Metastatic cancer is a type of cancer that has spread from its original site to other parts of the body. This is a result of cancer cells breaking away from the main tumor and traveling through the bloodstream or lymphatic system to form new tumors in different organs or tissues. Metastatic cancer is considered advanced stage cancer and is usually more difficult to treat than localized cancer. Research in this area focuses on understanding the underlying mechanisms of metastasis, developing targeted therapies to prevent metastatic spread, and improving treatment options for patients with metastatic cancer.