Initial Report of NRG Oncology/RTOG 0232: A Phase 3 Study Comparing Combined External Beam Radiation and Transperineal Interstitial Permanent Brachytherapy With Brachytherapy Alone for Selected Patients With Intermediate-Risk Prostatic Carcinoma

Overview of Radiation Therapy in the Management of Localized and Metastatic Prostate Cancer

PURPOSE OF REVIEW

The goal is to describe the evolution of radiation therapy (RT) utilization in the management of localized and metastatic prostate cancer.

RECENT FINDINGS

Long term data for a variety of hypofractionated definitive RT dose-fractionation schemes has matured, allowing patients and providers many standard-of-care options to choose from. Post-prostatectomy, adjuvant RT has largely been replaced by an early salvage approach. Multiparametric MRI and PSMA PET have enabled increasingly targeted RT delivery to the prostate and oligometastatic tumors. Areas of active investigation include determining the value of proton beam therapy and perirectal spacers, and optimally incorporate genomic tumor profiling and next generation hormonal therapies with RT in the curative setting. The use of radiation therapy to treat prostate cancer is rapidly evolving. In the coming years, there will be continued improvements in a variety of areas to enhance the value of RT in multidisciplinary prostate cancer management.

Cs-131 prostate brachytherapy boost and effect of hydrogel rectal spacer on long-term patient-reported rectal bleeding and bowel quality of life

PURPOSE

This study evaluates long-term patient-reported bowel quality of life (QOL), rectal bleeding, and bleeding bother in patients with prostate cancer treated with external beam radiation therapy (EBRT) and Cesium-131 LDR brachytherapy (LDR-BT) boost with and without hydrogel rectal spacer.

METHODS AND MATERIALS

This is a retrospective analysis of prostate cancer patients treated between 2007 and 2022 with 45 Gy EBRT followed by 85 Gy Cs-131 LDR-BT boost with or without hydrogel rectal spacer. Expanded Prostate Cancer Index Composite (EPIC) QOL questionnaires pre-treatment and at each follow-up were collected. Patient-reported rectal bleeding occurring more than "rarely" and bother from rectal bleeding occurring more than a "very small problem" were deemed clinically significant. Fisher's exact test was used to test the association of rectal spacer use and the incidence of clinically significant rectal bleeding and bleeding bother. Paired samples t-test was used to analyze mean bowel scores at each time point.

RESULTS

Three hundred and forty-one patients were included in the analysis. The rectal spacer was used in 108 patients. Overall median follow-up was 48 months (IQR, 24-72), with a median follow-up of 24 months (IQR, 12-37.5) for the hydrogel group and 60 months (IQR, 36-84) for the non-hydrogel group. EPIC questionnaire response rates at median follow-up were 33% and 37% for the hydrogel and non-hydrogel groups, respectively. A clinically significant decrease in mean bowel domain scores was seen in the bowel bother domain at 6 and 12 months for patients who did not receive a rectal spacer. At the last follow-up of 60 months, the prevalence of clinically significant rectal bleeding and bleeding bother were 2.2% and 2.2%, respectively. The cumulative incidence of clinically significant long-term rectal bleeding was 2.8% and 18.9% in the hydrogel group and non-hydrogel group, respectively (Fisher's exact test, p < 0.0001). The cumulative incidence of clinically significant long-term bowel bother was 4.6% and 19.7% in the hydrogel group and non-hydrogel group, respectively (Fisher's exact test, p < 0.001).

CONCLUSIONS

Use of hydrogel rectal spacer with EBRT and Cs-131 LDR-BT boost was significantly associated with a lower incidence of patient-reported rectal bleeding and bother from rectal bleeding, and better long-term bowel QOL. Cumulative incidence was 2.8% (hydrogel group) versus 18.9% (non-hydrogel group) and 4.6% (hydrogel group) versus 19.7% (non-hydrogel group) for clinically significant long-term rectal bleeding and long-term bleeding bother, respectively.

The oncologic and safety outcomes of low-dose-rate brachytherapy for the treatment of prostate cancer

Around 40 years have passed since a modern low-dose-rate (LDR) brachytherapy for prostate cancer was introduced. LDR brachytherapy has become one of the definitive treatment options besides radical prostatectomy (RP) and external beam radiation therapy (EBRT). LDR brachytherapy has several advantages over EBRT such as a higher prescribed dose to the prostate gland while avoiding unnecessary irradiation of organs at risk, a precipitous dose gradient, a brief treatment time, and a short hospital stay. Previous reports revealed that the long-term oncologic outcomes of LDR brachytherapy are superior to those of EBRT. The oncologic outcomes of low- to intermediate-risk patients are equivalent to those of RP using the recurrence definition of surgery of prostate specific antigen (PSA) >0.2 ng/mL, while the oncologic outcomes of LDR brachytherapy as tri-modality (combined EBRT and androgen deprivation therapy) for high-risk patients is superior to that of RP using the recurrence definition of surgery. In respect of toxicity, urinary disorders such as urgency and frequency are often observed after the acute phase of treatment, but these events usually resolve, while the quality of life of urinary continence is well preserved for a long time. Erectile function decreases yearly, but is relatively preserved compared to RP. In conclusion, the most noteworthy strength of LDR brachytherapy for low- to intermediate-risk patients is the "brief treatment time" that provides long recurrence-free survival, while that for high-risk patients who received LDR brachytherapy (tri-modality) is "excellent disease control."

The Current Trend of Radiation Therapy for Patients with Localized Prostate Cancer

A recent approach to radiotherapy for prostate cancer is the administration of high doses of radiation to the prostate while minimizing the risk of side effects. Thus, image-guided radiotherapy utilizes advanced imaging techniques and is a feasible strategy for increasing the radiation dose. New radioactive particles are another approach to achieving high doses and safe procedures. Prostate brachytherapy is currently considered as a combination therapy. Spacers are useful to protect adjacent organs, specifically the rectum, from excessive radiation exposure.

Late Toxicities of Prostate Radiotherapy: Can We Further SMARTen Up the Therapeutic Index?

Radiotherapy is a mainstay treatment option for localized prostate cancer (PCa), with oncological outcomes similar to those with surgery. Standard-of-care radiotherapy approaches include brachytherapy, hypofractionated external beam radiotherapy (EBRT), and EBRT with brachytherapy boost. Given the long survival associated with PCa and these curative-intent radiotherapy approaches, late toxicity is a paramount consideration. In this narrative mini-review, we summarize late toxicities associated with standard-of-care radiotherapy approaches including stereotactic body radiotherapy, an advanced radiotherapy technique supported by accumulating evidence. We also discuss stereotactic magnetic resonance imaging-guided adaptive radiotherapy (SMART), an emerging paradigm that may further improve the therapeutic index of radiotherapy and reduce late toxicities. PATIENT SUMMARY: This mini-review summarizes late side effects associated with standard and advanced radiotherapy techniques for localized prostate cancer. We also discuss a new radiotherapy approach called SMART that may reduce late side effects and increase treatment effectiveness.

Long-term oncologic outcomes of low dose-rate brachytherapy compared to hypofractionated external beam radiotherapy for intermediate -risk prostate cancer

PURPOSE

To compare the long-term oncologic outcomes of intermediate risk (IR) prostate cancer (PCa) patients treated with low dose-rate brachytherapy (LDR-BT) or moderate hypofractionated external beam radiotherapy (HF-EBRT).

METHODS AND MATERIALS

Patients diagnosed with IR PCa and treated with LDR-BT or HF-EBRT between January 2005 and December 2013 were included. Brachytherapy treatment involved a transperineal implant of iodine-125 to a dose of 145 Gy to the PTV, while HF-EBRT was delivered using intensity modulated radiotherapy with 60 Gy in 20 fractions. The Phoenix ''nadir +2'' threshold was used to define biochemical relapse (BR). The cumulative incidence function (CIF) of BR and metastases was reported for each group and compared using the Gray's test to account for the competing risk of death. The Kaplan-Meier (KM) method was used to estimate overall survival (OS) and prostate cancer specific survival (PCSS). Univariate (UVA) and multivariable (MVA) analysis of the CIF of BR and metastases were performed. A 2-tailed p-value ≤ 0.05 was considered statistically significant.

RESULTS

Overall, 122 and 124 patients were treated with LDR-BT and HF-EBRT respectively. Median follow-up was 95 months [interquartile range (IQR): 79-118] in the LDR-BT group and 96 months (IQR: 63-123) in the HF-EBRT group. BR was observed in 5 patients treated with LDR-BT and 34 treated with HF-EBRT. At 60 and 90 months, the CIF of BR was 0.9% and 3.5% in the LDR-BT group vs. 16.6% and 23.7% in the HF-EBRT (p < 0.001). The CIF of metastases at 90 and 108 months, was 0% and 1.6% vs. 3.4% and 9.1% in the LDR-BT and HF-EBRT groups (p = 0.003), respectively. At the last follow-up, 3 patients treated with HF-EBRT died from their cancer [PCSS of 97.5% at 8 years and none died in the LDR-BT group (p = 0.09). On UVA and MVA risk group and treatment modality were independently associated with CIF of BR. On UVA HF-EBRT and ISUP grade group 3 were associated with metastases.

CONCLUSION

LDR-BT was associated with higher biochemical and metastases control in our cohort when compared to moderately HF-EBRT. In the absence of a randomized trial, LDR-BT when feasible should be offered to patients with a life expectancy of >8 years.

A Contemporary Report of Low-Dose-Rate Brachytherapy for Prostate Cancer Using MRI for Risk Stratification: Disease Outcomes and Patient-Reported Quality of Life

PURPOSE

We examined a prospective consecutive cohort of low dose rate (LDR) brachytherapy for prostate cancer to evaluate the efficacy of monotherapy for unfavorable-intermediate risk (UIR) disease, and explore factors associated with toxicity and quality of life (QOL).

METHODS

149 men with prostate cancer, including 114 staged with MRI, received Iodine-125 brachytherapy alone (144-145 Gy) or following external beam radiation therapy (110 Gy; EBRT). Patient-reported QOL was assessed by the Expanded Prostate Index Composite (EPIC) survey, and genitourinary (GU) and gastrointestinal (GI) toxicity were prospectively recorded (CTC v4.0). Global QOL scores were assessed for decline greater than the minimum clinically important difference (MCID). Univariate analysis (UVA) was performed, with 30-day post-implant dosimetry covariates stratified into quartiles. Median follow-up was 63 mo.

RESULTS

Men with NCCN low (n = 42) or favorable-intermediate risk (n = 37) disease were treated with brachytherapy alone, while most with high-risk disease had combined EBRT (n = 17 of 18). Men with UIR disease (n = 52) were selected for monotherapy (n = 42) based on clinical factors and MRI findings. Freedom from biochemical failure-7 yr was 98%. Of 37 men with MRI treated with monotherapy for UIR disease, all 36 men without extraprostatic extension were controlled. Late Grade 2+/3+ toxicity occurred in 55/3% for GU and 8/2% for GI, respectively. Fifty men were sexually active at baseline and had 2 yr sexual data; 37 (74%) remained active at 2 yr. Global scores for urinary incontinence (UC), urinary irritation/obstruction (UIO), bowel function, and sexual function (SF) showed decreases greater than the MCID (p < 0.05) in UC at 2 mo, UIO at 2 and 6 mo, and SF at 2-24 mo, and >5 yr. Analysis did not reveal any significant associations with any examined rectal or urethral dosimetry for late toxicity or QOL.

CONCLUSION

Disease outcomes and patient-reported QOL support LDR brachytherapy, including monotherapy for UIR disease.

Comparative effectiveness of low-dose-rate brachytherapy with or without external beam radiotherapy in favorable and unfavorable intermediate-risk prostate cancer

We compared clinical outcomes associated with seed brachytherapy (SEED-BT) alone and SEED-BT plus external-beam radiotherapy (EBRT) for intermediate-risk prostate cancer using propensity score-matched analysis. From 2006 to 2011, 993 patients diagnosed with intermediate-risk were treated with either SEED-BT alone (n = 775) or SEED-BT plus EBRT (n = 158) at 3 tertiary hospitals. In the propensity score-matched analysis (102 pairs), median follow-up was 95 months (range 18–153 months). The 8-year biochemical recurrence-free rate (bRFR) was significantly better with SEED-BT alone than with combined radiotherapy (93.3% vs. 88.4%; HR 0.396; 95% CI 0.158–0.991). Grade 2 or greater late genitourinary toxicities were significantly fewer with SEED-BT alone than with combined radiotherapy (21.0% vs. 33.2%; HR 0.521; 95% CI 0.308–0.881). Similarly, grade 2 or greater late gastrointestinal toxicities were significantly fewer with SEED-BT alone (0% vs. 12.2%; HR 0.125; 95% CI 0.040–0.390). For the unfavorable intermediate-risk subgroups, SEED-BT alone yielded a significantly better bRFR than the combined radiotherapy (HR 0.325; 95% CI 0.115–0.915). SEED-BT alone might be a better disease-management plan than SEED-BT plus EBRT for intermediate-risk prostate cancer regardless of favorable and unfavorable characteristics.

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.

Stereotactic Radiation Therapy versus Brachytherapy: Relative Strengths of Two Highly Efficient Options for the Treatment of Localized Prostate Cancer

Stereotactic body radiation therapy (SBRT) has become a valid option for the treatment of low- and intermediate-risk prostate cancer. In randomized trials, it was found not inferior to conventionally fractionated external beam radiation therapy (EBRT). It also compares favorably to brachytherapy (BT) even if level 1 evidence is lacking. However, BT remains a strong competitor, especially for young patients, as series with 10-15 years of median follow-up have proven its efficacy over time. SBRT will thus have to confirm its effectiveness over the long-term as well. SBRT has the advantage over BT of less acute urinary toxicity and, more hypothetically, less sexual impairment. Data are limited regarding SBRT for high-risk disease while BT, as a boost after EBRT, has demonstrated superiority against EBRT alone in randomized trials. However, patients should be informed of significant urinary toxicity. SBRT is under investigation in strategies of treatment intensification such as combination of EBRT plus SBRT boost or focal dose escalation to the tumor site within the prostate. Our goal was to examine respective levels of evidence of SBRT and BT for the treatment of localized prostate cancer in terms of oncologic outcomes, toxicity and quality of life, and to discuss strategies of treatment intensification.

Direct comparison of low-dose-rate brachytherapy versus radical prostatectomy using the surgical definition of biochemical recurrence for patients with intermediate-risk prostate cancer

Background

We compared the oncological outcomes of patients who received seed brachytherapy (SEED-BT) with those who received radical prostatectomy (RP) for intermediate-risk prostate cancer.

Methods

Candidates were patients treated with either SEED-BT (n = 933) or RP (n = 334). One-to-one propensity score matching was performed to adjust the patients’ backgrounds. We compared the biochemical recurrence (BCR)-free rate using the Phoenix definition (prostate-specific antigen [PSA] nadir plus 2 ng/mL) for SEED-BT and the surgical definition (PSA cut-off value of 0.2 ng/mL) for RP. We also directly compared the BCR-free rates using the same PSA cut-off value of 0.2 ng/mL for both SEED-BT and RP.

Results

In the propensity score-matched analysis with 214 pairs, the median follow-up treatment was 96 months (range 1–158 months). Fifty-three patients (24.7%) were treated with combined SEED-BT and external-beam radiotherapy. Forty-three patients (20.0%) received salvage radiotherapy after RP. Comparing the BCR-free rate using the above definitions for SEED-BT and RP showed that SEED-BT yielded a significantly better 8-year BCR-free rate than did RP (87.4% vs. 74.3%, hazard ratio [HR] 0.420, 95% confidence interval [CI] 0.273–0.647). Comparing the 8-year BCR-free rate using the surgical definition for both treatments showed no significant difference between the two treatments (76.7% vs. 74.3%, HR 0.913, 95% CI 0.621–1.341). SEED-BT had a significantly better 8-year salvage hormonal therapy-free rate than did RP (92.0% vs. 85.6%, HR 0.528, 95% CI 0.296–0.942, P = 0.030). The 8-year metastasis-free survival rates (98.5% vs. 99.0%, HR 1.382, 95% CI 0.313–6.083, P = 0.668) and overall survival rates (91.9% vs. 94.6%, HR 1.353, 95% CI 0.690–2.650) did not significantly differ between the treatments.

Conclusions

The BCR-free rates did not significantly differ between patients treated with SEED-BT and those treated with RP for intermediate-risk prostate cancer even when they were directly compared using the surgical definition for BCR. SEED-BT and RP can be adequately compared for oncological outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-022-02046-x.

Clinical significance of unfavorable findings in intermediate-risk prostate cancer patients for predicting treatment outcomes after contemporary, dose-escalated multimodal radiotherapy

PURPOSE

Few studies have documented the long-term oncological outcomes of favorable and unfavorable intermediate-risk (IR) prostate cancer patients treated via contemporary high-dose irradiation. We analyzed the ultimate clinical outcomes of such patients using the current risk sub-stratification schema.

PATIENTS AND METHODS

We included 693 patients with localized IR prostate cancer treated via low-dose-rate brachytherapy (LDR-BT) with or without external beam radiation (EBRT) and with or without androgen-deprivation therapy (ADT) in a single institution. Treatment outcomes (biochemical recurrence-free survival [BCRFS] and clinical progression-free survival [CPFS]) were compared according to the numbers of unfavorable findings.

RESULTS

Out of the 693 IR patients, 292 (42.1%) exhibited favorable disease; the remaining 401 (57.9%) exhibited unfavorable disease. Compared with favorable IR status, unfavorable IR status was associated with shorter BCRFS and CPFS (p < 0.001 and p < 0.001, respectively). Patients with two to three unfavorable factors experienced the worst oncological outcomes (p < 0.001 and p < 0.001). Although patients with one or no unfavorable factors responded similarly to LDR-BT monotherapy, this treatment modality was insufficient for preventing biochemical and clinical progression in patients with multiple unfavorable findings.

CONCLUSION

Long-term treatment outcomes indicate that patients with IR disease scheduled for LDR-BT should undergo multimodal irradiation if they exhibit two or more unfavorable factors at diagnosis.

Influence of hydrogel spacer placement with prostate brachytherapy on rectal and urinary toxicity

OBJECTIVE

To determine the influence of rectal hydrogel spacer placement (HSP) on late rectal toxicity outcomes in prostate cancer patients treated with low-dose-rate (LDR) brachytherapy, with or without supplemental external beam radiotherapy (EBRT).

PATIENTS AND METHODS

A total of 224 patients underwent LDR brachytherapy with HSP, as monotherapy or combined with EBRT, between January 2016 and December 2019. Dosimetric variables reflecting the extent of rectal sparing and late rectal toxicity outcomes were evaluated. This spacer cohort was retrospectively compared to a similar patient group (n = 139) in whom HSP was not used.

RESULTS

Hydrogel spacer placement was associated with significantly reduced rectal doses for all dosimetric variables; the median percentage rectal dose to 1 cc of rectum and rectal dose to 2 cc of rectum of the spacer cohort were all significantly lower compared to the non-spacer cohort. The incidence rates of overall (any grade) and grade ≥2 rectal toxicity were lower in patients with HSP compared to patients who did not undergo HSP: 12% and 1.8% vs 31% and 5.8%, respectively. The 3-year cumulative incidence of overall rectal toxicity was significantly lower with HSP than without (15% vs 33%; P < 0.001), corresponding to an overall rectal toxicity reduction on univariable analysis (hazard ratio 0.45, 95% confidence interval 0.28-0.73; P = 0.001). In this patient cohort treated with prostate brachytherapy, none of the urethral dosimetric variables or the presence or absence of HSP was associated with late urinary toxicity.

CONCLUSION

Hydrogel rectal spacer placement is a safe procedure, associated with significantly reduced rectal dose. HSP translates to a decrease in overall late rectal toxicity in patients receiving dose-escalated brachytherapy-based procedures.

Case Report: Role of an Iodinated Rectal Hydrogel Spacer, SpaceOAR Vue™, in the Context of Low-Dose-Rate Prostate Brachytherapy, for Enhanced Post-Operative Contouring to Aid in Accurate Implant Evaluation and Dosimetry

We present a case series of 13 consecutive patients with prostate cancer treated with low-dose-rate (LDR) brachytherapy, utilizing SpaceOAR Vue™, the recent iodinated iteration of the SpaceOAR™ hydrogel rectal spacer. Low- and favorable intermediate-risk patients receiving monotherapy and unfavorable intermediate- and high-risk patients undergoing a brachytherapy boost were included. Permanent brachytherapy can result in subacute and late rectal toxicity, and precise contouring of the anterior rectal wall and posterior aspect of the prostate is essential for accurate dosimetry to confirm a safe implant. Clearly visible on non-contrast CT imaging, SpaceOAR Vue™ can substantially aid in post-implant contouring and analysis. Not previously described in the literature in the context of LDR brachytherapy, we demonstrate the added clinical benefit of placing a well-visualized rectal spacer.

Prostate cancer brachytherapy: SFRO guidelines 2021

Prostate brachytherapy techniques are described, concerning both permanent seed implant and high dose rate brachytherapy. The following guidelines are presented: brachytherapy indications, implant procedure for permanent low dose rate implants and high dose rate with source projector, as well as dose and dose-constraints objectives, immediate postoperative management, post-treatment evaluation, and long-term follow-up.

Treatment of intermediate-risk prostate cancer with Cs-131: Long-term results from a single institution

PURPOSE

To evaluate our institutional outcomes utilizing Cs-131 prostate brachytherapy (PB) for the intermediate-risk (IR) group of prostate cancer patients.

METHODS AND MATERIALS

We reviewed a prospectively collected database of men treated with Cs-131 PB between 2006 and 2019. Patients with less than 24-months follow-up were excluded. Patients were classified as IR if they had one of the following factors: Gleason Score 7, prostate specific antigen >10 but <20 ng/mL, or T2b-c on clinical exam. We defined unfavorable-IR (UIR) as having either Grade Group 3, >1 IR factors, or ≥50% positive core biopsies. The Kaplan-Meier method was used to estimate actuarial event-time probabilities for biochemical freedom from disease (BFD).

RESULTS

A total of 335 patients with a median follow-up of 70.1 months (IQR 48.3-106.3 months) were identified. Androgen deprivation therapy (ADT) was used in 7.2% of patients. Favorable-IR (FIR) patients were commonly treated with PB alone (91.8%). FIR patients who underwent PB alone had a 5-year BFD of 98.1%. UIR patients were commonly treated with external beam radiotherapy plus PB (61.2%). These patients had 5-year BFD of 91.1%. The 5-year BFD for UIR patients treated without ADT was 90.9%, whereas it was 95.0% among UIR patients treated with ADT (log-rank p = 0.83).

CONCLUSIONS

FIR patients have excellent outcomes when treated with PB alone. External beam radiotherapy plus PB is a reasonable treatment approach for UIR patients. Future studies may elucidate which IR patients would benefit from treatment intensification.

Low dose rate brachytherapy for primary treatment of localized prostate cancer: A systemic review and executive summary of an evidence-based consensus statement

PURPOSE

The purpose of this guideline is to present evidence-based consensus recommendations for low dose rate (LDR) permanent seed brachytherapy for the primary treatment of prostate cancer.

METHODS AND MATERIALS

The American Brachytherapy Society convened a task force for addressing key questions concerning ultrasound-based LDR prostate brachytherapy for the primary treatment of prostate cancer. A comprehensive literature search was conducted to identify prospective and multi-institutional retrospective studies involving LDR brachytherapy as monotherapy or boost in combination with external beam radiation therapy with or without adjuvant androgen deprivation therapy. Outcomes included disease control, toxicity, and quality of life.

RESULTS

LDR prostate brachytherapy monotherapy is an appropriate treatment option for low risk and favorable intermediate risk disease. LDR brachytherapy boost in combination with external beam radiation therapy is appropriate for unfavorable intermediate risk and high-risk disease. Androgen deprivation therapy is recommended in unfavorable intermediate risk and high-risk disease. Acceptable radionuclides for LDR brachytherapy include iodine-125, palladium-103, and cesium-131. Although brachytherapy monotherapy is associated with increased urinary obstructive and irritative symptoms that peak within the first 3 months after treatment, the median time toward symptom resolution is approximately 1 year for iodine-125 and 6 months for palladium-103. Such symptoms can be mitigated with short-term use of alpha blockers. Combination therapy is associated with worse urinary, bowel, and sexual symptoms than monotherapy. A prostate specific antigen <= 0.2 ng/mL at 4 years after LDR brachytherapy may be considered a biochemical definition of cure.

CONCLUSIONS

LDR brachytherapy is a convenient, effective, and well-tolerated treatment for prostate cancer.

The risk of death from prostate cancer in men with Gleason score 3+4 prostate cancer treated using brachytherapy with or without a short course of androgen deprivation therapy

OBJECTIVE

We evaluated whether intermediate-risk factors, in addition to age, were associated with risk of prostate cancer-specific mortality (PCSM) among men with Gleason 3+4 prostate cancer.

MATERIALS AND METHODS

We conducted a prospective cohort study of 1,920 men with Gleason 3+4 adenocarcinoma of the prostate who received brachytherapy (BT) or BT and a median of 4 months of androgen deprivation therapy (ADT). Separate multivariable Fine and Gray competing risks regression models among men treated with BT or BT and ADT were used to assess whether percentage of positive biopsies (PPB), cT2b-T2c stage, prostate-specific antigen (PSA) of 10.1-20.0 ng/ml, and age >70 years (median) were associated with risk of PCSM after adjustment for comorbidity.

RESULTS

After median follow-up of 7.8 years, 284 men (14.8%) had died (31 from prostate cancer). For BT alone, increasing PPB, PSA of 10.1-20.0 vs. 4.0-10.0 ng/mL, and age >70 vs. ≤70 were significantly associated with increased risk of PCSM (adjusted hazard ratio 1.015, 95% confidence interval 1.000-1.031, P = 0.048; 5.55, 2.01-15.29, P<0.001; and 3.66, 1.16-11.56, P = 0.03, respectively). The respective results for BT and ADT were 1.009, 0.987-1.031, P = 0.44; 4.17, 1.29-13.50, P = 0.02; and 3.74, 0.87-16.05, P = 0.08.

CONCLUSION

Among men with Gleason score 3+4 prostate cancer treated with BT, the risk of PCSM was elevated in those with PSA of 10.1-20.0 ng/mL and possibly age >70 years, despite the addition of ADT. Should these findings be validated in future studies, then advanced imaging and targeted biopsy of suspicious areas should be investigated in an effort to personalize treatment and minimize the risk of PCSM in these men.

Management of Lower Urinary Tract Symptoms after Prostate Radiation

PURPOSE OF REVIEW

To present urologists with guidance on how to approach and manage lower urinary tract symptoms (LUTS) in patients who have undergone radiation therapy (RT) for prostate cancer.

RECENT FINDINGS

There are few studies that specifically examine treatment approaches for LUTS in patients who have undergone prostate cancer RT. LUTS after prostate RT are unique when compared to de novo LUTS. Understanding these distinctions is important for urologists' practice as well as patients' quality of life. Discussion of the risks and management of post-RT LUTS should be included in the shared decision-making process when counseling patients on various treatment options for prostate cancer. Further studies evaluating treatments for storage and voiding symptoms after RT are needed to help guide future care.

Analysis of Patient-Reported Outcome Utilization Within National Clinical Trials Network Cooperative Group Radiation Oncology Trials Over the Past 2 Decades

PURPOSE

When treating cancer, both quantity and quality of life are valuable, though oncology trials have long placed greater emphasis on the former. The goal of this work was to evaluate how patient-reported outcomes (PROs) have been incorporated into radiation therapy trials within the National Clinical Trials Network over the last 2 decades to measure quality of life and to assess how PRO data have been disseminated in publications upon trial conclusion.

METHODS AND MATERIALS

This cross-sectional study analyzed the frequency of use of PROs in National Clinical Trials Network cooperative group radiation therapy phase 2 and 3 clinical trials over the past 2 decades. A literature review was performed to determine the publication outcomes of PRO data, including only trials that used PROs in their design and were mature enough to have published results.

RESULTS

Fifty-seven (56.4%) of the 101 trials included in this study included PROs in their design. Brain and head and neck trials demonstrated the largest proportional incorporation of PROs (81.8% and 76.9%, respectively), and thoracic and breast trials used the fewest (18.8% and 37.5%, respectively). The EQ-5D family of questionnaires was the most commonly used PROs, used in 22.8% of trials included. The literature review demonstrated a pattern of increased publication of PRO data alongside survival endpoints in manuscripts derived from these trials over time.

CONCLUSIONS

Though there is room for improvement, the field of radiation oncology has embraced the incorporation of PROs into multicenter, high-impact clinical trials over the past 2 decades and has increased its publication of this data alongside survival data from these trials.

Ablative Radiotherapy in Prostate Cancer: Stereotactic Body Radiotherapy and High Dose Rate Brachytherapy

Simple Summary

Radiation therapy is a standard of care treatment option for men with localized prostate cancer. Over the years, various radiation delivery modalities have contributed to the increased precision of radiation, employing radiobiological insights to shorten the overall treatment time with hypofractionation, while improving oncological control without increasing toxicities. Here, we discuss and compare two ablative radiation modalities, stereotactic body radiation therapy (SBRT) and high-dose-rate brachytherapy (HDRBT), in terms of oncological control, dose/fractionation and toxicities in men with localized prostate cancer. This review will highlight the levels of evidence available to support either modality as a monotherapy, will summarize safety and efficacy, help clinicians gain a deeper understanding of the safety and efficacy profiles of these two modalities, and highlight ongoing research efforts to address many unanswered questions regarding ablative prostate radiation.

Abstract

Prostate cancer (PCa) is the most common noncutaneous solid organ malignancy among men worldwide. Radiation therapy is a standard of care treatment option that has historically been delivered in the form of small daily doses of radiation over the span of multiple weeks. PCa appears to have a unique sensitivity to higher doses of radiation per fraction, rendering it susceptible to abbreviated forms of treatment. Stereotactic body radiation therapy (SBRT) and high-dose-rate brachytherapy (HDRBT) are both modern radiation modalities that allow the precise delivery of ablative doses of radiation to the prostate while maximally sparing sensitive surrounding normal structures. In this review, we highlight the evidence regarding the radiobiology, oncological outcomes, toxicity and dose/fractionation schemes of SBRT and HDRBT monotherapy in men with low-and intermediate-risk PCa.

Biochemical Control and Toxicity Outcomes of Stereotactic Body Radiation Therapy Versus Low-Dose-Rate Brachytherapy in the Treatment of Low- and Intermediate-Risk Prostate Cancer

PURPOSE

Low-dose-rate (LDR) brachytherapy and stereotactic body radiation therapy (SBRT) have both shown acceptable outcomes in the treatment of low- and intermediate-risk prostate cancer. Minimal data have been published directly comparing rates of biochemical control and toxicity with these 2 modalities. We hypothesize that LDR and SBRT will provide similar rates of biochemical control.

METHODS AND MATERIALS

All low- and intermediate-risk patients with prostate cancer treated definitively with SBRT or LDR between 2010 and 2018 were captured. Phoenix definition was used for biochemical failure. Independent t tests were used to compare baseline characteristics, and repeated measure analysis of variance test was used to compare American Urologic Association (AUA) and the Expanded Prostate Cancer Index Composite (EPIC) scores between treatment arms over time. Biochemical control was estimated using the Kaplan-Meier method. Differences in acute and late toxicity were assessed via Pearson χ².

RESULTS

In the study, 219 and 118 patients were treated with LDR and SBRT. Median follow-up was 4.3 years (interquartile range, 3.1-6.1). All patients treated with LDR received 125.0 Gy in a single fraction. SBRT consisted of 42.5 Gy in 5 fractions. Five-year biochemical control for LDR versus SBRT was 91.6% versus 97.6% (P = .108). LDR patients had a larger increase in mean AUA scores at 1 month (17.2 vs 10.3, P < .001) and 3 months posttreatment (14.0 vs 9.7, P < .001), and in mean EPIC scores at 1 month (15.7 vs 13.8, P < .001). There was no significant difference between LDR and SBRT in late grade 3 genitourinary toxicity (0.9% vs 2.5%, P = .238); however, LDR had lower rates of late grade 3 gastrointestinal toxicity (0.0% vs 2.5%, P = .018).

CONCLUSIONS

Our data show similar biochemical control and genitourinary toxicity rates at 5 years for both SBRT and LDR, with slightly higher gastrointestinal toxicity with SBRT and higher AUA and EPIC scores with LDR.

Utilization of multimodality therapy with primary radical prostatectomy versus radiation therapy for Gleason 8-10 prostate cancer

PURPOSE

The role of multimodality therapy (MMT) in the treatment of Gleason 8-10 prostate cancer remains controversial. We sought to evaluate factors associated with MMT utilization for primary radical prostatectomy (RP) and primary radiation therapy (RT).

METHODS AND MATERIALS

From the National Cancer Database, we conducted a retrospective review of 81,528 men with National Cancer Center Network Gleason 8-10 prostate cancer diagnosed between 2004 and 2015, who underwent (1) primary RP with or without early postoperative external beam RT (EBRT) or (2) primary RT (androgen deprivation therapy + EBRT) with or without brachytherapy (BT) boost. Using multivariable logistic regression models, we evaluated factors associated with the utilization of MMT, defined as early postoperative EBRT for primary RP or BT boost for primary RT.

RESULTS

For primary RP, the percentages of men who underwent MMT for Gleason 8 and 9-10 disease were 12.2% and 24.1%, respectively. On multivariable logistic regression, men with Gleason 9-10 were more likely to undergo MMT (odds ratio 1.03 [1.02, 1.04]), although adverse pathologic features such as T3b-4 (1.24 [1.23, 1.25]) disease demonstrated the strongest associations. For primary RT, the percentages of men who underwent BT boost for Gleason 8 and 9-10 disease were 11.8% and 9.8%, respectively. On multivariable logistic regression, men with Gleason 9-10 disease were less likely to receive BT boost (0.99 [0.98, 0.99]).

CONCLUSIONS

Men with more aggressive Gleason 9 disease were more likely to undergo MMT if they underwent primary RP but not primary RT. Further blood-based or imaging biomarkers may aid in identifying optimal candidates for MMT, especially for primary RT.

Predictors of urinary toxicity with MRI-assisted radiosurgery for low-dose-rate prostate brachytherapy

PURPOSE

MRI-assisted radiosurgery (MARS) is a modern technique for prostate brachytherapy that provides superior soft tissue contrast. The purpose of this analysis was to evaluate treatment planning factors associated with urinary toxicity, particularly damage to the membranous urethra (MUL) and external urethral sphincter (EUS), after MARS.

MATERIAL AND METHODS

We retrospectively reviewed 227 patients treated with MARS. Comparisons were made between several factors including preimplantation length of the MUL and EUS dosimetric characteristics after implantation with longitudinal changes in American Urological Association (AUA) urinary symptom score.

RESULTS

Rates of grade 3 urinary incontinence and obstructive urinary symptoms were 4% and 2%. A piecewise mixed univariate model revealed that MUL and V₂₀₀, V₁₅₀, V₁₂₅, and D₅ to the EUS were all associated with increased rates of urinary toxicity over time. On univariate logistic regression, MUL >14.2 mm (odds ratio [OR] 2.03 per cm³, 95% confidence interval [CI] 1.10-3.77, p = 0.025), V₁₂₅ to the EUS (OR 3.21 cm³, 95% CI 1.18-8.71, p = 0.022), and use of the I-125 isotope (OR 3.45, 95% CI 1.55-7.70, p = 0.001) were associated with subacute urinary toxicity (i.e., that occurring at 4-8 months). Optimal dose-constraint limits to the EUS were determined to be V₂₀₀ < 0.04 cm³ (p = 0.002), V₁₅₀ < 0.12 cm³ (p = 0.041), V₁₂₅ < 0.45 cm³ (p = 0.033), D₃₀ < 160 Gy (p = 0.004), and D₅ < 218 Gy (p = 0.016).

CONCLUSIONS

MARS brachytherapy provides detailed anatomic information for treatment planning, implantation, and quality assurance. Overall rates of urinary toxicity are low; however, several dosimetric variables associated with the EUS were found to correlate with urinary toxicity.

Impact of real-time, dose-escalated permanent seed implant brachytherapy in intermediate-risk prostate cancer

Purpose

To retrospectively evaluate biochemical control and toxicity in patients who underwent 125I seed brachytherapy (BT) for intermediate-risk prostate cancer (PCa).

Materials and Methods

Between January 2004-December 2014, 395 patients with intermediate-risk PCa underwent 125I BT. Of these, 117 underwent preoperative planning (PP; 145 Gy) and 278 real-time intraoperative preplanning (IoP; 160 Gy). All patients were followed for ≥ 6 months (> 5 years in 48% of patients and > 7 years in 13%). Median follow-up was 59 months.

Results

Biochemical relapse-free survival (BRFS) rates at 5 and 8 years were, respectively, 91.7% and 82.1%. By treatment group, the corresponding BRFS rates were 93.5% and 90% for IoP and 89% and 76.8% for PP. The maximum dose to the urethra remained unchanged (217 Gy) despite the dose escalation (from 145 to 160 Gy), without any significant increase in treatment-related toxicity (p = 0.13). Overall toxicity outcomes in the series were excellent, with only 3 cases (0.76%) of grade 3 genitourinary toxicity.

Conclusion

The real-time intraoperative planning technique at 160 Gy yields better biochemical controls than the preoperative planning technique at 145 Gy. Dose escalation did not increase urinary toxicity. The excellent results obtained with the IoP BT technique support its use as the first treatment option in this patient population.

Intermediate-risk Prostate Cancer: Stratification and Management

CONTEXT

Intermediate-risk prostate cancer consists of a highly heterogeneous group of patients. Owing to this heterogeneity and variable prognoses, it is challenging to provide uniform treatment recommendations for men in this group.

OBJECTIVE

To review the current literature regarding the best available evidence for stratification and treatment of intermediate-risk prostate cancer patients.

EVIDENCE ACQUISITION

We searched Medline and EMBASE, through September 2019 without year or language restriction, supplemented with hand search.

EVIDENCE SYNTHESIS

Different treatment options with good long-term oncological outcomes are available for intermediate-risk prostate cancer patients. Best available evidence with long follow-up exists for radical prostatectomy and dose-escalated radiotherapy with short-term androgen deprivation. In favorable intermediate-risk patients, active surveillance and brachy-monotherapy also represent two valid treatment options. In carefully selected men, partial gland ablation represents a reasonable option. Patient preferences and comorbidities should also be considered.

CONCLUSIONS

Treatment options for intermediate-risk patients range from active surveillance to partial gland ablation, radical prostatectomy, and various radiotherapy methods. The best stratification and the optimal treatment remain controversial. Classification systems, such as the National Cancer Comprehensive Network guidelines, stratify this large cohort into subgroups with favorable or unfavorable disease, which may simplify treatment recommendations but still leave substantial variability within strata. Advanced imaging may further improve current stratification systems of intermediate-risk patients.

PATIENT SUMMARY

In this review, we assessed the current literature regarding the best available evidence for stratification and treatment of intermediate-risk prostate cancer patients.

Modern Brachytherapy

Brachytherapy involves the placement of radioactive sources within or very close to the tumor. This placement allows a high dose of radiotherapy to be delivered to the tumor while sparing the surrounding normal tissue. The delivery of brachytherapy has changed markedly over the years, with newer radioactive sources making delivery safer, image guidance techniques allowing more accurate placement of sources, and advanced planning systems allowing brachytherapy to be truly adaptive. This article explores the most modern techniques and current uses of brachytherapy in the treatment of gynecological, prostate, breast, rectal, and skin cancers.

Low-dose-rate brachytherapy for prostate cancer: A 15-year experience in Japan

The history of prostate brachytherapy has passed one century. In 1983, modern low-dose-rate prostate brachytherapy using a transrectal ultrasound-guided procedure was introduced. In the early 1990s, low-dose-rate brachytherapy was introduced and rapidly spread across the USA due to its excellent oncological control, cost-effectiveness and technically easy procedure. Since low-dose-rate brachytherapy was introduced in Japan (2003), over 15 years have passed. More than 43 000 patients have undergone low-dose-rate brachytherapy. Japanese urologists and radiation oncologists are on course with leading brachytherapists in the USA. A nationwide prospective cohort study, J-POPS, was initiated in 2005. The J-POPS group also provides educational programs including an annual novel training course in low-dose-rate brachytherapy to familiarize urologists, radiation oncologists and pathologists with the procedure. Important information on Japanese patients has accumulated, especially by the J-POPS study group. The Japanese investigators reported excellent oncological outcomes of low-dose-rate brachytherapy, showing equivalent or superior efficacy to surgery in low- to intermediate-risk patients, and superior efficacy in high-risk patients using the surgery biochemical recurrence definition (prostate-specific antigen cut-off value of 0.2 ng/mL). Two randomized controlled studies (SHIP study: intermediate risk, and TRIP study: high risk) carried out by the J-POPS group are ongoing, and an additional follow-up study (J-POPS 2 study) has been started to evaluate survival outcomes over longer follow-up periods. Low-dose-rate brachytherapy is expected to provide a survival benefit, which must be confirmed by further studies with longer follow-up periods in the future.

Radiation therapy for prostate cancer: An evolving treatment modality

Radiation therapy for prostate cancer is evolving rapidly with advancing technology and with results from many clinical trials. This article summarizes highlights from the 5 articles published in this issue of Seminars on the current state of radiation treatment and areas of continued development.

Individualized Dose-Escalation of HDR Prostate Brachytherapy Implant to Decrease Required External Beam Radiation Dose: A Retrospective Feasibility Study

Purpose

High-dose-rate brachytherapy (HDR-BT) is commonly combined with external beam radiation therapy (EBRT) for the treatment of localized prostate cancer. Escalating the HDR-BT dose as far as organ-at-risk (OAR) constraints allow, on a personalized basis, would allow for a reduction in EBRT dose while achieving similar total biologic equivalence. The primary objective of this study was to determine the dosimetric feasibility of escalating the HDR-BT dose from 15 Gy to 16 or 17 Gy while continuing to meet OAR constraints from the original 15 Gy plan on an individualized basis.

Methods and materials

A total of 53 consecutive HDR-BT plans were retrospectively assessed to determine what percentage of plans could be reoptimized to deliver a dose of 16 Gy or 17 Gy, while meeting defined 15-Gy OAR constraints. Factors independently associated with dose escalation were examined.

Results

Thirty-nine plans (74%) and 2 plans (4%) were successfully escalated to a dose of 16 Gy and 17 Gy, respectively. Rectum V80 and urethra D_max were independently predictive of the ability to dose escalate to 16 Gy.

Conclusions

Individualized HDR-BT dose escalation beyond 15 Gy without compromising OAR constraints is dosimetrically feasible. This approach could allow for a corresponding reduction of EBRT fractions (ie, from 15 to 12 fractions) and would be beneficial in terms of resource savings for departments, convenience for patients, and potentially better tolerance of treatment with the expected reduction in biologically equivalent doses to OARs. A clinical trial is being developed to investigate the efficacy and tolerance of personalized HDR-BT/EBRT dose fractionation for localized intracapsular prostate cancer.

Survival after radiotherapy vs. radical prostatectomy for unfavorable intermediate-risk prostate cancer

BACKGROUND

The optimal treatment for unfavorable intermediate-risk prostate cancer is unknown. Given the lack of randomized evidence, large comparative studies may be useful in guiding clinical decision-making.

METHODS

We queried the National Cancer Database for patients with unfavorable intermediate-risk prostate cancer, as defined by the National Comprehensive Cancer Network. We compared overall survival between patients treated with radical prostatectomy (RP), external beam radiation therapy (EBRT), brachytherapy, and EBRT plus brachytherapy (EBRT+BT) using Cox proportional hazards models and propensity score matching.

RESULTS

A total of 10,439 patients were analyzed. There was no statistically significant difference in overall survival between RP and EBRT+BT (hazard ratio [HR] = 1.24; 95% confidence interval [CI] 0.58-2.65). RP was associated with higher survival when compared to EBRT (HR = 2.30, 95% CI 1.70-3.20) and brachytherapy (HR = 2.90, 95% CI 1.40-6.20). When accounting for androgen deprivation therapy (ADT), there was no statistically significant difference in survival between RP and brachytherapy with ADT (HR = 3.08; 95% CI 0.62-15.27) or EBRT to a dose of ≥7920 cGy with ADT (HR = 2.6, 95% CI 0.50-13.20).

CONCLUSION

We found no statistically significant difference in survival between RP and EBRT+BT. EBRT and brachytherapy had higher mortality, respectively, compared to RP. When including only radiotherapy patients who received ADT and, in the case of EBRT, a total dose ≥ 7920 cGy, there was no statistically significant difference in survival when comparing RP to EBRT or brachytherapy. These findings should be prospectively studied.

The current state of randomized clinical trial evidence for prostate brachytherapy

Interstitial brachytherapy is one of several curative therapeutic options for the treatment of localized prostate cancer. In this review, we summarize all available randomized data to support the optimal use of prostate brachytherapy. Evidence from completed randomized controlled trials is the focus of this review with a presentation also of important ongoing trials. Gaps in knowledge are identified where future investigation may be fruitful with intent to inspire well-designed prospective studies with standardized treatment that focuses on improving oncological outcomes, reducing morbidity, or maintaining quality of life.

Long-term biochemical progression-free survival following brachytherapy for prostate cancer: Further insight into the role of short-term androgen deprivation and intermediate risk group subclassification

Introduction

Brachytherapy is a well-established treatment of localized prostate cancer. Few studies have documented long-term results, specifically biochemical progression-free survival (bPFS) in men with brachytherapy alone, with or without short-term androgen deprivation therapy (ADT), or in combination with external beam radiotherapy (EBRT). Our aim was to analyze long-term bPFS of brachytherapy treated patients.

Materials and methods

Retrospective analysis of 1457 patients with low and intermediate risk prostate cancer treated with brachytherapy alone (1255) or combined with EBRT (202). Six-months ADT was administrated for all EBRT combined patients and for prostate volume downsizing when >55 cc (328). Failure was by the Phoenix definition. Kaplan-Meier analysis and multivariate Cox regression estimated and compared 10-yr and 15-yr rates of bPFS.

Results

Median follow-up was 6.1 yr. Ten and 15-yr bPFS rates of the entire cohort were 93.2% and 89.2%, respectively. On multivariate analysis, PSA density (PSAD), ADT and clinical stage were significantly associated with failure. The most powerful independent factor was PSAD with a HR of 3.5 (95% CI, 1.7–7.4) for PSAD above 0.15. No significant difference was found between low and intermediate risks patients regardless of treatment regimen. However, comparison of two intermediate risk groups, Gleason score (GS) 7, PSA<20 ng/ml versus GS≤6 and PSA = 10–20 ng/ml, revealed 10- and 15-yr bPFS rates of 94.2% and 94.2% compared to 88.2% and 79.9%, (P = 0.022), respectively. ADT improved bPFS rates in low risk patients. The ten and 15-yr bPFS rates were 97.6% and 94.6% compared to 92.3% and 88.2%, (P = 0.020), respectively.

Conclusions

Our retrospective large scale study suggests that brachytherapy provides excellent long-term bPFS rates in low and intermediate risk disease. Combination of brachytherapy with EBRT yields favorable outcomes in GS 7 intermediate risk patients and short-term ADT has a positive effect on outcomes in low risk patients.

Further prospective studies are warranted to discriminate the role of adding either EBRT and/or ADT to brachytherapy protocols.

A Phase 2 Randomized Pilot Study Comparing High-Dose-Rate Brachytherapy and Low-Dose-Rate Brachytherapy as Monotherapy in Localized Prostate Cancer

Purpose

To compare health-related quality of life (HRQOL) of high-dose-rate brachytherapy (HDRB) versus low dose-rate brachytherapy (LDRB) for localized prostate cancer in a multi-institutional phase 2 randomized trial.

Methods and Materials

Men with favorable-risk prostate cancer were randomized between monotherapy brachytherapy with either Iodine-125 LDRB to 144 Gy or single-fraction Iridium-192 HDRB to 19 Gy. HRQOL and urinary toxicity were recorded at baseline and at 1, 3, 6, and 12 months using the Expanded Prostate Cancer Index Composite (EPIC)-26 scoring and the International Prostate Symptom Score (IPSS). Independent samples t test and mixed effects modeling were performed for continuous variables. Time to IPSS resolution, defined as return to its baseline score ±5 points, was calculated using Kaplan-Meier estimator curves with the log-rank test. A multiple-comparison adjusted P value of ≤.05 was considered significant.

Results

LDRB and HDRB were performed in 15 and 16 patients, respectively, for a total of 31 patients. At 3 months, patients treated with LDRB had a higher IPSS score (mean, 15.5 vs 6.0, respectively; P = .003) and lower EPIC urinary irritative score (mean, 69.2 vs 85.3, respectively; P = .037) compared with those who received HDRB. On repeated measures at 1, 3, 6, and 12 months, the IPSS (P = .003) and EPIC urinary irritative scores (P = .019) were significantly better in the HDR arm, translating into a lower urinary toxicity profile. There were no significant differences in the EPIC urinary incontinence, sexual, or bowel habit scores between the 2 groups at any measured time point. Time to IPSS resolution was significantly shorter in the HDRB group (mean, 2.0 months) compared with the LDRB group (mean, 6.0 months; P = .028).

Conclusions

HDRB monotherapy is a promising modality associated with a lower urinary toxicity profile and higher HRQOL in the first 12 months compared with LDRB.

Long-term Outcomes of Stereotactic Body Radiotherapy for Low-Risk and Intermediate-Risk Prostate Cancer

Importance

Stereotactic body radiotherapy harnesses improvements in technology to allow the completion of a course of external beam radiotherapy treatment for prostate cancer in the span of 4 to 5 treatment sessions. Although mounting short-term data support this approach, long-term outcomes have been sparsely reported.

Objective

To assess long-term outcomes after stereotactic body radiotherapy for low-risk and intermediate-risk prostate cancer.

Design, Setting, and Participants

This cohort study analyzed individual patient data from 2142 men enrolled in 10 single-institution phase 2 trials and 2 multi-institutional phase 2 trials of stereotactic body radiotherapy for low-risk and intermediate-risk prostate cancer between January 1, 2000, and December 31, 2012. Statistical analysis was performed based on follow-up from January 1, 2013, to May 1, 2018.

Main Outcomes and Measures

The cumulative incidence of biochemical recurrence was estimated using a competing risk framework. Physician-scored genitourinary and gastrointestinal toxic event outcomes were defined per each individual study, generally by Radiation Therapy Oncology Group or Common Terminology Criteria for Adverse Events scoring systems. After central review, cumulative incidences of late grade 3 or higher toxic events were estimated using a Kaplan-Meier method.

Results

A total of 2142 men (mean [SD] age, 67.9 [9.5] years) were eligible for analysis, of whom 1185 (55.3%) had low-risk disease, 692 (32.3%) had favorable intermediate-risk disease, and 265 (12.4%) had unfavorable intermediate-risk disease. The median follow-up period was 6.9 years (interquartile range, 4.9-8.1 years). Seven-year cumulative rates of biochemical recurrence were 4.5% (95% CI, 3.2%-5.8%) for low-risk disease, 8.6% (95% CI, 6.2%-11.0%) for favorable intermediate-risk disease, 14.9% (95% CI, 9.5%-20.2%) for unfavorable intermediate-risk disease, and 10.2% (95% CI, 8.0%-12.5%) for all intermediate-risk disease. The crude incidence of acute grade 3 or higher genitourinary toxic events was 0.60% (n = 13) and of gastrointestinal toxic events was 0.09% (n = 2), and the 7-year cumulative incidence of late grade 3 or higher genitourinary toxic events was 2.4% (95% CI, 1.8%-3.2%) and of late grade 3 or higher gastrointestinal toxic events was 0.4% (95% CI, 0.2%-0.8%).

Conclusions and Relevance

In this study, stereotactic body radiotherapy for low-risk and intermediate-risk disease was associated with low rates of severe toxic events and high rates of biochemical control. These data suggest that stereotactic body radiotherapy is an appropriate definitive treatment modality for low-risk and intermediate-risk prostate cancer.

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

BACKGROUND

To compare the outcome of high-dose-rate interstitial brachytherapy (HDR-BT) monotherapy and low-dose-rate brachytherapy (LDR-BT) with or without external beam radiotherapy (EBRT) for localized prostate cancer.

METHODS AND MATERIALS

We compared 352 patients treated with HDR-BT as monotherapy (median follow-up time 84 months, NCCN risk classification; low: intermediate: high = 28:145:179) and 486 patients with LDR-BT with or without EBRT (90 months, 194:254:38). HDR-BT treated advanced disease with more hormonal therapy than LDR-BT. LDR-BT excluded patients with T3b-T4 tumor and initial PSA >50 ng/ml. Inverse probability of treatment weighting (IPTW) involving propensity scores was used to reduce background selection bias.

RESULTS

The actuarial 5-year biochemical failure-free survival rates (bNED) were 92.9% and 95.6% (p = 0.25) in the HDR-BT and LDR-BT groups, respectively, and it was 100% and 97.3% (p = 0.99) in the low-risk, 95.6% and 94.3% (p = 0.19) in the intermediate, 89.6% and 94.9% (p = 0.26) in the high-risk groups, and 93.1% and 94.9% (p = 0.98) in selected high-risk group excluding T3b-4 and initial PSA ≥50. IPTW correction also indicated no difference in bNED between LDR-BT and HDR-BT groups. LDR-BT showed a higher incidence of genitourinary (GU) toxicity grade ≥2 than that of HDR-BT in the acute phase and grade 1 toxicity in late phase. Acute GU toxicity grade ≥1 predicted late GU toxicity grade ≥2. External beam radiotherapy plus LDR-BT elevated GI toxicity than LDR-BT only group. Accumulated incidence of late grade ≥2 GU and GU toxicity was equivalent between HDR-BT and LDR-BT. No grade 4 or 5 toxicities were detected in either modality.

CONCLUSION

HDR-BT monotherapy showed an equivalent outcome to that of LDR-BT with or without EBRT for low-, intermediate- and selected high-risk patients. LDR-BT showed equivalent incidence of grade ≥2 late GI and GU toxicities and higher grade ≥2 acute GU toxicity as that of HDR-BT as a monotherapy.

Patient-reported health-related quality of life outcomes after HDR brachytherapy between small (<60 cc) and large (≥60 cc) prostate glands

PURPOSE

Patients with large prostate glands are underrepresented in clinical trials incorporating brachytherapy due to concerns for excessive toxicity. We sought to compare health-related quality of life (HRQOL) outcomes between small (<60 cc) and large (≥60 cc) prostates treated with high-dose-rate brachytherapy (HDR-B).

METHODS AND MATERIALS

One hundred thirty patients at Emory University were treated with HDR-B monotherapy (n = 75) or HDR-B in combination with external beam radiation therapy (n = 55). American Urologic Association Symptom Score (AUASS) and expanded prostate cancer index composite for clinical practice (EPIC-CP) scores were recorded. A linear mixed model was performed dichotomizing prostate volume (<60 and ≥ 60 cc) with AUASS, individual EPIC-CP domains (urinary incontinence, urinary irritation/obstruction [UIO], bowel function, sexual function, and vitality/hormonal function), and overall EPIC-CP HRQOL scores.

RESULTS

Median followup was 22.6 months (range 2.2-55.8). The median gland volume for the entire cohort (n = 130), <60 cc cohort (n = 104), and ≥60 cc cohort (n = 26) was 44 cc, 41.1 cc, and 68.0 cc, respectively. There were no baseline differences in HRQOL scores between cohorts. At 2 months, AUASS and UIO scores increased similarly between cohorts (AUASS p = 0.807; UIO p = 0.539), then decreased (longitudinal effect p < 0.001 and p = 0.005, respectively) to remain not significantly different at 12 months (AUASS p = 0.595; UIO p = 0.673). Overall, prostate volume was not significantly associated with change in AUASS (p = 0.403), urinary incontinence (p = 0.322), UIO symptoms (p = 0.779), bowel symptoms (p = 0.757), vitality/hormonal symptoms (p = 0.503), or overall HRQOL (p = 0.382).

CONCLUSIONS

In appropriately selected patients, HDR-B appears well tolerated in patients with ≥60 cc prostate glands without an increase in patient-reported toxicity. Volume should not be a strict contraindication in those with adequate baseline function.

Prostate Cancer Radiotherapy: An Evolving Paradigm

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors' suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice. A urologist referred a 69-year-old man for a radiotherapy opinion regarding a recently diagnosed adenocarcinoma of the prostate. Annual serum prostate-specific antigen (PSA) testing over 7 years demonstrated a rise in PSA from 1.36 ng/mL to 5.8 ng/mL, prompting a transrectal ultrasound that revealed a heterogeneous 37-mL gland containing no visualized hypoechoic nodules. Biopsy disclosed a Gleason score 3+4 (grade group 2) adenocarcinoma of the prostate. The synoptic report stated that six of 14 cores and 17% of the tissue were involved, with the greatest core involvement being 80% at the right apex. Perineural invasion was present without lymphovascular invasion. Disease was present bilaterally at the base, midgland, and apex.His medical history was significant only for treated peptic ulcer disease and he was taking no medication. His International Prostate Symptom Score was six of 35, and he reported being sexually active with good erectile function. There was no family history of prostate cancer. He is retired. Digital rectal examination revealed moderate benign prostatic hypertrophy with no suspicious nodules. A staging computerized tomography (CT) scan of the abdomen and pelvis and a whole-body bone scan ordered by his referring urologist reported no evidence of metastatic disease. The patient had discussed surgical options with his urologist and now wished to consider radiotherapy approaches.