Predictive factors of response in lung metastases treated by sbrt from colon rectal cancer.

To identify predictive factors of response in patients with lung metastases from primary colorectal cancer (CRC) treated with stereotactic body radiation therapy (SBRT). This retrospective, single-centre study included patients with histologically confirmed primary CRC, Karnofsky performance status > 60, and age > 18 years. Between 2008 and 2023, 149 lung metastases in 88 patients were treated with SBRT. Among the treated lesions, 23 were synchronous and 126 were metachronous. According to a simplified oligometastatic classification, 9 (6%) were synchronous, 57 (38%) oligorecurrent, 76 (51%) oligoprogressive, and 7 (5%) oligopersistent. Local control (LC) at 1 and 2 years was 76.8% and 64.0%, respectively. Time to polymetastatic conversion (tPMC) at 1 and 2 years was 76.0% and 73.0%. Progression-free survival (PFS) at 1 and 2 years was 76.0% and 73.0%. Overall survival (OS) at 1 and 2 years was 80.7% and 53.0%. On multivariate analysis (MVA), lesion diameter < 16 mm was the only statistically significant favorable prognostic factor for LC. No statistically significant prognostic factors were identified for tPMC or PFS on MVA. For OS, ECOG performance status 0 and female sex were the only statistically significant favorable prognostic factors on MVA. No toxicities ≥ grade 3 were reported. Outcomes and prognostic factors reported herein refer to the present single-centre cohort. In this cohort, SBRT was feasible and was associated with acceptable toxicity and encouraging local control in lung metastases from CRC. Further studies are needed to better define predictive factors and support tailored therapeutic strategies.