Optic neuropathy after proton-beam therapy for malignant choroidal melanoma

Proton-beam irradiation is a conservative therapy commonly used for the tre atment of uveal malignant melanomas. Some adverse effects such as optic neu ropathy can compromise the visual outcome. We were interested in determinin g the risk factors for radiation papillopathy. Since there is currently no effective therapy, this is an interesting way to improve prevention of opti c neuropathy. Six hundred sixty-two eyes bad more than 24-month follow-up after proton-be am irradiation for uveal melanoma. In five hundred twenty-two cases, the cl inical examination of the optic nerve head by ophthalmoscopy was possible. One-hundred eleven optic discs were pathologic, whereas 411 remained diseas e-free. Retrospective study of these two groups allowed to quantify the ris k factors for optic neuropathy. The irradiation of more than 2 mm of optic nerve at 30 Grays-equivalents ap peared to be the major risk factor for optic neuropathy. For a given irradi ation dose, the observed pattern of clinical responses was heterogenous. Th ese results are discussed and compared to the previous published reports. V isual results and life prognosis are also discussed, considering the optic nerve head status. Proton-beam therapy can preserve the optic nerve when the tumor location al lows to keep it away from the irradiation-field, Patients must be informed about the risk of optic neuropathy after proton-beam irradiation.