THE SENTINEL NODE IN BREAST-CANCER - A MULTICENTER VALIDATION-STUDY

Background Pilot studies indicate that probe-guided resection of radio active sentinel nodes (the first nodes that receive drainage from tumo rs) can identify regional metastases in patients with breast cancer. T o confirm this finding, we conducted a multicenter study of the method as used by 11 surgeons in a variety of practice settings. Methods We enrolled 443 patients with breast cancer. The technique involved the i njection of 4 mi of technetium-99m sulfur colloid (1 mCi [37 MBq]) int o the breast around the tumor or biopsy cavity. ''Hot spots'' represen ting underlying sentinel nodes were identified with a gamma probe. Sen tinel nodes subjacent to hot spots were removed. All patients underwen t a complete axillary lymphadenectomy. Results The overall rate of ide ntification of hot spots was 93 percent (in 413 of 443 patients). The pathological status of the sentinel nodes was compared with that of th e remaining axillary nodes. The accuracy of the sentinel nodes with re spect to the positive or negative status of the axillary nodes was 97 percent (392 of 405); the specificity of the method was 100 percent, t he positive predictive value was 100 percent, the negative predictive value was 96 percent (291 of 304), and the sensitivity was 89 percent (101 of 114). The sentinel nodes were outside the axilla in 8 percent of cases and outside of level 1 nodes in 11 percent of cases. Three pe rcent of positive sentinel nodes were in nonaxillary locations. Conclu sions Biopsy of sentinel nodes can predict the presence or absence of axillary-node metastases in patients with breast cancer. However, the procedure can be technically challenging, and the success rate varies according to the surgeon and the characteristics of the patient. (N En gl J Med 1998; 339:941-6.) (C)1998, Massachusetts Medical Society.