HIGHER BMI was linked to a smaller sex-related difference in lung cancer survival across large European cohorts.
A large real-world analysis has found that higher BMI may reduce the survival gap between male and female patients with lung cancer, adding new complexity to the relationship between sex, body composition, and cancer outcomes.
The retrospective study analyzed 7,327 patients with lung cancer diagnosed at Helsinki University Hospital between 2015 and 2024, with external validation using data from four European university hospitals. Patients were stratified by BMI into low, normal, and high BMI cohorts. High BMI was defined as BMI greater than 25 kg/m².
In the normal BMI cohort, 2-year overall survival was 46% among female patients and 29% among male patients. In the high BMI cohort, the difference narrowed, with 2-year survival of 51% among female patients and 41% among male patients.
BMI May Modify Sex-Related Survival Differences
Female patients continued to show longer survival overall, but the magnitude of this advantage was smaller among patients with high BMI. In multivariate restricted mean survival time analysis, the effect of male sex on survival was 32% smaller in patients with high BMI than in those with normal BMI.
The association varied by histology. The strongest effect was seen in squamous cell carcinoma, where normal BMI was associated with a wide sex-related survival difference, while high BMI was linked to more similar 2-year survival estimates between male and female patients. In adenocarcinoma, the effect was more moderate. No clear effect of high BMI on sex-related survival difference was observed in small cell lung cancer.
Real-World Data Highlight Need for BMI Reporting
External validation showed variation across European sites, influenced by differences in BMI data completeness, histologic subtype distribution, sex ratios, and cohort composition. The Helsinki and UK cohorts showed similar direction and magnitude of effect, while results were weaker or less consistent in Denmark and Belgium.
The findings support more routine reporting of BMI in lung cancer clinical trials and observational studies, particularly when evaluating sex-related survival differences. BMI may also act as a proxy for broader biologic or metabolic factors, including immune system activity and body composition, that warrant further investigation.
For clinicians, the study reinforces that lung cancer survival is shaped by multiple interacting variables, including sex, BMI, histology, stage, treatment, smoking status, and comorbidity burden. Future analyses that omit BMI may miss an important modifier of survival patterns.
Reference
Ryzhenkov A et al. Association Between Obesity and Sex-Related Survival Difference in Lung Cancer. JCO Clin Cancer Inform. 2026;10(2):e2500263.
Featured Image: Halfpoint on Adobe Stock.
