What is the most effective strategy for improving the cancer screening rate in Japan?

Background: Cancer screening rates in Japan are much lower than those in Western countries. This study evaluated the relationship between cancer screening rates and strategies used to improve screening rates, and determined which strategy is the most effective. Materials and Methods: All municipalities are responsible for conducting gastric, lung, colorectal, cervical, and breast cancer screenings in Japan. Of the 1,746 municipalities in total, 92-99% were included in the analyses for each cancer screening. Using national data in 2009, the correlations between cancer screening rates and strategies for improving screening rates of all municipalities, both large (populations of over 30,000) and small (populations of under 30,000), were determined. The strategies used were as follows: sending personal invitation letters, personal visits by community health workers, use of a clinical setting for screening, and free screening. Results: Of all four strategies used to improve cancer screening rates, sending personal invitation letters had the highest correlations with all screening rates, with the exception of breast cancer screening. The partial correlation coefficients linking this strategy with the screening rates in all municipalities were 0.28, 0.32, 0.30, and 0.26 for gastric, lung, colorectal, and cervical cancer screening, respectively. In large municipalities, the correlations between the number of examinees in a clinical setting and the screening rates were also relatively high, particularly for cervical cancer screening (r=0.41). Conclusions: Sending personal invitation letters appears to be particularly effective in improving cancer screening rates in all municipalities. All municipalities should implement a system that sends personal invitation letters for cancer screening. In large municipalities, increasing the availability of screening in a clinical setting is also effective in improving cancer screening rates.