Image guided intensity modulated hypofractionated radiotherapy in high-risk prostate cancer patients treated four or five times per week: analysis of toxicity and preliminary results.

To evaluate efficacy and toxicity of hypofractionated intensity-modulated simultaneous integrated boost (IMRT-SIB) and image-guided (IGRT) radiotherapy in the treatment of high-risk prostate cancer patients.Eighty-two patients with high-risk prostate cancer were analysed. An IMRT treatment was planned delivering 68.75 Gy to the prostate, 55 Gy to the seminal vesicles and positive nodes and 45 Gy to the pelvis in 25 fractions. The first 59 patients received 4 weekly fractions whereas the last 23 patients received 5 weekly fractions. All patients were submitted to hormonal therapy.The median follow-up was 31 months. Acute grade 1-2 gastrointestinal (GI) toxicity rates were 13.4\%. Grade 1-2 and grade 3 genitourinary (GU) toxicity rates were 22\% and 1.2\%, respectively.Grade 1 and 2 GI late toxicity rates were 1.2\%. No grade ≥3 toxicity was recorded. Grade 1 GU late toxicity rate was 2.4\%. No grade ≥2 toxicity was recorded.No significant difference was calculated in terms of acute and late toxicity between the group treated 4 or 5 times weekly.The actuarial 3-years Overall survival and Freedom from biochemical failure were 98.6\% and 91.3\%, respectively.The present study demonstrated that hypofractionated IGRT-IMRT-SIB in patients with high-risk prostate cancer is efficient with acceptable toxicity profile. Outcome in terms of survival are promising, but longer follow-up is needed.