ASRS 2018: Oncology Session
Nikisha Kothari, MD
Vitreoretinal Surgery Fellow
UCLA Jules Stein Eye Institute
Dr. Timothy Murray, the Program Chair of ASRS, started the morning with a discussion on the results comparing trans-scleral and trans-vitreal biopsy for gene expression profiling (GEP) posterior uveal melanoma. The study consisted of 353 patients with trans-vitreal biopsy in 214 eyes and trans-scleral in 137 eyes. Biopsy samples were sent to Castle Biosciences for molecular genomic profiling. A determinant biopsy was obtained in 333 eyes (94.3%). Twenty eyes (5.6%) failed to yield GEP analysis of which 18 eyes were in the trans-vitreal group. Although the rates of retinal detachment were very low, trans-vitreal group had a higher rate of retinal detachment (1.9% vs. 0.7%).
Dr. Tara McCannel from Stein Eye Institute, UCLA, then took the podium to discuss the results of 27-gauge biopsy for small uveal melanomas. Small tumors are often difficult to biopsy due to their location (often posterior, within the macula and close to the fovea). In addition, a trans-scleral needle approach may yield insufficient sample. Dr. McCannel described a technique with placing two 27 gauge trochars: one for illumination and one for the vitreous cutter (no infusion). A surgical video was demonstrated using the DORC EVA platform using the TDC cutter with a cute rate of 22 on the vacuum mode to obtain biopsy. A vitrectomy was not performed. Forty-one eyes were included in the study. The most common complication was vitreous hemorrhage (51%) with 7 (17%) hemorrhages over the macula and 3 (7%) requiring vitrectomy. Notably no patients developed retinal detachment. 92% of patients had a positive GEP result.
Next, Dr. Zelia Correa discussed the survival outcomes based on GEP. Her study included 538 patients with a tumor size ranging from 3.7mm to 24mm. During the follow up period, 62 patients died. As expected, the survival was worst in patients with class 2 tumors. However, very interestingly, the survival in class 1A was worse compared with class 1B and class 1 (based on historical data).
During the discussion of the first 3 talks by Drs. Murray, McCannel, and Correa, a very important point was raised that the purpose of performing a biopsy and interpreting the results is to provide the patient with information regarding their survival. Particularly with a rate of 50% metastasis for all patients with uveal melanoma, this was a very valiant point.
Dr. Amy Schefler shifted gears to discuss the exciting results of a Phase 1b-2 clinical trial of Light Activated AU-011 therapy for treatment of choroidal melanoma. The viral nanoparticle is injected into the vitreous cavity and then binds to heparin-sulfated proteoglycans expressed by ocular melanoma cells. Thereafter, the 689nm laser used for PDT is applied to the tumor (without injection of verteporfin). The clinical trial began in humans 16 months ago after successful studies in rabbit models demonstrating tumor necrosis with preservation of the surrounding retina. Tumors included in the study were 1.5mm to 3.4mm with documentation of growth or 2.0 to 3.4mm with at least 2 risk factors: subretinal fluid, orange pigment, or visual changes. 22 patients were included in the study. In regards to safety, the therapy appears well tolerated with an adverse effect of inflammation which was well controlled. Moreover, all patients preserved pretreatment for at 6 month follow up. This novel treatment is promising and we look forward to future studies evaluating its efficacy.
Dr. Rajiv Anand from Texas Retina Associates then took us to the next chapter of the uveal melanoma story: the aftermath. His study was a prospective, randomized, multicenter trial evaluating ranibizumab for treatment of macular edema secondary to radiation retinopathy. The study including 40 patients split into 3 cohorts: monthly ranibizumab, monthly ranibizumab + tPRP and a loading dose of ranibizumab then as needed + tPRP. Interestingly, the cohort that received monthly ranibizumab had significantly better vision at month 6 compared with the other 2 groups and compared with baseline. Targeted PRP did not appear to be advantageous at the 9 month follow up. These results are important to our understanding of management of radiation retinopathy as most studies thus far have been retrospective.
Dr. Brian Toy from University of South California Roski Eye Institute discussed his interesting findings evaluating OCT angiography changes in radiation retinopathy. A change in the retinal microvasculature with a statistically significant change in vessel diameter, vessel density, and flow. Interestingly, a particular spatial pattern was noticed based on amount of radiation such that areas with greater exposure had more vascular changes.
Finally, Dr. Scott Walter presented his work with co-investigator Dr. Bill Harbor from Bascom Palmer Eye Institute. The study compared dosimetry simulations of the Collaborative Ocular Melanoma Study (COMS) and EyePhysics (EP) plaques. Interestingly, COMS was preferred in 18% of cases, EP in 41% and either in 31% suggesting that selected cases have a preferred plaque design.