Five-year results of combined radiation therapy for high-risk prostate cancer

Abstract

The purpose of the study is to assess the effectiveness and toxicity of the treatment of prostate cancer (PCa) with combined radiation therapy (CRT), where high dose rate brachytherapy (HDR-BT) "boost".
 Materials and methods: CRT was carried out in 98 patients of high-risk and extremely high-risk PCa. External part of treatment (conformal external radiation therapy) provided total dose 46-50 Gy with a single focal dose (SFD) 2 Gy to the prostate gland (PG), seminal vesicles and regional lymphatic zones. Two regimes of "boost" to the PG and seminal vesicles were used: in the first group – two fractions of 10 Gy (81 patients), in the second - 15 Gy (17 patients).
 Results: median follow-up equals: I group - 57.5 months, II group - 55.2. Three- and five-year survival without biochemical progression in group I - 75.4% and 69.0%, II group - 76.4% and 52.9%, respectively. Similar indicators regardless of the CRT regime in groups of different risk of relapse were equal: high risk - 84.6% and 75.9%, extremely high risk - 69.4% and 60.7%, respectively (p=0.05).
 There were no late radiation genitourinary and gastrointestinal complications of 4-5 degrees. The most significant variants of late disorders were the formation of urethra stricture (one patient of the I group) and stenosis of the rectum (one patient of the II group). Late genitourinary radiation toxicity (L-GURT) was mainly represented by changes that can be characterized as 1 degree (RTOG/CTCAE): I group - from 40.6% to 53.2%, II - 18.8% to 35.3%.
 Conclusions: the studied CRT regimes showed perfectly acceptable survival rates with no signs of biochemical progression and radiation toxicity during the five-year period of follow-up.