Preplanned Studies: Breast Cancer Screening Coverage — China, 2018–2019

Breast cancer became the most commonly diagnosed form of cancer worldwide in 2020, with approximately 2.3 million women affected, surpassing the number of new cases of lung cancer for the first time. It is still the primary cause of cancer mortality in women and is also the fifth most common cause of cancer deaths globally (1). China had 24% of newly diagnosed cases and 30% of cancer-related deaths worldwide in 2020 (2). The age-standardized incidence of breast cancer increased from 17.07 per 100,000 in 1990 to 35.61 per 100,000 in 2019 over the past three decades (3). Early detection, along with available, low-cost, and effective treatment, can result in improved cancer staging upon presentation and reduced mortality. To combat this rising incidence of breast cancer since the 1990s, China implemented a free screening program nationally in 2009 for rural women aged 35–64 years. During the course of the study, 18.9% of all women aged 20 and above and 25.7% of women aged 35 to 64 participated in breast cancer screening (4), slightly higher than rates in the early 2010s (5). This study aimed to provide an update on the current status of breast cancer screening levels in China, estimating the screening rates across subgroups using the latest nationally and provincially representative surveillance data. The findings showed that 22.3% of women aged 20 years and above and 30.9% of women aged 35–64 years had ever participated in breast cancer screening in China. Lower screening uptake was noted among women from lower socioeconomic status (SES); with considerable variations observed across provincial-level administrative divisions (PLADs).

This study utilized data from the sixth field survey named China Adults Chronic Disease and Nutrition Surveillance, which is part of the China Chronic Disease and Risk Factor Surveillance (CCDRFS), to estimate the latest uptake of breast cancer screening in China (6). The field survey was conducted from August 2018 to June 2019 in 298 districts/counties across all 31 PLADs directly under the central government in Chinese mainland. A multistage and cluster randomized sampling approach was used to select adults aged 18 years or older who had lived at their residence for more than 6 months in the past year, were not pregnant, and did not have serious health conditions or illnesses that would prevent participation, including intellectual disability or language disorders. Trained local health staff conducted interviews with all participants to collect information on major chronic diseases and related risk factors. Female participants were also asked about their breast cancer screening history and the date of their most recent screening, if applicable. The Ethical Committee of the National Center for Chronic and Noncommunicable Disease Control and Prevention and Chinese Center for Disease Control and Prevention approved the CCDRFS survey, and all participants provided written informed consent. A total of 184,876 participants completed the survey, yielding a response rate of 97.4%. After data cleaning, 184,509 participants (including 109,317 females) were included in the basic database. For the final analysis, 15,354 female participants were excluded due to their age being less than 20 years old, having incomplete sociodemographic data, or lacking responses to the breast cancer screening questions. All estimates were weighted based on China’s 2010 census, which was released by the National Bureau of Statistics. The chi-square test was used to analyze differences in unordered categorical variables, and logistic regression was employed to investigate trends with ordered categorical variables. A multiple logistic regression analysis based on complex sampling design was conducted, and standard errors (SEs) were estimated using Taylor linearization with a finite population correction. Statistical significance was determined using a two-sided P-value of less than 0.05. All statistical analyses were performed using SAS software (version 9.4, SAS Institute Inc., Cary, USA).

This study included a total of 93,963 female participants who were 20 years of age or older. As of 2018–2019, 54.8% of Chinese women lived in rural areas, 37.3% had received primary school education or less, and 46.4% had undergone health examinations within the past three years (Table 1).

In 2018–2019, among women aged 20 years and above, 22.3% [95% confidence interval (CI): 21.1%–23.5%] of women reported undergoing at least one lifetime screening for breast cancer. The rate was higher in women aged 35 to 64 years with a prevalence of 30.9% (95% CI: 29.2%–32.5%) (Table 2). When considering the past three years, 20.5% of women had undergone screening. The highest ever screening rate was among women aged 40–49 years, with a prevalence of 36.0% (95% CI: 33.9%–38.2%), while women aged 70 years and above had the lowest screening rates (4.3%, 95% CI: 3.7%–4.9%). The study also found that reporting breast screening was less likely among women with the lowest education level (16.6%, 95% CI: 15.3%–18.0%) or income (17.2%, 95% CI: 15.4%–19.1%), unemployed women (14.8%, 95% CI: 12.6%–17.0%), and women who had not undergone a health examination during the past 3 years (14.3%, 95% CI: 13.2%–15.4%). Urban women (24.5%, 95% CI: 22.4%–26.6) were more likely to undergo screening than rural women (20.6%, 95% CI: 18.8%–22.4%). Additionally, women living in eastern China had higher screening rates (27.0%, 95% CI: 25.1%–29.0%) than those in central (20.6%, 95% CI: 18.3%–22.8%) and western China (16.7%, 95% CI: 14.9%–18.6%).

A multivariate logistic regression analysis was conducted on women between the ages of 35 and 64. Results showed that the odds of receiving breast cancer screening were higher among rural women compared to urban women [odds ratio (OR)=1.25, 95% CI: 1.03–1.50]. However, the likelihood of breast cancer screening in eastern China was still higher compared to western China (OR=1.58, 95% CI: 1.33–1.88). Additionally, the odds of screening were three times higher among women who had received a health examination within the past three years compared to those who had not (OR=3.17, 95% CI: 2.95–3.41) (Table 2).

In Beijing, over 40% of women aged 20 years and above and more than 60% of women aged 35–64 years underwent screening, and in economically developed eastern coastal PLADs such as Jiangsu Province, Zhejiang Province, Tianjin, and Shanghai, more than 30% of women aged 20 years and above and 40% of women aged 35–64 years underwent screening. In contrast, the Xizang (Tibet) Autonomous Region, Guizhou Province, and Hebei Province demonstrated the lowest rates of screening, all below 10%. Refer to Figure 1 for more details.

Figure 1. 

Provincial variations in breast cancer screening coverage in adult women in China, 2018–2019. (A) Screening rates among 20 years and above; (B) Screening rates among 35–64 years.