Marital status and competing risks of mortality in non-small cell lung cancer: a SEER-based nomogram analysis.

Background: Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related mortality worldwide. Beyond clinical prognostic factors, psychosocial determinants such as marital status may influence outcomes. However, its impact on cancer-specific death (CSD) and other-cause death (OCD) within a competing risk framework remains unclear. This study aimed to comprehensively evaluate the effect of marital status on CSD and OCD in patients with NSCLC using a large Surveillance, Epidemiology, and End Results (SEER)-based cohort, and to develop a competing risk nomogram for individualized prognostic prediction. Methods: We identified NSCLC patients from the SEER between 2010 and 2015. Baseline characteristics were balanced between married and unmarried groups using propensity score matching (PSM). Fine-Gray competing risk models were applied to estimate the effect of marital status on CSD and OCD. A competing risk nomogram was constructed and validated to predict individualized 1-, 3-, and 5-year CSD probabilities. Results: Among 47,170 patients, 54.8% were married. Married patients had consistently lower cumulative incidences of CSD and OCD before and after PSM (all P<0.001). In multivariable models, unmarried patients had a significantly higher CSD risk (subdistribution hazard ratio =1.11; 95% confidence interval: 1.08-1.14; P<0.001). The nomogram showed strong discrimination (area under the curve ranging from 0.81 to 0.84) and good calibration in both training and validation cohorts. Conclusions: Marital status independently influences NSCLC prognosis, with married patients showing lower cancer-specific and non-cancer mortality. These findings underscore the importance of incorporating marital and broader social support factors into survivorship care. Prospective studies are needed to confirm these findings and develop supportive strategies to improve survival and quality of life.