Metastasis is the process by which cancer cells spread from the original tumor to other parts of the body. This occurs when cancer cells break away from the primary tumor, travel through the bloodstream or lymphatic system, and form new tumors in distant organs or tissues. Metastatic cancer can make treatment more challenging and often indicates a more advanced stage of the disease. The ability of cancer cells to metastasize varies among different types of cancer, such as breast cancer, lung cancer, and prostate cancer. Early detection and treatment of the primary tumor can help reduce the risk of metastasis, improving the chances of successful outcomes for patients.