A preliminary toxicity study of different dose fractionation regimens in postoperative radiotherapy for prostate cancer / 中华放射肿瘤学杂志

ABSTRACT

Objective To compare the toxicity between different dose fractionation regimens in postoperative radiotherapy for prostate cancer. Methods Patients with prostate cancer who received postoperative radiotherapy with moderate hypo-fractionation ( 62. 75 Gy in 25 fractions, 2. 51 Gy per fraction) or conventional fractionation (72 Gy in 36 fractions, 2 Gy per fractions) in our hospital from 2011 to 2017 were enrolled as subjects.All patients received intensity-modulated radiotherapy and daily cone-beam computed tomography image-guided radiotherapy. According to the propensity score matching ( PSM ) method, 35 patients treated with moderately hypo-fractionated radiotherapy were matched to 35 patients treated with conventionally fractionated radiotherapy based on age, irradiated volume, hormonal therapy, interval between surgery and radiotherapy, and comorbidities ( diabetes and hypertension). Toxicity was evaluated according to Radiation Therapy Oncology Group criteria. Comparison was made by the Fisher's exact probability test. Results One hundred and thirteen patients, consisting of forty-one in moderate hypo-fractionation group and seventy-two in conventional fractionation group, were enrolled as subjects. The median follow-up time in the two groups was 5. 6 and 45. 0 months, respectively. There were no significant differences in incidence rates of grade 2 acute gastrointestinal (GI) or genitourinary (GU) toxicity between the two groups ( 7% vs. 7%, P＝ 1. 000; 15% vs. 17%, P＝ 0. 847). After PSM, there were still no significant differences in incidence rates of grade 2 acute GI or GU toxicity between the two groups (9% vs. 11%, P＝0. 814; 14% vs. 11%, P＝ 0. 670). None of patients reported ≥grade 3 GI or GU toxicity. Conclusions Preliminary results show that moderate hypo-fractionation, compared with conventional fractionation, does not increase the risk of acute GI or GU toxicity in patients undergoing postoperative radiotherapy for prostate cancer.