Tumor-related lipid exudation after plaque radiotherapy of choroidal melanoma: the role of Bruch's membrane rupture.

PURPOSE

To identify the risk factors predictive of development of tumor-related lipid exudation (TRLE) after plaque radiotherapy of posterior uveal melanoma.

DESIGN

Case-control study.

PARTICIPANTS

Cases included 294 patients with posterior uveal melanoma who had developed TRLE after plaque radiotherapy. Controls included 294 patients with posterior uveal melanoma who had not developed TRLE after plaque radiotherapy. Controls were matched with cases for age, gender, and initial tumor thickness.

METHODS

Data were extracted from medical charts containing demographic, clinical, and treatment information. Detailed fundus drawings and color fundus photographs were reviewed for each patient.

MAIN OUTCOME MEASURES

Tumor and ocular features of eyes with posterior uveal melanoma treated with plaque radiotherapy.

RESULTS

Multivariate analysis identified Bruch's membrane rupture (P<0.001), serous retinal detachment (RD) before radiation (P< or =0.019), closer proximity to the optic disc and foveola (P = 0.004 and 0.013, respectively), greater tumor base (P = 0.035), failure to receive transpupillary thermotherapy (TTT) after radiation (P<0.001), and initial increase of serous RD after radiation (P<0.001) as significant risk factors predictive of development of TRLE after plaque radiotherapy of posterior uveal melanoma. Radiation dose at the tumor base correlated with maximum extent of TRLE (P = 0.003). The mean interval between plaque radiotherapy and onset of TRLE was 14 months (median, 11 months; range, 2-97 months), with 88% of cases developing TRLE within 2 years of radiation. The interval between the onset of TRLE and the first evidence of its regression was a mean of 33 months (median, 38 months; range, 2-194 months).

CONCLUSIONS

Our study identified Bruch's membrane rupture as an important factor predisposing to development of TRLE after plaque radiotherapy of posterior uveal melanoma. Other predictive factors included serous RD before radiation, large tumor basal diameter, posterior tumor location, lack of adjunctive TTT, and early increase of serous RD after plaque radiotherapy.