Chemotherapy response assessment in stage IV melanoma patients – Comparison of FDG-PET/CT, CT, brain MRI and tumormarker S-100B

Abstract

1541

Objectives: To compare the use of FDG-PET/CT, CT and tumormarker S-100B in chemotherapy response assessment of stage IV melanoma patients.

Methods: In 25 patients with proven melanoma metastases serial PET/CT`s (n=96) and S-100B measurements (n=87) were performed before and during chemotherapy. In patients with suspicion for brain metastases brain MRI (n=18) or CCT (n=14) was performed. The first PET/CT and S-100B measurement was obtained after 2-3 months of chemotherapy and the response was correlated with the survival.

Results: There was complete agreement between PET/CT and CT regarding response to chemotherapy in all patients. There was a nearly significant trend to a longer survival of PET/CT – responders compared with PET/CT non-responders (p=.072) with remarkably better 1-year survival of 80% compared to 40%. S-100B was not suitable for assessment of disease progression in this patient population, being normal in 8/22 patients where it was available and misleading in the remaining 3/14 patients where there was disagreement with PET/CT. Further, chemotherapy response assessment with S -100B failed to show any correlation to survival in these 14 patients (p=.825). Brain metastases were first detected by PET/CT in 2 and by MRI in 9 of 11 patients.

Conclusions: PET/CT and CT alone are equally suitable for chemotherapy response assessment in melanoma patients and clearly superior to S-100B. PET/CT responders have much better early survival. Additional brain MRI is mandatory.