In this week’s JAMA, a study reported on the reliability of sentinel node lymph node surgery for women who start out with larger cancers and have cancer found in their lymph nodes when they receive chemotherapy treatment before undergoing surgery. After receiving chemotherapy, the breast cancer was removed. For 40% of the women in the study, chemotherapy cleared the cancer in the axillary lymph nodes. Furthermore, the study showed that for women who still had cancer in their axillary nodes after chemotherapy, the sentinel node procedure could not always identify cancer in the axilla. Women whose breast cancer has traveled to their axillary lymph nodes and have received chemotherapy may benefit by undergoing a complete axillary lymph node dissection when their breast cancer is surgically removed, although this has more adverse effects. Future studies may help clarify which such patients would be best suited for sentinel lymph node surgery.