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

Rep Pract Oncol Radiother. 2020 Nov-Dec;25(6):943-950. doi: 10.1016/j.rpor.2020.09.015. Epub 2020 Oct 3.

Abstract

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

Background: 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.

Materials and methods: 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.

Results: 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.

Conclusion: 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.

Keywords: AC, Adenocarcinoma; DSS, disease specific survival; Early-stage lung cancer; G-PFS, global progression-free survival; L-PFS, local progression-free survival; Lung neoplasms; MVA, multivariate analysis; ND-PFS, nodal or distant progression-free survival; OS, overall survival; Radiotherapy; SBRT; SCC, Squamous Cell Carcinoma; UVA, univariate analysis.