Acute and late toxicity and preliminary outcomes report of moderately hypofractionated helical tomotherapy for localized prostate cancer: a mono-institutional analysis.

ABSTRACT

AIMS: To assess toxicity and clinical outcomes of moderately hypofractionated helical tomotherapy (HT) for the curative treatment of localized prostate cancer (PC). METHODS: From December 2012 to May 2018, 170 patients were treated with definitive intent for PC. Thirty-four percent were low risk, 30% intermediate risk (IR) and 36% high risk (HR). All patients received 70 Gy in 28 fractions to the prostate; 61.6 Gy were delivered to the seminal vesicles for IR; pelvic lymph nodes irradiation for a total dose of 50.4 Gy was added in the HR subgroup. Toxicity was assessed using CTCAE V4.0, and biochemical failure was defined following Phoenix criteria. Time-to-event data were analyzed using the Kaplan-Meier method and log-rank test. RESULTS: The median follow-up was 36 months (range 12-78); acute toxicity was as follows G1 and G2 in 27.6% and 19.4% for GI; 53% and 24% for GU. No G ≥ 3 event was observed. For late toxicity, G ≥ 3 GI and GU rates were, respectively, 3% and 2.4% at 3 years and 3% and 4.8% at 4 years; no G4 occurred. A statistical correlation between acute or late G3 incidence and clinical or dosimetric parameters was not found. At the time of analysis, 2- and 3-year biochemical relapse-free survival rates were 90% and 87.5% and 2- and 3-year overall survival rates were 96.4% and 90%, respectively. The log-rank test revealed no difference between the risk groups in terms of biochemical control (p = 0.16). CONCLUSIONS: Moderately hypofractionated RT with HT for localized prostate cancer reported excellent outcomes with mild acute and late toxicity incidence, with promising biochemical control rates.