Estimating the overlap between sentinel lymph nodes and axillary node samples in breast cancer.

Management of the axilla in breast cancer patients is a controversial issue. Axillary sampling and sentinel lymphadenectomy are both conservative surgical approaches which aim to stage the disease. These procedures target selective treatment of node-positive patients and seem to allow the omission of axillary clearance in node-negative ones. In this way, they reduce the rate of complications in an otherwise overtreated subset of patients. Forty consecutive patients with palpable T1 and T2 breast carcinoma underwent sentinel lymphadenectomy following mapping with Patent blue dye, with subsequent axillary clearance and excision of the tumor or mastectomy. Then the largest/firmest 3,4,5 and 6 nodes were selected from all the lymph nodes in order to model an axillary sample. It was suggested that these are the nodes that are the most likely to be included in the specimen during sampling, because of their size and consistency. The probability of the sentinel lymph nodes falling into the sample of the 3-6 largest/firmest nodes was calculated. The sentinel nodes predicted the axillary nodal status in 95%, while the samples of the largest 3, 4, 5 and 6 nodes were predictive in 95, 96, 98 and 98%, respectively. The two methods of evaluation displayed a considerable overlap, as the sentinel node would have been included in the 3 6 largest/firmest nodes in 79 92% of the cases, depending on the number of largest nodes evaluated. The overlap was greater after fine needle aspiration of the primary tumor. Although the two alternative staging procedures of 3, 4, 5 or 6 node sampling and sentinel lymphadenectomy with the vital blue dye technique cannot be simultaneously done without one influencing the other, and the first method was only modeled, the results suggest that there is a considerable overlap between the two; axillary sampling may often remove the sentinel lymph nodes.