High-Dose-Rate Brachytherapy as Monotherapy for Low- and Intermediate-Risk Prostate Cancer. Oncological Outcomes After a Median 15-Year Follow-Up

High-dose-rate Brachytherapy Monotherapy in Patients With Localised Prostate Cancer: Dose Modelling and Optimisation Using Computer Algorithms

AIMS

Interstitial high-dose-rate brachytherapy (HDR-BT) is an effective therapy modality for patients with localized prostate carcinoma. The objectives of the study were to optimise the therapy regime variables using two models: response surface methodology (RSM) and artificial neural network (ANN).

MATERIALS AND METHODS

Thirty-one studies with 5651 patients were included (2078 patients presented as low-risk, 3077 patients with intermediate-risk, and 496 patients with high-risk). A comparison of these therapy schedules was carried out using an effective biologically effective dose (BEDef) that was calculated assuming the number of treatment days and dose (D) per day. The modelling and optimization of therapy parameters (BEDef and risk level) in order to obtain the maximum biochemical free survival (BFS) were carried out by the RSM and ANN models.

RESULTS

An optimal treatment schedule (BFS = 97%) for patients presented with low-risk biochemical recurrence would be D = 26 Gy applied in one application, 2 fractions at least 6 h apart, within an overall treatment time of 1 day (BEDef = 251 Gy) by the RSM and ANN model. For patients presented with intermediate- or high-risk an optimal treatment regime (BFS = 94% and 90%, respectively) would be D = 38 Gy applied in one application, 4 fractions at least 6 h apart, with an overall treatment time of 2 days (BEDef = 279 Gy) by the RSM and ANN models.

CONCLUSIONS

The RSM and ANN models determine almost the same optimal values for the set of predicted therapy parameters that make a feasible selection of an optimal treatment regime.

Long-term outcomes of ultra-hypofractionated 2 fractions single day HDR brachytherapy in localized prostate cancer

INTRODUCTION AND OBJECTIVES

We previously published the toxicity and initial results of a prospective cohort of patients treated with 2 fractions HDR-BRT administered in a single day. In the present analysis we report the long-term cancer control results of our prospective trial and investigate the relationship between PSA nadir and biochemical control.

MATERIAL AND METHODS

A total of 120 patients were treated with HDR Brachytherapy monotherapy administered in two fractions in a single day. Between November 2010 and February 2016, 84 patients with low-risk and 36 patients with intermediate-risk prostate cancer in accordance with the NCCN practice guidelines.

RESULTS

Median age was 66 years (range 45-84) and median PSA was 7.5 ng/ml (range 0.01-16 ng/ml). Overall, 84.2% had Gleason score 6 and 15.8% Gleason 7. Thirty-one percent of patients received ADT.After a median follow-up of the cohort was 123 months. Actuarial rates of no biochemical evidence of disease (bNED), overall survival, local control and metastasis-free survival for all patients were 93.3%, 86.7%, 95.2% and 96.1%, respectively.The median time to achieve PSA nadir was 80.5 months. Patients who attained a PSA Nadir ≤ 0.20 ng/mL exhibited a 10-year bNED survival rate of 96.9%, whereas thosewho failed to reach this PSA level had a survival rate of only 40%.

CONCLUSIONS

In patients with favorable localized prostate cancer, 2 fractions HDR-BT monotherapy is a highly curative radiation technique that attains PSA nadir levels < 0.2 ng/mL in 95% of cases.

Safety and efficacy associated with single-fraction high-dose-rate brachytherapy in localized prostate cancer: a systematic review and meta-analysis

OBJECTIVE

Although single-fraction high-dose-rate brachytherapy (SFHDR) for localized prostate cancer has been tried in clinical trials, relevant medical evidence is currently lacking. It is necessary to systematically analyze the safety and efficacy of SFHDR.

METHODS

Comprehensive and systematic searches for eligible studies were performed in PubMed, Embase, and the Cochrane Library databases. The primary endpoints included safety and efficacy, represented by toxic effects and biochemical recurrence-free survival (bRFS), respectively. The proportion rates were used as the effect measure for each study and were presented with corresponding 95% confidence intervals (CI) and related 95% prediction interval (PI). Restricted maximum-likelihood estimator (REML) and the Hartung-Knapp method were used in the meta-analysis.

RESULTS

Twenty-five studies met the inclusion criteria for quantitative analysis, including 1440 patients. The median age of patients was 66.9 years old (62-73 years old) and the median follow-up was 47.5 months (12-75 months). The estimates of cumulative occurrence for severe gastrointestinal (GI) and genitourinary (GU) toxic effects were 0.1% (95% CI 0-0.2%) and 0.4% (95% CI 0-1.2%), and for grade 2 toxic effects were 1.6% (95% CI 0.1-4.7%) and 17.1% (95% CI 5.4-33.5%), respectively. The estimate of 3‑year bRFS was 87.5% (95% CI 84.4-90.3%) and 71.0% (95% CI 63.0-78.3%) for 5‑year bRFS. The pooled bRFS rates for low-risk patients were 99.0% (95% CI 85.2-100.0%) at 3 years and 80.9% (95% CI 75.4-85.9%) at 5 years, and the risk group was found to be statistically correlated with bRFS (3-year bRFS, P < 0.01; 5‑year bRFS, P = 0.04).

CONCLUSION

SFHDR is associated with favorable tolerability and suboptimal clinical benefit in patients with localized prostate cancer. Ongoing and planned high-quality prospective studies are necessary to verify its safety and efficacy.