Cancer is caused by rapid, uncontrolled cell division. Cells lose normal functions and invade normal surrounding tissues. Metastasize means to travel to another location. A tumor is named according to tissue of origin. Cause of cancer can be chemical physical, and biological. Some biological cancers are caused by diseases that suppress the immune system (HIV or immunosuppressant drugs after transplants).
Multiple drugs from different classes affect different stages in the cell cycle. The combinations allow for lower doses, which reduce toxicity and slow the development of resistance. Specific dosing protocol depends on the type of tumor, stage of the disease and overall condition of the patient. The drugs can be given as a single does or several doses and given within several days or after several weeks. This gives normal cells a chance to recover. Sometimes, the optimum does must be delayed to let the patient recover from drug toxicities.
It is difficult to kill cancer cells without killing normal cells. Serious toxicity limits therapy. Prophylactic treatment of symptoms are used to decrease the serious side effects.
Drugs that are vesicants can cause tissue injury.
- Explain the significance of growth fraction and the cell cycle to the success of chemotherapy.
- Explain the three primary therapies for cancer: surgery, radiation, and chemotherapy.