Is colorectal cancer contagious?

Colorectal cancer is a common malignant tumor, including colon cancer and rectal cancer. The incidence of colorectal cancer is from high to low in the order of rectum, sigmoid colon, cecum, ascending colon, descending colon and transverse colon. In recent years, there is a trend of developing towards the proximal part (right colon). Is colorectal cancer contagious? Colorectal cancer is not a contagious disease, but if a person has colorectal cancer, it may metastasize to other organs through himself.

1. Direct spread: Cancer can spread around the intestinal wall, or infiltrate upward and downward along the intestinal cavity, while penetrating the intestinal wall, and can protrude from the intestinal wall and infiltrate into the intestine. It can directly infiltrate adjacent tissues, organs, and the abdominal wall. Cancer in the upper ascending colon can affect the descending part of the duodenum, and colon cancer in the hepatic region can affect the liver and gallbladder. The transverse colon can invade the greater omentum and stomach. Rectal cancer can invade the bladder, uterus, prostate, or sacrum.
2. Implantation and dissemination: When colorectal cancer infiltrates the serosa of the intestinal wall, cancer cells may fall off into the abdominal cavity and cause implantation and dissemination. There may be bloody ascites, which is one of the common transmission routes of colorectal cancer.
3. Lymphatic metastasis: If colorectal cancer invades the muscularis mucosa, there is a risk of lymphatic metastasis. Once tumor cells enter the lymphatic system, they can spread upward with the drainage of lymph fluid. Anal canal cancer may cause swollen inguinal lymph nodes.
4. Hematogenous metastasis: Hematogenous metastasis of colorectal cancer is quite common. After cancer cells invade the veins, liver metastasis is common due to the drainage of mesenteric blood vessels to the portal vein.