306P - The effect of initial metastatic site on survival in extensive-stage small cell lung cancer

Background

We aimed to evaluate the impact of the localization of distant metastases on overall survival (OS) in extensive-stage small cell lung cancer (ES-SCLC) and to compare the findings with predictions from Wu et al.’s nomogram.

Methods

Data of ES-SCLC patients treated with thoracic and/or prophylactic cranial radiotherapy between 2001 and 2024 in our clinic were retrospectively analyzed. Survival rates were assessed using the Kaplan-Meier method, and prognostic factors were analyzed using Cox regression. Estimated OS rates were calculated utilizing the nomogram developed by Wu et al.

Results

Thoracic radiotherapy was applied to 43(89%) patients. Among 48 patients at diagnosis: 22 had bone, 12 had liver, 10 had adrenal, 7 had pleural, 4 had contralateral lung, and 1 had brain metastasis. The median OS was 14 months (6–56). 6 months, 1 year, and 2 years OS were 96%, 60%, and 16%, respectively. In univariate analyses liver metastases (p=0.008), brain metastases (p=0.008), and ECOG performance status (p=0.001)were significantly associated with worse survival. Median OS for patients with liver metastases was 10 months compared to 13.8 months in those without. Multivariate analyses identified ECOG performance status (HR: 1.95 (CI: 0.97–3.93), p: 0.061) and liver metastases (HR: 2.32 (CI: 1.15–4.67), p: 0.019) as negative prognostic factors. Comparations of our patient data with Wu et al.’s nomogram predictions revealed higher 6-month OS for patients with bone and liver metastases (Table).

Comparison of OS between real patients and nomogram

Conclusions

Liver metastases negatively affected OS in patients with ES-SCLC. Comparison with Wu et al.’s nomogram highlighted better 6-month survival in patients with bone and liver metastases in our cohort, likely attributed to higher rates of mediastinal radiotherapy (89.6% vs. 37.8%). This discrepancy may contribute to improved early survival rates observed in our series.

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.