Lack of Benefit From the Addition of External Beam Radiation Therapy to Brachytherapy for Intermediate- and High-risk Prostate Cancer

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.

The Prognosis of Radical Prostatectomy, External Beam Radiotherapy plus Brachytherapy, and External Beam Radiotherapy Alone for Patients above 70 Years with Very High-Risk Prostate Cancer: A Population-Matched Study

OBJECTIVE

The aim of this study was to evaluate the survival outcomes of radical prostatectomy (RP), external beam radiotherapy plus brachytherapy (EBRT + BT), and EBRT alone among elderly men (aged 70 years and above) with very high-risk (VHR) prostate cancer (PCa).

METHODS

We identified elderly men diagnosed with VHR PCa between 2004 and 2015 in the Surveillance, Epidemiology, and End Results database. The propensity score-matching method was adopted to balance the covariates and generate new cohorts. -Kaplan-Meier and Cox analyses were conducted to build up survival curves and evaluate the overall survival (OS) and PCa-specific survival (PCSS) outcomes.

RESULTS

A total of 9,818 patients were identified. Of them, 5,839 were in the EBRT group, 725 in the EBRT + BT group, and 3,254 in the RP group. The survival curves of the overall cohort showed that RP was associated with the best OS, followed by EBRT + BT and EBRT (p < 0.001). As for the PCSS, RP shared similar outcomes with EBRT + BT (hazard ratio [HR]: 1.25 [0.93-1.69], p = 0.175). EBRT was associated with significantly worse PCSS than both RP (HR: 1.88, 95% confidence interval [95% CI] [1.64-2.15], p < 0.001) and EBRT + BT (HR: 1.48, 95% CI [1.19-1.85], p = 0.002). In the matched cohorts, RP presented better OS (HR: 1.41, 95% CI [1.07-1.86], p = 0.041) and similar PCSS with EBRT + BT (HR: 1.50, 95% CI [0.91-2.47], p = 0.12). RP was associated with significantly better OS and PCSS outcomes than EBRT alone (OS HR: 1.58, 95% CI [1.59-2.12], p < 0.001; PCSS HR: 2.08 [1.60-2.72], p < 0.001). EBRT + BT also had significantly better OS and PCSS outcomes than EBRT alone (OS HR: 1.33, 95% CI [1.11-1.60], p < 0.001; PCSS HR: 1.57 [1.13-2.19], p = 0.003).

CONCLUSIONS

For patients above 70 years with VHR PCa, RP was associated with better OS and similar PCSS than EBRT + BT. Both RP and EBRT + BT have better OS and PCSS than EBRT alone.

Outcomes with brachytherapy based dose escalation for gleason 8 versus 9-10 prostate cancer: An NCDB analysis

INTRODUCTION

The addition of brachytherapy (BT) in high risk prostate cancer is supported by Level 1 evidence. Whether all high risk patients benefit from BT to the same extent is unknown. The National Cancer Database (NCDB) was used to investigate overall survival (OS) differences between GS 8 and 9-10 treated with external beam radiation (EBRT) only or BT +/- EBRT.

MATERIALS AND METHODS

We included localized prostate adenocarcinoma definitively treated with radiation between 2004-2014. Patients were stratified into various radiation treatment groups: EBRT 7560 - 8640 cGy, EBRT 5940 - 7540 cGy, and BT +/- EBRT. All EBRT only and BT +/- EBRT patients received ADT. A multivariable Cox proportional hazard model was used to assess OS. Propensity score matching was used to account for differences between groups. Median survival was determined based on Kaplan-Meier survival curves.

RESULTS

30,698 patients were included. On multivariable analysis among GS 8 patients, BT was associated with improved OS compared to 7560 - 8640 cGy (HR-0.80 (95% CI 0.70-0.92, P = 0.002). In Gleason 9-10 BT did not result in improved OS compared to 7560 - 8640 cGy (HR- 0.91 (95% CI 0.79 - 1.05, P = 0.212). Results remained significant with propensity score matching and removing patients with medical comorbidities.

CONCLUSION

BT was associated with improved OS when compared to 7560 - 8640 cGy in GS 8, but not in Gleason 9-10 disease. This hypothesis generating study suggests there may be variable benefit with BT in high risk prostate cancer patients on OS. Future prospective studies are needed to investigate whether the benefit of BT is similar across all high risk prostate cancer patients.

Acute and late toxicities in localized prostate cancer patients treated with low-dose 125I brachytherapy (110 Gy) in combination with external beam radiation therapy versus brachytherapy alone (160 Gy)

Purpose

The aim of this analysis was to compare acute and late toxicities between low-dose-rate brachytherapy (LDR-BT) (110 Gy) in combination with 45 Gy in 25 fractions external beam radiation therapy (EBRT) and LDR-BT (160 Gy) alone for localized prostate cancer.

Material and methods

One hundred five consecutive patients with localized prostate cancer treated from May 2014 to May 2017 were included in this retrospective analysis. Sixty patients received combination therapy and 45 patients received BT monotherapy. The LDR-BT procedure was performed using ¹²⁵I seeds.

Results

The median follow-up time was 28 months in both groups. Three-year effect rates were overall survival: 100% in both groups. The biochemical failure rate was 2.3% in the combination group and 0% in the monotherapy group (p = 0.373). No patients died during the study period. In both groups, almost all the patients experienced acute urethritis. There was a significant difference between the combination therapy group (8.3%) and BT monotherapy group (11.1%) in late genitourinary (GU) toxicities ≥ grade 2 (p = 0.035). Only 2 patients (3.3%) in the combination therapy group developed late ≥ grade 2 rectal hemorrhage. There were no significant differences between two groups in hematuria ≥ grade 2 (p = 0.068) or rectal hemorrhage ≥ grade 2 (p = 0.206).

Conclusions

To our knowledge, this is the first report to compare the GU and gastrointestinal toxicities between the combination therapy and BT monotherapy (160 Gy) for localized prostate cancer. Unexpectedly, there were more late GU toxicities (except for hematuria) in the BT monotherapy group.