Association between autoimmune disease and cutaneous melanoma with regard to melanoma prognosis.

BACKGROUND: An association between autoimmune disease and malignant melanoma (MM) has often been reported in the literature as a positive prognostic factor for MM. Consequently, we evaluated the influence of different autoimmune diseases on the prognosis of MM. AIM: To evaluate the prognosis of patients with MM who also had an autoimmune disorder, whether tumour-associated, paraneoplastic or drug-induced. METHODS: Autoimmune diseases were classified and analysed as tumour-associated, paraneoplastic or drug-induced. Patients were enrolled according to their clinicopathological features and matched with control groups. Kaplan-Meier analysis was used to estimate disease-free survival (DFS) and overall survival (OS), and log-rank test was used to evaluate differences between the survival curves. RESULTS: In total, 49 patients with MM and tumour-associated autoimmune disease were included in our analysis. No case of paraneoplastic autoimmune disease was detected. The survival analyses showed a range of results, from a worsening of DFS and OS to a lack of any difference. In a second analysis, we separately analysed patients who developed autoimmune disorders after starting adjuvant therapy with interferon-α; we did not find significant differences between these patients and the untreated patients. CONCLUSIONS: Autoimmune disease, whether tumour-associated or drug-induced, was not associated with better prognosis in patients with MM. The results suggest that the reported relationship between autoimmunity and MM may be a result of individual variation in sensitivity to the autoimmune disease, the tumour or the treatments.