Efficacy and toxicity outcomes for patients treated with focal salvage high dose rate brachytherapy for locally recurrent prostate cancer

Abstract

Introduction: Isolated local recurrence of prostate cancer following primary radiotherapy or brachytherapy may be treated with focal salvage high dose rate brachytherapy, although there remains an absence of high quality evidence to support this approach. Methods: Men with prostate cancer treated consecutively between 2015 and 2018 using 19 Gy in a single fraction high dose rate brachytherapy (HDR) for locally recurrent prostate cancer were identified from an institutional database. Univariable analysis was performed to evaluate the relationship between patient, disease and treatment factors with biochemical progression free survival (bPFS). Results: 43 patients were eligible for evaluation. Median follow up duration was 26 months (range 1-60). Median bPFS was 35 months (95% confidence interval 25.6-44.4). Kaplan-Meier estimates for bPFS at 1, 2 and 3 years post salvage were 95.2%, 70.6% and 41.8% respectively. On univariable Cox regression analysis, only nadir PSA was significantly associated with bPFS although the majority of patients were also treated with androgen deprivation therapy. Only one late grade 3 genitourinary toxicity was observed. Conclusion: Focal salvage HDR brachytherapy may provide good biochemical control with a low risk of severe toxicity. Further evaluation within clinical trials are needed to establish its role in the management of locally recurrent prostate cancer.

Determining the safety of ultrafocal salvage high-dose-rate brachytherapy for radiorecurrent prostate cancer: A toxicity assessment of 150 patients

“…In recent years, an increasing amount of literature on focal salvage HDR-BT has become available. Table 4 summarizes four studies using different focal HDR-BT regimens and targeting strategies, who all reported GU and GI toxicities using the CTCAE 4.0 [13] , [14] , [15] , [16] . Across these studies, 2–10% grade 3 GU and 0% grade 3 GI toxicity was reported.…”

Salvage Reirradiation Options for Locally Recurrent Prostate Cancer: A Systematic Review

“…For the focal gland BT group (n=4) ( 16 , 34 , 36 , 38 ), the only grade 3 or higher toxicity reported was late GU toxicity – with a mean (range) of 4.8% (2-10%). For the focal gland SBRT group (n=4) ( 46 , 51 , 53 , 54 ), mean (range) grade 3 or higher toxicities were 0.5% (0-2%) (acute GU), 1.5% (0-4%) (late GU) and 1% (0-4%) (acute GI).…”

Focal therapy for (recurrent) prostate cancer

“…Patients with ePLND-proven (pN+) or image-suspected (iN+M+) metastatic disease represent a heterogeneous and complex group (often referred to as "very high risk"), for whom a clear consensus regarding optimal treatment is lacking. A subdivision based on metastatic volume (lowor high-volume) has been adopted as a predictor for survival and as a guideline for treatment decisions (64).…”

“…A study in which patients subsequently underwent mp-MRI, TRUS-biopsies and transperineal template prostate mapping (TPM) biopsies (sampling the whole gland every 5 mm), calculated that up to 18% more cases of clinically significant cancer might be detected if TRUS-bi-opsies were guided by MRI findings [50]. Adding mp-MRI information to subsequent TPM biopsies seems to achieve the highest diagnostic accuracy, with a sensitivity and specificity of 97% and 61%, a positive predictive value of 83% and a negative predictive value of 91% [64]. Different approaches to achieve biopsy under MRI-guidance (i.e.…”

“…In the primary whole-gland treatment setting, a prospective randomized controlled trial comparing two fractions of 13.5 Gy to a single dose of 19 Gy HDR-brachytherapy revealed a clear 5-year biochemical disease-free survival advantage in the two-fraction arm (95% versus 73.5%) (61). In the focal salvage treatment setting, the evidence is limited to individual cohort studies which show higher estimated 3-year biochemical disease-free survival among multi-fraction studies (±60% versus ±44%), with comparable toxicity rates (62)(63)(64)(65)(66). Although these results support the use of fractionated treatment, selection bias may affect this interpretation.…”