[Stereotactic Body Radiation Therapy for less than 3cm (stage I) and 5cm (stage II) inoperable lung tumors: 10 years experience of Montpellier Cancer Institute].

PURPOSE: Search for predictive factors on survival and local control for less than 3 centimeters (cm) (stage I) and 5cm (stage II) inoperable lung tumors treated by Stereotactic Body Radiation Therapy (SBRT) in a retrospective monocentric study from Montpellier Cancer Institute (ICM) PATIENTS AND METHOD: Every patients treated at ICM for a stage I or II inoperable lung tumors from 2009 to 2019 were analyzed.

RESULTS

One hundred and seventy nine lesions were treated in 176 patients, with a major part (82,7%) in operated due to chronic obstructive pulmonary disease. Median overall survival for all patients was 71,7 months with a 35 months follow-up and the 2 years loco-regional free survival was 94,0 months. Better associated outcomes were stage I (median overall survival 71,7 versus 29,0 months P=0,004 ; HR=2,37 P=0,005), BED≥150Gy (median time-to-progression not reached versus 76,7 months P=0,025), small size of Planning Target Volume (PTV) (HR=0,42 P=0,032 when PTV<15,6 cc). 7,3% of all patients developed radiation pneumonitis.

CONCLUSION

SBRT is associated with an excellent overall survival and a high rate of local control for less than 3cm (stage I) and 5cm (stage II) lung tumors but a low rate of toxicities. For these patients with many comorbidities, BED over 150Gy seems to be associated with a better loco-regional free survival, while cause of death is often other than lung cancer.