The role of intraoperative gamma-probe-guided sentinel lymph node biopsy in the treatment of malignant melanoma and breast cancer

In the treatment of malignant tumors regional lymphadenectomy is used for two purposes. It is used partly for staging the regional lymph nodes which is a significant and independent prognostic factor and determines the need for adjuvant oncologic treatment and partly for achieving locoregional disease control. Removal of tumor-free lymph nodes by regional lymph node clearance is unnecessary according to our current knowledge. Since the sensitivity and specificity of non-invasive clinical examinations are insufficient in predicting the nodal status the histological study of the regional lymph nodes cannot be abandoned. A new and minimally invasive surgical procedure, the mapping and removal of the first tumor draining lymph node, the sentinel node provides the possibility of pathological nodal staging without performing formal lymphadenectomy. Mapping of the sentinel node can be performed by the use of a radioisotope and intraoperative hand-held gamma-probe or a vital blue dye or a combination of these two. This latter method was used by the authors in 73 patients (25 with malignant melanoma and 48 with breast cancer). Sentinel lymph node biopsy was performed successfully in 92% of patients with melanoma and 90% of patients with breast cancer. In three breast cancer patients the sentinel node inaccurately predicted the axillary status as negative, but is was in 93% accurate in predicting the histologic nodal state. According to our preliminary experiences intraoperative gamma-probe guided sentinel lymph node biopsy is considered a feasible procedure in both malignant melanoma and breast cancer. More experiences are needed before introducing this method in the routine clinical practice.