Home > Encyclopedia of Nursing & Allied Health > Cancer Therapy, Supportive

Definition

Supportive cancer therapy is the use of medications to prevent or counteract the unwanted side effects of cancer treatment.

Purpose

Along with their beneficial effects, many cancer treatments cause uncomfortable and sometimes harmful side effects. Three of the most common untoward effects of cancer treatment are nausea and vomiting, destruction of red and white blood cells in bone marrow that results in anemia and neutropenia, and pain. Fortunately, several drugs have been developed that specifically target these adverse reactions.

Precautions

The patient should be questioned as to medications being taken, and if adverse reactions have ever occurred. Any allergies to foods, dyes, preservatives, or other substances should also be assessed.

Description

Various medications are available for use in supportive cancer therapy. Their use is dependent upon several factors, including the particular treatment the patient is undergoing and the severity of symptoms.

Nausea and vomiting

The prevention and control of nausea and vomiting are extremely important for patients receiving cancer treatment. Unrelieved nausea and vomiting may lead to nutritional deficiencies, dehydration, electrolyte imbalances, and a general deterioration of the patient's mental and physical status. The drugs used to treat nausea and vomiting are known as antiemetics. Each falls into one of several categories.

PHENOTHIAZINES. The drugs within this category that are most commonly used as antiemetics include prochlorperazine (Compazine) and promethazine (Phenergan). These drugs can be given orally, intramuscularly, intravenously, and rectally. The most common side effects include extrapyramidal reactions, and sedation. There may be a significant drop in blood pressure if the medication is given too rapidly via the intravenous route.

DOPAMINE 2 ANTAGONISTS. Metoclopramide (Reglan) is the most widely used drug for nausea and vomiting in this category. It may be given either orally or intravenously. Like phenothiazines, it may lead to extrapyramidal reactions. Metoclopramide increases the pressure in the lower esophageal sphincter and increases the rate of gastric emptying, which may be an important factor in its antiemetic effect.

5-HT3 ANTAGONISTS. Three medications within this category are available in the United States: ondansetron (Zofran), granisetron (Kytril), and dolasetron (Anzemet). They are thought to work by blocking some actions of serotonin. These drugs may be given orally or intravenously. The most common side effects are headache (which can be treated with mild analgesics), constipation or diarrhea, dry mouth, fatigue and weakness, and dizziness.

In general, 5-HT3 antagonists are more effective than other antiemetics. However, their effectiveness is improved when they are given in combination with corticosteroids.

CORTICOSTEROIDS. Steroids like dexamethasone (Decadron) and methylprednisolone (Prednisone) are occasionally used alone in treating mild to moderate nausea, but more frequently are used in combination with other antiemetic drugs. They may be given orally, intramuscularly, and intravenously. It is not known exactly how corticosteroids work in treating nausea and vomiting, but they may affect prostaglandin activity in the brain. In the short-term, steroids may not only relieve nausea, but may also produce a sense of well being and an increased appetite in the patient. Long-term use is usually avoided, as it may cause suppression of the immune system, muscle weakness, hyperglycemia, lethargy, weight gain, and mood changes.

CANNABINOIDS. A great deal of interest has been shown in using marijuana to treat nausea and vomiting in cancer patients. However, because of both societal and legal restrictions, cannabinoids are usually not among the first drugs selected to treat nausea and vomiting. Two forms of marijuana have been used: marijuana cigarettes and a medicine taken by mouth containing the active chemical component of marijuana. Dronabinol (Marinol) is a synthetic form of the active ingredient in marijuana that is given orally. It makes some people feel drowsy, dizzy, lightheaded, or "high," with a sense of well being. It takes longer to work than smoked marijuana and may be difficult for patients with nausea and vomiting to keep down. The active ingredients of marijuana are more quickly absorbed from smoking marijuana cigarettes. However, since many patients are unable to tolerate smoking and each marijuana cigarette may vary in its potency, research is being conducted into other ways to effectively administer marijuana, such as inhalers, nasal sprays, and skin patches.

Patients considering using marijuana to control nausea and vomiting should be encouraged to fully discuss this option with their health care professional. A careful consideration of both the legal and medical issues is important.

BENZODIAZEPINES. Benzodiazepines such as Lorazepam (Ativan) and Alprazolam (Xanax) are valuable tools in the prevention and treatment of nausea and vomiting when given in combination with other antiemetics. They are especially useful in preventing anticipatory nausea and vomiting. The adverse effects of benzodiazepines include lowered blood pressure, sedation, altered perception, and dependence.

Anemia and neutropenia

Anemia and neutropenia are two potentially very serious complications of cancer treatment. Hematopoietic agents and colony stimulating factors help combat these complications by stimulating the bone marrow to produce new cells.

HEMATOPOIETIC AGENTS. A weakened bone marrow occurring as a result of cancer treatment or certain cancers can lead to low erythropoetin levels. Erythropoietin is a hormone produced by the kidneys and liver in response to low blood oxygen levels or anemia. It stimulates the bone marrow to make new red blood cells. Synthetically made versions of human erythropoietin called epoetin (Procrit, Epogen) can perform the same function.

Epoetin, which is injected, is usually well tolerated by patients. Some side effects may include high blood pressure, tachycardia, minor allergies, edema, diarrhea, and iron deficiency. Patients taking this medication need to have adequate iron levels in the body. The physician may prescribe iron supplements along with Epoetin. Occasionally Epoetin may cause a flu-like reaction that shows up about one or two hours after an injection. Normally the symptoms will go away within 12 hours. Another possible side effect is bone pain, which may be treated with mild analgesics.

COLONY STIMULATING FACTORS. While chemotherapy is in the process of destroying cancer cells, it can also damage cells in the bone marrow, where in addition to other types, white blood cells are produced. White blood cells help to defend the body against infections, so a decreased number is associated with an increased risk for infection. The numbers of white blood cells usually drop to their nadir, or lowest value, around 10-14 days after the end of chemotherapy treatment. Normally it takes around

three to four weeks for the white blood cell count to recover. In order to speed up this process, drugs called colony stimulating factors can be given that can help the bone marrow to produce new white blood cells. Examples of colony stimulating factors are G-CSF (Filgrastim, Neupogen) and GM-CSF (Sargramostim, Leukine). Both are given by injection daily for around seven to 14 days. The patient or caregiver is often taught how to administer the injections.

Colony stimulating factors commonly cause mild bone pain, normally in the pelvis or lower back. This occurs around the same time that the white blood cells come back in the bone marrow. This symptom can be treated with mild analgesics. Other common side effects include headache, skin rash, muscle or joint pain, and itching.

Pain

Approximately 60%-90% of cancer will need some type of pain-relieving therapy, depending on the type and severity of their cancer. For example, cancers of the abdomen can cause intense pain while lymphomas often never cause pain. Supportive cancer therapy for pain can be vitally important. Pain causes suffering and can lead to depression and anger. There are many causes of cancer pain, including:

• Chemotherapeutic drugs may poison nerves in addition to tumors. For example, cisplatin, carboplatin and other cancer drugs can cause peripheral neuropathy, such as burning in the hands and feet.
• Radiation therapy can produce neuropathic pain by scarring nerves (fibrosis) or cause painful skin reactions.
• Tumor spread can cause neuropathic pain, for example, when spinal tumors pinch or press nerves.
• Cancers and various complications can cause somatic pain, such as obstructions in the intestine or urinary tract.
• Surgery can cause both somatic and neuropathic pain.

There are a variety of treatments for cancer pain, depending on it severity. Aspirin, acetaminophen (Tylenol), and other nonsteroidal anti-inflammatory drugs (NSAIDs) are often used for mild pain. Moderate pain treatments include codeine, Percocet, Percodan, hydrocodone (Vicodin), and propoxyphene (Darvon). Demerol, Dilaudid, and morphine are some of the drugs used to treat severe pain. These medications have various side effects, some of them potentially serious.

Preparation

The patient should be instructed on the particular medication being administered or prescribed, including the dosage, times of administration, expected side effects, and any potentially adverse reactions. Patients receiving colony stimulating factors may need to be instructed on subcutaneous injection technique.

Aftercare

The health care professional should assess the patient's response to the medication administered and if any side effects have occurred.

Complications

As with many medications, serious complications, though usually rare, can and do occur. A physician should be notified quickly if any of the following occur.

Phenothiazines

If sore throat and fever, unusual bleeding or bruising, or an increase in weakness occur, the physician should be notified. Seizures, severe drowsiness, facial flushing, hallucinations, muscle spasms, trembling and jerking movements may all be symptoms of an overdose.

Dolasetron, granisetron, and ondansetron

The physician should be notified immediately if any of the following occur: shortness of breath or other breathing difficulties, chest pain, skin rash, hives or itching, and fever. Prompt notification should also take place if patients taking dolasetron experience hematuria, anuria or dysuria; or swelling of the face, feet or legs.

Dronabinol

Dronabinol may worsen some medical conditions, including high blood pressure, heart disease, bipolar disorder, and schizophrenia. Any new symptoms suggestive of these conditions should be reported to the doctor. A variety of other side effects and possible signs of overdose should also be reported immediately, including tachycardia, difficulty urinating, slurred speech, mood changes, confusion and forgetfulness, sensory changes, and hallucinations.

Epoetin

Certain side effects should be brought to a physician's attention as soon as possible, including headache, visual disturbances, elevated blood pressure readings, tachycardia, edema, and weight gain. The physician should be notified immediately if the patient taking epoetin experiences chest pain or seizures.

Colony stimulating factors

Colony stimulating factors increase the risk of infection because of lowered white blood cell counts. Therefore, any signs of infection, including fever and chills, should be reported to the physician as soon as possible. Other symptoms that should be reported promptly include redness or pain at an injection site; chest pain; tachycardia; difficulty breathing and/or wheezing; and edema.

Results

The goal of antiemetic administration in supportive cancer therapy is relief of nausea and vomiting. For those receiving epoetin or either of the colony stimulating factors, normalized blood cell counts and prevention of infections are the desired results.

Health care team roles

Medications used in the supportive care of cancer patients are ordered by the physician. Some states may allow advanced practice nurses to prescribe. The pharmacist is responsible for dispensing the drugs. The nurse plays an important role in both administering medication, assessing the response of the patient, and teaching the patient about all aspects of the drug being given.

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KEY TERMS

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Antiemetics—Medications used to alleviate nausea and vomiting.

Extrapyramidal reactions—Muscular rigidity, tremors, and altered gait brought on by certain medications. Also called drug-induced parkinsonism.

Neutropenia—The presence of an abnormally small level of neutrophils in the blood, usually less than 1500-2000 per microliter. Patients with low levels of neutrophils are at high risk for infections.

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Deanna M. Swartout-Corbeil, R.N.