What are metastases?

Metastases refer to secondary tumors that develop as a result of cancer cells spreading from the original or primary tumor to other parts of the body. When cancer cells break away from the primary tumor, they can travel through the bloodstream or lymphatic system to distant sites, where they can establish new tumors. These secondary tumors retain the characteristics of the original cancer, meaning that if a breast cancer spreads to the lungs, the metastatic tumors in the lungs are still classified as breast cancer, not lung cancer.

Understanding metastases is crucial in cancer treatment and prognosis, as the presence of metastases often indicates a more advanced stage of cancer, which can affect treatment options and expected outcomes. The other options describe different forms of tumors or growths that do not relate to the concept of metastases. Primary tumors are the original tumors, non-cancerous growths refer to benign conditions, and healthy cell formations pertain to normal tissue, none of which capture the essence of what metastases are.