The Natural History of Choroidal Melanoma: A Systematic Review and Meta-analysis

Abstract

Purpose : Uveal melanoma is the most common primary intraocular tumor in adults with over 5 million cases per year worldwide. Choroidal melanoma accounts for 90% of these tumors. Due to the high risk of metastasis, choroidal melanoma is almost always treated and therefore the natural growth of untreated choroidal melanoma is unknown. In this study, we attempted to model the growth pattern of untreated choroidal melanoma and analyze the natural progression of the disease.

Methods : We conducted a systematic search of Clinicaltrails.gov, Ovid MEDLINE, PubMed for unindexed materials, Ovid Embase, Science Citation Index Expanded, and the Cochrane Library for publications involving untreated choroidal melanoma tumor size published prior to April 30, 2019. An exponential model of tumor growth was developed using tumor height over time from individual subjects. To correct for differences in the time of enrollment for subjects, a temporal translation factor was applied to convert “time after enrollment” to “inferred age of tumor.” Regression analysis was used to find optimal tumor doubling time and initial tumor height. The relationship between tumor volume and tumor height was modeled as a cubic function using a subset of the data. From this relationship, tumor volume and volume doubling time were estimated from tumor height and height doubling time, respectively.

Results : Forty-four patients from three studies were identified that met our inclusion criteria. The tumor height data were well described by our exponential model which estimated a tumor height doubling time of 27.2 months and initial tumor height of 1.05mm (R² = 0.77). Our model of tumor volume as a cubic function of tumor height found that volume = 2.07×height³ (R² = 0.86). This suggests that the tumor volume doubling time is one-third of tumor height doubling time, thus predicting a tumor volume doubling time of 9.05 months.

Conclusions : From our analysis, untreated choroidal melanoma tumors appear to grow exponentially with a volume doubling time that matches the current literature (5.1-17.0 months). Additionally, our model predicted the height at which the tumors begin to grow exponentially. This value corresponded to an initial tumor volume of 2.40mm³. This model of choroidal melanoma growth patterns may help to understand treatment efficacy compared to the natural progression of the disease as well the transition from benign nevus to malignant tumor.

This is a 2021 ARVO Annual Meeting abstract.