Possible Side Effects
The known side effects of chemotherapy are caused by the cell killing effect of anti-cancer drugs. Chemotherapy drugs act on normal cells as well as cancer cells. Cancer cells typically grow and divide more rapidly than normal cells. The fast-growing normal cells most likely to be affected by chemotherapy are blood cells forming in the bone marrow, and cells in the digestive tract, reproductive system, and hair follicles. Common side effects of chemotherapy include fatigue, nausea, diarrhea, mouth sores, hair loss, and anemia.
Bone marrow produces several types of blood cells essential to health. Because these cells are constantly dividing, they are vulnerable to the effects of chemotherapy. Blood cell precursors produce three important blood components: red blood cells (which carry oxygen throughout the body); white blood cells (which fight infection); and platelets (which help blood clot and stop bleeding). A drop in the levels of any of these blood cell counts results in specific side effects.
Fatigue is one of the most common side effects of chemotherapy. It may be the result of anemia (a decrease in oxygen-carrying red blood cells), which causes a feeling of lethargy, dizziness, weakness, and shortness of breath. Fatigue may also be a result of a lot of energy being used by the body to recover from the effects of the drugs, disposing of dead cells and building new cells. Other factors, such as pain, poor appetite, lack of rest, and emotional stress may also contribute to a patient's fatigue.
Some common signs of infection, such as fever, sore throat, and wounds that do not heal or become inflamed, may be experienced by cancer patients because the body's capability to fight infection is greatly compromised due to the lowered number of white blood cells.
Platelets are important for wound healing and blood clotting. With a low platelet count caused by chemotherapy, the cancer patient is at risk of bruising and bleeding easily. Such side effects as nose bleeds, bleeding gums, blood in the urine or stool, and unusually heavy menstrual flow, may be experienced by the patient receiving chemotherapy.
Nausea and vomiting occur when certain drugs stimulate an area of the brain called the chemoreceptor trigger zone. Overeating, motion sickness, or anxiety can also activate this zone. The effects of some drugs on the fast growing cells in the lining of the stomach may also cause nausea and vomiting.
Diarrhea may be caused from direct damage of the lining of the intestines by some anti-cancer drugs. Anti-nausea drugs may also cause diarrhea.
Hair loss can be extremely devastating to the patient. When some anti-cancer drugs kill cancer cells, they also kill fast-growing normal cells such as those in hair follicles, causing alopecia (hair loss).
As with other cancer therapies, changes in mood and emotions occur to cancer patients undergoing chemotherapy. Feelings of loss of control, missing normal daily activities, and fear of the unknown, coupled with the side effects brought about by chemotherapy, can take a toll on the patient's mental well-being. Cancer patients receiving chemotherapy may feel angry, depressed, anxious, afraid, confused, forgetful, and agitated.
Factors such as the type of drug, the amount of drug, and the condition of the cancer patient receiving chemotherapy may determine the kind and the degree of side effects that a cancer patient experiences. Each patient reacts to chemotherapy in a unique way. Some people have very few side effects, while others may experience more. For example, while some patients may experience very unpleasant nausea and vomiting, other patients may not have any treatment-related nausea and vomiting. Similarly, some patients may feel mild lethargy resulting from chemotherapy, but some patients may feel completely worn out.
To cope with all of the possible side effects brought about by chemotherapy, the cancer patient needs to be well-informed: knowing what to expect helps the patient to be prepared to handle any side-effects that may show up. The doctor has advice on how the patient may alter their lifestyle or eating habits to make some side effects more tolerable. Medication may also be prescribed to overcome certain side effects. Since normal cells usually recover when the chemotherapy is over, most side effects should gradually go away once the chemotherapy has ended.