Abstract: Objective：To observe the preventive effect of two fractionations for postoperative radiotherapy of keloid and discuss the optimal way for postoperative radiotherapy. Methods: We enrolled 107 consecutive keloid patients with 139 lesions from August 2011 to October 2012 in Department of Radiation Oncology of Peking University First Hospital. There were 114 lesions (the largest lesion part will be accounted if there are several lesions in the single body area) into the curative effect of the statistics. All the patients received irradiation after operation within 24 hours. The patients were divided into two groups: 5 Gy/f for continuous 4 days (5 Gy group); 4 Gy/f for continuous 5 days (4 Gy group). The lesions were treated by 6 MeV-E by Varian 21EX medical linear accelerator made in America. The irradiation field was surgical incision plus 1 cm in radial directions. One centimeter bolus was put on the skin to attain the therapeutical dose of skin surface. The total dose for each lesion was 20 Gy. The treatment effect of keloid was classified into cure, excellence and recurrence, referring to Darzi’s standard. Effectivity means the sum of cure and excellence. SPSS 14.0 was used to statistically analyze the data. Results: The total effective rate for 5 Gy group was 90.7% (49/54) and 66.7% (40/60) for 4 Gy group (P=0.001). The lesions were divided into three regions according to the tension of the skin: ear/face/neck region, chest wall/shoulder/back region and other regions. The treatment effects of 5 Gy group and 4 Gy group were 94.1% (16/17) vs. 85.0% (17/20) for ear/face/neck region, 89.7% (26/29) vs. 60.0% (18/30) for chest wall/shoulder/back region and 87.5% (7/8) vs. 50.0% (5/10) for other regions. Significant difference was found in chest wall/shoulder/back region (P=0.009). No obvious toxicities occurred in any group. Conclusion: Postoperative radiation therapy within 24 hours of 5 Gy/f for continuous 4 days and 4 Gy/f for continuous 5 days is effective, especially in 5 Gy/f group. It is suggested that hypofractionated radiation therapy is more effective for keloid patients, and it is also economical and convenient for patients and worth further discussing.

Key words: Keloid, Radiotherapy dosage, Dose fractionation, Treatment outcome