Visual outcome after fractionated stereotactic radiation therapy of benign anterior skull base tumors

Abstract

To determine visual outcome including the occurrence of radiation induced optic neuropathy (RION) as well as tumor control after fractionated stereotactic radiation therapy (FSRT) of benign anterior skull base meningiomas or pituitary adenomas. Thirty-nine patients treated with FSRT for anterior skull base meningiomas and 55 patients treated with FSRT for pituitary adenomas between January 1999 and December 2009 with at least 2 years follow-up were included. Patients were followed up prospectively with magnetic resonance imaging scans, visual acuity and visual field examinations. RION was found in four (10 %) patients with anterior skull base meningiomas and seven patients (13 %) with pituitary adenomas. The five-year actuarial freedom from 25 % RION visual field loss was 94 % following FSRT. Actuarial 2-, 5- and 10-year tumor control rates were 100, 88.4 and 64.5 % for anterior skull base meningiomas and 100, 98.2 and 94.9 % for pituitary adenomas, respectively. Patients with an impaired visual field function pre-FSRT were more likely to experience worsened function (p = 0.016). We found that RION, was a relatively uncommon event, in a large prospective cohort of patients that were systematically monitored following FSRT of benign anterior skull base tumors. Long term tumor control was favorable, especially for pituitary adenomas.

Visual outcome, endocrine function and tumor control after fractionated stereotactic radiation therapy of craniopharyngiomas in adults: findings in a prospective cohort

“…The patient with a radiation-induced optic neuropathy was the oldest patient in the present study. Also, median tumor volume was considerably smaller in the present study, with consequently less irradiated volumes [16]. The presence of pre-existing visual impairment did not appear to predispose patients to radiation-induced optic neuropathy in this cohort, in contrast to our previous study [16].…”

“…The crude incidence of radiation-induced optic neuropathy of the present craniopharyngioma cohort is similar, though direct comparison is difficult with only one event and shorter follow-up in the present study [16]. In our previous study [16], the occurrence of radiation-induced optic neuropathy correlated with increasing age. The patient with a radiation-induced optic neuropathy was the oldest patient in the present study.…”

“…However, for the whole cohort, the median dose to the optic system was 54.2 and there was direct tumor-optic contact in the majority of cases, yet only one patient was affected. We recently reported a 10-13% occurrence of mostly mild to moderate radiation-induced optic neuropathy in a larger cohort of anterior skull base meningiomas and pituitary adenomas [16], evaluated using the same methodology. The crude incidence of radiation-induced optic neuropathy of the present craniopharyngioma cohort is similar, though direct comparison is difficult with only one event and shorter follow-up in the present study [16].…”

“…We recently reported a 10-13% occurrence of mostly mild to moderate radiation-induced optic neuropathy in a larger cohort of anterior skull base meningiomas and pituitary adenomas [16], evaluated using the same methodology. The crude incidence of radiation-induced optic neuropathy of the present craniopharyngioma cohort is similar, though direct comparison is difficult with only one event and shorter follow-up in the present study [16]. In our previous study [16], the occurrence of radiation-induced optic neuropathy correlated with increasing age.…”

“…Visual acuity was measured with a Snellen eye chart and an improvement in visual acuity was defined as a gain of 0.2 or more, and worsening as a loss of 0.2 or more. Visual fields were divided into 24 sectors, representing the central 30 for each eye and quantified with Campimetry, Goldmann dynamic perimetry and Octopus static perimetry [16]. The visual outcome was defined as radiation-induced optic neuropathy if visual acuity dropped from greater than 0.20-0.20 or less on one or both eyes and/or if the visual fields decreased by 1/24 fields or more on one or both eyes, in the absence of tumor growth.…”