Abstract
BACKGROUND: Elderly women with clinically node-positive (cN+) breast cancer (BC) often have comorbidities that limit life expectancy and complicate treatment. We sought to determine whether the number of lymph nodes (LNs) retrieved among older women with node-positive BC was associated with overall survival (OS). METHODS: Using the National Cancer Database (2010-2015), women 70-90 y with cN + BC and ≥1 LNs removed were categorized by treatment sequence: upfront surgery or neoadjuvant chemotherapy (NAC). Multivariable Cox proportional hazards models with restricted cubic splines characterized the functional association of LN retrieval with OS; threshold values of LN retrieval were estimated. Cox proportional hazards models were used to estimate the association of LN retrieval groups with OS. RESULTS: In the upfront surgery cohort, a nonlinear association was identified between LNs retrieved and OS. In the NAC cohort, no association was identified. For the upfront surgery cohort, the optimal threshold value of LN retrieval was 21 LNs (90% confidence interval 18-23). Based on this estimate, LN retrieval groups were created: <6, 6-11, 12-17, 18-23, and >23 LNs. After adjustment, retrieval of <12 LNs in the upfront surgery group was associated with a worse OS. No differences were observed in the NAC group. CONCLUSIONS: For elderly women receiving upfront surgery, there is no survival benefit to removing more than 12 LNs, and for those receiving NAC, there is no association between number of LNs removed and survival. In older women who present with cN + BC, aggressive surgery to remove more than 12 LNs may not be necessary.