SENTINEL LYMPH-NODE BIOPSY IN BREAST-CANCER - GUIDELINES AND PITFALLSOF LYMPHOSCINTIGRAPHY AND GAMMA-PROBE DETECTION

Background: Sentinel node (SN) biopsy appears to offer an alternative to routine axillary lymph node dissection (ALND) for staging patients with breast cancer. Various techniques have been studied for identifyi ng the SN, using vital blue dye or radioactive colloid, and initial re ports are promising. The inherent limitations and pitfalls must be cle arly understood before SN biopsy can be implemented in clinical practi ce. Study Design: In a prospective trial, the feasibility of using lym phoscintigraphy and gamma probe detection for performing SN biopsy was studied. In 130 consecutive patients with T1-T2, NO breast cancer, pr eoperative lymphoscintigraphy was performed with technetium 99m-colloi dal albumin. During ALND, the radioactive axillary SNs were localized by the gamma probe. Histopathologic examination of the harvested SNs w as compared with the status of the axillary lymph nodes. Results: Axil lary focal accumulations were clearly identified on lymphoscintigraphy in 116 patients (89%). The failure rate was significantly higher in p atients who had a previous excision biopsy (36%) than in those with a palpable tumor in situ (4%). Using the gamma probe, radiolabeled axill ary SNs were successfully biopsied in 122 patients (94%). Because 18 o f these patients did not undergo formal lymphadenectomy, the predictiv e accuracy of SN biopsy was analyzed in 104 patients. Radioactive node s revealed metastases in 44 of 104 patients (42%); in 26 of them (59%) , these were the only involved axillary nodes. The SN was negative in 60 patients (58%); in one patient the ALND was found to contain metast atic disease (1.7% false negatives). Biopsy of the SN was 98% accurate in predicting the absence of nodal metastases. Conclusions: There are certain guidelines for performing SN biopsy by lymphoscintigraphy and gamma probe detection. Success depends primarily on an adequate funct ional capacity of the SN, necessary for sufficient nodal uptake to ens ure accurate identification. Lymphoscintigraphy defines the pattern of lymph flow and may prevent failure or false-negative biopsies. Biopsy of the SN is a highly accurate, minimally invasive method of staging patients with breast cancer and can substantially reduce the morbidity and costs of surgical treatment by avoiding unnecessary ALND in the m ajority of patients. (C) 1998 by the American College of Surgeons.