Purpose: To assess the incidence of clinically significant bronchial stenosis in patients treated with high doses (i.e., >70 Gy) of twice-daily external beam radiation therapy (RT).
Methods and materials: The outcomes of 103 patients with unresectable non-small-cell lung cancer, treated twice daily to doses ranging from 7080 to 8640 cGy between 1992 and 2001, were analyzed. Most were treated on prospective clinical trials. For the dose-effect comparison, the patients were divided on the basis of the total dose: 67 received 74 Gy (range, 70.8-74.5 Gy; median, 73.6 Gy), 20 received 80 Gy, and 16 received 86 Gy (range, 85.2-86.4 Gy; median, 86.4 Gy). Sixty-six patients received sequential chemotherapy before RT. RT-induced bronchial stenosis was defined as symptomatic airway narrowing diagnosed by bronchoscopy or computed tomography scan without evidence of recurrent tumor in that region.
Results: Eight patients developed RT-induced, clinically significant, bronchial stenosis 2-48 months (median, 6 months) after RT. The 1-year and 4-year actuarial rate of stenosis was 7% and 38%, respectively. The median overall survival was 2.5 years (5 of 8 were alive at the writing of this report). A suggestion was also found of a dose-response effect with external beam radiotherapy-induced stenosis, with a rate of 4% and 25% at a dose of approximately 74 Gy and 86 Gy, respectively.
Conclusion: Radiation therapy-induced bronchial stenosis is a significant clinical complication of dose escalation for lung cancer. This complication has been previously mentioned in the literature, but ours is the largest report to date, and the findings suggest that the risk rises with increasing dose. It is likely that this process would manifest in more patients if their disease were controlled well enough for more prolonged survival.