Preliminary experience in the treatment of choroidal melanoma with gamma knife radiosurgery

Abstract

Object. The authors report their early results from an ongoing experience treating patients with choroidal melanoma by using gamma knife radiosurgery (GKS). Methods. Between September 1998 and March 2000, 11 patients were treated for choroidal melanoma. Treatment was facilitated with specialized frame placement. Eye immobilization was accomplished with supra- and infraorbital nerve block and tethering sutures to the periorbital tissue. Magnetic resonance imaging was performed to localize the tumor for treatment planning. Plugging patterns were used to steer fall-off radiation away from the fovea, optic nerve, or lens. Tumor volume, tumor location relative to critical structures, and dose to critical structures were determined using GammaPlan. Tumor response was determined using ultrasonography. Toxicity was determined by clinical assessment, visual acuity testing, and ophthalmoscopy. All 11 patients successfully completed the treatment. In every case, 40 Gy was prescribed to the 50% isodose, which completely encompassed all visible tumor. Tumor height ranged from 2.9 to 7 mm. The tumor diameter ranged from 6 to 13 mm. The range of follow up was 2 to 19 months. No tumor has progressed. One patient had improvement in vision because of improvement in retinal detachment. Two patients experienced visual decline. One patient's visual decline was due to a vitreous hemorrhage, and the other's was due to hard exudates encroaching on the macula. One patient has developed a dry eye that is managed effectively with topical eye lubricants. Conclusions. This preliminary experience demonstrates that GKS is a feasible treatment option for small- to medium-sized choroidal melanomas. Longer follow up and additional patients will be required to improve the assessment and the ultimate tumor control and toxicity in this ongoing series.

Dose De-Escalation With Gamma Knife Radiosurgery in the Treatment of Choroidal Melanoma

“…Langmann et al have reported the lowest doses of definitive single fraction radiosurgery for the treatment of ocular melanoma (29). Using a mixture of dose regimens ranging (32,33). The high control rates and minimal radiation related complication rates in these two series are likely related to the relatively short follow-up periods of less than 14 months.…”

Long-term results of Gamma Knife surgery for uveal melanomas

“…Previous retrospective series, in which the outcomes of GKS in the treatment of uveal melanoma were evaluated, have shown mixed results. 4,7,15,16,19,21,24,28,29 Modorati et al 18 reported that the 3-year probability of survival for uveal melanoma after GKS was 88.8% and the 5-year probability of survival was 81.9%. Fakiris et al 9 showed that the 3-and 5-year overall survival rates were 86% and 55%, respectively.…”

Experience using frameless fractionated radiosurgery for the treatment of orbital and ocular tumors

“…A report from the Journal of Neuroscience in 2000 described this technique of immobilization in which patients were required to have local nerve block in the form of injectable anesthetic applied before tethering sutures were inserted to keep the eye fixed during treatment. While not a limitation for the use of GKS, it is important to note that the authors also used a 40-Gy dose prescribed to the 50% isodose line, as compared to our study, which used a lower dose, 30 Gy, to a median 74% isodose line [20]. When considering enucleation versus radiation therapy for treatment, it is important to mention the Cooperative Melanoma Study (COMS), which demonstrated similar 5-year survival rates for both scleral plaques (82%) and enucleation (81%) [21].…”