study suggests HypoF EBRT can be delivered in combination with HDR for patients with ntermediate-risk and high-risk adenocarcinoma of the prostate without increasing toxicity compared to SF with an HDR boost.

Predictive Factors for Prolonged Urination Disorder After Permanent 125I Brachytherapy for Localized Prostate Cancer

BACKGROUND

We assessed the change in LUTS after prostate brachytherapy to reveal factors for prolonged urination disorder.

MATERIALS AND METHODS

Four hundred and four patients received prostate brachytherapy at our institution and were followed-up for at least 2 years. We evaluated the correlation of mean IPSS changes and clinical factors. Using multivariate analysis, we also evaluated clinical factors with potential to delay IPSS resolution.

RESULTS

In cases with prostate volume more than 30 cm³, radiation dose to 90% of prostate volume (D90) more than 160 Gy, and radiation dose to 30% of the urethral volume (UD30) more than 240 Gy, mean IPSS levels were significantly higher, even 30 months after treatment. On multivariate analysis, baseline IPSS more than 8 points and D90 more than 160 Gy were significant predictors for delayed IPSS resolution.

CONCLUSION

Our data suggest that higher baseline IPSS and higher D90 were predictors for prolonged urination disorder.