Discontinuous or "skip" metastases in breast carcinoma. Analysis of 1228 axillary dissections.

Patterns of axillary lymph node metastases were analyzed in 1228 recently performed modified, radical, and extended radical mastectomies. In these specimens the position or level of lymph nodes was designated intraoperatively by the surgeon. No lymph node metastases were found in 720 (58) of the specimens while the remainder (508 or 41%) had at least one affected lymph node. The distribution of involvement by level showed progressive spread from level I to III as the number of positive lymph nodes increased. Discontinuous or "skip" metastases not following this pattern occurred in 1.6% of all cases and 3% of those with lymph node metastases (95% confidence interval, 1-5%). Half of those with "skip" metastases had tumor limited to level II. The presence of "skip" metastases was not related to the size, location in the breast, or histologic type of the primary tumor. It is apparent that the potential risk from "skip" metastases is not great and that this should not be a major consideration in therapeutic decisions. The risk is likely to be negligible for women treated by axillary dissections that include level II.