A prospective monitoring study on the value of LDH and protein S-100B as indicators of progressive disease during adjuvant interferon a treatment in melanoma

Abstract

7542 Background: Despite adjuvant interferon treatment, a significant number of patients with high-risk melanomas will develop progressive disease within the following years. Currently, the recommendations for blood tests in the follow-up of these patients are inconsistent. Methods: A prospective evaluation compared the value of lactate dehydrogenase (LDH) and protein S-100B serum tests (Sangtec 100 LIA mat) as indicators of progressive disease. Therefore, blood samples from 98 melanoma patients were taken 3-monthly and the upper institutional limits (LDH 240 U/l; S-100B 0,20 μg/l) were considered as cut-off points. A total of 1273 sera were analyzed. All patients belonged to prospective-randomized phase III trials (Dermatologic Cooperative Oncology Group; DeCOG) and were treated either if clinically lymph node negative (n=53) with two different Interferon a2b schedules or if clinically lymph node positive (n=54) in another interferon-based trial with observation controls. Results: During the median observation period of 30 months 52 out of 98 patients (53.1%) progressed to either stage III or IV according to the new AJCC melanoma classification. Neither S-100B nor LDH represented indicators of in-transit metastases. The detection of clinically apparent lymph node metastasis by abnormal serum values was feasible in only 11.8% (LDH) and 35.3% (S-100B) of the patients, respectively. Whereas S-100B elevations led to the detection of early distant metastasis (stage IV) in half of the patients (50.0%), only 15.4% of the patients demonstrated abnormal LDH concentrations. The rate of false-positive serum levels in currently disease-free patients did not differ between the two serum markers (S-100B: 13.0%, LDH: 10.9%). Conclusions: Now as before, loco-regional relapses in high-risk melanoma patients have to be detected by clinical examinations and lymph node ultrasound. However, S-100B serum tests are superior to LDH assessments as indicators of early distant metastasis. Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration DiaSorin DiaSorin