In colorectal cancer, which is the most common site of metastasis?

In colorectal cancer, which is the most common site of metastasis?

• A. Liver
• B. Bones
• C. Brain
• D. Lungs

Answer: (A)

Colorectal cancer most often spreads to the liver because its venous drainage is through the portal system, which carries tumor cells directly from the colon and rectum to the liver. Once circulating tumor cells reach the liver, they can lodge in the sinusoidal microvasculature, extravasate, and grow into metastatic deposits. This hepatic predilection shapes how doctors monitor and treat the disease, since liver metastases are a common and early metastatic event and may be addressed with surgical or ablative strategies when feasible. While the lungs can be involved too—especially from rectal cancers that drain into systemic veins—bone and brain metastases are less common compared with liver involvement.

Colorectal cancer most often spreads to the liver because its venous drainage is through the portal system, which carries tumor cells directly from the colon and rectum to the liver. Once circulating tumor cells reach the liver, they can lodge in the sinusoidal microvasculature, extravasate, and grow into metastatic deposits. This hepatic predilection shapes how doctors monitor and treat the disease, since liver metastases are a common and early metastatic event and may be addressed with surgical or ablative strategies when feasible. While the lungs can be involved too—especially from rectal cancers that drain into systemic veins—bone and brain metastases are less common compared with liver involvement.