When cancer cells have spread through the bloodstream or lymphatic system they have?

When cancer cells have spread through the bloodstream or lymphatic system, they have undergone a process known as metastasis. This allows them to invade other tissues and organs beyond their original site, complicating treatment and prognosis. Metastatic cancer often requires more aggressive therapeutic approaches due to its advanced stage. The presence of metastases can significantly affect the overall management and outcomes of the disease.