Women's cancers in China: a spatio-temporal epidemiology analysis

Abstract

Background: Women's cancers, represented by breast and gynecologic cancers, are emerging as a significant threat to women's health, while previous studies paid little attention to the spatial distribution of women's cancers. This study aims to conduct a spatio-temporal epidemiology analysis on breast, cervical and ovarian cancers in China, thus visualizing and comparing their epidemiologic trends and spatio-temporal changing patterns.

Methods: Data on the incidence and mortality of women's cancers between January 2010 and December 2015 were obtained from the National Cancer Registry Annual Report. Linear tests and bar charts were used to visualize and compare the epidemiologic trends. Two complementary spatial statistics (Moran's I statistics and Kulldorff's space-time scan statistics) were adopted to identify the spatial-temporal clusters.

Results: The results showed that the incidence and mortality of breast cancer displayed slow upward trends, while that of cervical cancer increase dramatically, and the mortality of ovarian cancer also showed a fast increasing trend. Significant differences were detected in incidence and mortality of breast, cervical and ovarian cancer across east, central and west China. The average incidence of breast cancer displayed a high-high cluster feature in part of north and east China, and the opposite traits occurred in southwest China. In the meantime, the average incidence and mortality of cervical cancer in central China revealed a high-high cluster feature, and that of ovarian cancer in northern China displayed a high-high cluster feature. Besides, the anomalous clusters were also detected based on the space-time scan statistics.

Conclusion: Regional differences were detected in the distribution of women's cancers in China. An effective response requires a package of coordinated actions that vary across localities regarding the spatio-temporal epidemics and local conditions.

Keywords: Breast cancer; Cervical cancer; China; Geographical clusters; Moran’s I; Ovarian cancer; Space–time scan; Spatial clusters.

Fig. 1

Bar chart of region-specific incidence and mortality for women’s cancers in China (1/100,000)

Fig. 2

Hierarchical maps (left) and univariate LISA cluster maps (right) of the incidence of breast, cervical and ovarian cancers among women in China. * High-High cluster presents geographical units with high incidence surrounded by geographical units with high incidence, High-Low cluster presents geographical units with high incidence surrounded by geographical units with low incidence, and so on

Fig. 3

Hierarchical maps (left) and univariate LISA cluster maps (right) of the mortality of breast, cervical and ovarian cancers among women in China. * High-High cluster presents geographical units with high mortality surrounded by geographical units with high mortality, High-Low cluster presents geographical units with high mortality surrounded by geographical units with low mortality, and so on

Fig. 4

High-risk clusters of the breast, cervical and ovarian cancers among women in China (incidence clusters on the left and mortality clusters on the right)