What are the ways that colorectal cancer spreads?

Colorectal cancer can spread through:

(1) Direct spread: Cancer can spread around the intestinal wall, or it can infiltrate upward and downward along the intestinal cavity, penetrate the intestinal wall, and break through the intestinal wall to infiltrate the intestine. It can directly infiltrate adjacent tissues, organs, and the abdominal wall. Cancer in the upper part of the 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 intestinal wall serosal layer, cancer cells may fall off into the abdominal cavity and cause implantation and dissemination, which may cause bloody ascites

(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 enlarged inguinal lymph nodes.

(4) Hematogenous metastasis: Hematogenous metastasis of colorectal cancer is quite common. After cancer cells invade the veins, the mesenteric blood vessels drain into the portal vein, and liver metastasis is common.