What Is Combination Chemotherapy?

Advantages and Disadvantages of Combination Chemotherapy

women with IV for chemotherapy
What is combination chemotherapy, when is it used, and what are the risks and benefits?. istockphoto.com

What is combination chemotherapy, when is it used, and what are the advantages and disadvantages of this approach to treatment?

DefinitionWhat Is Combination Chemotherapy?

Combination chemotherapy refers simply to the use of more than one chemotherapy medication at a time to treat cancer. In the past, cancer was often treated with a single drug, but current treatments for many types of cancer use a combination of two or more different drugs simultaneously.

History of Combination Chemotherapy

The use of combination chemotherapy to treat cancer was inspired in the 1960s when scientists wondered whether the approach to treating tuberculosis – using a combination of antibiotics to reduce the risk of resistance – would work for the treatment of cancer as well. Using this approach, cancers that had previously been almost universally fatal such as acute lymphocytic leukemia and Hodgkin’s lymphoma became largely curable. Since that time, combination chemotherapy has been adopted for the treatment of many other cancers as well.

In the 1970's, combination chemotherapy was found to be more effective for people with lung cancer, and more effective than "sequential chemotherapy" or using chemotherapy drugs one at a time in sequence, rather than at the same time.

Benefits

There are several theoretical advantages to using a combination of chemotherapy medications rather than single agents alone.

Some of these include:

  • Decreasing the chance that a tumor will be resistant to the treatment. Just as a combination of antibiotics may be used in case a particular bacteria is resistant to one of the medications, using two or more chemotherapy drugs reduces the risk that a tumor will be resistant to the treatment.
     
  • Making it possible to give all medications as early as possible in the disease.
     
  • Being able to address several targets in the cancer process at the same time. Cancer is a complex disease involving many steps. The use of chemotherapy medications that work on different molecular targets, or points in the cancer process should, in theory, raise the chances of eliminating the cancer.                                                                                                               
  • Tumor "heterogeneity" - Scientists use the term tumor heterogeneity to describe how the cancer cells in tumors vary from each other.  While the initial cells in a cancer are "clones" - in other words identical -  successive divisions result in changes in the cells.  Some of the resulting cells in a tumor may respond to a particular drug while others may be more responsive to another drug.                                                                                                                        
  • Recently research is also looking at ways in which using a combination of chemotherapy medications can be used to allow oncologists to use some of the drugs at lower doses, and hence reduce the likelihood of toxic effects.

In practice, the use of combination chemotherapy with many cancers has either been found to improve survival, or result in a better response to treatment.

Possible Disadvantages

Some possible disadvantages of combination include:

  • An increased likelihood of chemotherapy side effects -.It goes without saying that any time more medications are used it is more likely that side effects will occur. 
  • Difficulty knowing which drug caused a particular side effect - If a patient develops a side effect when several medications are used, it may be difficult to know which of the medications is responsible.
  • Drug interactions - Sometimes side effects occur not due to a particular medication, but due to reactions between the medications.
  • Accumulation of side effects - For example, if you use two drugs which cause a low white blood cells count, the risk of chemotherapy-induced neutropenia (a reduced number of the type of white blood cells known as neutrophils) is increased.

Examples

There are many combinations of chemotherapy drugs that are used for different types of cancer. An example with lung cancer is using the combination of Platinol (cisplatin) and Navelbine (vinorelbine) to treat non-small cell lung cancer.

Sometimes an acronym is used to describe combination chemotherapy. One example is ABVD for Hodgkin's disease which stands for the combination of the chemotherapy medications Adriamycin (doxorubicin), Blenoxane (bleomycin), Oncovin (vinblastine) and DTIC-Dome (dacarbazine).

Coping with Chemotherapy

Become familiar with common chemotherapy side effects as well as long-term side effects of chemotherapy, but keep in mind that methods of controlling these symptoms have improved dramatically in recent years.  For example, many people no longer experience nausea and vomiting even on the drugs most likely to cause these symptoms.

To make you days during chemo go just a little bit smoother, check out the essentials list of what to pack for chemotherapy.

Sources:

Delbaldo, C., Michiels, S., Syz, N. et al. Benefits of Adding a Drug to a Single-Agent or a 2-Agent Chemotherapy Regimen in Advanced Non–Small-Cell Lung Cancer A Meta-analysis. JAMA. 2004. 292(4):470-484.

DeVita, V. and E. Chua. A History of Cancer Chemotherapy. Cancer Research. 2008. 68:8643.

Hu, M., Huang, P., Wang, Y., Su, Y., Zhou, L., Zhu, X., and D. Yan. Synergistic Combination Chemotherapy of Camptothecin and Floxuridine through Self-Assembly of Amphiphilic Drug-Drug Conjugate. Bioconjugate Chemistry. 2015. 26(12):2497-506.

Zimmermann, G. et al. Multi-target therapeutics: when the whole is greater than the sum of the parts. Drug Discovery Today. 2007. 12(1-2):34-42.

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