Adherence to surgical and oncologic standards improves survival in breast cancer patients

Abstract Background Adherence to evidence‐based standards can lead to improved outcomes for patients with breast cancer. However, adherence rates to standards and their effects on patient outcomes are unknown. Objectives To examine adherence rates to standards compiled by the American College of Surgeons Clinical Research Program and its effects on patient outcomes. Methods Using the National Cancer Database (2004‐2015), we identified cohorts of breast cancer patients: clinical T1N0M0 under age of 70 (cT1), clinical T2N0M0 or T3N0M0 (cT2/3), and clinical M0 and pathologic N2 or N3 (pN2/3). Standards included negative margins, any adjuvant therapy, and two or more lymph nodes (LNs) examined (for cT1 or cT2/3 patients) or more than 10 LNs examined (for pN2/3 patients). We performed Kaplan‐Meier and Cox proportional hazards analysis. Results We identified 318 853 (65.0%) cT1, 164 593 (67.3%) cT2/3, and 77 626 (67.7%) pN2/3 patients who met the standards. More than 90% of patients had negative margins and adjuvant therapy, but less than 80% met LN standards. The median overall survival (OS) was significantly longer for patients who met the standards. Individual components of the standards were predictors of improved OS. Conclusions One‐third of patients did not meet the evidence‐based standards in their treatment for breast cancer. Efforts to improve the knowledge of and adherence to these standards should be emphasized.