Biological Factors, Tumor Growth Kinetics, and Survival After Metastasectomy for Pulmonary Melanoma

Abstract

Approximately 23% of melanoma patients will eventually develop pulmonary metastases and have a median survival of only about 7-11 months. Because pulmonary metastasectomy can improve this statistic, we investigated clinicopathologic features and biological correlates that might be used to identify surgical candidates. Archived operative specimens and clinical records were retrieved for 20 melanoma patients who underwent resection of isolated pulmonary metastases at the John Wayne Cancer Institute, Saint John's Health Center. Five-year postmetastasectomy survival (PMS) rate was correlated with age, number of pulmonary metastases, tumor doubling time (TDT), tumor necrosis, and immunohistochemical expressions of four biological markers: Ki-67, glucose transporter-1 (Glut-1), caspase-3, and CD31. Median TDT was 61 days. On multivariate analysis, TDT (P = 0.008), Glut-1 intensity (P = 0.04), and CD31 expression (P = 0.004) were the significant predictors of PMS. Age, number of pulmonary metastases, tumor necrosis, and expression of Ki-67 or caspase-3 did not significantly impact survival. Median TDT was 56 days with Glut-1 expression versus 165 days without Glut-1 expression (P = 0.002), and Glut-1 staining intensity independently affected TDT (P = 0.012). Surgical resection may be preferable to toxic systemic therapies in melanoma patients whose isolated pulmonary metastases have a long TDT (> or = 61 days) and no biopsy evidence of Glut-1 expression.