Is the American College of Surgeons National Surgical Quality Improvement Program surgical risk calculator applicable for breast cancer patients undergoing breast-conserving surgery?

BACKGROUND: We aimed to analyze the applicability of the National Surgical Quality Improvement Program (NSQIP) calculator to patients undergoing breast-conserving surgery. METHODS: A total of 287 consecutive patients treated with breast-conserving surgery from 2010 to 2012 were identified retrospectively. The risk calculator was applied to each patient to generate an individual risk profile. Risk calculations were then compared with actual outcomes. The performance of the risk calculator was evaluated using 2 metrics: the Brier score and c statistic. RESULTS: The NSQIP calculator performed adequately for all complications, with Brier scores less than .05. However, 37 patients (12.9%) returned to the operating room for oncologic indications. Twenty-nine patients (10.1%) had positive margins, whereas 8 patients (2.8%) returned due to an upgrade in diagnosis. CONCLUSIONS: When considering return to the operating room for oncologic management, the observed rate of 13.9% is significantly higher than the NSQIP prediction. This deviation must be addressed when using the NSQIP risk calculator model during preoperative risk discussion.