Relative risk of stroke in head and neck carcinoma patients treated with external cervical irradiation.

Objective. To determine the rate of cerebrovascular events (stroke) in patients irradiated to high doses for squamous cell carcinoma of the head and neck. Study Design. Retrospective chart review of 413 patients treated from 1987 to 2000 with squamous cell carcinoma of the head and neck was performed to determine the risk of stroke compared with the expected rate. Methods. Surgical, radiotherapeutic, radiological, and clinical or office records of 413 patients were analyzed, and data were collected regarding clinical risk factors for stroke, irradiation parameters, and follow-up on whether or not a stroke event occurred. The actuarial risk of stroke for this population was calculated and compared with expected risk from population-based data. Results. Of the 413 patients, 20 had strokes in follow-up, occurring between 2 and 146 months after radiotherapy. The 5-year actuarial rate of stroke was 12%, which corresponded to a relative risk of 2.09 (P = .0007) compared with the population-based "expected" data. Median radiation therapy dose was 64 Gy; there was no correlation between radiation therapy dose and stroke risk. No correlation was identified between surgery near the carotids and stroke risk. Conclusions. An association between high-dose cervical irradiation for squamous cell carcinoma of the head and neck and stroke is demonstrated. Although the relative risk is approximately doubled, the absolute risk is modest in comparison to the risk of cancer recurrence. Further study of this association and possible interventions is warranted.