The incidence of axillary lymph node metastasis in patients with T1 breast carcinoma has been reported by incidence of 6-31%. Axillary node involvement is the single most prognostic factor and a guideline for adjuvant treatment. But the necessity of routine axillary dissection for staging is recently been questioned. We studied to investigate the possibility of using clinicopathologic characteristics to predict axillary node status of T1 breast carcinoma sparing routine axillary dissection.

Five hundreds fourteen patients with T1 breast cancer whose pathological diagnosis were invasive ductal carcinoma NOS, were elligible for this study. All patients underwent axillary dissection by modified radical mastectomy or conservative surgery in the period between Jan. 1990 and Dec. 1998 at department of surgery, Seoul National University Hospital. The clinicopathologic characteristics of primary tumor include age (35>, ≤35), tumour size, nuclear grade, histologic grade, hormone receptor status, lymphatic vessel invasion (LVI), and various tumor markers (p53, cerbB2, cathepsinD, bcl-2, and ki67) were evaluated according to lymph node status.

Frequency of axillary lymph node metastases in T1 invasive ductal carcinomas was 34% of 514 patients. In about 78% of patients, the size of primary tumors was over 1cm. And the mean number of metastatic lymph node was 3.7. Age35 or less and lymphatic vessel invasion were statistically significant predictors of lymph node metastases in univariate analysis (p=0.006, p<0.001). However, in mulivariate analysis, lymphatic vessel invasion was the only significant predictor for lymph node metastases.

Lymphatic vessel invasion was the only significant predictor for lymph node metastases in T1 invasive breast carcinoma. There is still limitations to advocate sparing axillary lymph node dissection because of insufficient predictors for axillary lymph node metastases and relatively high incidence of lymph node metastases. New prognostic indicators must be investigated for predicting axillary lymph node status.