Effect of 21-gene recurrence score in decision-making for surgery in early stage breast cancer

Aim: We aimed to assess the role of 21-gene recurrence score (RS) in the decision-making for surgical treatment in early stage breast cancer and compared the outcomes between breast-conserving surgery (BCS) and mastectomy (MAST) among various 21-gene RS groups. Methods: We included patients with stage T1-2M0M0 and estrogen receptor-positive breast invasive ductal carcinoma who underwent BCS + radiotherapy or MAST between 2004 and 2012 as part of the Surveillance, Epidemiology, and End Results program. Data were analyzed using binomial logistic regression, multivariate Cox proportional hazards models, and propensity score matching (PSM). Results: We enrolled 34,447 patients including 22,681 (65.8%) and 11,766 (34.2%) who underwent BCS and MAST, respectively. Patients with high-risk RS were more likely to receive MAST. Multivariate analysis indicated that patients with intermediate-risk (P<0.001) and high-risk (P<0.001) RS had poor breast cancer-specific survival (BCSS), as compared to those with low-risk RS. Moreover, patients who underwent MAST also exhibited poor BCSS (P<0.001), as compared to those who underwent BCS. In low-risk (P<0.001) and intermediate-risk (P=0.020) RS groups, patients who underwent MAST had poor BCSS, as compared to those treated with BCS. However, BCSS was comparable between patients who underwent MAST and BCS (P=0.952); similar trends were also observed after PSM. Conclusion: The 21-gene RS may impact the decision-making for surgery in early stage breast cancer. Our study provides additional support for a shared decision-making process for BCS when both local management options are appropriate choices regardless of the 21-gene RS.