Conformal High Dose External Radiation Therapy, 80.5 Gy, Alone for Medically Inoperable Non-small Cell Lung Cancer: A Retrospective Analysis

Background:Retrospective analysis of patients with medically inoperable non-small cell lung cancer treated with continuous high-dose external beam radiation therapy at the Medical University of South Carolina.Methods:We identified 35 patients with non-small cell lung cancer treated 1998-2002. None were candidates for resection for reasons including: pulmonary function (n = 23), previous cancer (n = 9), other co-morbidities (n = 2), and refusal of surgery (n = 1). Median percent predicted forced expiratory volume in 1 second was 41.5%. Median age was 71 years. Five patients had more than one primary tumor: three were concurrently treated, two were sequentially treated. Lesion sizes were <3 cm (n = 24); 3-5 cm (n = 12), and >5 cm (n = 5). Nodal stage was as follows: N0 (n = 33) and N1 (n = 2). Radiation therapy was administered once daily: median dose was 80.5 Gy/35 fx/2.3 Gy/fx. The clinical target volume was tumor plus nodes ≥1.0 cm. V20 data were available for 12 patients, with a mean value of 15.7%.Results:Thirty-four patients completed treatment. Median follow-up was 23.0 months. There were 26 deaths: 19 died from non-small cell lung (73%) and seven died from co-morbid illness (27%). Median survival was 24 months (95% CI, 18.0-31.9 months). Four patients were alive with disease, and five were alive disease-free at 10- and 68-month follow-ups. Of 41 lesions, local failure occurred in 15 lesions (37%) of which 3 local failure patients (9%) failed concomitantly in untreated regional lymph nodes. There were no isolated nodal recurrences. Distant progression: 10 patients (29%) of which 6 distant progression without local failure. Two patients who both had prior lobectomies experienced grade 5 toxicities.Conclusion:Continuous high-dose external beam radiation therapy 80.5 Gy administered in 35 fractions was tolerated. Treatment-related death was rare (6%) and isolated to patients with prior lobectomies in an extremely high-risk population. Most mortality was lung cancer-related. The dose of 80.5 Gy in 7 weeks is supported for patients with single lesions and no prior lobectomy. Local failure dominates and higher effective doses should be explored.