Abstract 318P
Background
Chemoimmunotherapy has become the standard first-line treatment for extensive-stage small-cell lung cancer (ES-SCLC), improving survival outcomes. This study aimed to evaluate the impact of prophylactic cranial irradiation (PCI) on overall survival (OS) in patients with ES-SCLC after chemoimmunotherapy administration.
Methods
This retrospective analysis included 261 patients with ESSCLC treated with first-line chemoimmunotherapy between January 2019 and December 2023. All patients underwent MRI scans to confirm the absence of brain metastases. After 1:2 propensity score matching (PSM), 46 and 81 patients were assigned to the PCI and observation groups, respectively. The primary endpoint was OS, with additional exploration of progression-free survival (PFS), the cumulative incidence of intracranial metastases, and intracranial progression-free survival (iPFS).
Results
After PSM, the two groups were well-balanced in baseline characteristics. Survival analysis showed a median OS of 19.9 months (95% CI 11.8–28.0) in the PCI group and 15.6 months (12.3–18.9) in the observation group, without a significant difference (hazard ratio HR 0.763 [95% CI 0.484–1.206], log-rank p=0.265). PCI significantly reduced the risk of brain metastasis (Fine-Gray p=0.002), with 1-year cumulative incidence rates of 13.8% (3.4–24.2%) in the PCI group and 53.4% (41.3–65.6%) in the observation group. Subgroup analysis showed that for ES-SCLC patients achieving a partial response (PR) to initial chemoimmunotherapy, the PCI group had longer median OS (25.7 months [95% CI 15.4–36.1] vs 19.4 months [15.4–23.4]); HR 0.502 [0.284–0.886]; log-rank p=0.021).
Conclusions
PCI did not improve OS in ES-SCLC patients receiving first-line chemoimmunotherapy, while it may confer a survival benefit for patients who achieve remission following chemoimmunotherapy. Additionally, PCI significantly reduced the incidence of brain metastases. These findings warrant further randomized studies for verification.
Legal entity responsible for the study
Zhejiang Cancer Hospital.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.