Factors Affecting Long-Survival of Patients with Esophageal Cancer Using Non-Mixture Cure Fraction Model

Document Type : Research Articles


1 Modeling in Health Research Center and School of Public Health, Department of Epidemiology and Biostatistics, Shahrekord University of Medical Sciences, Shahrekord, Iran.

2 Department of Biostatistics, School of Paramedicine, Shahid Beheshti University of Medical Science, Tehran, Iran.

3 Department of Epidemiology and Reproductive Health, Reproductive Epidemiology Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran.

4 Department of Epidemiology and Biostatistics, Tehran University of Medical Sciences, Tehran,Iran.

5 School of Public Health, University of Alberta, Edmonton, Alberta, Canada.


Objective: Esophageal cancer (EC) is one of the gastrointestinal malignancies with a very high morbidity and
mortality rate due to poor prognosis. This study aims to assess the effects of risk factors on survival and cure fraction of
patients with EC in a population of Iranian patients using a non-mixture cure fraction model. Methods: This retrospective
cohort study was conducted on 127 patients with EC who were diagnosed during 2009-2010 and were followed
up for 5 years in East-Azarbaijan, Iran. Stepwise selection and non-mixture cure fraction model were used to find
the risk factors of EC survival patients. Results: The mean (±standard deviation) diagnosis age of the EC was
66.92(±11.95). One, three and five-year survival probabilities were 0.44 (95% confidence interval (CI): 0.36-0.54),
0.2 (95% CI: 0.14-0.28) and 0.13 (95% CI: 0.08-0.2) respectively. Female sex (Estimate=-0.99; 95% confidence interval
(CI): -1.41,-0.58; p-value<0.001), low level socioeconomic status (Estimate=0.39; 95%CI: 0.12,0.66; p-value=0.043),
the group who did not do esophagectomy surgery (Estimate=0.58; 95%CI: 0.17,0.99; p-value=0.005) and unmarried
group (Estimate=0.58; 95%CI: 0.11-1.05; p-value=0.015) were found as the significant predictor of survival and
cure fraction of the EC patients. Population cure rate was 0.11 (95%CI: 0.07-0.19) and Cure fraction was estimated
5.11 percent. Conclusion: This study found gender, socioeconomic status, Esophagectomy surgery and marital status
as the potential risk factors for survival and cure fraction of Iranian EC patients. Moreover, non- mixture cure fraction
provides more accurate and more reliable insight into long-term advantages of EC therapy compared to standard classic
survival analysis alternatives.


Main Subjects