Objectives: Lung tumors in which the planning target volume (PTV) overlaps the trachea or main bronchi are called "ultracentral" . We studied outcomes after delivery of 60 Gy in 12 fractions using stereotactic techniques (BED10=90Gy) to ultra-central tumors, in patients unfit for surgery or chemo-radiotherapy.

Methods: 47 consecutive patients with single primary or recurrent ultra-central NSCLC treated between 2010-2015 using volumetric modulated arc therapy were evaluated. Previously irradiated patients, or those with metastasis to sites other than the brain/adrenal glands, were excluded.

Results: The median age was 78 years; 49% had a WHO performance score =2. The median PTV size was 105cm3 (range 18-509). Median follow-up was 29 months, median overall survival 15.9 months, and 3-year survival 20.1%. No isolated local recurrences were observed. Grade 3 or higher toxicity was recorded in 38% of patients. 21% had a 'possible' (n=2) or 'likely' (n=8) treatment-related death, 5-18 months after treatment. Pulmonary hemorrhage was observed in 15% of patients.

Conclusions: Poor-risk patients treated with this scheme achieved a high rate of local control and acceptable median survival. Fatal hemorrhage was seen in 15% of patients, a rate similar as reported after conventional radiotherapy in endobronchial tumors.