Doxorubicin Health Dictionary

ANTIBIOTICS that destroy tumour cells: examples include aclarubicin, daunorubicin, doxorubicin, epirubicin and idarubicin.... anthracyclines

Cytotoxic means destructive to living cells. Cytotoxic drugs possess anti-cancer properties but also have the potential to damage normal tissue. Their use is twofold: to eliminate a cancer and so prolong life; or to alleviate distressing symptoms, especially in patients whose prospects of a cure are poor. In many cases CHEMOTHERAPY with cytotoxic drugs is combined with surgery, RADIOTHERAPY or both. Chemotherapy may be used initially to reduce the size of the primary TUMOUR (a process called neoadjuvant therapy) before using radiotherapy or surgery to eliminate it. Cytotoxic drugs may also be used as adjuvant treatment to prevent or destroy secondary spread of the primary tumour that has either been removed by surgery or treated with radiotherapy. All chemotherapy causes side-effects: the ONCOLOGIST – a specialist in cancer treatment – has to strike a balance between hoped-for bene?ts and acceptable (for the patient) toxic effects, which include nausea and vomiting, BONE MARROW suppression, ALOPECIA (hair loss) and teratogenic effects (see TERATOGENESIS).

Cytotoxic drugs are used either singly or in combination, when an enhanced response is the aim. Chemotherapy of cancer is a complex process and should be supervised by an oncologist in co-operation with physicians, surgeons, radiotherapists and radiologists as appropriate.

The cytotoxic drugs include:

(1) The alkylating agents which act by damaging DNA, thus interfering with cell reproduction. Cyclophosphamide, ifosfamide, chlorambucil, kelphalan, busulphan, thiotepa and mustine are examples of alkylating agents.

(2) There are a number of cytotoxic antibiotics used in the treatment of cancer – doxorubicin, bleomycin, dactinomycin, mithramycin and amsacrine are examples. They are used primarily in the treatment of acute leukaemia and lymphomas.

(3) Antimetabolites – these drugs combine irreversibly with vital enzyme systems of the cell and hence prevent normal cell division. Methotrexate, cytarabine, ?uorouracil, mercaptopurine and azathioprine are examples.

(4) Another group of cytotoxic drugs are the vinca alkaloids such as vincristine, vinblastine and vindesima.

(5) Platinum compounds such as carboplatin, cisplatin and oxaliplatin are e?ective. All of them are given intravenously, but the latter two tend to have more unpleasant side-effects. Carboplatin and cisplatin are useful in the treatment of solid tumours. Carboplatin, a derivative of cisplatin, is given intravenously in ovarian cancer and in small-cell lung cancer. Better tolerated than cisplatin, the drug causes less nausea and vomiting, nephrotoxicity, neurotoxicity and ototoxicity. Where platinum-containing therapy has failed, intravenous treatment with paclitaxel may be tried. With only a limited success rate, it is relatively toxic and should be carefully supervised; responses, however, are sometimes prolonged.

Also of increasing importance in treating cancer are interferons. These are naturally occurring proteins with complex effects on immunity and cell function. Although toxic, with numerous adverse effects, they have shown some anti-tumour e?ect against certain lymphomas and solid tumours.... cytotoxic

A cytotoxic anthracycline antibiotic drug used in the treatment of solid tumours, acute LEUKAEMIA and LYMPHOMA. It is related structurally to DOXORUBICIN and is given intravenously, and by instillation into the URINARY BLADDER to treat bladder cancer under specialist supervision.... epirubicin

A semi-synthetic vinca alkaloid (see VINCA ALKALOIDS) CYTOTOXIC drug recently introduced for the treatment of advanced breast cancer, when anthracycline cytotoxic antibiotics such as DOXORUBICIN have failed. Vinorelbine is also used to treat advanced non-small-cell lung cancer (see LUNGS, DISEASES OF). As with all vinca alkaloids, the drug has neurotoxic effects, usually affecting the PERIPHERAL NERVOUS SYSTEM and AUTONOMIC NERVOUS SYSTEM. It may also cause (reversible) hair loss (ALOPECIA). The drug is given intravenously.... vinorelbine

A wide range of disorders can disrupt the heart’s action.

In general, genetic factors do not play a large part in causing heart disorders, however they do contribute to the hyperlipidaemias that predispose a person to atherosclerosis and coronary artery disease. Structural abnormalities in the heart are among the most common birth defects (see heart disease, congenital).

Infections after birth may result in endocarditis or myocarditis. Tumours arising from the heart tissues are rare. They include noncancerous myxomas and cancerous sarcomas.

The heart muscle may become thin and flabby from lack of protein and calories. Thiamine (vitamin B1) deficiency, common in alcoholics, causes beriberi with congestive heart failure. Alcohol poisoning over many years may cause a type of cardiomyopathy. Obesity is an important factor in heart disease, probably through its effect on other risk factors, such as hypertension, diabetes, and cholesterol.

The coronary arteries may become narrowed due to atherosclerosis, depriving areas of heart muscle of oxygen. The result may be angina pectoris or, eventually, a myocardial infarction.

Some drugs, such as the anticancer drug doxorubicin, tricyclic antidepressants, and even drugs used to treat heart disease, may disturb the heartbeat or damage the heart muscle.

Many common and serious heart disorders may be a complication of an underlying condition, such as cardiomyopathy or a congenital defect. Such disorders include cardiac arrhythmia, some cases of heart block, and heart failure. Cor pulmonale is a failure of the right side of the heart as a consequence of lung disease.... heart, disorders of

n. any of 500 or so antibiotics synthesized or isolated from species of Streptomyces. *Doxorubicin is the most important member of this group of compounds, which have wide activity, particularly against breast cancer and lymphoma; others include *daunorubicin and epirubicin. See cytotoxic drug.... anthracycline

n. any one of a group of drugs that inhibit cell division and growth, e.g. *doxorubicin. The drugs used to treat cancer are mainly antimitotics. See also antimetabolite; cytotoxic drug.... antimitotic

any drug that damages or destroys cells: usually refers to those drugs used to treat various types of cancer. There are various classes of cytotoxic drugs, including *alkylating agents (e.g. *chlorambucil, *cyclophosphamide, *melphalan), *antimetabolites (e.g. *fluorouracil, *methotrexate, *mercaptopurine), *anthracycline antibiotics (e.g. *doxorubicin, *daunorubicin, *dactinomycin), *vinca alkaloids, and platinum compounds (e.g. *carboplatin, *cisplatin). Other cytotoxic drugs include *taxanes and *topoisomerase inhibitors, and some *monoclonal antibodies (e.g. *bevacizumab, *trastuzumab) have cytotoxic activity. All these drugs offer successful treatment in some conditions and help reduce symptoms and prolong life in others. Cytotoxic drugs destroy cancer cells by interfering with cell division, but they also affect normal cells, particularly in bone marrow (causing *myelosuppression), hair follicles (causing hair loss), the stomach lining (resulting in severe nausea and vomiting), mouth (causing soreness), and fetal tissue (they should not be taken during the later stages of pregnancy). Dosage must therefore be carefully controlled. See also chemotherapy.... cytotoxic drug

n. a microscopic spherical membrane-enclosed vesicle or sac (20–30 nm in diameter) made artificially in the laboratory by the addition of an aqueous solution to a phospholipid gel. The membrane resembles a cell membrane and the whole vesicle is similar to a cell organelle. Liposomes can be incorporated into living cells and may be used to transport relatively toxic drugs into cancer cells, where they can exert their maximum effects. The cancerous organ is at a higher temperature than normal body temperature, so that when the liposome passes through its blood vessels the membrane melts and the drug (e.g. *doxorubicin) is released. Liposomes are also undergoing clinical trials as vehicles in *gene therapy for cystic fibrosis.... liposome

n. cancer of the lymph nodes, including *Hodgkin’s disease and non-Hodgkin’s lymphomas. There is a broad spectrum of malignancy, with prognosis ranging from a few months to many years. The patient usually shows evidence of multiple enlarged lymph nodes and may have constitutional symptoms such as weight loss, fever, and sweating (the so-called ‘B symptoms’). Disease may be widespread, but in some cases is confined to a single area, which may be extranodal (such as the tonsil). Treatment is with drugs such as chlorambucil or combinations of cyclophosphamide, vincristine, and prednisolone, sometimes with the addition of doxorubicin and/or bleomycin; response to these drugs is often dramatic. New *targeted agents are used depending on the expression of cell surface molecules, particularly *rituximab against CD20 in diffuse B-cell lymphoma. Localized disease may be treated with radiotherapy followed by drugs. Patients with non-Hodgkin’s lymphoma who do not respond to chemotherapy may be considered for a bone-marrow transplant.... lymphoma

(osteogenic sarcoma) n. a highly malignant tumour arising from within a bone, usually in the *metaphysis of the long bones of the body and especially around the knee and the proximal end of the humerus. It is usually seen in children and adolescents but can occur in adults of all ages, occasionally in association with *Paget’s disease of bone. In children the usual site for the tumour is the leg, particularly the femur. Secondary growths (metastases) are common, most frequently in the lungs (though other sites, such as the liver, may also be involved). The symptoms are usually pain and swelling at the site of the tumour and there is often a history of preceding trauma, although it is doubtful whether this contributes to the cause. Treatment of disease localized to the primary site was traditionally by amputation of the limb; limb-sparing surgery is now possible after *neoadjuvant chemotherapy, with replacement of the diseased bone by a metal prosthesis. Many centres also give *adjuvant therapy in an attempt to kill any microscopic tumour that might have already spread. The drugs used include doxorubicin, cisplatin, vincristine, cyclophosphamide, and methotrexate.... osteosarcoma

any one of a class of *cytotoxic drugs that work by blocking the action of topoisomerase enzymes, which promote the uncoiling of the DNA double helix, a necessary preliminary to replication. Topoisomerase I inhibitors include irinotecan, used for treating advanced colorectal cancer (especially in combination with *fluorouracil); and topotecan, given for treating advanced ovarian cancer, relapsed small-cell lung cancer, and recurrent cervical cancer. Side-effects include delayed but severe diarrhoea and reduction in blood-cell production by the bone marrow. Topoisomerase II inhibitors include *etoposide and *doxorubicin.... topoisomerase inhibitor