Trends of incidence rate and age at diagnosis for cervical cancer in China, from 2000 to 2014

Abstract

Objective: To analyze the trends of incidence rate and age at diagnosis for cervical cancer incidence in China using population-based cancer registration data from 2000 to 2014.

Methods: Data were from National Central Cancer Registry of China. Crude incidence rates (CIRs), age-specific incidence rate, age-standardized incidence rates (ASIRs), age percentage distribution, standardized age percentage distribution, mean age at diagnosis and standardized mean age at diagnosis for cervical cancer in all areas of China, urban China and rural China were calculated separately. The world Segi's population was applied to remove the age structure influence. Joinpoint regression was performed to obtain average annual percent change (AAPC) and age-period-cohort analysis was used to examine the incidence trends.

Results: CIRs and ASIRs for cervical cancer increased in China from 2000 to 2014. The AAPC of ASIRs in China was at 9.2% [95% confidence interval (95% CI): 7.0%-11.5%, P<0.05], and the AAPC in rural areas was relatively high. The age-specific incidence rate in groups aged 0-69 years have significantly increased over time. Groups aged 40-69 years showed the highest incidence risk, and the annual percent changes (APCs) of incidence rate in groups aged 40-59 years in urban China and groups aged 0-49 years in rural China were more than 10%. For each age group, the urban-to-rural incidence rate ratios (IRRs) got close to 1 over time. There were clear birth cohort effects in successive generations born from 1940 to 1970 in China. In rural China, the standardized mean age at diagnosis had significantly declined by 5.18 years. In China, the main peak and secondary peak of standardized age percentages appeared in the groups aged 45-49 and 40-44 years, respectively. In rural China, the main peak of standardized age percentage moved from the group aged 55-59 years to the group aged 45-49 years, and the standardized age percentages of groups aged 25-34 years also increased. In China, the standardized age percentages has significantly increased in groups aged 35-64 and 30-64 years over time, and accounted for about 80% and 85% in 2014, respectively.

Conclusions: The cervical cancer incidence increased in China and the gap of incidence between urban and rural China was narrowed. The trends of increasing cervical cancer incidence among younger women existed in China, especially in rural China. A more appropriate screening, vaccination and health education strategies should be established.

Keywords: Cervical cancer; age; incidence.

1

Trends of incidence rates for cervical cancer in China, 2000–2014. (A) Trends of crude incidence rates (CIRs) and age-standardized incidence rates (ASIRs) for cervical cancer in urban and rural China; (B, C, D) Age-specific incidence rates for cervical cancer by year of diagnosis in all areas of China, urban China and rural China, respectively.

2

The disparity of incidence rate for cervical cancer between urban and rural China, 2000–2014.

3

Incidence rates for cervical cancer by birth cohort in China, 2000–2014. (A) Urban China; (B) Rural China.

4

Standardized mean age and standardized age composition at diagnosis for cervical cancer in China. (A, B, C) Standardized mean age for cervical cancer by year of diagnosis in all areas of China, urban China and rural China, respectively, 2000−2014; (D, E, F) Comparison of standardized age percentage at diagnosis for cervical cancer in all areas of China, urban China and rural China between 2000 and 2014, respectively.

5

The trends of standardized age percentages of women aged 35–64 years at diagnosis for cervical cancer in China, 2000–2014.