Clinicopathological features and management needs of hereditary tumors in young-onset colorectal cancer patients

Abstract

　Young-onset colorectal cancer is on the increase in western countries, and there is concern that the number will increase in Japan as well. We investigated the heritability and clinicopathologic characteristics of 22 cases of young-onset colorectal cancer who were younger than 40 years old at the time of surgery among 981 cases of colorectal cancer whose primary tumor was resected between January 2011 and December 2022 at our hospital. Excluding the 2 patients with unknown family history, seven (35%) of the 20 patients had a family history of colorectal cancer in the second degree of consanguinity. The presumed causative disease was inflammatory bowel disease in 2 cases (9.1%) and genetic disease in 5 cases (22.7%). The genetic disease included two cases of familial colorectal adenomatosis, two cases of Lynch syndrome, and one case of Li-Fraumeni syndrome. Compared to control, there was no difference in stage, but the undifferentiated type was more common in young-onset colorectal cancer. Genetic testing was performed in only one LS case and led to a definite diagnosis. Young-onset colorectal cancer patients did not differ from the control group near the median in 5-year overall survival and cancer specific survival.