Role of axillary node dissection after mastectomy with positive sentinel nodes.

Abstract

554 Background: The ACOSOG Z11 trial demonstrated that sentinel lymph node biopsy (SLNB) alone was safe for women with early stage node positive cancer undergoing breast conservation therapy with radiation. Little data exists regarding management of this population undergoing mastectomy. The purpose of our study is to determine the benefit of axillary lymph node dissection (ALND) or SLNB with adjuvant radiation in patients with 1-3 positive SLN after mastectomy. Methods: Using data from the National Cancer Database (2004-2014), we performed a retrospective review of patients who underwent mastectomy and were clinically node negative at presentation, but were found to have 1-3 positive nodes on pathology. Patients were categorized as undergoing SLNB alone (1-5 nodes examined) or ALND (≥8 nodes examined). Patients who received SLNB without ALND were further categorized by receipt of radiation treatment (RT). Patients with either neoadjuvant chemotherapy or stage IV disease were excluded. Results: Of 42,371 patients, 10.0% had SLNB+RT, 22.4% had SLNB alone, and 67.5% had ALND. Median age of the cohort was 58 years and median tumor size 2.3 cm. Median follow up was 4.1 years. After adjustment for covariates including age at diagnosis, tumor size, chemotherapy, endocrine therapy and receptor status, SLNB+RT had comparable overall survival to ALND (HR = 1.06, p = 0.52), but SLNB alone was found to be associated with a 25% increase in hazard of death compared to ALND (HR = 1.25, 95% CI 1.11-1.41, p < 0.001). Conclusions: In clinically node negative patients with 1-3 positive sentinel nodes treated with mastectomy, SLNB alone was associated with a significantly increased risk of all-cause mortality compared to ALND or SLNB+RT. These results suggests that ALND may be avoided in these patients in the setting of adjuvant radiation, possibly avoiding the morbidity associated with axillary lymphadenectomy.