How does cancer spread?

Cancer spread occurs through any or all of the three routes
Local spread: cancer infiltrates the adjoining parts, organs, tissues, etc.
Lymphatic spread: the lymph glands or nodes trap the cancer cells present in the lymph fluid and cancer grows within them. Progressive spread along lymph vessels and glands may occur and in the process quite distant glands may become involved

Bloodstream spread: if cancer invades blood vessels then the cancer cells may break into the bloodstream and be carried to other parts of the body and settle over there, producing secondary cancers. The major site of spread in cases of bowel cancer is liver. The lungs are the commonest site of metastasis from other cancer sites. The spread to many other organs is also common