Tumor-height regression rate after brachytherapy between choroidal melanoma gene expression profile classes: effect of controlling for tumor height.

PURPOSE

To evaluate the relationship between choroidal melanoma regression rate and its gene expression profile class after iodine-125 brachytherapy at 3 and 6 months, controlling for baseline tumor height.

METHODS

Patients from October 2012 to January 2015 at a single Ophthalmic Oncology Center who had undergone iodine-125 brachytherapy for the treatment of choroidal melanoma and who had a gene expression profile test result obtained from intraoperative fine-needle aspiration biopsy at the time of plaque surgery were retrospectively reviewed. Baseline patient and tumor characteristics were obtained, including tumor height and gene expression profile test result. Tumor height at 3 and 6 months following treatment was obtained. Regression rate was analyzed with two-way analysis of variance to class type and baseline pre-operative tumor height. Class 2 patients were matched to class 1 patients by tumor height and resulting distributions of paired regression rate differences were compared.

RESULTS

A total of 114 patients were studied. When preoperative tumor height was controlled for in the comparative analysis, neither group of patients at 3 or 6 months had a significant dependency between gene expression profile class and tumor regression rate. Additionally, class 1 and class 2 patients matched for pre-operative tumor height did not express different regression rates.

CONCLUSIONS

Our study adds to a growing body of evidence that tumor regression rate does not necessarily depend on gene expression profile class type in choroidal melanoma after brachytherapy at 3 and 6 months when controlling for baseline tumor height.