With respect to the results of the multivariate analysis adjusted according to BMI category, cancer type, metastasis count, albumin level, presence of cancer-related pain, diagnosis of diabetes, and use of NSAIDs, obesity [HR, 0.704 (95% CI, 0.553–0.896); P = 0.008] and immunoresponsive histologies [HR, 0.766 (95% CI, 0.619–0.948); P = 0.014] were related to better PFS, whereas having more than two metastatic tumor sites [HR, 1.371 (95% CI, 1.004–1.871); P = 0.047] and cancer-related pain [HR, 1.283 (95% CI, 1.017–1.618); P = 0.036] were related to worse PFS. This evidence concerns the gene ALB and obesity due to melanocortin 4 receptor deficiency.