Observation of the breast cancer patient with a tumor-positive sentinel node: Implications of the ACOSOG Z0011 trial

Axillary lymph node status has been the most important prognostic factor fo r breast cancer throughout the past century. During the past decade, intrao perative lymphatic mapping with sentinel lymph node dissection (SLND) has b een investigated as an alternative staging modality. This technique may be as accurate as ALND, and certainly is less invasive. Adjuvant treatment rec ommendations, which historically were made on the basis of lymph node statu s alone, now take into account primary tumor features, molecular markers, a nd patient characteristics. This evolution of current treatment patterns is driven in part by the diminishing size of tumors, the simultaneous decreas e in the presence of axillary metastases, and a better understanding of tum or-specific risk factors. How do these trends affect the interpretation of a tumor-positive sentinel node (SN)? Can an axilla with a positive SN be ob served? Should it be observed? This review examines the implications of a p ositive SN in the context of smaller tumor size, decreased nodal disease, a nd increased reliance on alternative prognostic factors for treatment decis ions. The historical data comparing ALND to no ALND in clinically node-nega tive patients is reviewed and discussed in the context of observation for a positive SN. These are the issues underlying the ACOSOG ZOO10 and ZOO11 tr ials. (C) 2001 Wiley-Liss, Inc.