Hypofractionated intensity-modulated simultaneous integrated boost and image-guided radiotherapy in the treatment of high-risk prostate cancer patients: A preliminary report on acute toxicity

Aims and background. To evaluate acute toxicity of hypofractionated intensity-modulated radiotherapy with simultaneous integrated boost and image-guided radiotherapy in the treatment of high-risk prostate cancer patients. Methods. Between November 2009 and March 2012, 59 patients with high-risk prostate cancer were enrolled. The eclipse inverse planning system (Varian) was used to calculate an IMRT plan with simultaneous integrated boost, delivering 68.75 Gy (2.75 Gy per fraction) to the prostate, 55 Gy (2.2 Gy per fraction) to the seminal vesicles and positive nodes, and 45 Gy (1.8 Gy per fraction) to the pelvis, 4 fractions per week, 25 fractions. Prior to each treatment, patients underwent a kilo-voltage conebeam CT performing an image-guided radiation therapy (IGRT). All patients were submitted to neoadjuvant, concomitant and adjuvant hormone therapy. Results. The median follow-up for all patients was 13 months (range, 3-28). At the last follow-up, no grade 3 or 4 side effect was observed. Toxicity occurred as follows during the treatment: grade 1 and 2 gastrointestinal toxicity 5.2% and 6.9%, respectively; grade 1 and 2 genitourinary toxicity 24.1% and 1.7%, respectively. Only 1.7% of the patients developed grade 3 genitourinary toxicity. No grade 3 gastrointestinal toxicity was observed. Conclusions. The present study demonstrated that 4/w hypofractionated intensity-modulated radiotherapy with simultaneous integrated boost and image-guided radiotherapy in patients with high-risk prostate cancer is feasible and safe. Low acute toxicity rates were verified. Longer follow-up is needed to evaluate the outcomes in terms of late toxicity and survival.