Scientific Letter Acute Toxicity Profiles of Hypofractionated Adjuvant and Salvage Radiation Therapy After Radical Prostatectomy: Results of a Prospective Study Simonetta Saldi, MD,* Rita Bellavita, MD,* Valentina Lancellotta, MD,* Isabella Palumbo, MD,* Marco Lupattelli, MD,* Sara Chierchini, MD,* Lorenzo Falcinelli, MD,* Claudio Zucchetti, Phys, y Vittorio Bini, DS, z and Cynthia Aristei, MD* Sections of *Radiation Oncology and y Medical Physics and z Department of Medicine, Section of Internal Medicine, Endocrinology & Metabolism, University of Perugia and Santa Maria della Misericordia Hospital, Perugia, Italy Received Dec 13, 2017, and in revised form Jul 29, 2018. Accepted for publication Aug 6, 2018. Summary Moderate hypofractionated adjuvant and salvage radia- tion therapy, as administered with not Helical Tomother- apy, was acutely safe after radical prostatectomy; it was associated with acceptable rates of slight-to-moderate acute genitourinary and gastrointestinal toxicity in 112 patients. Uroflowmetry emerged as a reliable test for radiation therapyerelated genitourinary toxicity. A longer follow-up is needed to confirm these promising clinical outcomes. Purpose: Hypofractionated radiation therapy (RT) is controversial after radical prostatec- tomy (RP). In this interim analysis, our prospective observational study assessed acute genitourinary (GU) and gastrointestinal (GI) toxicity after hypofractionated adjuvant and salvage RT, as delivered by helical tomotherapy (HT), in patients with prostate cancer. Methods and Materials: After undergoing RP with or without pelvic lymph node dissec- tion, 112 patients were enrolled. Hypofractionated adjuvant RT (2.25 Gy daily for 29 frac- tions; total 65.25 Gy) was administered to 40 patients with high-risk features. Hypofractionated salvage RT (2.25 Gy daily for 32 or 33 fractions; total 72-74.25 Gy) was prescribed for 72 patients (24 with biochemical relapse, 48 with local relapse). Toxicity was graded according to the Common Terminology Criteria for Adverse Events version 4.02. The impact of RT on urinary flow was assessed by uroflowmetry. Results: Acute GU toxicity occurred in 41 of 112 patients (36%) (G1 31, G2 10). Acute GI toxicity was observed in 55 (49%) patients (G1 44, G2 11). Uroflowmetry showed that only salvage RT reduced maximum flow significantly (maximum, 68 vs 50 mL/s; P Z .003), perhaps because a higher RT dose had been administered. Conclusions: After RP, moderate hypofractionated adjuvant and salvage RT were associ- ated with acceptable incidences of slight-to-moderate acute GU and GI toxicity and had little impact on urinary flow. Prospective trials are warranted with longer follow-up in larger cohorts to confirm these findings. Ó 2018 Elsevier Inc. All rights reserved. Reprint requests to: Simonetta Saldi, MD, Radiation Oncology Section, Department of Surgical and Biomedical Sciences, University of Perugia, Santa Maria della Misericordia Hospital, Sant’Andrea delle Fratte, 06156 Perugia, Italy. Tel: (075) 578-3614; E-mail: saldisimonetta@gmail.com Conflict of interest: none. Int J Radiation Oncol Biol Phys, Vol. 103, No. 1, pp. 105e111, 2019 0360-3016/$ - see front matter Ó 2018 Elsevier Inc. All rights reserved. https://doi.org/10.1016/j.ijrobp.2018.08.016 Radiation Oncology International Journal of biology physics www.redjournal.org