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

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.