Outcomes of treatment with stereotactic radiosurgery or proton beam therapy for choroidal melanoma

Abstract

Aim: To present our experience of the use of stereotactic radiosurgery and proton beam therapy to treat posterior uveal melanoma over a 10 year period.

Methods and materials: Case notes of patients treated with stereotactic radiosurgery (SRS), or Proton beam therapy (PBT) for posterior uveal melanoma were reviewed. Data collected included visual acuity at presentation and final review, local control rates, globe retention and complications. We analysed post-operative visual outcomes and if visual outcomes varied with proximity to the optic nerve or fovea.

Results: 191 patients were included in the study; 85 and 106 patients received Stereotactic radiosurgery and Proton beam therapy, respectively. Mean follow up period was 39 months in the SRS group and 34 months in the PBT group. Both treatments achieved excellent local control rates with eye retention in 98% of the SRS group and 95% in the PBT group. The stereotactic radiosurgery group showed a poorer visual prognosis with 65% losing more than 3 lines of Snellen acuity compared to 45% in the PBT group. 33% of the SRS group and 54% of proton beam patients had a visual acuity of 6/60 or better.

Conclusions: Stereotactic radiosurgery and proton beam therapy are effective treatments for larger choroidal melanomas or tumours unsuitable for plaque radiotherapy. Our results suggest that patients treated with proton beam therapy retain better vision post-operatively; however, possible confounding factors include age, tumour location and systemic co-morbidities. These factors as well as the patient's preference should be considered when deciding between these two therapies.

Figure 1

(a): Fundus photograph of a 64 year-old female patient with a melanoma encircling 8 clock hours of the left optic disc before stereotactic radiosurgery. Visual acuity at presentation was 6/12. (b): Fundus photograph of the patient in figure 1a, 2 years post-stereotactic radiosurgery showing the melanoma to be in regression with oedema and haemorrhage involving the optic disc consistent with radiation optic neuropathy. Final visual acuity was counting fingers. (c): Fundus photograph of the right eye of a 28 year-old male patient with a juxtafoveal melanoma before proton beam therapy. Visual acuity at presentation was 6/12. (d): Fundus photograph of the patient in figure 1c, 2 years following proton beam therapy showing the melanoma to be in regression with scattered retinal haemorrhages and a small vascular occlusion consistent with radiation retinopathy. Visual acuity at this stage was 6/18.