Abstract C11: The effect of payer status on small cell lung cancer survival
Authors: Shi Runhua , Liu Hong , Bishop Ruth , Mills Glenn 
Published: March 2017

Background: The overall survival for small cell lung cancer (SCLC) patients at 5 years is only about 5% to 10% and improvements in treatment have proved to be unsatisfactory in prolonging SCLC survival. One of the challenges in improving cancer survival beyond treatment is identifying disparities in health care access. In this study, we determined how disparities in payer status affected SCLC patient survival by analyzing data from the National Cancer Data Base (NCDB) between 1998 and 2011.

Materials and Methods: We evaluated a cohort of 71,724 patients ages 18-65 diagnosed with stage III or IV SCLC who had not undergone surgery or hormonal therapy registered in the NCDB. Overall survival (OS) was the outcome variable, and payer status was the primary predictor variable. Other variables adjusted for included sex, age, race, Charlson Comorbidity Index, income, education, distance travelled, type of cancer program, diagnosing/treating facility, stage, chemotherapy and radiation therapy. Multivariate Cox regression was used to investigate the effect of payer status on OS in SCLC while adjusting for other factors.

Results: The majority of patients diagnosed at stage III-IV had private insurance (57.93 %), while 17.75%, 14.69% and 9.64% of patients had Medicare, Medicaid or were uninsured, respectively. The overall mean age in the study population was 56.3 and the mean age for privately insured, uninsured, Medicaid and Medicare patients was 56.3, 55, 54.6, and 58.2 years, respectively. Privately insured patients, which had a median OS of 10.71 months, lived longer in comparison to uninsured, Medicare, and Medicaid patients (median OS of 8.02, 8.25, and 8.67 months for uninsured, Medicare, and Medicaid patients, respectively).

Multivariate Cox regression analysis revealed a statistically significant relationship between payer status and overall survival when controlling for other variables. Uninsured, Medicaid, and Medicare patients were found to have a 25% higher risk of death (HR=1.25) from SCLC compared to privately insured patients.

Female patients (HR=0.83) had a reduced risk of dying by 17% compared to male patients. Asian (HR=0.82) and black patients (HR=0.95) were found to have an 18% and 5% lesser risk of death, respectively, compared to white patients. For patients receiving radiation therapy, the addition of chemotherapy (HR=0.45) reduced mortality by 55% compared to patients not receiving chemotherapy. For patients not receiving radiation therapy, the addition of chemotherapy (HR=0.50) reduced mortality only by 50% compared to patients not receiving chemotherapy.

Conclusion: In the multivariate analysis, payer status proved to be a statistically significant predictor of overall survival for SCLC, which remained true after adjusting for all other factors. Payer status presented as a disparity since uninsured, Medicaid, and Medicare patients had higher mortality compared to privately insured patients. The study also revealed that patients receiving a combination of chemotherapy and radiation therapy had a reduced risk of death in comparison to patients only receiving chemotherapy. Further study is needed to investigate the mechanism of payer status on survival of SCLC.

Citation Format: Runhua Shi, Hong Liu, Ruth Bishop, Glenn Mills. The effect of payer status on small cell lung cancer survival. [abstract]. In: Proceedings of the Ninth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2016 Sep 25-28; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(2 Suppl):Abstract nr C11.