POMC and cancer: When calculating the ACTH to F-ODS ratio, NAPACA patients with second malignant neoplasm displayed significantly higher ratios both at the baseline visit and at follow-up (baseline: with second malignant neoplasm ACTH/F-ODS: 23.65 (2.5–214) vs. without second malignant neoplasm: 12.64 (0.92–222), p < 0.05; follow-up: with second malignant neoplasm ACTH/F-ODS: 23.38 (2.43–163) vs. without second malignant neoplasm: 12.18 (0.50–163), p < 0.05), indicating that the lower cortisol secretion, paired with slightly higher ACTH levels, correlates with the presence of second malignant neoplasms.