A prognostic model and staging for metastatic uveal melanoma

To identify factors that independently contribute to overall survival in Stage IVB uveal melanoma and to subcategorize by prognosis.

Data of 91 consecutive patients who died of metastatic uveal melanoma in 1985-2000 were analyzed by Kaplan-Meier and Cox regression analysis. Main covariates were participation in annual review, symptoms, Karnofsky index, metastatic burden, liver function tests, and age. Time on chemotherapy was modeled as a confounder. A working formulation for staging patients according to predicted survival was designed.

Of the 91 patients, 85% underwent annual liver imaging and function tests, 63% were asymptomatic, and 73% received chemotherapy. The median survival period was 8.4 months (95% confidence interval [CI], 6.3-11.8). Karnofsky index, largest dimension of the largest metastasis, metastatic burden, serum transaminase, lactate dehydrogenase, and alkaline phosphatase (AP) levels, and time on chemotherapy were strongly (P < 0.001) associated with survival. Symptoms (P = 0.031) and regular review (P = 0.081) were weakly associated with survival. Karnofsky index (P = 0.013), the largest dimension of the largest metastasis (P = 0.003), and serum AP level (P = 0.042) retained independent significance, adjusting for time on chemotherapy. Predicted median survival calculated for relevant covariate combinations was divided into three periods (> or =12 months vs. 6-11 months vs. < 6 months). Observed median survival for Stage IVBa was 14.9 months (95% CI, 11.7-21.3), for Stage IVBb 8.9 months (95% CI, 2.7-13.7), and for Stage IVBc 2.0 months (95% CI, 1.0-3.7).

The model and working formulation for categorization can be tested as an aid in patient counseling and as a tool in design and analysis of clinical trials.