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

Abstract

To compare the outcomes of localized prostate cancer treatment with high-dose-rate brachytherapy (HDR-BT) and low-dose-rate brachytherapy (LDR-BT), we examined 924 patients treated with HDR-BT + external beam radiotherapy (EBRT) and 500 patients treated with LDR-BT ± EBRT using multi-institutional retrospective data. The HDR-BT treated advanced disease with more hormonal therapy than LDR-BT. To reduce background selection bias, we performed inverse probability of treatment weighting (IPTW) analysis using propensity scores and excluded patients with T3b-4 disease/ initial prostate-specific antigen (PSA) levels > 50 ng/ml. The actuarial 5-year biochemical control rates (5y-bNED) were 96.3% and 95.7% in the HDR-BT and LDR-BT groups, respectively. The corresponding values were 100% and 96.5% in the low-risk group; 97.4% and 97.1% in the intermediate-risk group (97.2% and 97% in the higher titer group and 97.5% and 94.6% in the lower titer group, respectively); and 95.7% and 94.9% in the selected high-risk group, respectively. IPTW correction indicated no significant difference among the groups. The 5y-bNED in the HDR-BT + EBRT, LDR-BT + EBRT, and LDR-BT alone groups were 96.3%, 95.5%, and 97%, respectively (P = 0.3011). The corresponding values were 97.4%, 94.7%, and 96.6% (P = 0.1004) in the intermediate-risk group (97.5%, 100%, and 94.5% in the lower titer group [P = 0.122] and 97.2%, 96.2%, and 100% [P = 0.664] in the higher titer group, respectively) and 95.7%, 95.5%, and 100% (P = 0.859) in the high-risk group, respectively. The HDR-BT group showed a lower incidence of acute grade ≥ 2 genitourinary toxicities; the incidence of other early and late grade ≥ 2 toxicities were similar between the HDR-BT and LDR-BT groups. Acute genitourinary toxicity predicted the occurrence of late genitourinary toxicity. EBRT increased the risk of grade ≥ 2 gastrointestinal toxicity. HDR-BT + EBRT is a good alternative to LDR-BT ± EBRT for low-, intermediate-, and selected high-risk patients.

Treatment Strategies for High-Risk Localized and Locally Advanced and Oligometastatic Prostate Cancer

“…Thus, the current clinical evidence for equivalent outcomes with either LDR and HDR or HDR brachytherapy having a theoretical advantage was supported by radiobiological models. There are no other prospective randomized comparisons of EBRT and HDR boost, although some single institution reports have demonstrated favorable biochemical control rates for high-risk localized and locally advanced PC [69][70][71][72][73][74]. Yamazaki [74].…”

Single- and dual-source-strength focal boost planning in low-dose-rate prostate brachytherapy: feasibility study

“…Focal boost techniques could improve outcomes for patients with localised disease and DIL; however, there are no recommendations on the level of dose escalation required for the most appropriate technique. 1,14 The key dosimetric focus of this work was to ascertain the dose escalation achievable using SSS and DSS techniques while not exceeding current clinically implemented OAR constraints.…”

Stereotactic Ablative Brachytherapy: Recent Advances in Optimization of Radiobiological Cancer Therapy

“…For instance, HDR-BT was shown effective in early-stage intra-tracheal [53] and cervical cancers [57], while LDR-BT is successfully used in prostate cancers [58]. Recent retrospective analysis indicated that HDR-BT patients had a lower incidence of acute genitourinary toxicities (grade ≥ 2) [59]. The same study suggested that HDR-BT in combination with external beam RT may serve as a good alternative to LDR-BT (±EBRT) [59].…”

“…Recent retrospective analysis indicated that HDR-BT patients had a lower incidence of acute genitourinary toxicities (grade ≥ 2) [59]. The same study suggested that HDR-BT in combination with external beam RT may serve as a good alternative to LDR-BT (±EBRT) [59]. The precisely calculated ablative dose is the major advantage that facilitates the achievement of better curative effects using SABT, compared to palliative BT.…”