Objective: To determine prognosis of small choroidal melanoma (≤3 mm thickness) comparing diffuse versus nondiffuse variants.
Methods: Retrospective chart review of 1,751 patients with small choroidal melanoma classified as diffuse (thickness/base ≤20%) versus nondiffuse (thickness/base >20%).
Results: Of 1,751 patients with small choroidal melanoma, 297 (17%) were diffuse and 1,454 (83%) nondiffuse. Features with statistical differences (diffuse vs. nondiffuse) included mean distance to optic disk (3 vs. 4 mm), mean tumor base (12 vs. 8 mm), and mean tumor thickness (1.9 vs. 2.5 mm). Using Kaplan–Meier estimates, melanoma-related metastasis (diffuse vs. nondiffuse) was 8% versus 4% at 5 years, 16% versus 10% at 10 years, and 19% versus 16% at 15 years (P = 0.0344). Melanoma-related death was 6% versus 2% at 5 years, 11% versus 4% at 10 years, and 16% versus 6% at 15 years (P < 0.0001). In the subgroup of thin melanoma 2 mm or less in thickness, melanoma-related death was 7% versus 2% at 5 years, 10% versus 2% at 10 years, and 16% versus 4% at 15 years (P = 0.0077). By multivariate analysis, factors predictive of metastasis from diffuse melanoma included larger tumor basal dimension (P = 0.0027) and plateau/flat tumor configuration (P = 0.0257).
Conclusion: Of 1751 patients with small (≤3 mm thickness) choroidal melanoma, those with diffuse tumor show higher probability of metastasis and death than those with nondiffuse tumor. This finding is evident even in the thinnest melanomas (≤2 mm thickness).
Of 1,751 eyes with small choroidal melanoma, the probability of metastasis and death at 10 years in patients with diffuse (n = 297) versus nondiffuse (n = 1,454) choroidal melanoma were 16% versus 10% (P = 0.0344) and 11% versus 4% (P < 0.0001), respectively.
Ocular Oncology Service, Wills Eye Institute, Thomas Jefferson University, Philadelphia, Pennsylvania.
Reprint requests: Carol L. Shields, MD, Ocular Oncology Service, Wills Eye Institute, Suite 1440, 840 Walnut Street, Philadelphia, PA 19107; e-mail: firstname.lastname@example.org
Presented in part as the 2012 F. Phinizy Calhoun Lecture, Atlanta, GA, on September 28, 2012.
Support provided by the Eye Tumor Research Foundation, Philadelphia, PA (C.L.S.). Statistical analysis provided by Rishita Nutheti, PhD, Hyderabad, India.
The funders had no role in the design and conduct of the study, in the collection, analysis, and interpretation of the data, and in the preparation, review, or approval of the manuscript. C. L. Shields has had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.