A drug may be taken every day, every week, or every month. A drug may be taken in cycles alternated with a rest period when no drug is taken. Effectiveness of treatment is evaluated regularly with physical exams, blood tests and x-rays. A drug is considered effective if it causes the cancer cells to shrink, to stop growing, or to die. Because anti-cancer drugs attempt to kill cancer cells, many of them will also attack and kill healthy cells.
Side effects are a direct result of the killing of healthy cells.
Certain cells are more susceptible to damage than others, including bone marrow cells, cells in the digestive tract, reproductive system and hair follicles. Most of these side effects will disappear in a few days or weeks after chemotherapy ends. Metastatic colon cancer to the liver can be treated with chemotherapy in a variety of ways. In addition, active research protocols are investigating the effectiveness of administering chemotherapy by mouth with the goal of making the treatment easier for the patient. Chemotherapy can also be administered directly into the liver artery and is called intra-arterial chemotherapy.