Correlation of Baseline Tumor Burden with Clinical Outcome in Melanoma Patients Treated with Ipilimumab.

Introduction: Tumor burden is a frequently mentioned parameter; however, a commonly accepted definition is still lacking.

Methods: In this double-center prospective and retrospective study, 76 patients with unresectable stage III or stage IV melanoma treated with ipilimumab were included. We defined the baseline tumor burden (BTB) as the global sum of all metastases' longest diameters before treatment started and correlated the calculated BTB with disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and with the baseline levels of LDH, S100B, and sULPB2.