RADIATION-THERAPY ALONE FOR STAGE-I NONSMALL CELL LUNG-CANCER

Purpose: This paper is a retrospective analysis of patients with clini cal Stage I non-small cell carcinoma of the lung treated with definiti ve radiation therapy alone. The results of therapy, patterns of failur e and the relationship of technical aspects of the delivery of radioth erapy to outcome are presented. Materials and Methods: From 1980 throu gh 1990, 53 patients with Stage I non-small cell lung cancer were trea ted with definitive radiation therapy alone at the Radiation Oncology Center of the Mallinckrodt Institute of Radiology and its affiliated h ospitals. All patients had a pathologic diagnosis of non-small cell lu ng cancer and were not candidates for surgical resection because of ei ther patient refusal (10 patients), poor performance status (5 patient s), or premorbid medical problems (38 patients). The median age was 73 years. Histologic cell type included squamous (32), adenocarcinoma (1 1), large cell (4), and unclassified non-small cell (6). Initial tumor size was less-than-or-equal-to 3 cm in 23 patients, between 3 and 5 c m in 13 patients and greater-than-or-equal-to 5 cm in 17 patients. Dia gnostic staging varied during the study period. All patients had chest X-rays and computed tomography scans of the chest. A majority had liv er and bone scans, but only four underwent mediastinoscopy. The radiat ion therapy was of megavoltage energy in all patients, with a median p rimary prescription tumor dose of 63.2 Gy. Survival was measured from the date radiation therapy was initiated. Results: The actuarial overa ll survival rate for the entire group was 19% at 3 years and 6% at 5 y ears, with a median survival time of 20.9 months. Of the 49 deaths, 35 died of lung cancer; 13 died of intercurrent illness, and one died of pancreatic cancer, which made the actuarial cause-specific survival 3 3% at 3 years and 13% at 5 years. The actuarial 3-year disease-free su rvival was 33%. Local primary tumor progression occurred in 22 patient s, resulting in a 51% 3-year actuarial freedom from local progression. An additional four patients failed in regional lymph nodes that were included in the original treatment portals. Multivariate analysis foun d only T stage to be associated with overall survival (p = .02). Howev er multivariate analysis showed age as a prognostic factor to be appro aching statistical significance (p = .07). Patients under 70 years of age showed an increased survival rate compared to patients over 70 yea rs. Radiation therapy doses greater-than-or-equal-to 65 Gy appeared to result in a decreased proportion of patients dying of lung cancer wit h no apparent increase in either acute or long-term complication rates . Conclusion: Results of definitive radiation therapy for inoperable S tage I non-small cell lung remain inferior to surgical therapy. Potent ial methods to improve local control with radiotherapy are discussed.