Significant association of brachytherapy boost with reduced prostate cancer-specific mortality in contemporary patients with localized, unfavorable-risk prostate cancer

A Systematic Review of the Efficacy and Toxicity of Brachytherapy Boost Combined with External Beam Radiotherapy for Nonmetastatic Prostate Cancer

CONTEXT

The optimum use of brachytherapy (BT) combined with external beam radiotherapy (EBRT) for localised/locally advanced prostate cancer (PCa) remains uncertain.

OBJECTIVE

To perform a systematic review to determine the benefits and harms of EBRT-BT.

EVIDENCE ACQUISITION

Ovid MEDLINE, Embase, and EBM Reviews-Cochrane Central Register of Controlled Trials databases were systematically searched for studies published between January 1, 2000 and June 7, 2022, according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. Eligible studies compared low- or high-dose-rate EBRT-BT against EBRT ± androgen deprivation therapy (ADT) and/or radical prostatectomy (RP) ± postoperative radiotherapy (RP ± EBRT). The main outcomes were biochemical progression-free survival (bPFS), severe late genitourinary (GU)/gastrointestinal toxicity, metastasis-free survival (MFS), cancer-specific survival (CSS), and overall survival (OS), at/beyond 5 yr. Risk of bias was assessed and confounding assessment was performed. A meta-analysis was performed for randomised controlled trials (RCTs).

EVIDENCE SYNTHESIS

Seventy-three studies were included (two RCTs, seven prospective studies, and 64 retrospective studies). Most studies included participants with intermediate-or high-risk PCa. Most studies, including both RCTs, used ADT with EBRT-BT. Generally, EBRT-BT was associated with improved bPFS compared with EBRT, but similar MFS, CSS, and OS. A meta-analysis of the two RCTs showed superior bPFS with EBRT-BT (estimated fixed-effect hazard ratio [HR] 0.54 [95% confidence interval {CI} 0.40-0.72], p < 0.001), with absolute improvements in bPFS at 5-6 yr of 4.9-16%. However, no difference was seen for MFS (HR 0.84 [95% CI 0.53-1.28], p = 0.4) or OS (HR 0.87 [95% CI 0.63-1.19], p = 0.4). Fewer studies examined RP ± EBRT. There is an increased risk of severe late GU toxicity, especially with low-dose-rate EBRT-BT, with some evidence of increased prevalence of severe GU toxicity at 5-6 yr of 6.4-7% across the two RCTs.

CONCLUSIONS

EBRT-BT can be considered for unfavourable intermediate/high-risk localised/locally advanced PCa in patients with good urinary function, although the strength of this recommendation based on the European Association of Urology guideline methodology is weak given that it is based on improvements in biochemical control.

PATIENT SUMMARY

We found good evidence that radiotherapy combined with brachytherapy keeps prostate cancer controlled for longer, but it could lead to worse urinary side effects than radiotherapy without brachytherapy, and its impact on cancer spread and patient survival is less clear.

High-Risk Prostate Cancer: A Very Challenging Disease in the Field of Uro-Oncology

Prostate cancer (PCa) is the most common cancer in males and affects 16% of men during their lifetime [...].

Survival after neoadjuvant approaches to gastroesophageal junction cancer

BACKGROUND

Gastroesophageal junction (GEJ) cancers can be treated with equipoise using neoadjuvant chemoradiation (NACRT) or chemotherapy alone (NAC), but the comparative outcomes are unclear.

METHODS

Patients with non-metastatic T2-4 or N1-3 GEJ adenocarcinoma who underwent definitive surgery and NAC or NACRT were selected from the National Cancer Database. The primary outcome was overall survival (OS). Multivariable regression and propensity score analysis were used to adjust for age, comorbidity, and other characteristics.

RESULTS

We identified 2435 patients treated with NACRT and 648 patients treated with NAC. OS was not significantly different between NACRT and NAC (51% versus 54% at 3 years, respectively, P = 0.11). Extent of pathological downstaging (complete, partial/mixed, none) after NACRT or NAC was highly prognostic of survival. Patients with no response did equally poorly after either preoperative regimen, and NAC was significantly less likely than NACRT to produce any response (adjusted odds ratio 0.62, P < 0.0001). Rate of adjuvant chemotherapy usage was significantly lower after NACRT than after NAC (12% versus 34%, P < 0.0001). In patients with residual tumor and nodal disease, adjuvant chemotherapy was associated with higher OS after NACRT (adjusted hazard ratio 0.81, P = 0.05), but not after NAC. These results were further validated by propensity score analysis.

CONCLUSIONS

NACRT had similar survival to NAC despite superior pathological downstaging. Adjuvant chemotherapy is relatively underused after NACRT and warrants further study as a risk-adapted means to improve survival, especially in patients with larger burden of residual disease.

Survival benefit of radiation in high-risk, early-stage endometrioid carcinoma

OBJECTIVE

To better delineate optimal management of high-risk, early-stage endometrial cancer, as national guidelines permit substantial practice variations.

METHODS

Patients with International Federation of Gynecology and Obstetrics (FIGO) stage IB grade 3 and stage II endometrioid carcinoma who underwent at least total hysterectomy were identified in SEER-Medicare. Adjuvant treatments were brachytherapy (BT), external beam radiation therapy (EBRT), and chemotherapy. Death from endometrial cancer (cancer-specific mortality [CSM]) and local recurrence were analyzed using Gray's test and Fine-Gray regression.

RESULTS

In total, 1,095 patients were identified: 52% received BT, 56% received EBRT, 16% received chemotherapy, and 29% received no adjuvant treatment. Survival outcomes were significantly worse for stage IB grade 3 and stage II grade 3 relative to stage II grades 1-2 (5-year CSM: 18% and 23% vs. 10%; p<0.001 and p=0.003, respectively), while there was no difference between stage IB grade 3 and stage II grade 3 (p=0.618). BT had a local control benefit across all patients (p<0.001) that translated into a survival benefit in stage IB grade 3 (adjusted hazard ratio [HR] for CSM=0.47, p=0.003). EBRT had a survival benefit in stage II grade 3 (adjusted HR for CSM=0.36; p=0.031), as did lymph node dissection (p=0.015). Chemotherapy was not significantly correlated with CSM.

CONCLUSIONS

High-risk, early-stage endometrioid carcinoma is a heterogeneous population. BT was associated with a survival benefit in stage IB grade 3, whereas regional treatment with EBRT and lymphadenectomy was associated with a survival benefit in stage II grade 3.

Gleason pattern 5 is associated with an increased risk for metastasis following androgen deprivation therapy and radiation: An analysis of RTOG 9202 and 9902

BACKGROUND/PURPOSE

Stratification of Gleason score (GS) into three categories (2-6, 7, and 8-10) may not fully utilize its prognostic discrimination, with Gleason pattern 5 (GP5) previously identified as an independent adverse factor.

MATERIALS/METHODS

Patients treated on RTOG 9202 (n = 1292) or RTOG 9902 (n = 378) were pooled and assessed for association of GS and GP5 on biochemical failure (BF), local failure (LF), distant metastasis (DM), and overall survival (OS). Fine and Gray's regression and cumulative incidence methods were used for univariate and multivariate analyses.

RESULTS

With median follow-up of 9.4 years, patients with GS 8-10 with GP5 had worse outcome than GS 4 + 4 for DM on both RTOG9202 (p = 0.038) and RTOG9902 (p < 0.001) with a trend toward worse OS (p = 0.059 and p = 0.089, respectively), but without differences in BF or LF. At 10-years DM was higher by 11% (RTOG 9202) and 18% (RTOG 9902) with GP5 compared to GS 4 + 4. On multivariate analysis restricted to long-term androgen deprivation therapy the presence of GP5 substantially increased distant metastasis (HR = 0.43, 95%CI: 0.24-0.76, p = 0.0039) with a trend toward worse OS (HR:0.74, 95% CI:0.54-1.0, p = 0.052) without association with LF (HR:0.55, 95%CI:0.28-1.09, p = 0.085) or BF (HR:1.15, 95%CI:0.84-1.59, p = 0.39). We did not observed substantial differences between Gleason 3 + 5, 5 + 3, or Gleason 9-10.

CONCLUSIONS

These results validate GP5 as an independent prognostic factor which is strongest for DM. As a result GP5 should be considered when stratifying patients with GS 8 and may be a patient population in which to evaluate newly approved systemic therapies or additional local treatments.

Benefit of Cisplatin With Definitive Radiotherapy in Older Women With Cervical Cancer

Background: Cisplatin with definitive radiotherapy (RT) is considered the standard of care for cervical cancer; however, older women are frequently undertreated and have worse outcomes compared with younger patients. Because women aged ≥65 years have been disproportionately underrepresented in clinical trials, uncertainties exist regarding how much they benefit from the addition of cisplatin to RT. Patients and Methods: Women aged ≥65 years with nonmetastatic cervical cancer treated with definitive external-beam RT and brachytherapy were identified in the SEER-Medicare database. Death attributable to cervical cancer (cancer-specific mortality [CSM]) was evaluated against competing risks of death using Gray’s test. Propensity score analysis and the Fine-Gray multivariable regression model were used to adjust for baseline differences, including comorbidity. Results: The total cohort comprised 826 patients, of whom 531 (64%) received cisplatin, 233 (28%) were FIGO stage I, 374 (45%) were stage II, and 219 (27%) were stage III–IVA. Older age and chronic kidney disease significantly predicted omission of cisplatin. Virtually all cisplatin dosing was weekly, with a median of 5 cycles. Death from cervical cancer was significantly lower with cisplatin than without (5-year CSM, 31% vs 39%; P=.02; adjusted hazard ratio, 0.72; P=.02), which persisted in propensity score analysis. Receiving ≥5 cycles was required for benefit, as no difference in CSM was seen in patients receiving 1 to 4 cycles versus no cisplatin. Subgroup analyses revealed that the benefit of cisplatin persisted in women aged ≥75 years and those with early-stage disease. Incidence of cytopenia, nausea/vomiting, and hypovolemia increased in patients treated with cisplatin. Conclusions: Administration of cisplatin with definitive RT in women aged ≥65 years was associated with a significant benefit in the incidence of death attributable to cervical cancer, despite competing risks for mortality in an older population. Receiving at least 5 cycles of weekly cisplatin was required for benefit.

Adjuvant treatment and survival in older women with triple negative breast cancer: A Surveillance, Epidemiology, and End Results analysis

Patients with triple negative breast cancer were identified using the Surveillance, Epidemiology, and End Results database. Competing risks analysis was used to assess the cumulative incidence of breast cancer-specific mortality (BCSM). Multivariable Fine-Gray regression was used to identify predictors of BCSM. Women age 70+ (n = 4221) were less likely to receive chemotherapy and radiation treatment (P < 0.0001) and had higher BCSM compared to younger women (P < 0.0001). There were no differences in BCSM in patients who received adjuvant treatment (P = 0.10). Stage II patients derived the greatest relative and absolute benefit from adjuvant treatment. Age was not a significant predictor of BCSM.

National patterns of care and cancer-specific outcomes of adjuvant treatment in patients with serous and clear cell endometrial carcinoma

OBJECTIVES

To investigate outcomes of adjuvant therapy for serous and clear cell endometrial carcinoma, as prior studies are limited by sample size and/or patient heterogeneity. National guidelines permit substantial variations in treatment, suggesting the need for additional data.

METHODS

Patients with FIGO stages I-III serous or clear cell uterine carcinoma who underwent at least total hysterectomy were identified in SEER-Medicare. Adjuvant external beam radiation, brachytherapy, and chemotherapy were determined using SEER fields and Medicare claims. The primary outcome was death from endometrial cancer (cancer-specific mortality [CSM]) evaluated using Gray's test (univariable analysis, UVA) and Fine-Gray regression (multivariable analysis, MVA).

RESULTS

A total of 1789 patients (1437 serous, 352 clear cell) were identified. In stages I-II patients (n = 1188), brachytherapy was significant for survival in UVA (P = 0.03) and MVA (P = 0.02). Additionally, in the subset with serous histology (n = 947), chemotherapy was also significant in UVA (P = 0.002) and approached significance in MVA (P = 0.05). The 4-year CSM for stages I-II serous cancers was 25% without brachytherapy or chemotherapy, 15% with one, and 9% with both (P ≤ 0.05 for all pairwise comparisons). In stage III patients (n = 601), chemotherapy was significant in UVA (P = 0.002) and MVA (P = 0.006). Most (81%) patients underwent lymph node dissection, which predicted lower CSM in stage III (P = 0.001) but not stages I-II patients.

CONCLUSIONS

Our results suggest brachytherapy benefits stages I-II serous/clear cell cancers, chemotherapy benefits stage III serous/clear cell cancers, and both chemotherapy and brachytherapy benefit stages I-II serous cancers.

Survival of patients with head and neck cancer treated with definitive radiotherapy and concurrent cisplatin or concurrent cetuximab: A Surveillance, Epidemiology, and End Results-Medicare analysis

BACKGROUND

Cisplatin and cetuximab are both systemic therapies commonly used in combination with radiation (RT) for the definitive treatment of head and neck cancers, but their comparative efficacy is unclear.

METHODS

Patients with locoregionally advanced (American Joint Committee on Cancer stage III-IVB) squamous cell carcinomas of the oropharynx, larynx, or hypopharynx were identified in the Surveillance, Epidemiology, and End Results-Medicare database. Patients received either cisplatin or cetuximab concurrent with RT, as determined by Medicare claims. The primary study outcome was head and neck cancer-specific mortality (CSM) analyzed with competing risks. Filtering, propensity score matching, and multivariable Fine-Gray regression were used to adjust for differences between the cisplatin and cetuximab cohorts, including age, comorbidity, and cycles of systemic therapy received.

RESULTS

The total cohort consisted of 1395 patients, of whom 786 (56%) received cisplatin and 609 (44%) received cetuximab; the median follow-up was 3.5 years in the patients who remained alive. In the cetuximab cohort, CSM was significantly higher than in the cisplatin cohort (39% vs 25% at 3 years; P < .0001). In the matched cohorts (n = 414), the adjusted hazard ratio of CSM for cetuximab was 1.65 (95% confidence interval, 1.30-2.09; P < .0001) relative to cisplatin, corresponding to an absolute difference of approximately 10% in both CSM and overall survival at 3 years. Cetuximab was associated with less dysphagia, more dermatitis, and a similar incidence of mucositis.

CONCLUSIONS

In this sizeable, national patient population, treatment with cetuximab was associated with significantly higher CSM than cisplatin. These results suggest that cisplatin may be the preferred chemotherapeutic agent in this setting.

Under-utilisation of high-dose-rate brachytherapy boost in men with intermediate-high risk prostate cancer treated with external beam radiotherapy

INTRODUCTION

The aim of this study was to evaluate the use of high-dose-rate brachytherapy (HDR-BT) boost with definitive external beam radiotherapy (EBRT) in prostate cancer (CaP) management.

METHODS

The study population comprised men with intermediate-high risk CaP captured in the population-based Prostate Cancer Outcome Registry Victoria (PCOR-Vic), treated with EBRT from January 2010 to December 2015. The primary outcome is the proportion of men who received HDR-BT boost. Multivariate logistic regressions were used to evaluate the effect of patient-, tumour- and treatment-factors on the likelihood of HDR-BT use. Medicare Benefit Schedule (MBS) data was accessed to evaluate the Australia-wide pattern of HDR-BT use.

RESULTS

One thousand eight hundred and six patients were included in this study - 886 (49%) intermediate-risk, and 920 (51%) high-risk CaP patients. Overall, only 124 (7%) patients had EBRT + HDR-BT - 47 (5%) intermediate-risk and 77 (8%) high-risk CaP patients (P = 0.01). There is higher proportion of patients who had HDR-BT in public institutions (7% public vs. 3% private, P = 0.005) and in metropolitan centres (9% metropolitan vs. 2% regional, P < 0.001). In multivariate analyses, older patients were less likely to have HDR-BT (OR = 0.92; 95% CI = 0.89-0.94, P < 0.001), while patients with high-risk CaP (OR = 1.8; 95% CI = 1.3-2.7; P = 0.002) treated in metropolitan centres (OR = 5.0; 95% CI = 2.6-9.8; P < 0.001) and public institutions (OR = 3.8; 95% CI = 1.5-9.4; P = 0.005) were more likely to have EBRT + HDR-BT. There was significant decline in numbers of HDR-BT performed throughout Australia, from 313 cases in 2010 to 125 cases in 2015.

CONCLUSION

High-dose-rate brachytherapy is under-utilised with EBRT in this contemporary population-based cohort of Victorian men with CaP. The decline in HDR-BT use was also observed nationally.

High-dose-rate brachytherapy boost for prostate cancer: Comparison of three different fractionation schemes

PURPOSE

Dose escalation for prostate cancer can be achieved with a combination of external beam radiotherapy (EBRT) and brachytherapy (BT) boost to increase local control. For high-dose-rate (HDR)-BT, optimal fractionation remains under debate. The objective was to assess the clinical outcome of three schemes of HDR-BT boost.

METHODS AND MATERIALS

Retrospective single institution data collection was performed. Patients received 46 Gy EBRT then an HDR-BT boost: 3 × 6 Gy, 2 × 9 Gy, or 1 × 14 Gy. HDR needles were placed under general anesthesia with endorectal ultrasonography guidance. CT-scan and treatment were performed postoperatively.

RESULTS

Between 2009 and 2012, 159 patients were included. Nine patients (5.7%) were low, 32 (20.1%) intermediate, and 118 (74.2%) high risk (D'Amico classification) without significant difference between the three BT schemes. With a median followup of 61 months, 5-year biochemical relapse-free survival, 5-year local relapse-free survival, 5-year metastases-free survival, and 5-year overall survival rates were 86.6% (SE 2.7%), 98.3% (SE 1%), 95.3% (SE 1%), and 96.5% (SE 1.5%), respectively, with no significant difference between the BT schemes. The rates of acute ≥ G2 genitourinary and ≥G2 gastrointestinal toxicities were 11.3% and 6.3%, respectively (p = NS). The rates of late genitourinary ≥ G2 and gastrointestinal ≥ G2 toxicities (at last followup) were 9.4% and 0.6% with, respectively, 0.6% and 0% of G4 (p = NS).

CONCLUSIONS

Hypofractionation up to a single-fraction HDR-BT boost for prostate cancer yields similar results in terms of biochemical control and late toxicity compared with two or three-fraction schemes. Single fraction HDR-BT appears acceptable for boosting prostate cancer after definitive EBRT.

Stereotactic radiotherapy of the prostate: fractionation and utilization in the United States

Purpose

To analyze the utilization and fractionation of extreme hypofractionation via stereotactic body radiotherapy (SBRT) in the treatment of prostate cancer.

Materials and Methods

Data was analyzed on men diagnosed with localized prostate cancer between 2004–2012 and treated with definitive-intent radiation therapy, as captured in the National Cancer Database. This database is a hospital-based registry that collects an estimated 70% of all diagnosed malignancies in the United States.

Results

There were 299,186 patients identified, of which 4,962 (1.7%) were identified as receiving SBRT as primary treatment. Of those men, 2,082 had low risk disease (42.0%), 2,201 had intermediate risk disease (44.4%), and 679 had high risk disease (13.7%). The relative utilization of SBRT increased from 0.1% in 2004 to 4.0% in 2012. Initially SBRT was more commonly used in academic programs, though as time progressed there was a shift to favor an increased absolute number of men treated in the community setting. Delivery of five separate treatments was the most commonly utilized fractionation pattern, with 4,635 patients (91.3%) receiving this number of treatments. The most common dosing pattern was 725 cGy × 5 fractions (49.6%) followed by 700 cGy × 5 fractions (21.3%).

conclusions

Extreme hypofractionation via SBRT is slowly increasing acceptance. Currently 700-725 cGy × 5 fractions appears to be the most commonly employed scheme. As further long-term data regarding the safety and efficacy emerges, the relative utilization of this modality is expected to continue to increase.

Brachytherapy improves outcomes in young men (≤60 years) with prostate cancer: A SEER analysis

PURPOSE

The aim of the study was to compare prostate cancer-specific mortality (PCSM) in young men with clinically localized prostate cancer treated by either external beam radiation (EBRT) alone or brachytherapy with or without external beam radiation.

METHODS AND MATERIALS

Utilizing the Surveillance, Epidemiology and End Results database, 15,505 patients ≤60 years of age diagnosed with prostate cancer between 2004 and 2009 and treated with radiation therapy alone were identified. Incidence of PCSM was determined for both groups and compared using competing risk models.

RESULTS

The overall 8-year PCSM for the study population was 1.9% (95% confidence interval [CI]: 1.6-2.2). For patients treated with EBRT or brachytherapy with or without external beam, the 8-year PCSM was found to be 2.8% (CI: 2.2-3.4) and 1.2% (CI: 0.9-1.6), respectively (p < 0.001). Univariable analysis demonstrated that brachytherapy was associated with lower PCSM risk (hazard ratio = 0.40; CI: 0.30-0.54; p < 0.001). High Gleason risk category, black race, higher Tumor (T) stage, and higher grade were all associated with greater mortality risk (p < 0.01). On multivariable analysis, brachytherapy continued to be associated with a significantly lower mortality risk (hazard ratio = 0.65; CI: 0.47-0.89; p = 0.008). Subgroup analyses found that among those with Gleason score ≥8, younger patients had increased risk of PCSM (p = 0.001).

CONCLUSIONS

In men ≤60 years of age with prostate cancer, radiation therapy continues to offer excellent outcomes. After adjusting for relevant variables, the use of brachytherapy was associated with reduced PCSM compared to treatment with EBRT alone.

Optimization of the Radiation Management of High-Risk Prostate Cancer

Radiation and androgen-deprivation therapy (ADT) are mainstays of treatment for men with high-risk prostate cancer. High-risk disease is heterogeneous and subcategories of "favorable" high risk and very high risk can identify subgroups with particularly good or poor prognosis to help personalize treatment. Overall, randomized trials show that the combination of radiation and ADT improves survival when compared with either by itself. The optimum duration of ADT remains controversial, but for most healthy men with aggressive disease, approximately 2-3 years of ADT is well supported by the literature. The role of prophylactic pelvic nodal irradiation remains controversial, and there is an ongoing trial testing whether it improves overall survival. The use of brachytherapy boost appears to improve recurrence-free survival without yet improving survival, and may come at the cost of slightly higher toxicity. The addition of docetaxel to radiation and ADT may also improve failure-free survival, but a meta-analysis did not find that it improved overall survival. Retrospective data about the relative value of surgery vs radiation for high-risk disease have yielded varied conclusions and are ultimately hampered by the major issue of selection bias in retrospective series.

Radiation safety of receptive anal intercourse with prostate cancer patients treated with low-dose-rate brachytherapy

PURPOSE

Prostate low-dose-rate (LDR) brachytherapy involves implantation of radioactive seeds permanently into the prostate gland. During receptive anal intercourse, the penis of the partner may come in close proximity to the implanted prostate gland. We estimate the potential intrarectal dose rates and suggest guidance on radiation precautions.

METHODS AND MATERIALS

One hundred two patients were included in the study. After implantation, with patients under anesthesia in the dorsal lithotomy position, a new set of ultrasound (US) images and a CT scan were obtained. The images were fused, radioactive seeds and US probe locations were determined on the CT, and prostate, bladder, and rectal contours were drawn on the US. Dose rates (cGy/h) were calculated for the portion of the US probe spanning the prostate for several dose-volume histogram parameters.

RESULTS

Twenty patients were treated with (125)I and 82 patients with (103)Pd. Average dose rates at Day 0 to the portion of the US probe spanning the prostate were 2.1 ± 1.3 cGy/h and 2.5 ± 0.8 cGy/h for patients treated with (125)I and (103)Pd, respectively. After 60 days, average calculated probe dose drops to 1.0 ± 0.6 cGy/h and 0.2 ± 0.1 cGy/h for (125)I and (103)Pd, respectively.

CONCLUSIONS

During the immediate weeks after prostate seed implant, the estimated intrarectal dose rates are higher in (103)Pd compared to (125)I. As (103)Pd decays faster than (125)I, 2 months after the implant, radiation exposure from (103)Pd becomes lower than (125)I. Receptive anal intercourse time should be kept as low as possible during 2 and 6 months after low-dose-rate brachytherapy of the prostate with (103)Pd and (125)I, respectively.

Brachytherapy boost and cancer-specific mortality in favorable high-risk versus other high-risk prostate cancer

Purpose

Recent retrospective data suggest that brachytherapy (BT) boost may confer a cancer-specific survival benefit in radiation-managed high-risk prostate cancer. We sought to determine whether this survival benefit would extend to the recently defined favorable high-risk subgroup of prostate cancer patients (T1c, Gleason 4 + 4 = 8, PSA < 10 ng/ml or T1c, Gleason 6, PSA > 20 ng/ml).

Material and methods

We identified 45,078 patients in the Surveillance, Epidemiology, and End Results database with cT1c-T3aN0M0 intermediate- to high-risk prostate cancer diagnosed 2004-2011 treated with external beam radiation therapy (EBRT) only or EBRT plus BT. We used multivariable competing risks regression to determine differences in the rate of prostate cancer-specific mortality (PCSM) after EBRT + BT or EBRT alone in patients with intermediate-risk, favorable high-risk, or other high-risk disease after adjusting for demographic and clinical factors.

Results

EBRT + BT was not associated with an improvement in 5-year PCSM compared to EBRT alone among patients with favorable high-risk disease (1.6% vs. 1.8%; adjusted hazard ratio [AHR]: 0.56; 95% confidence interval [CI]: 0.21-1.52, p = 0.258), and intermediate-risk disease (0.8% vs. 1.0%, AHR: 0.83, 95% CI: 0.59-1.16, p = 0.270). Others with high-risk disease had significantly lower 5-year PCSM when treated with EBRT + BT compared with EBRT alone (3.9% vs. 5.3%; AHR: 0.73; 95% CI: 0.55-0.95; p = 0.022).

Conclusions

Brachytherapy boost is associated with a decreased rate of PCSM in some men with high-risk prostate cancer but not among patients with favorable high-risk disease. Our results suggest that the recently-defined “favorable high-risk” category may be used to personalize therapy for men with high-risk disease.