Cancer isn’t just one disease; in fact, there are >100s of cancer types. But all cancers have one thing in common: cells become abnormal and grow out of control. Ignoring the body’s signal to stop, malignant cells multiply to form tumors. Tumors can form in organs and tissues or, in blood cancers, crowd out normal cells in the bloodstream and bone marrow.
Cancer Progression and Spread
Cancer takes time to develop. The length of time depends on several factors, such as type, order, and speed at which cell mutations accumulate.
Cancer stage describes the progression of the disease in the body. Stages start from precancer to cancer that has spread to distant organs or tissue (metastatic cancer).
Metastasis (or metastatic cancer) happens when cancer spreads through the body. Cancer cells break away from their original location, travel through blood or the lymphatic system, and form new tumors in other parts of the body. Cancer metastasis is most commonly found in bones, liver, or lungs.
Cancer Types
Cancers are classified based on the organ or cell type from which they originate:
- Carcinomas: occur on skin or tissues that line internal organs.
- Sarcomas: occur in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.
- Leukemias: occur in cells of the blood and bone marrow.
- Lymphomas: occur in cells of the immune system and typically appear within the lymphatic system.
- Central nervous system cancers: occur in cells of the brain and spinal cord.
