Long-term Evaluation of Radiation-Induced Optic Neuropathy After Single-Fraction Stereotactic Radiosurgery

• Published in: International journal of radiation oncology, biology, physics Vol. 87; no. 3; pp. 524 - 527
• Main Authors: Leavitt, Jacqueline A., MD, Stafford, Scott L., MD, Link, Michael J., MD, Pollock, Bruce E., MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.11.2013
• Subjects: Adenoma - surgery; ADENOMAS; Adolescent; Adult; Aged; Aged, 80 and over; Child; Craniopharyngioma - surgery; EVALUATION; EXTERNAL BEAM RADIATION THERAPY; Follow-Up Studies; Hematology, Oncology and Palliative Medicine; Humans; Incidence; Meningeal Neoplasms - surgery; Meningioma - surgery; Middle Aged; Optic Nerve - radiation effects; PATIENTS; Pituitary Neoplasms - surgery; RADIATION DOSES; Radiation Injuries - epidemiology; Radiation Tolerance; Radiology; RADIOLOGY AND NUCLEAR MEDICINE; Radiosurgery - adverse effects; Radiosurgery - methods; Radiotherapy Dosage; Retrospective Studies; Risk Assessment; SINUSES; SKULL; Skull Base Neoplasms - surgery; SURGERY; Young Adult
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2013.06.2047

Purpose To determine the long-term risk of radiation-induced optic neuropathy (RION) in patients having single-fraction stereotactic radiosurgery (SRS) for benign skull base tumors. Methods and Materials Retrospective review of 222 patients having Gamma Knife radiosurgery for benign tumors adjacent to the anterior visual pathway (AVP) between 1991 and 1999. Excluded were patients with prior or concurrent external beam radiation therapy or SRS. One hundred twenty-nine patients (58%) had undergone previous surgery. Tumor types included confirmed World Health Organization grade 1 or presumed cavernous sinus meningioma (n=143), pituitary adenoma (n=72), and craniopharyngioma (n=7). The maximum dose to the AVP was ≤8.0 Gy (n=126), 8.1-10.0 Gy (n=39), 10.1-12.0 Gy (n=47), and >12 Gy (n=10). Results The mean clinical and imaging follow-up periods were 83 and 123 months, respectively. One patient (0.5%) who received a maximum radiation dose of 12.8 Gy to the AVP developed unilateral blindness 18 months after SRS. The chance of RION according to the maximum radiation dose received by the AVP was 0 (95% confidence interval [CI] 0-3.6%), 0 (95% CI 0-10.7%), 0 (95% CI 0-9.0%), and 10% (95% CI 0-43.0%) for patients receiving ≤8 Gy, 8.1-10.0 Gy, 10.1-12.0 Gy, and >12 Gy, respectively. The overall risk of RION in patients receiving >8 Gy to the AVP was 1.0% (95% CI 0-6.2%). Conclusions The risk of RION after single-fraction SRS in patients with benign skull base tumors who have no prior radiation exposure is very low if the maximum dose to the AVP is ≤12 Gy. Physicians performing single-fraction SRS should remain cautious when treating lesions adjacent to the AVP, especially when the maximum dose exceeds 10 Gy.