Effect of Postmastectomy Radiotherapy in Patients <35 Years Old With Stage II-III Breast Cancer Treated With Doxorubicin-Based Neoadjuvant Chemotherapy and Mastectomy

Purpose: Postmastectomy radiotherapy (PMRT) improves locoregional control (LRC) in patients with high-risk features after mastectomy. Young age continues to evolve as a potentially important risk factor. The objective of this study was to assess the benefits of PMRT in patients <35 years old treated with doxorubicin-based neoadjuvant chemotherapy for Stage II-III breast cancer. Patients and Methods: We retrospectively analyzed 107 consecutive breast cancer patients <35 years old with Stage IIA-IIIC disease treated at our institution with doxorubicin-based neoadjuvant chemotherapy and mastectomy, with or without PMRT. The treatment groups were compared in terms of LRC and overall survival. Results: Despite more advanced disease stages, the patients who received PMRT (n = 80) had greater rates of LRC (5-year rate, 88% vs. 63%, p = 0.001) and better overall survival (5-year rate, 67% vs. 48%, p = 0.03) than patients who did not receive PMRT (n = 27). Conclusion: Among breast cancer patients <35 years old at diagnosis, the use of PMRT after doxorubicin-based neoadjuvant chemotherapy and mastectomy led to a statistically greater rate of LRC and overall survival compared with patients without PMRT. The benefit seen for PMRT in young patients provides valuable data to better tailor adjuvant, age-specific treatment decisions after mastectomy.