539P - Epidemiology and prognostic factors of lung cancer and brain metastases: A 10-year retrospective population cohort study in Girona, Spain

Background

Lung cancer (LC) has the highest rate of brain metastases (BM). The aim of this study is to analyze the incidence, survival, and prognostic factors of LC patients with BM from a retrospective cohort.

Methods

Population-based study of LC patients with BM diagnosed in the province of Girona, Spain between 2010-2019. Clinical records were searched for BM in June 2021 and the end follow-up was 31 December 2022. The age-standardized rates (ASR) (2013 European) were calculated. Kaplan-Meier method and Cox regression model were used for analysis of survival and prognostic factors.

Results

3,952 LC cases were identified, 15.8% (n=625) developed BM. According to histology, BM were more common in adenocarcinoma (ADC) (21.1% [306/1450]), followed by small cell lung cancer (SCLC) (20.3% [108/533]), not otherwise specified (NOS) (14.2% [133/936]), and squamous (SQ) (7.6% [78/1033]). Among the 625 patients with LC and BM, 72.6% were male and the median age was 63 years [IQR: 56-70]. Histologically, 49.0% had ADC, 21.3% had NOS, 17.3% had SQ, and 12.5% had SCLC. Most were diagnosed at stage IV (79.8%) and 68.7% had synchronous BM. The ASR of LC and BM was 9.3 cases per 100,000 p-y (95%CI: 8.6-10.1). During follow-up, 602 patients died; median survival was 2.8 months (95%CI: 2.5-3.2). However, median survival increased from was 2.4 months in 2010-2014, to 3.3 months in 2015-2019 (p=0.009). In multivariate analysis, histology, targetable mutant status, extra-cranial disease, number of BM, BM size, BM surgery, radiotherapy, and systemic treatment were statistically significant independent prognostic factors (Table).

Table: 539P

Prognostic factors

Conclusions

There is a high rate of BM in patients with LC, especially in ADC and SCLC. Our data suggest that many factors may have an impact on the survival of patients. Although the prognosis for patients with LC and BM remains a major challenge, data show an improving trend.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Institut d'Investigació Biomèdica de Girona (IDIBGI).

Funding

Fundació LaMarató de TV3 (201906-30). Ministry of science and innovation, Carlos III health Institute, Spain (CM22/00276).

Disclosure

All authors have declared no conflicts of interest.