[Iodine-125-brachytherapy of malignant choroid melanoma. II: Long-term functional outcome]

Following I-125 brachytherapy of choroidal melanoma, a good primary postoperative visual acuity results. The aim of this study is to evaluate postoperative, longterm visual acuity answering the following questions: 1) When do radiogenic complications begin to develop; 2) How long does the postoperative visual acuity remain stable; 3) Is there a difference if the treated tumor is < or = or > 3 mm off the disc and foveola respectively.

Between 12/1984-12/1989, 19 patients were treated with I-125 brachytherapy for choroidal melanoma. Height of tumor was x 5.8 mm, maximum base diameter x 11.6 mm. In 10 eyes (group A), the posterior tumor border was < or = 3 mm off the disc and foveola respectively, in 9 (group B) > 3 mm. The plaque was in situ x 7.5 days, apical radiation dose x 70 Gy, and scleral contact dose x 355 Gy. Follow-up ranged at x 6.3 years.

Between preoperative visual acuity in group A and group B there was a statistically significant difference (p < 0.05), which remained stable 1 1/2 years postoperatively. Subsequent deterioration of visual acuity occurred later in group B than in group A, but was present after 4 1/2 years in all patients and ranged at < or = 20/400. This decrease was due to subsequent radiogenic oculopathy.

Radiogenic complications following I-125 brachytherapy begin within the first 6 months. In group B visual acuity deteriorated later, but after 4 1/2 years, it decreased due to radiogenic oculopathy to 20/400 in all patients. Prospective longterm studies are needed to evaluate whether I-125 should be indicated for larger melanomas and Ruthenium-106 for smaller melanomas to obtain better longterm visual results.