Chemotherapy refers to drugs given to kill or slow the growth of cancer cells. However, because chemotherapy drugs work throughout the body (for example on all cells in a particular stage of development), healthy cells are attacked as well as cancerous ones. Because healthy cells are also damaged during chemotherapy, side effects are likely.
Chemotherapy commonly causes nausea, vomiting, loss of appetite, weight loss, fatigue, and low blood cell counts that lead to anemia and increased risk of infections. People also often lose their hair, but other side effects vary according to the type of drug.
Gastrointestinal Effects
Gastrointestinal (digestive tract) effects are very common and include
Loss of appetite
Nausea and vomiting
Diarrhea
These effects also may be caused by the cancer itself
Loss of appetite is common and may cause weight loss. People who lose more than 10% of their ideal body weight do not do as well as those who are able to maintain their weight or lose less weight. Doctors encourage people to maintain good nutrition. There are several drugs that increase appetite, but it is not clear whether they actually can reverse weight loss, improve quality of life, or prolong survival.
Nausea and vomiting
Diarrhea
Low Blood Cell Concentrations
Cytopenias, a deficiency of one or more types of blood cell, can develop because of the toxic effects that chemotherapy drugs have on the bone marrow (where blood cells are made). For example, a person may develop abnormally low numbers of
Red blood cells (anemia)
White blood cells (neutropenia or leukopenia)
Platelets (thrombocytopenia)
Red blood cells carry oxygen from the lungs to all the cells of the body. Without enough red blood cells, people may be pale or have fatigue or weakness. People with more severe anemia may have dizziness, thirst, sweating, or even shortness of breath and chest pain. If anemia is severe, packed red blood cells can be transfused. A red blood cell growth factor, erythropoietin, also can be given, but transfusion is preferred because there is less risk of a blood clot.
A person with neutropenia is at increased risk of developing an infection because white blood cells are an essential defense against infection. A fever higher than 100.4° F (38° C) in a person with neutropenia is treated as an emergency. Such a person must be evaluated for infection and may require antibiotics and even hospitalization. White blood cells are rarely transfused because, when transfused, they survive only a few hours and produce many side effects. Instead, certain substances (such as granulocyte-colony stimulating factor) can be administered to stimulate white blood cell production.
Platelets are small cell-like particles in the blood that help it to clot when there is a cut or broken blood vessel. A person without enough platelets (thrombocytopenia) is likely to bruise and bleed easily. If thrombocytopenia is severe, people may have severe digestive tract bleeding or bleeding into their brain. Platelets can be transfused to treat or help prevent bleeding.
Mouth Sores
Many people develop inflammation or even sores of the mucous membranes, such as the lining of the mouth. Mouth sores are painful and can make eating difficult. Various oral solutions (usually containing an antacid, an antihistamine, and a local anesthetic) can reduce the discomfort. On rare occasions, people need nutritional support by a feeding tube that is placed directly into the stomach or small intestine or even by vein.
Depression
Depression may be the result of cancer therapy as well as the cancer itself.
Organ Damage and Other Cancers
People treated with chemotherapy, particularly alkylating agents, may have an increased risk of developing leukemia several years after treatment. Some drugs, especially alkylating agents, cause infertility in some women and in most men who receive these treatments.
Tumor Lysis Syndrome and Cytokine Release Syndrome
Tumor lysis syndrome may occur after chemotherapy because, when cancer cells are killed, they may release their contents into the bloodstream. These contents may damage the kidneys or heart. Tumor lysis syndrome occurs mainly in acute leukemias and non-Hodgkin lymphomas
Cytokine release syndrome is related to but distinct from the tumor lysis syndrome. Cytokine release syndrome occurs when large numbers of white blood cells are activated and release inflammatory substances called cytokines. It is a frequent complication of cell-based therapies such as those using CAR-T-cells and some monoclonal antibodies. Symptoms include fever, fatigue, loss of appetite, muscle and joint pain, nausea, vomiting, diarrhea, rashes, rapid breathing, headache, confusion, and hallucinations. In general, treatment for mild cytokine release syndrome is supportive and involves relieving symptoms like fever, muscle pain, or fatigue. Oxygen therapy, fluids and drugs to raise blood pressure, and drugs to decrease inflammation may be needed in people with more severe cytokine release syndrome.
