Chemotherapy is the use of toxic drugs to treat cancer. There are a number of classes of chemotherapy agents which affect different cellular structures. All chemotherapeutic agents, however, work by preventing essential cellular processes to kill cells. Chemotherapy targets rapidly dividing cells, which is why they are efficient in treating cancer. Other proliferating cells within the body are affected as well, including cells required for maintenance of tissues. High doses of chemotherapy can result in a number of unpleasant side effects throughout the body.
Anemia
One notable side effect of high dose chemotherapy is anemia, which occurs when tissues throughout the body are deprived of oxygen. The cells responsible for delivering blood to tissues are red blood cells, which contain a molecule called hemoglobin that binds to oxygen near the lungs. These cells then release the oxygen into tissues as blood is pumped throughout the body. Anemia occurs following chemotherapy because the stem cells that make red blood cells are damaged during treatment, resulting in fewer red blood cells to deliver oxygen.
Anemia can result in chronic fatigue, dizziness and headache, according to the Mayo Clinic. Anemia as a result of chemotherapy is temporary, and will resolve itself a few weeks after the cessation of chemotherapy treatment.
Immunodeficiency
High-dose chemotherapy can also result in temporary immunodeficiency due to a decrease in white blood cell counts in the blood. The white blood cells are an essential part of the immune system---they recognize foreign infectious objects, then attack and destroy them to prevent infection and disease. The same population of stem cells, which is affected by chemotherapy, generates both red and white blood cells. Chemotherapy treatment, therefore, decreases the production of white blood cells. This leads to a condition called neutropenia, which in turn causes immunodeficiency.
Like anemia, immunodeficiency as a result of low white blood cell counts is temporary, and will resolve itself a few weeks after the end of treatment. In the meantime, patients experiencing immunodeficiency may take medication to boost white blood cell counts to protect against infection.
Diarrhea
A common side effect of high-dose chemotherapy is diarrhea. The digestive tract has specific populations of cells which function to maintain the integrity of the digestive tract. Since these cells are constantly dividing, they are affected by chemotherapy treatment, leading to digestive problems. Specifically, chemotherapy can have an effect on the body's ability to regulate water absorption from digested food, leading to watery and loose stools.
If left untreated, diarrhea can lead to electrolyte imbalances and dehydration due to loss of fluids, according to Stanford Medicine. Prescription medicines to help regulate the digestive system can alleviate diarrhea.
