Background: Axillary lymph node metastases (ALNM) are the most important predictor of survival in patients with T1 breast carcinoma. Due to a relatively low incidence of axillary metastasis in tumors < or = 2 cm, the role of axillary lymph node dissection for these patients has been questioned. The purpose of this study was to determine the association between the incidence of ALNM and 11 clinical/pathologic factors by univariate and multivariate analysis.
Methods: The authors reviewed data from 918 patients with T1 breast carcinoma who underwent level I/II axillary dissection between 1979 and July 1995. The association between the incidence of ALNM and 11 clinical/pathologic factors (size, lymph/vascular invasion, nuclear grade, S-phase, ploidy, palpability, age, estrogen receptor status, progesterone receptor status, HER-2/neu, and histology) was analyzed by univariate and, when significant, by multivariate analysis.
Results: Approximately 23% of the 918 patients with T1 breast carcinoma had ALNM. Multivariate analysis identified four factors as independent predictors of ALNM: lymph/vascular invasion (P < 0.0001), tumor palpability (P < 0.0001), nuclear grade (P = 0.0004), and tumor size (P = 0.01). Among the 117 patients with nonpalpable, nonhigh grade tumors < or = 1 cm without lymph/vascular invasion, the incidence of ALNM was only 3%. However, the 43 patients with T1c tumors with all 3 additional risk factors had a 49% incidence of ALNM.
Conclusions: Clinical and pathologic features of the primary tumor can be used to estimate the risk of ALNM in patients with T1 breast carcinoma. Such a risk assessment might facilitate appropriate management. Routine axillary dissection can be omitted in patients at minimal risk of ALNM, if the treatment decision is not influenced by lymph node status. Axillary lymph node dissection should be performed routinely for all patients with lesions > 1 cm. [See editorial counterpoint on pages 1856-61 and reply to counterpoint on pages 1862-4, this issue.]