B. Zhao1, C. Tsai1, K. K. Hunt2, S. L. Blair1 2University Of Texas MD Anderson Cancer Center,Breast Surgical Oncology,Houston, TX, USA 1University Of California – San Diego,Surgery,San Diego, CA, USA
Introduction:
The American College of Surgeons Clinical Research Program published evidence-based surgical and oncologic standards for breast cancer in the Operative Standards for Cancer Surgery. Recommended standards include surgical resection with negative margins, removal of all sentinel lymph nodes (SLN) and removal of >10 lymph nodes (LN) for complete axillary dissection (ALND), and the use of adjuvant therapy after surgical resection. However, the rates of adherence to these standards nationwide is unknown.
Methods:
Using the National Cancer Database from 2004-2015, we selected distinct cohorts of breast cancer patients who underwent surgical resection: clinical T1N0M0 under age 70 (CT1), clinical T2N0M0 or T3N0M0 (CT2/3), and clinical M0, pathologic N2 or N3 (PN2/3). For CT1 and CT2/3 patients, we considered patients with negative margins, any form of adjuvant therapy, and ³2 LNs examined as meeting standards. For PN2/3 patients, we considered those with negative margins, any form of adjuvant therapy, and ³10 LNs examined as meeting standards. We compared outcomes of those who met standards versus those who did not for all cohorts. We performed Kaplan-Meier analysis with log-rank test to compare survival for patients based on achieving standards and Cox proportional hazards model for individual predictors of improved survival while controlling for patient comorbidities.
Results:
We identified 318,853 (65.0%) CT1 patients, 164,593 (67.3%) CT2/3 patients, and 77,626 (67.7%) PN2/3 patients who met surgical and oncologic standards. Survival data is shown in the table. For PN2/3 patients, the median survival for those who met standards was significantly longer than those who did not meet standards (109.34 months versus 72.97, p<0.001). Patients were significantly more likely to meet standards if they were treated at an academic center (p<0.001 for all cohorts). For CT1 and CT2/3 patients, ³2 LNs examined, endocrine therapy, radiation therapy, and negative margins were predictors of improved survival. For CT1 patients, chemotherapy was a predictor of worse survival, but was a predictor of improved survival in CT2/3 patients. For PN2/3 patients, ³10 LNs examined, endocrine therapy, chemotherapy, radiation therapy, and negative margins were predictors of improved survival.
Conclusion:
Approximately a third of patients are not receiving evidence-based minimal standards as part of their surgical and oncologic treatment for breast cancer. Adhering to surgical and oncologic standards improves survival in CT1, CT2/3, and PN2/3 breast cancer patients. Efforts to improve knowledge of, and adherence to, these surgical and oncologic standards should be emphasized.
