Lung metastases from melanoma: when is surgical treatment warranted?

Surgical treatment of lung metastases from melanoma is highly controversial as the expected outcome is much poorer than for other primary tumours and a reliable system for selecting patients is lacking. This study evaluated the long-term results of lung metastasectomy for melanoma, with the aim of defining a subset of patients with better prognosis. By reviewing the data of the International Registry of Lung Metastases (IRLM), we identified 328 patients who underwent lung metastasectomy for melanoma in the period 1945-1995. Survival was calculated by Kaplan-Meier estimate, using log-rank test and Cox regression model for statistical analysis. After complete pulmonary metastasectomy (282 patients) the 5- and 10-year survival was 22% and 16%, respectively. In this group of patients, a time to pulmonary metastases (TPM) shorter than 36 months or the presence of multiple metastases were independent unfavourable prognostic factors. There were no long-term survivors after incomplete resection (46 patients, P< 0.01). Using the IRLM grouping system, patients without risk factors (TPM > 36 months and single lesion) experienced the best survival (29% at 5 years), followed by those with one risk factor only (20% at 5 years). On the other hand, those with two risk factors or incomplete resection showed a significantly poorer survival (7% and 0% at 5 years). Surgery plays an important role in carefully selected cases of pulmonary metastatic melanoma. The prognostic grouping system proposed by the International Registry of Lung Metastases provides a simple and effective method for improving the selection of surgical candidates.