Prognostic factors and clinical outcomes after stereotactic radiotherapy for primary lung tumors

To characterize the population treated with SBRT for early-stage primary lung tumors in our institution, determine their outcomes, and identify potential prognosis factors.

Stereotactic radiotherapy (SBRT) is an alternative treatment for inoperable patients with early-stage lung cancer. It confers a local control rate around 90% at 3 years, and 2-3 year overall survival rates of 43-60% in this population.

We retrospectively analyzed all patients treated in our department between 2012 and 2017 and evaluated local progression-free survival (L-PFS), nodal or distant progression-free survival (ND-PFS), global progression-free survival (G-PFS), overall survival (OS), and disease specific survival (DSS). Univariate (UVA) and multivariate (MVA) models were built to assess the influence of each variable.

We identified 218 patients with 233 tumors. Most were male (78.9%) with a median age of 73 years. Median follow-up was 22 months. At 18 months, L-PFS was 93.7%, ND-PFS was 82.2%, G-PFS was 76.0%, DSS was 90.5%, and OS was 78.0% in ≤ T2 tumors. On UVA, T2 tumors were associated with lower L-PFS, G-PFS and DSS than T1, with no significant impact on ND-PFS or OS, an effect that persisted on MVA. On UVA, L-PFS and G-PFS were negatively influenced by female gender and a 5-fraction schedule was associated with worse G-PFS, which was not confirmed on MVA.

Our local and distant control rates and survival were similar to those previously reported. On MVA, T2 tumors displayed lower L-PFS, G-PFS and DSS, with no difference in OS.