Hypofractionated radiation therapy in low-risk prostate cancer: Outcome, toxicity, and sexual function.

Abstract

e16575 Background: To evaluate efficacy, toxicity of image-guided hypofractionated radiotherapy (HFRT) in patients with low-risk prostate cancer. Methods: Eighty-five low-risk prostate cancer patients (Gleason score ≤6, clinical stage T1/T2a-b N0 M0, and PSA ≤10 ng/mL) were treated with HFRT from March 2007 to November 2015. All patients were staged with multi-parametric contrast-enhanced MRI. Clinical target volume (CTV) encompassed prostate with proximal seminal vescicles. Margin from CTV to PTV was 5 mm in all directions. Patients received a total dose of 60 Gy in 20 fractions with 3D-CRT. Daily cone beam CT (IGRT) was executed. RTOG/EORTC morbidity Scoring Scale was used for evaluate toxicities. Results: Median follow-up was 54 months (range 11-116 months). The actuarial 8-years Overall Survival was 97.1%. Eight-years Cancer Specific Survival was 100%, 8-years Biochemical Relapse Free Survival was 98.8%, no patients presented clinical local recurrence. Median of PSA at diagnosis was 3.27 ng/mL (range 1.69-9.98 ng/mL) and at the last follow-up was 0.39 ng/mL (range 0.01-2.26 ng/mL). Acute grade 1-2 gastrointestinal (GI) toxicity occurred in 13 patients (15.3%), grade 1-2 genitourinary (GU) toxicity in 33 cases (38.8%). Grade 3 GU toxicity occurred in 2 patients (2.4%). Grade 1-2 GI and GU late toxicities were observed in 4 (4.7 %) and 25 (29.4 %) patients, respectively. Sexual functionality was qualitatively evaluated, scoring 0 for absence, 1 for presence of erection but insufficient for intercourse, 2 for a sufficient one. Before RT, 4.7 % had score 0, 47.1% had score 1 and 48.2% had score 2. After RT, 34.1% of patients presented score 0, 51.8% score 1 and 14.1% score 2 (Chi-square p = 0,004). After treatment, patients with < 70 years presented score 0 in 4.7% of patients, score 1 in 20% and score 2 in 8.2%. Those with > 70 years, 29.4% presented score 0, 31.8% score 1 and 5.9% score 2 (Chi square p = 0.011). Conclusions: Long-term results of our study demonstrated that HFRT in low-risk prostate cancer is efficacy and well tolerated. HFRT significantly worsened sexual function, even if patients with age < 70 years had a higher probability to maintain any form of sexual function after therapy.