POSITRON-EMISSION-TOMOGRAPHY PLUS SERUM TA90 IMMUNE-COMPLEX ASSAY FORDETECTION OF OCCULT METASTATIC MELANOMA

Background: Whole-body positron emission tomography (PET) using F-18-f luorodeoxyglucose is very sensitive for detection of metastatic melano ma. We previously reported the accuracy of a serum TA90 enzyme-linked immunosorbent assay (ELISA) in predicting the recurrence of early-stag e melanoma. This serum ELISA measures a circulating immune complex com posed of TA90 a tumor-associated 90-kD glycoprotein antigen, and its I gG antibody. We hypothesized that using PET examination in conjunction with our serum TA30 ELISA would increase the detection of occult mela noma lesions. Study Design: From November 1, 1993 to December 31, 1995 , 87 patients underwent PET examination followed within 6 weeks by ser um TA30 ELISA. All patients had undergone complete resection of local, regional, or distant metastatic melanoma and had no clinical evidence of disease at the time of PET examination. Each patient had complete followup for 12 months after PET examination. The clinical course was determined by chart review of clinical and radiographic findings. Resu lts: Of the 25 patients who experienced recurrence of disease within 6 months of followup, 22 (88%) had a positive result on one or both tes ts. Of the 52 patients with a negative result on both tests, 49 (94%) remained disease-free at G months of followup. Of the 14 patients who developed distant metastases within G months after PET examination, 13 (93%) had a positive PET examination and/or a positive TA90 ELISA. Co nclusions: The TA30 ELISA correlated well with PET examination for det ection of metastatic melanoma. The high sensitivity of PET examination plus TA30 ELISA suggests that this combination may have a role in the surveillance of patients at high risk of developing metastatic melano ma. (J Am Coll Surg 198;187: 191-198. (C) 1998 by the American College of Surgeons)