Determination of Cut Point in the Age of Colorectal Cancer Diagnosis Using a Survival Cure Model

Document Type: Research Articles

Authors

1 Department of Public Health, School of Health, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran.

2 Health Sciences Research Center, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran.

3 Gastroenterology and Liver Diseases Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

4 Department of Biostatistics, Faculty of Paramedical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

5 Department of Biostatistics, Faculty of Health, Mashhad University of Medical Sciences, Mashhad, Iran.

Abstract

Background and Objectives: Colorectal Cancer (CRC) is the fourth cancer-related cause of death worldwide.
CRC is a multi-stage cancer, which is curable during the early stages of the disease. Therefore, determining the time of
cut-point existence could improve treatment planning and help directly allocate resources. This study aims to determine
the cut point in the age of CRC diagnosis. Methods: This study, covering the course 1985 to 2012, consisted of 345
colorectal cancer patients registered in Taleghani Hospital, Tehran, Iran and followed up to 2013. The cut-point in the
age of CRC diagnosis was obtained using a mixture cure model. The data were analyzed using SPSS and R, V. 20 and
2.15.0, respectively. Results: The results showed that the cut point in the age of CRC diagnosis was 50 years. Based
on our estimation, 65% of the patients diagnosed with CRC at or younger than 50 were cured, while 31% of them
diagnosed older than 50 were cured, and the younger group had a better survival over the older group. Conclusion:
Since access to a cut-point and analysis of created prognostic groups are important in screening and treatment planning,
our results suggested that it is better to estimate the cut-point in the age of curable cancers in early stages via survival
cure models, and the cure rate would increase by CRC timely screening.

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