| Theme |
Current topics in interval colorectal cancers |
| Title |
Prevalence, risk factors, and prognoses of interval cancers |
| Author |
Nozomu Kobayashi |
Department of Gastroenterology, Tochigi Cancer Center |
| Author |
Jun Konishi |
Department of Gastroenterology, Tochigi Cancer Center |
| Author |
Maki Konno |
Department of Gastroenterology, Tochigi Cancer Center |
| [ Summary ] |
The prevalence of interval cancers is reported to be between 3 % and 7 %. However, this varies according to the definition of interval cancer, study design, and study population. Most interval cancers are thought to be lesions which were missed in previous examinations or residual lesions. Different biological factors may contribute to the development of interval cancer. Interval cancers are more likely to arise in the right colon and have microsatellite instability as well as exhibiting CpG island methylator phenotypes than sporadic colorectal cancers. Sessile serrated adenomas share these features with interval cancers. In addition, sessile serrated adenomas are difficult to detect and remove completely, because of their inconspicuous borders. This is because sessile serrated adenomas are considered to be precursors of interval cancer, as are non-polypoid type lesions, which are also common in the right colon and difficult to detect. Most studies have reported that the stage of interval cancers and prognoses for these patients does not differ from those with sporadic lesions. These results also suggest that the cause of interval cancers is not aggressive biology but missed lesions. If this is true, interval cancers may be prevented by improving colonoscopic quality. |