chemotherapy

chemotherapy is a topic covered in the Taber's Medical Dictionary.

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(kē″mō-ther′ă-pē )

[chemo- + therapy]
Drug therapy used to treat infections, cancers, and other diseases and conditions.
SEE: Nursing Diagnoses Appendix

Descriptive text is not available for this imageChemotherapeutic agents to treat cancer are toxic or poisons and pose risks to those who handle them, primarily pharmacists and nurses. Usually, only oncology practitioners specifically trained in chemotherapy administration should perform this task. The most important factor in reducing exposure is proper protection in the preparation and administration of these agents. After washing his or her hands, the health care provider dons appropriate apparel. Protective clothing may be used if drugs are prepared under a hood, but generally only surgical powder-free or hypoallergenic latex-free chemotherapy gloves are used for administration. He or she then gathers equipment to administer the drugs, including normal saline or 5% dextrose in water (D5W) solution as prescribed (the same solution should be used for both priming and mixing); IV tubing; the drugs, alcohol swabs, and sterile gauze (required to start an IV line or enter a port); and plastic-backed absorbent pads. Hydration is provided before administration of the chemotherapy drugs, along with an antiemetic, antihistamine, or other required agents. Patients may often eat or drink during the administration of chemotherapy. The drugs should be administered in a calm environment, and all chemotherapy waste and equipment must be discarded in waste containers. Health care providers must follow Occupational Safety and Health Administration guidelines when cleaning up drug spills. Spill kits should be available and used, and spill areas cleaned three times using soap and water (for the skin) or detergent, followed by clean water (for other surfaces). Gloves should also be worn when handling the patient's excreta. Exposure to drugs poses additional risks to female reproductive health, including ectopic pregnancies, spontaneous abortions, and fetal abnormalities.

PATIENT CARE
Cancer chemotherapeutic agents include alkylating agents and nitrosureas, antimetabolites, antitumor antibiotics, plant alkaloids, monoclonal antibodies, immunomodulating agents, and steroid hormones. Antineoplastic agents kill cancer cells but also kill or injure normal cells, esp. those that normally divide rapidly and may therefore compromise the patient's comfort and safety. Bone marrow suppression is a common and potentially serious adverse reaction. Chemotherapy can decrease the numbers of leukocytes, erythrocytes, and platelets. Leukopenia increases the patient's risk for infection, esp. if the granulocyte count falls below 1000/mm3. The patient is given information about personal hygiene and potential sites for infection and is taught to recognize signs and symptoms, e.g., fever, cough, sore throat, or a burning sensation when urinating. The patient is cautioned to avoid crowds and people with colds or flu. Filgrastim (Neupogen) or pegfilgrastim (Neulasta) is administered as prescribed to stimulate proliferation and differentiation of neutrophils. Thrombocytopenia increases a patient's risk for bleeding when the platelet count falls below 50,000/mm3; the risk is highest when the platelet count falls below 20,000/mm3. Oprelvekin (Neumega) may be used to treat this complication. The patient is assessed and taught to observe for bleeding gums, increased bruising or petechiae, hypermenorrhea, tarry stools, hematuria, and coffee-ground emesis. He or she is advised to avoid cuts and bruises and to use a soft toothbrush and an electric razor. The patient must report sudden headaches, which could indicate intracranial bleeding. He or she should use a stool softener, as prescribed, to avoid colonic irritation and bleeding. Intramuscular injections are avoided to prevent bleeding. Anemia develops slowly over the course of treatment; therefore the patient's hemoglobin, hematocrit, and red blood cell counts are monitored. Dehydration can lead to a false-normal hematocrit reading, which decreases when the patient is rehydrated. The patient is assessed for and taught to report any dizziness, fatigue, pallor, or shortness of breath on minimal exertion. He or she must rest more frequently, increase dietary intake of iron-rich foods, and take a multivitamin with iron, as prescribed. Growth factors or colony-stimulating factors are administered as prescribed: e.g., epoetin alfa (Procrit) enhances erythrocyte production to increase hemoglobin levels; whole blood or packed cells are transfused as prescribed for a symptomatic patient.

Antineoplastics attack cancer cells because they divide rapidly. For the same reason, they also destroy rapidly dividing normal cells. While epithelial damage can affect any mucous membrane, the oral mucosa is the most common site of destruction. Stomatitis is a temporary but disabling phenomenon that may interfere with eating and drinking. It can range from mild and barely noticeable to severe and debilitating malnutrition. Preventive mouth care is initiated and taught to the patient to provide comfort and decrease the severity of mouth pain. Therapeutic mouth care is also provided, including topical antibiotics if needed. The patient may experience nausea and vomiting from gastric mucosal irritation (from oral or parenteral chemotherapy), chemical irritation of the central nervous system (from parenteral chemotherapy), or psychogenic factors activated by sensations, suggestions, or anxiety. Chemotherapy-induced nausea and vomiting are troublesome because they can cause fluid and electrolyte imbalance, noncompliance with the treatment regimen, tears at the esophageal-gastric junction that lead to massive bleeding (Mallory-Weiss syndrome), wound dehiscence, and pathological fractures. They also reduce quality of life by interfering with the patient's ability and motivation to take an active role in his or her self-care. Such complications are assessed for and prevented as much as possible. Chemical irritation is controlled by administering prescribed combinations of antiemetics that act by different mechanisms, e.g., serotonin antagonists, prochlorperazine, diphenhydramine, droperidol, and dronabinol. Signs and symptoms of aspiration are monitored because most antiemetics are sedating. Psychogenic factors can be relieved by relaxation techniques to minimize feelings of isolation and anxiety before and during each treatment. The patient is encouraged to express feelings of anxiety, listen to music, engage in relaxation techniques, meditation, or self-hypnosis to help promote feelings of well-being and a sense of control.

Hair loss is distressing for the patient, esp. when the patient's body image or self-esteem is closely linked to his or her appearance. The patient is informed that hair loss usually is gradual, affects both men and women, and may be partial or complete, depending on the drug or drug combination employed. He or she is reassured that alopecia is reversible after treatment ends. A wig can be prescribed as a cranial prosthesis (for insurance coverage of the expense). The patient is encouraged to purchase it before hair loss begins and is informed where to acquire one. Although some patients prefer to expose their baldness, the scalp should be protected from exposure to the sun. Some chemotherapeutic agents have irreversible effects such as peripheral neuropathy although treatment is available to reduce these.

Chemotherapy extravasation may lead to tissue necrosis if the drug is a vesicant, and the patient is taught to immediately report any pain, stinging, burning, swelling, or redness at the injection site. Extravasation must be distinguished from vessel irritation or flare reaction. Vein irritation is felt as aching or tightness along the blood vessel, and the length of the vein may become reddened or darkened, accompanied by swelling. In flare reaction, itching is the major complaint; redness occurs in blotches along the vessel, may look like hives, and subsides within 30 min. Blood return from the IV can usually be obtained with both irritation and flare reaction. To help prevent extravasation, most known vesicant drugs are administered through a central venous catheter. If extravasation is suspected, the infusion is stopped, and any drug is aspirated. The extremity is elevated, and cold compresses are applied, except for Vinca alkaloids, for which heat is recommended. Depending on agency protocol, the oncologist is notified, and, if a specific antidote for the drug exists, it is administered as prescribed. The main line IV provides direct access to the patient if an undesired reaction occurs; other drugs can be administered quickly to counteract the adverse reaction. SEE TABLE: Important Considerations in the Administration of Chemotherapy

Complementary and alternative therapies are often used to help patients undergoing chemotherapy to feel better and more in control of their illness and its treatment.

ETHICAL DILEMMA
Patients with widely metastatic cancer often have an optimistic bias about chemotherapy: they are very likely to believe that chemotherapy offers a high likelihood of cure, but studies clearly show that chemotherapy may prolong life or palliate illness, but it may not achieve remission or cure. Health care providers face the challenge of supporting the hopeful patient with advanced cancer while maintaining realistic expectations about treatment outcomes.

Important Considerations in the Administration of Chemotherapy

• Has the patient had allergic reactions to this medication in the past?
• What fluids are compatible, or incompatible, with the agent to be administered?
• What is the exact dosage for this patient's body size and weight?
• How is the drug mixed or prepared?
• What is the proper route of administration?
• How stable is the drug once prepared?
• How should it be stored?
• What other drugs is the patient taking? Are any likely to cause drug interactions?
• Can the drug cause skin or vein irritation during administration? How will these complications be managed?
• What is the anticipated schedule of administration?
• What are the specific side effects of the agent? How should the patient and health care team prepare for early or delayed effects?
• How are effects of the drug to be monitored?
• How often should the patient have physical examinations, imaging studies, or blood tests?
• What findings suggest further drug administration should be delayed or cancelled?
• Who should the patient contact with concerns?

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SUBCUTANEOUS PORT

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