Research Papers:
Agespecific sex difference in the incidence of hepatocellular carcinoma in the United States
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Pian Liu1, Shao-Hua Xie2, Shaobo Hu3, Xiang Cheng3, Tianyi Gao4, Chen Zhang3 and Zifang Song3
1Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
2Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, Stockholm 17176, Sweden
3Department of Hepatobiliary Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
4The First Clinical Medical School, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
Correspondence to:
Chen Zhang, email: [email protected]
Keywords: hepatocellular carcinoma, liver cancer, sex difference, incidence, estrogen
Received: February 28, 2016 Accepted: June 11, 2017 Published: July 12, 2017
ABSTRACT
Background: Hepatocellular carcinoma possesses a notable sex difference in incidence, and a protective role of estrogens has been hypothesized.
Methods: Using data from 13 cancer registries in the Surveillance, Epidemiology, and End Results Program, we describe the age-specific sex difference in the incidence of hepatocellular carcinoma in the United States during 1992-2013. We used a curve fitting by non-linear regression to quantitatively characterize the age-specific incidence rate of hepatocellular carcinoma by sex.
Results: A total of 44,287 incident cases of hepatocellular carcinoma (33,196 males and 11,091 females) were included, with an overall male-to-female ratio in age-standardized rate of 3.55. The sex ratio was below 2 at ages <25 years, increased with age from ages 25-29 years until peaking at 5.40 at ages 50-54 years, and declined thereafter. We also observed additional peaks in the age-specific sex ratio curves at ages 25-34 years across racial/ethnic groups. Modelling of age-specific incidence rates indicated a 15-year delayed increase with age in females compared with males in Asian and Pacific Islanders, and an 11-year delay in Hispanic whites.
Conclusions: The age-dependent patterns in the sex difference in the incidence of hepatocellular carcinoma support the hypothesis of a protective role of estrogens. The underlying reasons for the sex difference in hepatocellular carcinoma remain to be further explored in analytic epidemiological studies.