Combination chemotherapy consists of the use of two or more chemicals to achieve maximum destruction of cancer cells and tumors. For example, different drugs attack cancer cells at varying stages of growth, or with varying intensities, making combination therapy a powerful weapon. Using a combination of chemotherapy drugs may reduce the likelihood of drug resistance. Combination chemotherapy is known to improve the survival rate of patients with many forms of cancer, and the intensity of the treatment can be adjusted by using a greater number of drugs in combination. Unfortunately, combination chemotherapy almost always introduces more (and more severe) side effects, including hair loss, nausea, vomiting and lethargy.
The treating oncologist will usually be the one to decide which drugs to use in combination chemotherapy, and his or her decision will be based on the kind of cancer, the stage of malignancy (metastasized, or not), the health and age of the patient, and the toxicity of the individual chemicals. If two drugs both impact liver function, an oncologist will either substitute for one or request frequent liver function tests.
The individual drugs in the combination regimen should each be effective against the cancer on their own.
Each drug should have a different mechanism and a different dose-limiting toxicity.
In mesothelioma treatment by chemotherapy, the most common regimen is a combination of Alimta and cisplatin.
Background
Combination chemotherapy arose out of a 1965 discovery that cancer therapies, like tuberculosis treatments, should follow a course of multiple drugs, each with its different mechanism of action. Cancer cells that could predictably mutate in response to a single chemical would be much less likely to do so when confronted by multiple agents.
The success of this multiplicity of chemicals, as discovered by James Holland, Emil Freireich, and Emil Frei, under the auspices of St. Jude Children’s Research Hospital, the UK’s Medical Research Council, and the German Berlin-Frankfurt-Münster clinical trials group, has led to acute lymphoblastic leukemia (ALL) becoming a largely curable disease among children.
Administration
More modern protocols, such as ABVD chemotherapy for Hodgkin lymphoma, provide even more favorable results. ABVD, named after the initials of the chemotherapy drugs used (doxorubicin, or Adriamycin; bleomycin; vinblastine; and dacarbazine), is often given as an outpatient, or day-patient, course in a hospital or similar clinical setting following simple blood tests and a doctor’s exam.
Combination chemotherapy is commonly given intravenously, at least the first time to monitor patient’s reactions. It can be injected directly into the IV line, or through a saline or glucose drip, which is more likely. It is usually preceded by an anti-emetic, to prevent nausea and vomiting. The procedure can take up to two hours, with patients either lying on a bed or sitting in a recliner-type chair.
The line is removed, and patients usually go home. Many are again given anti-emetics for nausea, and these should be taken as directed. It is much easier to prevent nausea and vomiting than it is to stop it once it has started.
Treatments are given about two weeks apart, and the whole regimen, or course of treatments, may involve as few as two sessions, or as many as eight. Every person’s reaction to combination chemotherapy is different, but many will experience headaches, nausea, vomiting, dizziness, sores inside the mouth or taste changes, feverishness, numbness or tingling in the hands or feet, a lack of energy (from anemia), some hair loss, and a lowered resistance to infections. However, running a temperature above 100.5 degrees or suddenly feeling extremely ill are serious symptoms and require immediate attention.
Patients receiving combination chemotherapy should also be aware of the risk of developing blood clots, having medication interactions between the chemotherapy agents and regular medication, leaking around the intravenous site (which can be serious), and fertility issues like the cessation of menstruation in women and the subsequent onset of menopausal symptoms, or poor sperm count in men.
Different kinds of cancer require different drugs. ABDV is used to treat Hodgkin lymphoma, but an almost completely different therapy, CVP (cyclophosphamide, vincristine, and prednisolone) is used to treat non-Hodgkin lymphoma, as is CHOP (cyclophosphamide, hydoxydaunorubicin, Oncovin®) and prednisolone). ECX (epirubicin, cisplatin, capecitabine), on the other hand, is used to treat cancers of the esophagus, stomach and the gastro-esophageal junction.
The oncology community has developed about 55 different combination chemotherapy protocols, each directed at either a form of cancer, or metastatic phase of a given cancer. These therapies may be given in a clinical setting, as described above, or in pill form to be taken at home after the first dose, or even topically – that is, applied to the skin.
Because combination chemotherapies increase the risk for serious infection, many patients do not qualify, either because of ill general health, age or advanced cancer.
Report of the combination chemotherapy trial of pemetrexed and cisplatin in mesothelioma treatment.
Sources for Information on this page: CancerBackupUK, Amgen, MayoClinic
