Mortality in Older Patients with Breast Cancer Undergoing Breast Surgery: How Low is "Low Risk"?

ABSTRACT

BACKGROUND: Breast surgery carries a low risk of postoperative mortality. For older patients with multiple comorbidities, even low-risk procedures can confer some increased perioperative risk. We sought to identify factors associated with postoperative mortality in breast cancer patients ≥70 years to create a nomogram for predicting risk of death within 90 days. METHODS: Patients diagnosed with nonmetastatic invasive breast cancer (2010-2016) were selected from the National Cancer Database. Unadjusted OS was estimated using the Kaplan-Meier method. Multivariate logistic regression was used to estimate the association of age and surgery with 90-day mortality and to build a predictive nomogram. RESULTS: Among surgical patients ≥70 years, unadjusted 90-day mortality increased with increasing age (70-74 = 0.4% vs. ≥85 = 1.6%), comorbidity score (0 = 0.5% vs. ≥3 = 2.7%), and disease stage (I = 0.4% vs. III = 2.7%; all p < 0.001). After adjustment, death within 90 days of surgery was associated with higher age (≥85 vs. 70-74 odds ratio [OR] 3.16, 95% confidence interval [CI] 2.74-3.65), comorbidity score (≥3 vs. 0 OR 4.79, 95% CI 3.89-5.89), and disease stage (III vs. I OR 4.30, 95% CI 3.69-5.00). Based on these findings, seven variables (age, gender, comorbidity score, facility type, facility location, clinical stage, and surgery type) were selected to build a nomogram; estimates of risk of death within 90 days ranged from <1 to >30%. CONCLUSIONS: Breast operations remain relatively low-risk procedures for older patients with breast cancer, but select factors can be used to estimate the risk of postoperative mortality to guide surgical decision-making among older women.