Ming Sun,1,2 Youxin Wang,2 Jan Sundquist,1,3,4 Kristina Sundquist,1,3,4 Jianguang Ji1

1Center for Primary Health Care Research, Lund University/Region Skne, Malm, Sweden; 2Beijing Key Laboratory of Clinical Epidemiology, School of Public Health, Capital Medical University, Beijing, Peoples Republic of China; 3Department of Family Medicine and Community Health, Department of Population Health Science and Policy, Icahn School of Medicine at Mount Sinai, New York, NY, USA; 4Center for Community-Based Healthcare Research and Education (CoHRE), Department of Functional Pathology, School of Medicine, Shimane University, Shimane, Japan

Correspondence: Jianguang JiCenter for Primary Health Care Research, Jan Waldenstrms Gata 35, Skne University Hospital, Malm 205 02, SwedenTel +46 40391382Fax +46 40391370Email Jianguang.ji@med.lu.seYouxin WangBeijing Key Laboratory of Clinical Epidemiology, School of Public Health, Capital Medical University, 10 Youanmen Xitoutiao, Beijing 100069, Peoples Republic of ChinaTel +86 10 8391 1779Fax +86 10 8391 1501Email wangy@ccmu.edu.cn

Purpose: The incidence of colorectal cancer (CRC) varies by age, sex, and anatomical subsite. Few studies have examined the temporal trends of age-specific sex disparity in incidence and survival by age at diagnosis and anatomical site.Patients and Methods: The study was performed on all incident cases of CRC, using data derived from the nationwide Swedish Cancer Register between 1960 and 2014, including right-sided colon cancer (RCC), left-sided colon cancer (LCC), and rectal cancer. Male-to-female age-standardized incidence rate ratio (IRR) and male-to-female five-year survival rate ratio (SRR) were calculated as the main indicators. Furthermore, we performed joinpoint regression analyses to estimate average annual percentage change.Results: The overall male-to-female IRR was 1.05 for RCC, 1.31 for LCC, and 1.66 for rectal cancer. Male-to-female IRR increased steadily for RCC by an average of 0.4% per year until the mid-1990s and then decreased gradually by an average of 1.0% per year. LCC patients showed an increase of 0.6% per year since the mid-1970s. For rectal cancer, a non-significant random fluctuation was noted during the study period. The temporal trends of male-to-female IRR varied by age at diagnosis. The male-to-female SRR was 0.87 for RCC, 0.88 for LCC, and 0.86 for rectal cancer, which remained relatively stable during the study period.Conclusion: Sex disparity of CRC is age-, period-, and anatomical subsite-dependent. Further studies are needed to investigate the underlying contributing factors.

Keywords: colorectal cancer, sex disparity, incidence, survival, temporal trend

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Temporal Trends of Sex Disparity in Incidence and Survival of Colorect | CLEP - Dove Medical Press