Prognostic factors and results of radiation therapy in optic pathway tumors

The role of radiotherapy in the management of patients with optic pathway tumors remains controversial. This study analyzes the outcome of patients treated with radiotherapy and attempts to identify the groups of patients that may require early therapy.

We retrospectively reviewed 36 patients with optic pathway tumors treated with radiotherapy alone (26 patients) or with postoperative radiotherapy (10 patients). Seven patients had optic nerve tumors and 29 patients had chiasmal tumors. The actuarial progression free survival and observed survival probabilities were calculated using the Kaplan-Meier method and differences between curves were evaluated by the Mantel-Cox test. The obtained significant variables in the univariate analysis were analyzed using the Cox proportional hazards model.

The 10-year actuarial progression-free survival (10-y PFS) rate was 86% for patients with optic nerve gliomas and 47% for patients with chiasmal tumors. The 10-year actuarial observed survival (10-y OS) rate was 75% for patients with optic nerve gliomas and 53% for patients with chiasmal gliomas. In the group of patients with chiasmal tumors, progression-free survival and observed survival rates were significantly lower in infants (10-y PFS: 30%; 10-y OS: 37%), in patients with neurological deficits (10-y PFS and 10-y OS: 23%), in patients with signs of elevated intracranial pressure (10-y PFS and 10-y OS: 9%), with hydrocephalus (10-y PFS and 10-y OS: 0%), or with impairment of consciousness (10-y PFS and 10-y OS: 17%). Evaluation by computed tomography scanning was associated with a significantly higher probability of PFS. Radiation doses lower than 50 Gy were associated with significantly lower PFS and OS rates. In the Cox multivariate analysis, presence of neurological deficits and radiation dose significantly influenced observed survival. Presence of hydrocephalus significantly influenced progression-free survival.

The prognosis of patients with chiasmal gliomas presenting with neurologic deficits is poor and should be treated at diagnosis. A minimum tumor dose of 50 Gy is recommended.