Tumor Doubling Time: a Selection Factor for Pulmonary Resection of Metastatic Melanoma

Background And Objectives: Melanoma patients have a 20-27% rate of 5-year survival after surgical resection of pulmonary metastases. We evaluated tumor doubling time (TDT) and other prognostic factors in an attempt to identify candidates for pulmonary metastasectomy.

Methods: Review of our large melanoma database identified 129 patients who underwent complete or partial resection of pulmonary metastases. At least two preoperative chest roentgenograms were available for 45 patients; these images were used by a single examiner to measure tumor width and length. The mean of the diameters was plotted against time on semilogarithmic paper: the slope of the line approximated tumor growth rate, and TDT was proportional to the inverse of the tumor growth rate.

Results: For the 45 patients with a calculated TDT, median survival was 23.1 months and 5-year survival rate was 15.6% (7/45). By multivariate analysis, the only prognostically significant factors were TDT (P=0.006) and type of pulmonary resection (P=0.022). When TDT was <60 days, median survival was 16.0 months, and 5-year survival rate was zero; when TDT was > or = 60 days, median survival was 29.2 months (log-rank test; significant at P < 0.0001) and 5-year survival rate was 20.7% (6/29) (P < 0.0001).

Conclusions: TDT is the most significant preoperative prognostic factor for patients undergoing pulmonary resection of metastatic melanoma. If TDT is <60 days, a preoperative neoadjuvant regimen of chemotherapy and biologic therapy is recommended. Pulmonary metastasectomy should not be attempted if TDT cannot be increased to > or = 60 days by systemic therapy.