Intensity Modulated Radiotherapy (IMRT) after Prostatectomy: Acute Toxicity Comparison of Conventional Versus Moderately Hypo-Fractionated Radiation Regimens

Abstract

To compare the acute toxicity of a moderately hypo-fractionated radiotherapy (RT) with that of conventionally fractionated RT to the prostatic bed after prostatectomy. From September 2011 to Jul. 2018, Patients with prostate adenocarcinoma who were recommended to receive adjuvant or salvage RT were prescribed to moderately hypo-fractionated RT (62.75 Gy delivered in 2.51 Gy per fractions) or conventionally fractionated RT (72 Gy delivered in 2 Gy per fraction). All patients received IMRT with daily image-guided radiotherapy (IGRT). Patients who received hypo-fractionated RT were matched (for age, hormonal therapy, irradiated volume, interval between surgery and RT, and comorbidities such as diabetes mellitus and hypertension.) with propensity scores to patients who underwent conventionally fractionated RT. Acute and late toxicity was recorded and graded according to CTCAE 4.0. One hundred and fifty-one patients were enrolled with seventy-nine patients received moderately hypo-fractionated RT versus seventy-two patients received conventionally fractionated RT. The median follow-up is 13 and 50 months respectively. Grade 2 acute GI and GU toxicities were 8.8% vs 6.9% and 13.9% vs 16.6%, respectively (p>0.05). After propensity score matching, there are fifty-eight patients in hypoPORT and coPORT groups respectively. Grade 2 acute gastrointestinal (GI) and genitourinary (GU) toxicity were observed in 10.3% vs 8.6% and 13.7% vs 15.5% of patients, respectively (p>0.05). None of patients reported ≥ grade 3 acute and late GI or GU toxicity. After prostatectomy, moderately hypo-fractionated RT (2.51 Gy/f X 25 f) demonstrated an acute toxicity profile which compares favorably with that of conventionally fractionated RT.