Hypofractionated Radiotherapy in Low Risk Prostate Cancer: Preliminary Experience

Objective: Get free interval biochemical failure and toxicity in patients treated with hypofractionated radiotherapy (HFRT, for its acronym in English, Hypofractionated Radiation Therapy) with IMRT (Intensity Modulated Radiation Therapy), administering 70 Gy in 28 fractions of 2.5 Gy. Methods: In May 2013 began in CDD Radioterapia Radioterapia Unit of Radiotherapy and Radiosurgery of Clinica Abreu, an hypofractionation program with IMRT as an alternative treatment for patients with localized prostate cancer favorable risk. The four selected patients had histologically confirmed prostate adenocarcinoma without prior radical treatment and categorized as low risk according to the criteria of D'Amico et al. For each patient a treatment plan is made based on Intensity Modulated Radiation Therapy (IMRT) more Image Guided Radiation Therapy (IGRT) with 18 MV photons from a linear accelerator CLINAC 21iX of the prestigious brand Varian®, administering doses of 70 Gy in 28 fractions of 2.5 Gy/day using an α/β 3, biologically equivalent to 76 Gy in 38 fractions of 2 Gy, under-Quadratic Linear Model. Patients were followed every 3 months for 18 months. The gastrointestinal and genitourinary toxicity (GI) (GU), was evaluated prospectively and classified according to the criteria of the RTOG (Radiation Therapy Oncology Group). As a definition of biochemical failure we use the RTOG criteria (definition Phoenix), considered the elevation of post- radiotherapy PSA≥2 ng/mL above the nadir. Results: During follow-up of 18 months, all patients (100%) were free of biochemical failure. Only one patient presented grade 2 acute genitourinary toxicity, without having reported genitourinary or gastrointestinal late toxicity. This study is preliminary, with short follow and discreet patient population, however, is the first program and the first publication of hypofractionated treatment for prostate cancer radiotherapy in our country.