Hyperfractionation in the radiation therapy of unresectable non-oat cell carcinoma of the lung: preliminary report of a RTOG Pilot Study.

Patients with localized unresectable non-oat cell carcinoma of the lung were treated by supervoltage radiation therapy to the primary tumor, mediastinum and supraclavicular lymph nodes with 50.4 Gy, 42 fractions of 1.2 Gy, twice daily, 4 to 6 hours apart, 5 times a week. Small field treatment to the known involved areas of primary and lymph nodes was given from 9.6 to 24 Gy, also with 1.2 Gy, twice daily. One hundred twenty-five patients were entered, three of whom were cancelled and two were ineligible. Of the remaining 120 eligible patients, 10 patients received a dose of 50.4 Gy, 20 received 60.0 Gy, 79 received 69.6 Gy and 11 patients received 74.4 Gy. Of these, nine patients were unable to complete hyperfractionated radiation therapy for various reasons. Treatment was discontinued or stopped in 14 patients because of early death or deterioration of the patient's condition. Four additional patients were found to have unacceptable doses to tumor or normal tissues, for a total of 27 patients with protocol violations. Complete regression occurred in 19% of T1-T3, N0-N2 patients with 9% among T3.3b, T4 or N3 patients. Partial regression was 29 and 41%, respectively. There were six cases of severe and two of life-threatening toxicity, but there were no fatalities attributable to the treatment. Toxicity consisted mainly of pneumonitis and pulmonary fibrosis as well as esophagitis. Median survival of the entire group was 7.2 months, which is consistent with previous experience with the treatment of localized inoperable non-oat cell carcinoma of the lung by radiation therapy. Further study of this method of treatment is warranted.