What Is the Main Idea?

The use of biologically-based complementary and alternative medicines (CAMs) by patients with long-term health conditions is increasing. In the research article “Biologically-Based Complementary and Alternative Medicine Use in Breast Cancer Patients and Possible Drug-Drug Interactions”, published in the journal Breast Care, the authors describe how the use of biologically based CAMs by patients with breast cancer has the potential to cause drug interactions, both with anticancer medicines as part of a chemotherapy treatment and with each other.

What Else Can You Learn?

In this blog post, standard medical treatment for breast cancer and the possibility of drug interactions when medicines are taken together are discussed. Different types of complementary and alternative medicine are also described.

What Is Breast Cancer?

Breast cancer can start in one or both breasts. It develops when cells in the breast become abnormal, start to grow out of control, and begin to invade the surrounding tissue. Breast cancer cells can also spread to other areas of the body by being carried there by the blood and lymphatic systems. The lymph fluid that is transported around the body by the lymphatic system is an important part of the immune system. There are different types of breast cancer, with the exact type determined by which type of cells in the breast has become cancerous. Breast cancers are also classified on the basis of whether or not the cancer cells produce certain proteins or have changes (mutations) in specific genes. Genes are short sections of DNA that carry the genetic information for the growth, development, and function of your body.

How Is Breast Cancer Treated?

Treatments that have been assessed and accepted as effective treatments for particular diseases by the medical community are known as “standard medical treatments”. The standard medical treatments for breast cancer include surgery, chemotherapy, radiotherapy, hormone therapy, and targeted therapy.

  • Types of surgery that are used to treat breast cancer include breast-conserving surgery (where a cancerous lump is removed) and mastectomy (where a whole breast is removed).
  • Chemotherapy uses medicines that are “cytotoxic” (which means that they are toxic to cells, damaging them or causing them to die) to kill cancer cells. However, because cells in the body that are not cancerous can also be affected by chemotherapy medicines, many people who receive this type of treatment experience side effects. As this term is used to describe any unintended effects of a medicine, it can refer to beneficial and/or unfavorable effects.
  • Radiotherapy aims to kill cancer cells by using controlled doses of radiation.
  • Hormone therapy is used to lower the levels of the hormones estrogen and progesterone, which naturally circulate in the body, because some breast cancers develop the ability to be stimulated to grow by them.
  • Targeted therapy specifically targets molecules that cancer cells need to survive and spread.

What Is Complementary and Alternative Medicine?

The term “complementary and alternative medicine” (CAM) is an umbrella term that describes medical practices and products that are not part of standard medical care. Complementary medicine is used alongside standard medical treatment, whereas alternative medicine is used instead of standard medical treatment. A wide range of different types of products and practices are included in CAM that can be broadly divided into five groups.

  • Whole medical systems, such as ayurveda and naturopathy
  • Mind–body therapy, including meditation, yoga, and hypnotherapy
  • Manipulative and body-based practices, such as reflexology and massage
  • Energy healing, such as reiki
  • Biologically-based approaches, such as vitamins and dietary supplements, plants and plant extracts, and special foods or diets

The effectiveness and safety of most types of CAM approaches are less well understood than for standard medical treatment and more research is needed. However, while some CAM therapies have been shown to be generally safe and effective (such as acupuncture and yoga), some may be harmful and others may not work. Some may also cause drug interactions.

What Is a Drug Interaction?

A drug interaction happens when a medicine that is being taken by a person reacts with something else. Drug interactions can happen when one medicine reacts with another medicine or medicines, with something that the person is consuming (such as a herbal supplement or a particular food), or starts to cause side effects in the person because of another condition. When drug interactions occur, the results can range from mild side effects to a drug working less well or not at all. This means that a drug interaction has the potential to have a serious effect on the patient.

What Did the Study Investigate?

Advances in standard medical treatment for breast cancer have led to significant increases in 5- and 10-year survival rates in all countries in the European Union and in the UK in recent years. At the same time, health information has become more widely available and a large proportion of patients with long-term health conditions look for ways to improve their health and quality of life that fall outside of standard medical treatment.

Research has shown that the use of biologically-based CAMs is particularly popular among women with cancer, primarily because it is hoped that biologically-based CAMs can lessen the side effects of chemotherapy and strengthen the body against the effects of anticancer treatments. However, many of the biologically-based CAMs that people use carry the risk of drug interactions, and patients may begin taking them without consulting or notifying their medical team, making it difficult for any effects caused by drug interactions that do occur to be identified.

The authors of this study followed 47 patients with breast cancer as they began chemotherapy treatment, and asked them to complete questionnaires on their first day of treatment and again 10–12 weeks later. During this time period, 91% of the participants in the study reported that they used a biologically-based CAM, with the most popular types of biologically-based CAMs including the taking of vitamins, minerals, trace elements, and plants or plant extracts.

Drug interactions that had the potential to be clinically relevant (i.e., that could affect the effectiveness of a chemotherapy medicine or increase its toxicity in the body) were identified for 30 out of the 43 patients who reported using biologically-based CAMs. This was particularly true for patients who were using turmeric and ginger supplements together, which shows that the taking of more than one biologically-based CAM at once can cause drug interactions with each other, not just with anticancer medicines.

While the consumption of turmeric and ginger in food has generally been reported to have health benefits, they can both have a blood-thinning effect when high levels are consumed. This puts a person at risk of dangerous bleeding if they are also taking an anticoagulant (a type of medicine that prevents blood clots form forming). There are also some instances where drug interactions only occur if two substances are taken together. In such cases, it is possible for a patient’s medical team to help put together a medication plan that can help avoid drug interactions by ensuring that the taking of the two medicines is done at safe time intervals.

Take-Home Message

Although some biologically-based CAMs may have beneficial effects on the health of patients undergoing treatment for breast and other cancers, further studies are needed to identify potential interactions that can occur with chemotherapy drugs and with other biologically-based CAMs. If you are undergoing treatment for breast cancer, let your medical team know if you start to use a biologically-based CAM. This will enable them to monitor you for any potential drug interactions and will also add to the pool of knowledge regarding the best CAM options for patients undergoing anticancer treatment. There may also be known potential drug interactions that should be taken into consideration, and your medical team will be able to provide advice to help you support your standard medical treatment safely.

Note: This post is based on an article that is not open-access; i.e., only the abstract is freely available.

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