Final answer:
Cancer can spread from a tumor to other parts of the body through a process called metastasis, which involves local spread, lymphatic system, and bloodstream.
Step-by-step explanation:
Cancer can spread from a tumor to other parts of the body through a process called metastasis. There are three main ways in which cancer cells can spread. The first is through local spread, where cancer cells directly invade nearby tissues. The second is through the lymphatic system, where cancer cells can spread to regional lymph nodes through lymph vessels. The third way is through the bloodstream, where cancer cells can enter the bloodstream and travel to distant sites, leading to the formation of new cancers called metastases.