No thoracic radiation myelitis after spinal cord dose > or = 50.4 Gy using 1.2. Gy b.i.d. fractionation in patients with Stage III non-small cell lung cancer treated with hyperfractionated radiation therapy with and without concurrent chemotherapy.

We investigated a risk of developing radiation myelitis during four prospective studies using hyperfractionated radiation therapy (HFX RT) with and without concurrent chemotherapy (CHT) during which a portion of thoracic spinal cord received a dose > or = 50.4 Gy given via 1.2 Gy b.i.d. fractionation. Of 536 patients with Stage III non-small cell lung cancer (NSCLC) which were treated on three prospective randomised Phase III studies and one Phase II study, 336 patients received irradiation dose > or = 50.4 Gy to a portion of their spinal cord and survived >1 year after the beginning of therapy. None of these 336 patients developed thoracic radiation myelitis. Therefore, the influence of potentially contributing factors on the occurrence of radiation myelitis, such as cord length, interfraction interval, or administration of concurrent CHT was not possible to investigate. These results give new insight about the influence of total dose/dose per fraction/interfraction interval with or without concurrent CHT on the thoracic spinal cord toxicity.