Adding immune checkpoint inhibitors to chemotherapy confers modest survival benefit in patients with small cell lung cancer and brain metastases: a retrospective analysis.

Background: Brain metastases (BM) are highly prevalent and associated with a poor prognosis in patients with small cell lung cancer (SCLC). However, the evidence regarding the efficacy of immune checkpoint inhibitors (ICIs) in combination with chemotherapy for patients with SCLC and BM remains limited. Therefore, the objective of this study is to evaluate whether the addition of ICIs confers survival benefits for patients with SCLC and BM.

Methods: This retrospective study enrolled patients with SCLC and BM at the Sun Yat-sen University Cancer Center between January 2018 and December 2022. Clinical characteristics were extracted from medical records. Depending on whether ICIs were added to the first-line treatment, the patients were categorized into the chemotherapy group and the chemoimmunotherapy group. The efficacy of these two treatment approaches was analyzed and compared.

Results: A total of 165 patients were enrolled, with 85 in the chemotherapy group and 80 in the chemoimmunotherapy group. The chemoimmunotherapy group showed a tendency towards prolonged intracranial [6.6 vs. 5.9 months, hazard ratio (HR) =0.77; P=0.14] and extracranial (6.9 vs. 6.5 months, HR =0.73; P=0.12) progression-free survival (PFS) and overall survival (OS) (15.6 vs. 14.5 months, HR =0.98; P=0.93) compared to the chemotherapy group. Cox regression analysis identified liver metastases and local treatment for BM as independent prognostic factors for OS in patients. Furthermore, the chemotherapy group and the chemoimmunotherapy group demonstrated similar patterns of initial disease progression.

Conclusions: Adding ICIs to chemotherapy confers modest survival benefits in patients with SCLC and BM.