Hypofractionated intensity-modulated radiotherapy with simultaneous integrated boost after radical prostatectomy: Preliminary results of a phase II trial

Aim: To report the acute toxicity of a hypofractionated regimen of intensity-modulated radiotherapy with simultaneous integrated boost (SIB-IMRT) to the pelvic nodes and the prostatic bed after radical prostatectomy. Patients and Methods: Patients with prostate adenocarcinoma at high risk of relapse after radical prostatectomy or with biochemical relapse were deemed eligible for study. SIBIMRT was prescribed to the whole pelvis (45-Gy delivered in 1.8-Gy fractions) and the prostatic bed [62.5 Gy, 2.5-Gy fractions, Equivalent Dose in 2-Gy fraction (EQD2)=68.75 Gy, a/β=3]. Acute toxicity was recorded and graded according to Radiation Therapy Oncology Group (RTOG) criteria. Results: Forty-nine patients were enrolled. No cases of grade =3 acute toxicity were recorded. Grade 2 acute genitourinary and gastrointestinal toxicity was observed in 9.6% and 29.7% of patients, respectively. Conclusion: After radical prostatectomy, hypofractionated high-dose SIB-IMRT enables for reduction of the overall treatment time, with an acute toxicity profile which compares favourably with that of conventionally fractionated high-dose three-dimensional conformal radiotherapy (3D-CRT).