Stereotactic radiotherapy (SABR) for the treatment of primary non-small cell lung cancer; systematic review and comparison with a surgical cohort

Background and purpose: To assess the efficacy of stereotactic ablative radiotherapy (SABR) for the treatment of non-small cell lung cancer (NSCLC) through a systematic review of all relevant publications from 2006 to the present compared to controls treated with surgery. In the absence of Grade I evidence, the objective outcome data should form the basis for planning future studies and commissioning SABR services.

Materials and methods: Standard systematic review methodology extracting patient and disease characteristics, treatment and outcome data from published articles reporting patient data from populations of 20 or more Stage I NSCLC patients treated with SABR with a median follow up of minimum of 1 year. The individual outcome measures were corrected for stage and summary weighted outcome data were compared to outcome data from a large International Association for the Study of Lung Cancer (IASLC) cohort matched for stage of disease with survival as the principal endpoint and local control (local progression free survival - local PFS) as the secondary endpoint.

Results: Forty-five reports containing 3771 patients treated with SABR for NSCLC were identified that fulfilled the selection criteria; both survival and staging data were reported in 3171 patients. The 2 year survival of the 3201 patients with localized stage I NSCLC treated with SABR was 70% (95% CI: 67-72%) with a 2 year local control of 91% (95% CI: 90-93%). This was compared to a 68% (95% CI: 66-70) 2 year survival of 2038 stage I patients treated with surgery. There was no survival or local PFS difference with different radiotherapy technologies used for SABR.

Conclusions: Systematic review of a large cohort of patients with stage I NSCLC treated with SABR suggests that survival outcome in the short and medium term is equivalent to surgery for this population of patients regardless of co-morbidity. As selection bias cannot be assessed from the published reports and treatment related morbidity data are limited, a direct comparison between the two treatment approaches should be a priority. In the meantime, SABR can be offered to stage I patients with NSCLC as an alternative to surgery.