Disparities in the increases of cervical cancer incidence rates: observations from a city-wide population-based study

BACKGROUND: Globally cervical cancer incidence rate has been declining continuously. However, an unfavorable trend has been observed in China during the past decades, and the underlying reasons remain unclear. We hereby explore the recent trends of cervical cancer incidence, as well as the underlying determinants using data from Guangzhou, one of biggest cities in China. METHODS: City-wide cancer registration data were obtained from the Guangzhou Center for Disease Prevention and Control from 2004 to 2018. We used the Joinpoint regression models to estimate the average annual percentage change (AAPC) of age-standardized and age-specific incidence rates by regions and by histological subtype. Age-period-cohort models were applied to analyze the period and birth cohort effects on the time trends. RESULTS: The age-standardized rates (ASRs) of cervical cancer incidence increased at an annual rate of 2.1% [95% confidence interval (CI): 1.0%-3.2%] during 2004–2018. The largest increase in ASRs was found for rural regions, with AAPC of 6.6% [95% CI: 3.7%-9.5%], followed by the suburbs (2.2% [95% CI: 1.0%-3.4%]), while there was no statistically significant increase in urban regions. The ASRs of adenocarcinoma increased faster than those of the squamous cell carcinoma (AAPC = 6.53% [95% CI: 5.0%-8.1%] versus 1.79% [95% CI: 0.8%-2.8%]). A downward trend in urban regions was found in the 20–49 age group, whereas an upward trend was found in the 50 + age group, especially in rural regions. An inverted V-shape was found for cohort effects, with the peak varied by regions, i.e., peaked in the 1966 and 1971 birth cohort in the urban and suburb regions, respectively. Period effects kept increasing during the study period. CONCLUSIONS: We systematically examine the disparities in the increases of cervical cancer incidence rates using city-wide data from Guangzhou. Extensive efforts are warranted to address the large urban–rural disparities in cervical cancer prevention. The combined strategies of vaccination, screening, and health education should be reinforced and locally customized.