Abstract
Abstract: :
Background: In some patients treated with plaque radiotherapy for medium–sized choroidal melanomas, the tumor blood supply leaks large volumes of fluid and exudates. It has been anecdotally noted that those patients who experience post–treatment lipid leakage often have elevated serum lipids. If higher serum lipids are a marker for greater post–treatment lipid leakage, then preventative measures may reduce the morbidity of treating the tumor. Purpose: To attempt to identify factors associated with post–brachytherapy lipid exudation in patients with malignant melanoma of the choroid. Methods: A retrospective chart review was performed on 139 consecutive patients treated by the Washington University Ocular Oncology Service with brachytherapy for malignant melanoma. Data collected included: demographics, available serum lipid parameters, visual acuity, tumor size, features, and location, treatment parameters, exudative retinal detachment and features, additional treatments, ultrasound parameters, and tumor vascularity. Results: Sixteen of the 139 (11.5%) patients treated with plaque radiotherapy developed lipid exudation. Median Pre–operative visual acuities were similar at approximately 20/30 with significantly lower post–operative acuities in the exudation group (20/800) versus the non–exudation group (20/100). Pre–operative serum lipid values were available in 42% of all treated patients; of these patients, 64% had at least one lipid parameter outside the normal range. All patients in the lipid exudation group with known serum lipids had lipid values outside of the normal range. 32% of the 62 patients with a fluorescein angiogram had a noted intrinsic circulation. 6 of 8 patients with FA in the exudation group had both an intrinsic circulation and hot spots. Patients in the exudation group had statistically greater tumor height, higher serum LDL cholesterol, younger age, shorter distance from the tumor to the macula, and lower apical tumor radiation dosage(t–test, p<0.05). The rate of enucleation was 7.3% in the non–exudation group and 25% in the exudation group. Conclusions: Lipid exudation occurs in a subset of patients treated with plaque radiotherapy and leads to a poorer visual outcome. Higher serum lipids and the presence of an internal circulation may be associated with a higher probability of lipid exudation post treatment. Prospective collection of serum lipid data will allow us to further define these relationships and possibly recommend pharmacologic treatment of lipids pre–operatively and laser demarcation of the tumour intra– or post–operatively.
Keywords: melanoma • tumors • radiation therapy