Metastatic cancer occurs when cancer cells spread from the original tumor to other parts of the body. This process can happen through the bloodstream or lymphatic system, allowing the cancer to form new tumors in organs such as the lungs, liver, or bones. Once cancer has metastasized, it is often more challenging to treat than localized cancer. Treatment options may include chemotherapy, radiation therapy, or targeted therapies, depending on the type of cancer and its location. Early detection and treatment of the primary tumor can help reduce the risk of metastasis.