Treatment sequence of aromatase inhibitors and radiotherapy and long-term outcomes of breast cancer patients.

BACKGROUND The optimal sequence of radiotherapy (RT) and hormone therapy using aromatase inhibitors (AI) in patients with breast cancer treated with breast-conserving surgery is unclear. Several short-term analyses have shown that there are no differences in breast cancer outcomes according to the treatment sequence. However, long-term outcomes have not been reported. PATIENTS AND METHODS We retrospectively analyzed disease-free survival events in 315 consecutive breast cancer patients who underwent breast-conserving surgery, RT, and received adjuvant AI at our Institute between 2001 and 2009. We compared the outcomes between treatment sequences of AI and RT (concurrent vs. sequential). RESULTS With a median follow-up of 5.6 years, no significant differences between the 2 groups in terms of disease-free survival (unadjusted p=0.6; adjusted p=0.5) were observed. CONCLUSION Similarly to previous short-term reports, AI administration after RT and AI concurrently with RT are both reasonable treatment options for early-stage breast cancer patients treated with breast-conserving surgery.