Another question that the investigators looked at was whether performing more surgery increased the metastatic risk. “Metastasis developed in 8 patients [40%] in the vitrectomy/silicone oil group and in 12 patients [60%] in the phacoemulsification/vitrectomy group,” Dr. McCannel said. “The individualized Kaplan-Meier survival estimates in the 2 groups showed no significant difference (88.4% versus 88.2%, respectively).”
When the investigators evaluated the biopsies from those patients in whom metastasis developed, 19 patients underwent fluorescence in situ hybridization for chromosomes 3 and 6 and most had monosomy 3. Gene expression profile results in 13 of the 19 patients showed that most patients were in class 2, she pointed out.
The investigators also compared the Kaplan-Meier survival estimates with that of the Collaborative Ocular Melanoma Study (COMS). “The comparison showed there was no difference in the 5-year cumulative mortality estimate compared to the COMS patients who were treated with plaque alone and those in the current cohort treated with vitrectomy and silicone oil and 60% of those underwent phacoemulsification, IOL implantation, and silicone oil placement,” Dr. McCannel said.
The study results indicated that vitrectomy with silicone oil placement resulted in no significant difference in the 3- and 5-year survival rates compared to the COMS data.
“More surgery did not result in greater mortality,” Dr. McCannel outlined. “Metastatic death was associated with the molecular biology of the tumor, specifically monsomy 3 or class 2, and not additional intraocular procedures. Finally, vitrectomy with silicone oil radiation attenuation is a vision-improving strategy without evidence of increased systemic risk.”
Tara A. McCannel, MD, PhD
This article was adapted from a presentation Dr. McCannel delivered at the 2017 American Society of Retina Specialists. Dr. McCannel is a consultant and advisor to Impact Genetics and Novartis Pharmaceuticals.