Appropriate resource utilization is crucial for cancer screening programs. Overscreening is defined as screening provided beyond the upper age limit of the target age or at a shorter interval than recommended in national programs. In Japan, there are no upper age limits set for cancer screening programs, and the recommended screening interval for cervical and breast cancer screening is 2 years. To examine the efficient use of resources for cervical and breast cancer screening, we investigated how often overscreening occurred in both programs.

The target age for this study was defined as 20-69 years for cervical cancer screening and 40-69 years for breast cancer screening. We used the national report for cancer screening in 2017 in Japan and estimated the number of participants over 70 years old or those who participated in screening annually. The percentage of overscreening was compared between cervical cancer and breast cancer screening by chi-square test.

The number of participants was 4,294,127 for cervical cancer screening and 3,087,781 for breast cancer screening in 2017. The percentage of overscreening in total participants was 38.0 percent for cervical cancer screening and 35.7 percent for breast cancer screening (p<0.01). The percentage of screening at overage was higher in breast cancer screening than in cervical cancer screening (21.1% vs. 13.9%, p<0.01), whereas more frequent screening was seen more often in cervical cancer screening than in breast cancer screening (29.7% vs. 19.6%, p<0.01). If the resources used in overscreening could be used for the target population, it was estimated that the participation rate could increase by 4.1% for cervical cancer screening and 4.3% for breast cancer screening.

In Japan, screening for overage participants and short intervals may have contributed to unnecessary screening for cervical cancer and breast cancer. These resources used for overscreening could be allocated to screening for the target population.