Breast conserving therapy is associated with improved overall survival compared to mastectomy in early-stage, lymph node-negative breast cancer

• Published in: Radiotherapy and oncology 2020-01, Vol.142, p.186-194
• Main Authors: Almahariq, Muayad F., Quinn, Thomas J., Siddiqui, Zaid, Jawad, Maha S., Chen, Peter Y., Gustafson, Gregory S., Dilworth, Joshua T.
• Format: Article
• Language: English
• Subjects: Breast cancer; Breast conserving therapy; Mastectomy; Recurrence score; Whole breast radiotherapy
• ISSN: 0167-8140; 1879-0887
• DOI: 10.1016/j.radonc.2019.09.018

•Breast conserving therapy (BCT) is associated with higher OS compared to mastectomy.•The benefit of BCT is highest in women with a high Recurrence Score and >50 years.•These findings warrant prospective validation. Recent retrospective studies suggest improved overall survival (OS) with breast conserving therapy (BCT), including breast conserving surgery and adjuvant whole breast radiotherapy, compared to mastectomy in the modern era. The patient subset most likely to benefit from BCT remains unclear, and the role of Oncotype DX Recurrence Score (RS) in this context is unknown. We compared BCT to mastectomy in early-stage, node-negative breast cancer. We further explored outcomes after stratification by RS and age. We performed a matched-cohort analysis of National Cancer Database (NCDB) patients with pT1-2, pN0, cM0 breast cancer treated between 2006 and 2014 with BCT or mastectomy. Patients were matched for all available baseline characteristics using propensity scores with inverse probability of treatment weighting (IPTW) with stabilized weights. We identified 144,263 eligible patients treated with BCT and 87,379 patients treated with mastectomy. After IPTW-matching, OS was higher with BCT compared to mastectomy: 5-year OS of 94.4% vs. 91.8% (P 50 years of age. Prospective validation of these findings is required.