Infiltrating breast carcinoma smaller than 0.5 centimeters - Is lymph nodedissection necessary?

BACKGROUND. The incidence of axillary lymph node metastases from infiltrati ng breast carcinomas measuring 1.0 cm or smaller reported in the literature varies from 0% (for tumors measuring less than or equal to 0.5 cm) to 27.1 % (for all tumors less than or equal to 1 cm]. METHODS. The authors examined all infiltrating breast carcinomas measuring 1.0 cm or smaller with axillary lymph node dissections in patients seen at their institution between January 1990 and March 1997 (117 cases) to determ ine the incidence of axillary lymph node metastases. All tumors were evalua ted for patient age, histologic type of tumor, modified Bloom-Richardson gr ade, estrogen and progesterone receptor status, ploidy, S-phase fraction, a nd angiolymphatic vessel invasion, to determine whether there was a relatio n between the indicators and axillary lymph node metastases. The authors al so performed immunohistochemical stains for the basement membrane component s laminin and Type IV collagen on the tumors demonstrating metastases and o n an equal number of size- and date-matched tumors not demonstrating metast ases. RESULTS. Twelve cases of infiltrating carcinoma with axillary lymph node me tastases were identified (a 10.3% overall incidence of metastases). Lymph n ode metastases were not identified in any of the cases with tumors measurin g less than or equal to 0.5 cm (24 cases). The incidence of axillary lymph node metastases for carcinomas 0.6-1.0 cm was 12.9% (12 of 93 cases). High nuclear grade was found to correlate with the presence of lymph node metast ases (P = 0.007). No statistically significant correlation was found betwee n the other indicators examined and axillary lymph node metastases or betwe en basement membrane staining and axillary lymph node metastases. CONCLUSIONS. The authors concluded that infiltrating breast carcinomas meas uring less than or equal to 0.5 cm are unlikely to have demonstrable axilla ry lymph node metastases. Lymph node dissections in these women may be unne cessary. Nuclear grade may be the best predictor of lymph node metastases i n T1b tumors. Cancer 1999;85: 2206-11. (C) 1999 American Cancer Society.