Prognostic factors of liver metastases in extensive-stage small cell lung cancer receiving chemo-immunotherapy.

BACKGROUND

Chemoimmunotherapy combining platinum-based chemotherapy and etoposide with an anti-programmed death-ligand 1 (PD-L1) antibody is the standard treatment for patients with extensive-stage small cell lung cancer (ES-SCLC). However, the biomarkers that can predict outcomes after chemo-immunotherapy remain unclear. This study retrospectively investigated the prognostic factors after first-line chemoimmunotherapy in patients with ES-SCLC.

METHODS

This study included 110 patients with ES-SCLC who received chemoimmunotherapy as a first-line treatment. Clinical data were extracted from medical records, and inflammatory and nutritional factors such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), prognostic nutrition index (PNI), and advanced lung cancer inflammation index (ALI) were analyzed to determine the prognostic predictors. Survival data were analyzed using the log-rank test. Univariate and multivariate analyses of variables were performed using Cox regression.

RESULTS

The median patient age was 72 years (range, 50-88 years). At diagnosis, metastases were present in the brain, liver, and bones in 32.7%, 25.5%, and 39.1% of cases, respectively. The platinum-based chemotherapy regimens included atezolizumab in 67.3% of cases and durvalumab in 32.8%, respectively. Univariate analysis identified sex, ALI, pro-gastrin-releasing peptide (ProGRP), liver metastasis, and bone metastasis as significant predictors of progression-free survival (PFS), meanwhile, age, sex, performance status (PS), NLR, ALI, ProGRP, liver metastasis, and bone metastasis as significant predictors of overall survival (OS). Multivariate analysis identified liver metastasis as an independent predictor of PFS and OS. High ProGRP levels, bone metastasis, occurrence of immune-related adverse events (irAEs) of any grade, and partial response (PR) were significantly associated with the presence of liver metastasis. Multivariate analysis identified a combination of maximal tumor diameter >30 mm and the presence of >10 metastatic lesions as independent predictors of OS in 28 patients with liver metastasis.

CONCLUSIONS

Liver metastasis is a significant predictor of outcomes after chemoimmunotherapy in patients with ES-SCLC. The maximal diameter and number of liver metastases may affect the immune response in patients with liver metastasis.