Cancer Research UK : Questions over DCA 'cancer drug'

Questions over DCA 'cancer drug'

You may have seen articles in the news about a drug called DCA (dichloroacetate), that is claimed to be cheap, safe and "kill most cancers". Understandably this has caused a great deal of interest, especially as DCA is an off-patent drug and appears to be non-toxic to humans.

DCA has now been approved for a trial in brain cancer patients in Canada. The researchers have raised $800,000 in public donations to fund the trial. But many people wanted to know why organisations such as Cancer Research UK did not immediately plough resources into the development of DCA as a treatment for cancer. Some people have suggested that the fact the drug's patent has expired might have been behind this. But the reason is that the story is not as simple as the newspaper headlines make out.

What is DCA and how does it work?
Does it cure cancer?
Is it safe?
What will happen in the future?

What is DCA and how does it work?

All our cells need energy to grow and function, including cancer cells. Simply put, our cells usually generate energy by breaking down sugar (glucose). To do this, they use a process known as the Krebs cycle, which takes place in tiny structures within the cell called mitochondria. But cancer cells bypass this cycle and produce energy using a simpler process, known as glycolysis, which takes place outside the mitochondria in the cell's cytoplasm (the main part of the cell).

Mitochondria play a crucial role in cells. As well as generating energy for the cell, they can also trigger the cell to die if it is faulty – a process that helps stop cancers from forming in the first place. Because cancer cells seem to "turn off" their mitochondria, scientists think this is one way in which cancer cells are able to evade death and remain "immortal".

DCA, or dicholoacetate, is a very simple chemical and is similar to some of the chemicals involved in the Krebs cycle. Researchers at the University of Alberta recently found that adding DCA to cancer cells grown in the lab kick-starts the Krebs cycle, turning the mitochondria back on again. This caused the cancer cells to stop multiplying and die. The team discovered that DCA didn’t affect healthy cells, because their mitochondria were functioning normally.

DCA has been tested as a treatment for children with a rare metabolic disorder. It has also been tested in adults with certain metabolic problems. This means that, at the doses needed to treat these diseases at least, DCA has been through clinical trials aimed at assessing its safety. Based on their results, the Alberta researchers argue that DCA could also be a potential cancer treatment. Because it is selective for the faulty energy production process in cancer cells, it might not harm healthy cells and therefore cause fewer side effects than conventional cancer treatments.

Does it cure cancer?

The paper from the University of Alberta researchers described experiments carried out using cancer cells grown in the lab. The team also carried out experiments on rats that had been injected with cancer cells. They found that DCA could slow the growth of tumours, and reduce their size. This did not prove that the cancers were completely cured, or that DCA could prevent cancers from growing.

It is important to stress that DCA had not then been tested as a cancer treatment in humans, despite the implication in news headlines that it "kills most cancers". There are many research papers produced by scientists around the world every year that reveal potential new treatments for cancer. But it is important that every discovery is carefully investigated to make sure that it is effective and safe for use in patients, and DCA is no exception.

The University of Alberta researchers received approval for a human cancer trial in September 2007, and hope to start the study as soon as possible. Fifty patients with brain tumours will be treated with DCA to see if it can have an effect on cancer.

Is it safe?

DCA is not "completely safe and non-toxic". A clinical trial of DCA for a childhood disease found that the drug caused significant side effects, affecting the nervous system. It is also known to be an environmental pollutant. Researchers have found that DCA can actually cause cancer in animals, so it is far from being a completely safe treatment.

This is not necessarily a barrier to the use of DCA as a treatment for cancer – there are a number of powerful anti-cancer drugs that are carcinogens. However, these have been thoroughly tested in clinical trials to discover how they can be safely used to treat patients while minimising any harmful effects.

Clinical trials of DCA will help determine whether it is safe to use in cancer patients, what dose is needed, and whether the treatment is more effective than the cancer therapies that are currently available.

It is understandable that people with cancer will want to try anything to help treat their disease. However, there is still no evidence to support the immediate and untested use of DCA for treating cancer patients. The trial in Canada will be conducted under stringent conditions both to ensure the validity of the results and to protect the participants from any unforeseen effects.

There are reports that people are buying personal supplies of DCA from sources such as the internet. Cancer Research UK would strongly advise against this, as DCA has not been tested for this purpose, and as explained above, may be harmful when given to cancer patients.

What will happen in the future?

It is clear that DCA is an interesting and potentially useful cancer drug – one of many currently being investigated by scientists around the world. It will be interesting to see the results of more extensive lab-based experiments and clinical trials of DCA, such as the trial in Canada.

The fact that DCA is off-patent is no barrier to its development as a treatment for cancer. For example, Cancer Research UK recently secured a licence for an off-patent drug that could be used to treat rare childhood cancers. And there is certainly no "conspiracy" by pharmaceutical companies to prevent research into DCA – there is just not enough evidence at the moment to start using it in the clinic.

However, it is unlikely that this one compound represents "the cure" for cancer – and it is also unlikely that DCA is the "wonder drug" that the headlines portray. Cancer is a complex and multi-faceted disease, and it can be caused by a range of different faults within the cell. It is unlikely that any single drug could ever treat all forms of the disease.

There are many promising new treatments for cancer currently in development, funded by Cancer Research UK and other organisations. It is important to carry out research into all aspects of cancer, to develop new and effective ways to diagnose, prevent and treat the disease. This is why Cancer Research UK funds such a wide range of research.