Non-participation of asymptomatic candidates in screening protocols reduces early diagnosis and worsens prognosis of colorectal cancer.

The Agatsuma 's study shows that despite the evidence of the benefits of an early colorectal cancer (CRC) diagnosis, through screening in asymptomatic subjects, up to 50% of candidates reject this option and many of those affected are diagnosed later, in advanced stages. The efficacy of screening programs has been well-established for several years, which reduces the risk of CRC morbidity and mortality, without taking into account the test used for screening, or other tools. Nevertheless, a significant proportion of patients remain unscreened, so understanding the factors involved, as well as the barriers of the population to adherence is the first step to possibly modify the participation rate. These barriers could include a full range of social and political aspects, especially the type of financial provision of each health service. In Japan, health services are universal, and this advantageous situation makes it easier for citizens to access to these services, contributing to the detection of various diseases, including CRC. Interestingly, the symptomatic CRC group had a lower early-stage diagnosis rate than the patients detected during follow-up for other comorbidities, and symptomatic and cancer screening groups showed similar early-stage diagnosis.