Tumor Size May Be a Prognostic Indicator for Uveal Melanoma Metastasis
Source: American Academy of Ophthalmology, December 2024
The Cancer Genome Atlas (TCGA) classification is based on tumor cytogenetic and gene expression profiling findings and has been shown to be highly predictive of uveal melanoma metastasis and death. Other studies have shown uveal melanoma metastatic risk to be closely related to tumor thickness and basal dimensions. In this retrospective study, investigators correlated TCGA classification with uveal melanoma tumor thickness and found that smaller tumors were more likely to have favorable TCGA classification and had better odds of metastasis-free survival at 10 years than larger ones. The authors suggest that tumor size is a cost-effective way to predict metastasis and could serve as a surrogate for TCGA classification, though additional validation is needed.
Study Design
This is a retrospective analysis of 1001 cases of uveal melanoma managed at a single ocular oncology center between 2004 and 2020. Fine-needle aspiration biopsy for cytogenetic evaluation was performed in the operating room on the tumors prior to treatment. The tumors were categorized into 3 groups based on tumor thickness: small (?3.0 mm), medium (3.1–8.0 mm), or large (?8.1 mm). The tumors were also categorized based on TCGA classification: Group A (disomy chromosome 3, disomy chromosome 8), Group B (disomy chromosome 3, chromosome 8q gain), Group C (monosomy chromosome 3, chromosome 8q gain possible), Group D (monosomy chromosome 3, chromosome 8q gain multiple). Patients were monitored by a medical oncologist or local medical physician for evidence of systemic metastasis.
Outcomes
Of 1001 tumors, 270 were small, 503 were medium, and 228 were large. The distribution of TCGA groups (A, B, C, D) across size categories was 75%, 11%, 13%, and 1% for small tumors; 46%, 14%, 27%, and 13% for medium tumors; and 23%, 19%, 38%, and 20% for large tumors. Low-risk cytogenetics (TCGA groups A or B) were present in 86% of small, 60% of medium, and 42% of large tumors. The 5-year Kaplan–Meier estimates for metastasis-free survival in TCGA groups A, B, C, and D were 98%, 100%, 86%, and 100% for small tumors; 95%, 90%, 68%, and 44% for medium tumors; and 94%, 85%, 40%, and 23% for large tumors. Overall, metastasis-free survival at 10 years for tumors with low-risk cytogenetics was 98% for small tumors, 92% for medium tumors, and 54% for large tumors.