The difference between complementary and alternative therapies | Cancer Research UK
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The difference between complementary and alternative therapies

Nurse and patients talking about cancer

This page has information about complementary therapies (CAMs) used by people with cancer. It tells you about the difference between complementary and alternative therapies.


The difference between complementary and alternative therapies

The phrases complementary therapy and alternative therapy are often used as if they mean the same thing. They may also be combined into one phrase – complementary and alternative therapies (CAMs). It is not always easy to decide whether something is a complementary or an alternative therapy. But there is an important difference. 

A complementary therapy means you can use it alongside your conventional medical treatment. It may help you to feel better and cope better with your cancer and treatment. It is important to discuss with your doctor any complementary therapy that you are thinking of using.

An alternative therapy is generally used instead of conventional medical treatment. All conventional cancer treatments have to go through rigorous testing by law in order to prove that they work. Most alternative therapies have not been through such testing and there is no scientific evidence that they work. Some types of alternative therapy may not be completely safe and could cause harmful side effects. 


If you are thinking of using CAMs

If you are considering using any complementary or alternative therapy it is very important to talk to your cancer doctor, GP, or specialist nurse for advice about the safety of the therapy. It is also very important to let your complementary or alternative therapist know about your conventional cancer treatment. Some treatments may interact.

Nurse talking with patient


What complementary therapies are

Complementary therapies are used alongside conventional medical treatments prescribed by your doctor. They can help people with cancer to feel better and may improve your quality of life. They may also help you to cope better with symptoms caused by the cancer or side effects caused by cancer treatment. 

You can go to information about some of the reasons why people with cancer use complementary therapies.

A good complementary therapist won't claim that the therapy will cure your cancer. They would always encourage you to discuss any therapies with your cancer doctor or GP. Complementary therapies are available from many different types of people and organisations.

We have information about where you can have complementary therapies

There are many different types of complementary therapy, including the following

Many health professionals are very supportive of people with cancer using complementary therapies. They can see that the therapies help people to cope better with the cancer and its treatment. But some health professionals have been reluctant for their patients to use such therapies. This is because many therapies have not been scientifically tested in the same way as conventional treatments. 

Some research trials have been carried out to see how well complementary therapies work for people with cancer. Some trials are still in progress. But we need more studies to help us develop our knowledge about the best way to use complementary therapies.


What alternative therapies are

Unlike complementary therapies, alternative therapies are used instead of conventional medical treatment. People with cancer have various reasons for wanting to try alternative therapies. Some people may not start conventional treatment and may choose to use an alternative therapy instead. Some people might stop conventional cancer treatment and switch to an alternative therapy.

Some alternative therapists may claim to be able to cure your cancer with their treatments, even if conventional medical treatments haven’t been able to do so. Or a therapist may say that conventional cancer treatments are harmful. A trustworthy therapist with a good reputation won't claim this.

There is no scientific or medical evidence to show that alternative therapies can cure cancer. Some alternative therapies are unsafe and can cause harmful side effects or they may interact with your conventional medical treatment. This could increase the risk of harmful side effects or may stop the conventional treatment working so well. Giving up your conventional cancer treatment could reduce your chance of curing or controlling your cancer. 

Some alternative therapies are very cleverly promoted so that people reading about them think that they work very well. But the claims are not supported by scientific evidence and they may unfortunately give some people false hope.

Examples of alternative cancer therapies include

You can find out more about the safety of complementary and alternative therapies

Our information about commonly used types of complementary and alternative therapies also has information about the safety of the individual therapies.


Other terms used to describe CAM therapies

There are several different terms commonly used to describe complementary or alternative therapies. If you are not familiar with them, it can be confusing. You may see therapies described as

Unconventional therapies

This generally means treatments that aren’t normally used by doctors to treat cancer. In other words, any treatment that is not thought of as part of conventional medicine.

Health professionals working in cancer care are becoming more aware of the differences between complementary therapies and alternative therapies. And they know how important it is to make a distinction between the two terms. Now most doctors and nurses describe therapies as either complementary or alternative, rather than unconventional.

CAM (Complementary and Alternative Medicine)

CAM is a term which covers both complementary and alternative medical therapies.

Integrated healthcare or integrated medicine

These terms are generally used to describe the use of conventional medicine and complementary therapies together. The terms are commonly used in the USA but are becoming more widely used in the UK. In cancer care, integrated medicine usually includes making sure that you have access to all of the following:

Traditional medicine

Health professionals usually use the term traditional medicine to mean a therapy or health practice that has developed over centuries within a particular culture. It is usually formed around a particular belief system. 

This term can be confusing because in the western part of the world conventional medicine could be considered to be a traditional medicine. But we don't usually use the term traditional medicine in this way. We usually mean it to refer to therapies or treatments that developed in the eastern part of the world such as 


What conventional medicine means

Conventional medicine is the sort of medicine and treatment your doctor would usually use to treat your cancer. You may also hear this called orthodox medical treatment. The most common treatments include

  • Chemotherapy
  • Radiotherapy
  • Surgery
  • Biological therapies
  • Hormone therapy

You can read about conventional cancer treatments.

The aim of conventional treatment is to kill or remove, and hopefully cure, the cancer. If the cancer is not curable the aim may be to control it for as long as possible. Your doctor will discuss with you how likely the treatment is to help in your particular situation. 

Nearly half of all conventional medicines or drugs are developed from plants or other natural substances. As conventional drugs, they are tested and used in a controlled way. 

All conventional cancer treatments are tested thoroughly in clinical trials to prove that they work for specific types of cancer. 

Clinical trials are carried out to

  • Make sure that conventional treatments work
  • Make sure we know what the side effects are
  • Show us that the benefits of a treatment for cancer outweigh any risks

You can read all about clinical trials.

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Updated: 24 October 2014