Prognostic factors for pulmonary metastasectomy in malignant melanoma: size matters

Pulmonary metastasectomy for malignant melanoma requires an individualized therapeutic decision. Due to recently developed novel treatment options, the prognosis of patients with melanoma has improved significantly. Validated prognostic factors that identify patients who are most likely to benefit from metastasectomy are urgently needed.

We retrospectively reviewed all consecutive patients with melanoma undergoing complete pulmonary metastasectomy between January 2010 and December 2016. The impact of age, sex, extrapulmonary metastases, preoperative systemic therapy, number of metastases, laterality and largest diameter of metastasis on survival after metastasectomy was analysed.

A total of 29 male and 32 female patients were included in the study. The median follow-up time was 25.6 months. The mean number of resected metastases was 1.7 ± 1.1 (range 1-5). Ten patients had repetitive pulmonary metastasectomies. The median survival time was 31.3 months with a 2-year survival rate of 54%. Bilateral metastases or multiple nodules were not associated with a significantly decreased overall survival rate after metastasectomy. Shorter overall survival times were observed in male patients [hazard ratio (HR) 2.9, 95% confidence interval (CI) 1.42-5.92; P = 0.0035] and in patients with nodules larger than 2 cm (HR 3.18, 95% CI 1.45-6.98; P = 0.004). In multivariable analysis, both gender and tumour size remained significant independent prognostic factors.

Excellent overall survival rates after pulmonary metastasectomy for melanoma metastases were observed in patients with a metastatic diameter less than 2 cm and in female patients. In view of improved long-term outcome due to novel treatment options, the selection of patients for pulmonary metastasectomy based on prognostic factors will become increasingly important.