Tumor-associated antigen TA90 immune complex assay predicts recurrence andsurvival after surgical treatment of stage I-III melanoma

Purpose: Immune complexes (IC) containing the tumor-associated antigen TA90 can be identified in the sera of melanoma patients. We have shown that an enzyme-linked immunosorbent assay for TA90-IC can detect subclinical metast asis before surgical treatment of early-stage melanoma. We assayed the TA90 -IC levels of postoperative sera from patients with melanoma and evaluated their relationship to recurrence and survival. Patients and Methods: Multiple archival serum samples prospectively collect ed during postoperative surveillance of 166 patients with American Joint Co mmittee on Cancer stage I, II, or III melanoma were analyzed for TA90-IC in a blinded fashion. Results were correlated with disease recurrence and sur vival determined by database and chart review. Results: TA90-IC status in the early postoperative period was strongly corr elated with survival. Five-year overall survival rates were 84% far TA90-IC -negative patients and 36% for TA90-IC-positive patients (P = .0001). Respe ctive 5-year disease-free survival rates were 74% and 24% (P = .0001). The TA90-IC assay was a significant predictor of survival for both stage II and III patients. Multivariate analysis identified TA90-IC status as the stron gest independent prognostic factor for both overall and disease-free surviv al. The TA90-IC essay wets elevated in 54 (77%) of 78 patients who develope d recurrent disease, becoming positive 19 +/- 7 months before clinical evid ence of recurrence. Overall, the assay detected recurrence with a sensitivi ty of 78% and specificity of 77%. Exclusion of patients receiving postopera tive immunotherapy with a polyvalent melanoma cell vaccine increased sensit ivity and specificity to 92% and 86%, respectively. Conclusion: The TA90-IC assay can accurately predict survival and detect th e presence of subclinical disease after surgery for melanoma, which should be useful in selecting patients for adjuvant therapy. Because the TA90-IC a ssay detected recurrence on an average of 19 months sooner than did routine clinical and radiographic evaluation, it may allow more timely therapeutic interventions.