Background: The optimal sequence of chemotherapy (CT) and radiotherapy (RT) remains uncertain after breast-conserving surgery (BCS). The current study was performed to evaluate whether the concurrent RT with CT increases the toxicities.
Methods: Two hundred and thirty-eight patients with stages I and II breast cancers were prospectively allocated to concurrent CT and RT (n = 133) and sequential CT and RT (n = 105) after BCS. In the sequential group, RT was started after the completion of three cycles of CT and additional three cycles of CT were delivered after RT.
Results: There was no significant difference in Grade 3 or 4 hematologic toxicities during CT between the two groups. Radiation related adverse effects were not different between the two groups. During the median follow-up period of 42 months (range: 16-60 months), 18 patients (13.5%) of the concurrent group had systemic recurrence of breast cancer, whereas 20 patients (19.1%) of the sequential group had systemic recurrence. Disease-free survival and local recurrence were not different between the two groups.
Conclusions: Concurrent CT and RT were not associated with increased toxicity and showed reasonable cosmetic results. The current study indicates that concurrent RT and CT after BCS is a feasible treatment modality with an advantage of shortening the treatment time.