What does metastasis refer to in the context of cancer?

Metastasis is a term used in oncology to describe the process by which cancer cells spread from the original (primary) site of the tumor to other parts of the body, forming secondary malignant growths. This is a critical concept in understanding the progression and severity of cancer. When cancer cells break away from the primary tumor, they can travel through the bloodstream or lymphatic system to distant organs or tissues, where they can establish new tumors. This process is significant as it often indicates an advanced stage of the disease and can complicate treatment options.

The primary growth of a tumor, treatment of primary cancer, and prevention of cancer spread relate to different aspects of cancer diagnosis and management but do not capture the essence of what metastasis entails. Understanding metastasis is essential as it informs decisions on patient care, treatment approaches, and prognosis.