Characteristics of long-survivor metastatic melanoma after polychemotherapy and interferon: a retrospective study

The development of immunotherapy and tyrosine kinase inhibitors dramatically improved the prognosis of metastatic melanoma. Consequently, chemotherapy is now rarely used. Here, we describe the characteristics of long-surviving patients with metastatic melanoma treated with immunochemotherapy.

We retrieved retrospective clinical and pathological data for patients diagnosed with metastatic melanoma between January 1993 and December 2015 who received the CVD-INF (cisplatin, vinblastine, dacarbazine, and interferon α-2b) regimen at the Hôpitaux Universitaires de Genève. We estimated their progression-free survival and overall survival. This ad hoc study's primary aim was to describe the clinical and biological characteristics of long-term survivors, defined as patients surviving more than two years after immunochemotherapy initiation. The spatial distribution pattern of CD8+ T cells (inflamed, excluded, or desert) was immunohistochemically determined.

Ninety patients received CVD-INF. Their median age at metastatic melanoma diagnosis was 55 years (20-75). Their median progression-free survival was 2.8 months, and median overall survival was 7.2 months. Eleven (12%) patients were long-term survivors. In multivariate analysis, central nervous system metastases (hazard ratio [HR]: 2.66; 95% confidence interval [CI]: 1.43-4.95; p = 0.001), multiple metastases (HR: 1.82; 95% CI: 1.01-3.29; p = 0.047), and elevated lactate dehydrogenase (LDH) (HR: 1.92; 95% CI: 1.12-3.30; p = 0.016) were independently associated with shorter survival. Most long-survivors (6/8; 75%) had a tumour-inflamed pattern compared to 25% of non-long survivors (5/20; Fisher's test p = 0.030).

A subset of patients with metastatic melanoma and a tumour-inflamed phenotype treated with CVD-INF survived over two years. Factors associated with prolonged survival are consistent with those previously reported in metastatic melanoma.