بررسي تاثير كاهش دوره راديوتراپي بعد از ماتسكتومي بر ميزان عود موضعي در بيماران مبتلا به سرطان پستان

Historical cohort study of breast irradiation schedules after modified radical mastectomy (MRM) for women with breast cancer

Background: Breast irradiation after MRM is an integral component in patients with high loco regional recurrence of breast cancer. Because an optimal fractionation schedule (radiation dose given in a specified number of fractions or treatment sessions over a defined time) for breast irradiation has not been uniformly accepted , we examined whether a 21-day fractionation schedule was as effective as the more traditional 35-day schedule in reducing recurrence. Materials and methods: 100 women with invasive carcinoma of the breast treated by MRM that referred to Imam hossein and Madaen hospitals for irradiation were studied. 50 patients( case group) received short course radiotherapy (40 Gy in 15 fractions over 21 days) and the control group received traditional radiotherapy (50 Gy in 25 fractions over 35 days). Patients in both groups were matched by age, stage of cancer, laterality, chemotherapy and hormone therapy items. Results: Mean age (±S.E.) in the case group(49.9±10.99) and the control group (49.12±9.74) were similar approximately. Three patients experienced local breast cancer recurrence as a first event during 5 years: 1 in the short treatment arm and 2 in the long treatment arm. Local recurrence-free survival was approximately similar in both groups. During 5 years, local recurrence-free survival was 98% in short arm and 96% in long arm. in this study, no difference were detected for disease-free survival (P<0.84) or overall survival (P<0.76). Conclusion: Results from this study support the use of a modest increased in daily fraction size for breast irradiation when the total dose and overall treatment time is reduced. This study demonstrates that a shorter fractionation schedule of 40 Gy in 15 fractions over 21 days is as effective as the more traditional schedule of 50 Gy in 25 fractions over 35 days in terms of preventing recurrence of cancer in the breast.