Clinical outcomes of patients with localized and locally advanced prostate cancer undergoing high-dose-rate brachytherapy with external-beam radiotherapy at our institute

Abstract

Aim: To report the clinical outcomes of localized and locally advanced prostate cancer patients undergoing high-dose-rate brachytherapy (HDR-BT) with external-beam radiotherapy (HDR-BT+EBRT) at the Kanazawa University Hospital.

Patients and methods: From 1999 until 2012, we examined 327 patients with T1c-T3bN0M0 prostate cancer that underwent HDR-BT+EBRT and were followed-up for ≥1 year. Before 2005, treatment consisted of HDR-BT at 18 Gy/3 fractions and EBRT to the prostate at 44 Gy/22 fractions, whereas after 2006, treatment consisted of HDR-BT at 19 Gy/2 fractions and EBRT to the prostate at 46 Gy/23 fractions.

Results: Median age was 68 years (range=45-84 years), median follow-up duration was 57 months (range=12-148 months), and median prostate-specific antigen (PSA) level at diagnosis was 9.2 ng/ml (range=2.6-458.6 ng/ml). The patients' clinical stages were T1c:82, T2a:112, T2b:70, T2c:5, T3a:29, T3b:29, and their Gleason score was ≤6:120, 7:108, ≥8:99, respectively. The 5-year overall survival, and biochemical recurrence-free survival (bRFS) was 97.5% and 95.3%, respectively. Recurrence was reported in 20 cases (6.1%), and 11 patients died during follow-up, but only 1 patient died of prostate cancer. The 5-year recurrence-free survival bRFS for the patients in low-risk, intermediate-risk, and high-risk groups according to the D'Amico risk classification criteria were 100%, 95.6%, and 90.7%, respectively. Regarding adverse events genitourinary toxicity was major, and thus, 8.8% patients had urethral stricture and 4.3% patients were classified as grade 3.

Conclusion: HDR-BT+EBRT is considered a suitable treatment modality for localized and locally advanced prostate cancer, including high-risk cases. However, genitourinary toxicity is observed frequently, and therefore, it may be necessary to modify the therapeutic planning of the HDR-BT+EBRT modality.

Keywords: Prostate cancer; high-dose-rate brachytherapy.