Stereotactic ablative radiotherapy as single treatment for early stage non-small cell lung cancer: A single institution analysis

Background: Stereotactic ablative radiotherapy (SABR) is the current standard-of-care in cases of inoperable early stage non-small cell lung cancer (ES-NSCLC). This study aimed to assess the survival outcomes and recurrence patterns after SABR for ES-NSCLC in a hospital setting.

Methods: A single-institution retrospective study was performed which included 109 patients who had undergone SABR. The main study endpoints were overall survival (OS), cancer specific survival (CSS), local recurrence-free survival (LRFS), regional recurrence free survival (RRFS) and distant metastasis-free survival (DMFS). Univariate and multivariate analysis were conducted to explore the potential factors which might be related to patient survival.

Results: A total of 109 patients were enrolled into the study. Median follow-up was 44 months (range: 2-93 months). (i) Recurrence results: Among 45 patients with recurrence, 30 patients (28%) had distant metastasis (DM), 17 patients (16%) had local recurrence (LR), 10 patients (9%) had regional recurrence (RR) of lymph nodes and two patients (2%) had second primary lung cancer (SPLC). (ii) Survival results: Median OS, CSS, PFS was 78 months, 78 and 40 months. Two-year OS, CSS, PFS, LRFS, RRFS and DMFS was 84.7%, 87.1%, 69.2%, 86.8%, 92.7% and 78.0%, respectively. Four-year OS, CSS, PFS, LRFS, RRFS and DMFS was 55.6%, 60.7%, 37.3%, 76.3%, 88.4% and 59.4%, respectively. (iii) Univariate and multivariate analyses indicated that age was a prognostic factor of CSS in patients aged <75 years (P = 0.04 HR 2.12 95% confidence interval [CI]: 1.04-4.33).

Conclusions: Although high survival rates can be achieved in ES-NSCLC patients treated with SABR, using SABR on its own may not be enough. Prolonged surveillance and adjuvant therapy is therefore needed.