Survival of localized NSCLC patients without active treatment or treated with SBRT

Background: Little information on the natural history of patients with localized NSCLC is available since many of the studies covering the subject lack information on pathological confirmation, staging procedures and comorbidity. No randomized studies have compared SBRT with no treatment for patients with localized NSCLC. The purpose of this study was to evaluate whether SBRT has influence on overall survival for patients with localized NSCLC and investigate the effect of baseline ventilatory lung function on overall survival.

Material and methods: From 2007 to 2013, 136 patients treated with SBRT at Odense University Hospital were prospectively recorded. The thoracic SBRT consisted of three fractions of 15-22 Gy delivered in 9 days. For comparison, a national group of 73 untreated patients in the same time period was extracted from the Danish Lung Cancer Registry. All patients had histologically/cytologically proven NSCLC T1-2N0M0 with a tumour diameter ≤5 cm.

Results: The 5-year relative survival was 44% versus 7% for the SBRT and untreated groups, respectively. In a propensity score matched comparison the median overall survival was 47 months versus 11 months for the SBRT and untreated groups, respectively (p < .05). On multivariate analysis, SBRT was significantly associated with improved prognosis while ECOG performance status 2+ and tumour diameter ≥3 cm significantly predicted poorer prognosis. Severe to very severe reduction of forced expiratory volume in one second (FEV1) did not predict poorer survival for the SBRT treated patients with localized NSCLC.

Conclusions: SBRT offers more favourable survival than no treatment for patients with localized NSCLC. Performance status of 0-1, tumour diameter less than 3 cm and SBRT predicted improved survival. SBRT should not be withheld for patients with localized NSCLC based on poor ventilatory lung function.