The incidence of cerebral infarction was studied in 156 patients irradiated for treatment of pituitary adenomas. Seven patients experienced strokes at intervals of 3.2 to 14.6 years after irradiation. The observed incidence was not significantly greater than the expected value of 3.5 strokes (P = 0.078). Six strokes occurred in patients receiving equivalent doses (ED) of 1070 ret or more (observed to expected ratio 3.87, significantly elevated; P < 0.001). Univariate log-rank analysis showed that the risk of stroke was significantly higher (P = 0.010) in patients receiving an ED of 1070 ret or more (4180 cGy/22 fractions) than those receiving lower doses. Multivariate analysis, however, demonstrated that the increased risk of stroke was associated only with increasing age (P < O.OOOl), not ED (P = 0.148). Due to these inconsistent statistical results, no definitive conclusions could be reached about the relationship between radiation dose to the pituitary and subsequent cerebral infarction.
Cancer 63:2404-2408, 1989.
N REVIEWING a series of patients receiving radiation I therapy for nonfunctional adenomas of the pituitary gland at the University of Pittsburgh, a number of patients were found to suffer subsequent cerebral infarctions. There are a number of well-documented reports in the literature of children and adults in whom cerebral infarction has developed after radiation for pituitary adenoma and other brain tumors.'-23 Many of these reports document arteriographic changes within the radiation portals. Because strokes are a common problem in older patients, a moderate increase in risk after radiation therapy might go unnoticed. For this reason, a review of all patients receiving radiation therapy at our institution for functional and nonfunctional pituitary adenomas during the last 24 years was undertaken to try to identify factors associated with subsequent cerebral infarction.
Patients and Methods