Predicting axillary lymph node metastases in breast cancer patients with tumors under 2 cm in size

Background  To assess whether lymph nodes are consistently negative below a certain tumor size, we investigated the incidence and predictors of lymph node metastasis in breast cancer patients with tumors under 2 cm in size. Methods  A total of 238 breast cancer patients with tumors under 2 cm in size were retrospectively reviewed. Results  Preoperatively, 219 tumors were palpable while 19 were not. There was no lymph node metastasis in the nonpalpable tumors (n=19) or those 5 mm or less in size (n=1) tumors, but 17% of those greater than 5 mm but less than 10 mm (n=30) and 29% of those greater than 10 mm but 20 mm or less (n=188) tumors had nodal involvement. Conclusions  Our sample size was too small to determine a specific tumor size that would warrant omission of axillary lymph node dissection. However, axillary lymph node dissection may be avoided in breast cancer patients with clinically nonpalpable tumors.