Predictive role of preoperative lymphoscintigraphy on the status of the sentinel lymph node in clinically node-negative patients with cutaneous melanoma.

We reviewed our experience to assess the predictive role of preoperative lymphoscintigraphy with regard to the pathological status of sentinel lymph node (sN) in patients with cutaneous melanoma, to optimize the surgical treatment planning with regard to the use of intraoperative frozen section examination of sN. Eighty-eight patients with clinically node-negative cutaneous melanoma pT1b-T4 stage underwent preoperative lymphoscintigraphy for the lymphatic mapping of sN. A lymphoscintigraphic 'score' (from L1 to L5) was developed based on the ratio of radiotracer concentration within sN nodes as compared with the injection site. Our score allowed us to foresee that sN of patients with thick melanomas (T3 and T4) and a low preoperative score (L1-L2-L3) had a 90% expected likelihood (P<0.001) of harboring metastasis, whereas sN in patients with thin melanomas (T1b-T2) and high preoperative score (from L4 to L5) showed a 100% likelihood of being metastasis free. In conclusion, the sN is a reliable predictor of regional lymph node status in patients with cutaneous malignant melanoma. Moreover, we suggest that a low score (L1-L2-L3) associated with a thick melanoma is a good predictive factor of the positive sN involvement. This information could be useful in scheduling the intraoperative frozen-section examination with an expected benefit of a positive test in almost 90% of patients. Such patients might be selected for a 'one-stage' procedure with a more effective cost/benefit ratio and decreased hospitalization costs.