A decision analysis of the effect of avoiding axillary lymph node dissection in low risk women with invasive breast carcinoma

(BACKGROUND). Evidence that avoiding axillary lymph node dissection (AxD) strikes an appropriate balance between morbidity and recurrence risk in patients with invasive breast carcinoma generally is anecdotal and without a formally quantified basis. The current study presents a decision analysis of the difference in 5‐year disease free survival (DFS) rate between treatment scenarios with and without routine AxD. (METHODS). To derive quantitative estimates of the effect of avoiding AxD on 5‐year DFS, the authors examined outcomes for women undergoing 2 treatment scenarios: AxD or no AxD with adjuvant therapy decisions based on risk factors in the primary tumor. Eligible patients belonged to 2 lymph node metastases risk groups: low (patients without palpable lymph nodes and lymphatic or vascular invasion [LVI] negative tumors ≤ 0.5 cm in greatest dimension) and moderate (patients with mammographically detected, LVI negative tumors, between 0.6‐2.0 cm in greatest dimension or patients with palpable LVI negative tumors between 0.6‐1.0 cm in greatest dimension with nonpalpable lymph nodes). Along with observed data regarding treatment and recurrence, the authors employed estimates of the efficacy of chemotherapy, tamoxifen, and regional radiation therapy derived from published randomized trials to estimate the 5‐year DFS rate for treatment scenarios with and without AxD. (RESULTS). Patients in the low risk group had a 5% risk of lymph node metastases. In these women, eliminating AxD and treating no patients with chemotherapy and/or tamoxifen resulted in a < 1% decrease in the 5‐year DFS rate. Patients in the moderate risk group had a 10% risk of lymph node metastases. Eliminating AxD and treating only those women with Grade 3 tumors > 1 cm in greatest dimension with chemotherapy and/or tamoxifen resulted in a 1.8% decrease in the 5‐year DFS rate. However, if all patients in this group were treated with chemotherapy and/or tamoxifen and no AxD, the 5‐year DFS rate increased by 2.7%. (CONCLUSIONS). In patients with a low risk of lymph node metastases, it was estimated that eliminating AxD may result in only minimal changes in the estimated 5‐year DFS rate.