The Natural History of Cervical Cancer in Chinese Women: Results from an 11-Year Follow-Up Study in China Using a Multistate Model

BACKGROUND: It is important to understand the natural history of cervical cancer, which has implications for cancer prevention and management. However, a dearth of studies on the long-term development of cervical cancer exists in China. METHODS: We investigated the natural history of cervical cancer in Chinese women by creating a multistate model using 11 years of follow-up data from the Shanxi Province Cervical Cancer Screening Study I conducted from 1999 to 2010. In 1999, a total of 1,997 eligible women, ages 35 to 45 years, were enrolled in Xiangyuan County, Shanxi Province. Participants were followed up in 2005 and 2010, respectively. RESULTS: The average time a subject spent in CIN1 before transiting into another state was 1.4693 years [95% confidence interval (CI): 1.1215-1.9251] and the average time a subject spent in CIN2 was 2.9822 years (95% CI: 1.9790-4.4938). A subject's transition probability from CIN1 to normal increased with time. However, the transition probability from CIN1 to CIN2 was relatively lower, with 3-, 5-, and 10-year transition probabilities of 0.1415, 0.1066, and 0.0437. Comparison of 5-year transition probabilities between CIN2 to normal/CIN1 and CIN2 to CIN3(+) yielded a ratio of 2.74. CONCLUSIONS: Women with CIN1 had a substantial tendency for regression. Similarly, women with CIN2 had a higher probability of regression to normal/CIN1 than progression to CIN3(+). Findings in this study may have significant implications for the development and evaluation of formal cervical cancer preventive strategies in China. IMPACT: This study may serve as a valuable reference to future research on other multistate cancer processes.