Abstract
Purpose :
There is an increase in pigmentation that occurs in many tumors following plaque brachytherapy for choroidal melanoma. Correctly distinguishing between increased pigment at the tumor border versus true growth is imperative. We performed a retrospective review of patients treated with I-125 brachytherapy for choroidal melanoma at our institution to study this phenomenon.
Methods :
Records were reviewed for all patients undergoing plaque brachytherapy for uveal melanoma for a five-year period (2016-2021; N=195). Patients with iris and anterior tumors were excluded. Fundus images for patients with increased pigmentation at any of the borders of the tumor at 6 month follow up that extended beyond the initial pigmented margin were included (N=31; 11 F, 20 M). Imaging at last follow up was reviewed and it was confirmed that all tumors involuted appropriately with no evidence of local recurrence. The date of initial exam, time to treatment, and follow up interval were recorded for each included patient.
Results :
Of 195 patients, 31 patients (15.9%) exhibited increased pigment deposition at any of the borders of the tumor at 6 month follow up that extended beyond the initial pigmented margin (Figure 1). Average tumor thickness was 3.0 mm (1.2-6.3), average largest tumor basal diameter was 11.3 mm (5.5-15.5). Average time from diagnosis to treatment was 29 days (17-55). Average length of follow up was 37 months (17-70). No patient developed recurrence during the duration of follow up, and one patient had developed metastasis.
Conclusions :
We describe the phenomenon of increased pigment deposition, “edge creep,” at the borders of choroidal melanomas treated with plaque brachytherapy that gave the appearance of initial tumor growth, but then subsequently remained stable over time. It is important treating ocular oncologists be aware of this phenomenon to avoid unnecessary diagnosis of local recurrence. It is important that all tumor features be carefully monitored following treatment in order to ensure adequate tumor regression. The precise mechanism behind edge creep in treated choroidal melanomas warrants further histopathologic investigation and study in the future.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.