External beam irradiation for choroid metastases: identification of factors predisposing to long-term sequelae

To improve overall quality of life, palliative treatments should attempt to minimize associated complications while effectively controlling specific symptoms. We reviewed our experience treating posterior uveal metastases with external beam radiotherapy (EBRT) to determine the complication rate and to identify the relationship between patient, tumor, or treatment-related factors and the development of ocular complications.

483 consecutive patients (pts) (578 eyes) were diagnosed with intraocular metastatic disease from solid tumors between 1972-1995. Of these, 233 eyes (188 pts) had lesions of the posterior uveal tract and received EBRT. Median follow-up time was 5.8 months (range: 0.7-170.0 months). Follow-up information regarding the development of complications was documented for 230 eyes. Complete EBRT details were available for 189 eyes. Seventy-two percent of the patients received 30.0-40.0 Gy in 2.0-3.0 Gy fractions. Biologically effective dose (BED) was calculated to allow meaningful comparisons between various fractionation regimens and total doses. Concurrent chemotherapy and/or hormonal therapy was used for 101 eyes (44%).

Median BED was 61 Gy3 (range, 6.7-105 Gy3), and 80% of treated eyes received BED 50-70 Gy3. EBRT energies included photons (70%), 60Co (19%), electrons (6%), mixed energies (3%), and orthovoltage (2%). Lens-sparing techniques were used in 136 eyes (71%). At last follow-up 28 eyes (12%) developed one or more significant complications, including cataracts (16 eyes), radiation retinopathy (6 eyes), optic neuropathy (5 eyes), exposure keratopathy (5 eyes), and neovascularization of the iris (4 eyes). Two eyes developed narrow-angle glaucoma, and one of these required enucleation. On univariate analysis, Caucasian race (vs. Black/Hispanic, p = 0.03), increased intraocular pressure at diagnosis (>21 mmHg, p = 0.02), and diagnosis by biopsy (vs. no biopsy, p = 0.03) predisposed toward the development of complications. Factors not correlated with complications included BED (p = 0.18), energy type (p = 0.81), lens-sparing technique (versus whole globe, p = 0.57), and concurrent systemic treatment (p = 0.60). The small number of complications did not support a multivariate analysis.

Despite the employment of a variety of EBRT treatment techniques and the proximity of choroidal metastases to radiosensitive structures, significant complications of palliative EBRT were infrequent. Although complications do occur, they are related to host factors and do not appear to be a function of irradiation parameters. We conclude that the potential benefits of vision and globe preservation after palliative EBRT outweigh the small risk of treatment induced complications.