Marital status independently predicts non-small cell lung cancer survival: a propensity-adjusted SEER database analysis

Purpose Marital status has been demonstrated as an independent prognostic factor in many cancer types. The impact of marital status on non-small cell lung cancer (NSCLC) survival has not been assessed at the population level. Here, we used the surveillance, epidemiology and end results (SEER) database, a US national cancer registry, to address this issue. Methods All patients diagnosed with NSCLC from 2004 to 2009 were identified in the SEER database (version 8.3.2, updated at April 14, 2016). Those with incomplete clinicopathological information were excluded. The tumor, node, metastasis (TNM) staging was based on the criteria of the American Joint Committee on Cancer (AJCC) 6th edition. We used propensity-score matching analysis to balance baseline characteristics between the patients who were married and those who were not married. The impact of marital status on cancer-specific survival was analyzed with Cox proportional-hazards regression. Result A total of 72, 984 NSCLC patients (41, 095 married patients, 56.3%) were enrolled in this study. After propensity-score matching, 25, 617 patients in the married group were 1:1 matched with patients in the unmarried group. Being unmarried was found to be associated with significantly decreased cancer-specific survival (hazard ratio (HR): 1.142, 95% CI: 1.119-1.166, p < 0.001). Among the unmarried group, patients who were single had worse cancer-specific survival (median survival 12 months, 95% CI: 11.37-12.63 months) than those who were divorced (median survival 15 months, 95% CI: 14.24-15.76 months, p < 0.001) or widowed (median survival 15 months, 95% CI: 14.25-15.76 months, p < 0.001). Conclusion This study shows that marital status is an independent prognostic factor for cancer-specific survival in NSCLC patients. Patients who were married had better cancer-specific survival compared to the unmarried ones.