Chronic radiation myelitis.

From March 1971 to September 1973, 200 patients with primary bronchogenic carcinoma received 4,000 rad (40 Gy) by means of split-course accelerated fractionation. Forty-five patients (22.5%) survived more than 11 months; and of these, 6 (13.3%) were found to have progressive myelitis. Recent reports indicate that rapid fractionation is preferred in some centers and may be undergoing a resurgence. The authors review their experience with this technique and the current understanding of the factors which affect the development of radiation myelitis.