Comparative Analysis of Breast Cancer Incidence Rates between Australia and Japan: Screening Target Implications.

Background: The purpose of this analysis was to compare the age-specific incidence rates (ASIRs) of breast cancer in Australia and Japan to determine the appropriateness of national screening target age groups.

Methods: The paper is based on secondary sources of data. The ASIRs in 2006-2015 were collected from the Australian Institute of Health and Welfare (AIHW) and the National Cancer Center Japan. Descriptive analysis was performed for a comparison of ASIRs between Australia and Japan by age and over time. Percentage change, rolling average and risk ratio were calculated for further analysis.

Results: In Australia, ASIRs rose sharply from age 40 years and peaked at 65-69 years. Japanese data demonstrated a considerable increase each year and two peaks were recorded, at ages 45-49 and 60-64. The ASIRs after age 65 decreased with age in Japan but increased with age in Australia. The ASIRs of women aged 40-49 was lowest among Australian women and the highest among Japanese women, while they had similar ASIRs in the direct comparative analysis.

Conclusions: The screening age range of Australian and Japanese national breast cancer screening guidelines covers incidence peak ages in each country and therefore provides benefit for cancer screening. Our findings also indicated that further evidence is required to investigate the inclusion of Japanese migrant women in Australia aged 40-49 years into the screening target and the BCI rates of post-migrant women in Australia as different migrant groups have different ASIRs. This is to ensure that the groups of women with the highest cancer incidence are appropriately covered in screening programs.
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