The contribution of axillary node dissection to the management of breast cancer is controversial. Certain types of breast carcinoma (such as tubular, colloid [or mucinous], papillary, medullary, and ductal carcinoma in situ with microinvasion) are believed to have a low incidence of axillary metastasis. Some experts recommend against routine axillary dissection in these cases. Wong and colleagues examined the rate of axillary involvement in these “favorable” types of breast cancer using sentinel node biopsy to evaluate the axilla.

Data were examined from more than 3,300 women treated at a regional breast cancer center for T1-2, N0 breast cancer between 1997 and 2002. All of the patients underwent sentinel lymph node (SLN) biopsy followed by axillary dissection. Infiltrating ductal carcinoma was the most common type of cancer, occurring in 85 percent of cases. The favorable subtypes accounted for 5 percent (181 cases).

Axillary node metastases were identified in 985 (35 percent) women with infiltrating ductal carcinoma and in 19 (11 percent) favorable subtypes. As shown in the accompanying table, the prevalence of axillary metastasis varied with tumor type, but the differences were not statistically significant. A trend associating the prevalence of metastasis with tumor size was noted, but small patient numbers prevented statistical significance being achieved. Seventy-one percent of patients with axillary nodes associated with favorable tumors had primary lesions larger than 1 cm in diameter.

The authors conclude that although certain histologic types of breast cancer are conventionally associated with good prognosis, axillary metastases may be detected in up to one third of such cases, and SLN biopsy should be undertaken to establish the need for axillary dissection regardless of histologic type of breast cancer.