Visual outcomes of macular melanocytic lesions after early or delayed proton beam therapy.

PURPOSE: During their initial management, some macular melanocytic lesions can be closely monitored to wait for a documented growth before advocating a treatment by irradiation. However, the visual outcomes of this strategy have not yet been assessed. This study compares the visual outcomes of macular melanocytic lesions that underwent delayed proton beam therapy (PBT) after an initial observation to those treated early. METHODS: A total of 162 patients with suspicious melanocytic lesions whose margins were located within 3 mm of the fovea were recruited from two French ocular oncology centers. RESULTS: Overall, 82 patients treated with PBT within 4 months after the initial visit (early PBT group) were compared to 24 patients treated with delayed PBT (delayed PBT group) and 56 patients not treated with PBT (observation group). Visual acuity was not significantly different between baseline and last visit in the observation group (p = 0.325). Between baseline and last visit, the median [IQR] loss in visual acuity was significant in both the early (0.7 [0.2; 1.8], p < 0.001) and the delayed (0.5 [0.2; 1.5], p < 0.001) PBT groups. After irradiation, there was no significant difference between the early and delayed PBT groups for visual loss (p = 0.575), diameter reduction (p = 0.190), and thickness lowering (p = 0.892). In multivariate analysis, history of diabetes mellitus and Bruch's membrane rupture remained significantly associated with greater visual loss (p = 0.036 and p = 0.002, respectively). CONCLUSION: For small lesions in which there is no clear diagnosis of malignant melanoma, an initial close monitoring to document tumor growth does not impact visual prognosis, despite the potential complications associated with the untreated tumor. However, the survival should remain the main outcome of the treatment of these lesions.

QUANTITATIVE ANALYSIS OF CHORIOCAPILLARIS ALTERATIONS IN SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY-ANGIOGRAPHY DURING RADIATION RETINOPATHY.

PURPOSE: To evaluate choriocapillaris alterations following proton beam therapy irradiation using swept-source optical coherence tomography-angiography, and to assess their correlation with the grade of radiation retinopathy (RR). METHODS: Eyes with uveal melanoma evaluated before and after irradiation with proton beam therapy were included, as well as the healthy fellow eye. The gradation of RR was based on a previously published classification. Choriocapillaris flow voids area was analyzed using Phansalkar thresholding. Retinal vascularization was described by foveal avascular zone (FAZ) perimeter, FAZ area, FAZ circularity index, and percentage of nonperfusion area (PAN) in the superficial capillary plexus (SCP) or deep capillary plexus. RESULTS: A total of 157 eyes of 83 patients were analyzed. Overall, there was a significant difference between the control group, the uveal melanoma before proton beam therapy group, and the grades of RR in the uveal melanoma after proton beam therapy group for FAZ perimeter ( P < 0.001), FAZ area ( P < 0.001), FAZ-circularity index ( P < 0.001), PAN-SCP ( P < 0.001), PAN-deep capillary plexus ( P < 0.001), and choriocapillaris flow voids area ( P < 0.001). Moreover, choriocapillaris flow voids area was significantly increased in the early stages of RR ( P = 0.003) and was further significantly correlated with FAZ perimeter ( P < 0.001), FAZ area ( P < 0.001), FAZ-circularity index ( P = 0.010), PAN-SCP ( P < 0.001), and PAN-deep capillary plexus ( P < 0.001). CONCLUSION: Quantitative optical coherence tomography-angiography alterations in the choriocapillaris microvascularization are an early biomarker of RR and are correlated to the severity of the disease.