General Aspects of Chemotherapy

Neoplastic disease is a result of proliferation of abnormal cells. It can affect every system in the body and is a major cause of mortality and morbidity around the world.

Chemotherapy is used to kill neoplastic cells - however, there are usually a number of healthy cells which are also killed. The abnormal malignant cells take longer than the normal cells to grow. Therefore, chemotherapy is given in cycles to allow the "normal" cells to recover.¹

Chemotherapy can be used for curative intent or palliation. It can be used alone or as an adjunct to surgery or radiotherapy. Often chemotherapeutic agents are used in combination, but occasionally they are used alone.

• Alkylating agents
• Cytotoxic antibiotics
• Antimetabolites
• Vinca alkaloids
• Platinum compounds
• Taxanes

• Oral
• Intramuscular
• Intravenous
• Intrathecally
• Topical
• Others e.g. intravesical, subcutaneous

See individual drug monographs for details.

As a result of targeting healthy cells:

• Myelosuppression
• Hair loss
• Sterility
• Impaired wound healing e.g. mouth ulcers
• Nausea and vomiting
• Tiredness
• Teratogenicity
• Some agents may lead to menopausal symptoms in female patients e.g alkylating agents in Hodgkin's Lymphoma²

• Chemotherapy initiation is a decision made by oncology consultants.
• First cycle must be prescribed by senior doctors, some hospitals say consultants.
• Only trained personnel should administer cytotoxic agents.
• Gloves and eye protection are worn.
• Waste products are disposed by incineration.
• Prior to administering cytotoxics, basic blood counts and appropriate other tests are checked e.g. liver function tests (LFTs).
• Patients may need antiemetics prior to drug delivery.
• Patients need to be aware that for some agents high concentrations are found in urine, sweat and vomit. They should be advised on appropriate clothing and how to dispose of soiled linen.

Extravasation

• Associated with pain, redness and inflammation. Very serious as may lead to skin necrosis which could require limb amputation.
• There may be blotching of the skin or blistering and necrosis in severe cases.
• Treatment involves high index of suspicion and careful monitoring if symptoms develop.
• Extravasation is reduced by administration of chemotherapeutic agents by trained personnel.³
• The actual management of extravasation, once it has occurred varies. Topical agents can be applied to act as antidotes e.g. dimethyl sulfoxide topically. In more severe cases debridement and grafting may be necessary. However, evidence base in this area is lacking and the best method is prevention.⁴

Nausea and vomiting

• Nausea and vomiting is a major cause of distress and reluctance for further therapy.
• Cytotoxic agents vary in their potency to cause vomiting, with agents such as, cisplatin and high dose cyclophosphamide as highly potent and methotrexate and etoposide as least likely to cause vomiting.
• If the risk is low then agents such as, domperidone and metoclopramide have good effect. With more emetogenic therapy serotonin antagonists, such as ondansetron, are more effective.⁵
• However, serotonin receptor antagonists are generally thought to be most useful with all forms of chemotherapeutic agents.⁶

Bone marrow suppression

• All cytotoxics save a few, lead to myelosuppression. This tends to occur one week after administration of the agent.
• Full blood counts are checked prior to administration and should be checked in anyone presenting with fever or symptoms suggestive of infection following a course of chemotherapy.
• If the patient is neutropenic (< 1.0 x 10⁹/lt) they will need treatment with intravenous antibiotics urgently.

Alopecia

• This is reversible and varies between agents.
• Alopecia can have psychosocial consequences on patients in an already difficult situation.
• Again there is no clear evidence, but use of scalp hypothermic regimens may be helpful e.g. cold caps.⁷

Fertility

• Most agents are teratogenic so should not be given during pregnancy (although will need to be a risk-benefit decision). They should also not be handled by pregnant personnel.
• Pre-treatment counselling and storage of sperm or ova and/or embryo formation may be appropriate. See further reading below for more detailed information.