High-dose-rate brachytherapy as monotherapy (HDR-M), or as a boost combined with external beam radiotherapy (HDR-B), are both suitable treatments for intermediate-risk prostate cancer. However, data directly comparing these two approaches for men with unfavorable intermediate-risk (UIR) patients are lacking.
Patients with NCCN-defined UIR prostate cancer treated from 1997 to 2020 were identified in a prospectively maintained, single institution database. HDR-M and HDR-B patients were matched using three factors: age ±3 years; Gleason score (major and minor); and clinical T stage. Biochemical failure was defined as PSA nadir (nPSA) + 2. Available acute and chronic toxicities are additionally reported.
A total of 247 patients were identified (170 receiving HDR-B, 77 receiving HDR-M), ultimately yielding 70 matched pairs (140 patients) for inclusion. The median followup time was 5.2 years for HDR-M compared with 9.3 years for HDR-B (p < 0.001). The two cohorts had similar calculated prostate EQD2 (HDR-B 118 Gy vs. HDR-M 115 Gy, p = 0.977). No significant differences in OS, CSS, DM, LRR, or FFBF were identified. HDR-B had an increased rate of any acute grade 2+ gastrointestinal toxicity and worse acute dysuria and diarrhea. Chronic gastrointestinal and genitourinary toxicity was similar.
These data suggest that HDR brachytherapy as monotherapy is an effective treatment option for selected patients with unfavorable intermediate-risk prostate cancer and provides a more favorable gastrointestinal toxicity profile than HDR-B. Prospective trials should be conducted to refine the selection process for this heterogeneous cohort of patients.
Brachytherapy. 2023 Jun 14 [Epub ahead of print]
Benjamin D Willen, Kamran Salari, Andrew H Zureick, Doyle Lang, Hong Ye, Kimberly Marvin, Sirisha R Nandalur, Daniel J Krauss
Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI. Electronic address: ., Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI., Oakland University William Beaumont School of Medicine, Rochester, MI., Department of Radiation Oncology, William Beaumont Hospital-Troy, Sterling Heights, MI.