A deficit survival analysis to assess the natural history of uveal melanoma

A deficit survival analysis was conducted using a retrospective series of 230 patients with uveal melanoma. All underwent enucleation as primary treatment for their disease. Considering the three leading prognostic factors (epithelioid cells per high power field, tumor size, and tumor location), median age was plotted against median survival to determine pathways of disease spread, local and metastatic disease phases, consequences of delayed diagnosis, and the timing of enucleation. The subgroup with all three factors favorable could be subdivided into younger and older subsets on the basis of a bimodal age distribution. Only the older subset could be identified as a local disease state where survival following enucleation corresponded to normal population survival. All remaining subgroups were metastatic because of survival deficits compared to the normal population. Disease tended to progress according to three well defined pathways with 6-8 years required to progress from one subgroup to the next along these paths. These pathways were characterized by constant deficit survivals, suggesting that delays in diagnosis did not translate into loss in survival. Moreover, the value of enucleation as primary therapy can be questioned in the context that it does not appear to alter the natural history of the disease, except for tumors greater than 10 mm in largest dimension which are located anterior to the equator with fewer than 2 epithelioid cells per high power field. Findings suggest that uveal melanoma can be treated by means other than enucleation to allow a chance for prolonged survival with vision preservation.