New trial to test spice extract curcumin against bowel cancer

Could a spice extract help to treat bowel cancer? (image by Sanjay Acharya)

Headline writers take note: curry doesn’t cure cancer.

But over the years, several studies have given researchers a tantalising glimpse of the cancer-fighting potential of a chemical called curcumin, an extract of the yellow curry spice turmeric. This is the chemical that gives some drinks, sweets and foods – notably curries and Jaffa cakes – their bright colouring.

But it seems that as well as its culinary properties, curcumin can slow the growth of cancer cells in the lab.

Our scientists are now building on this early work by starting a clinical trial to find out if curcumin could help to treat people with advanced bowel cancer.

This doesn’t mean that a curry or Jaffa cake a day will keep the doctor away. In fact, taken to extremes, such a diet could increase your chances of being overweight, which ups the risk of developing cancer.

And the evidence just isn’t there yet to recommend anyone starts taking curcumin-containing supplements to ward off cancer.

But this small trial will answer some important questions about whether curcumin’s promise in the lab can be translated into an effective, standardised treatment for bowel cancer.

Treatments from nature

Tumeric is a member of the ginger family, and has been used for hundreds of years in many Indian, Persian and Thai dishes.

The idea that a plant extract could help fight disease isn’t a new one. Indeed, some of today’s cancer drugs came from the natural world. For example, the cancer drug paclitaxel (Taxol) originally came from the Pacific yew tree, while eribulin was discovered in sea sponges.

Even ‘head and heart’ tablet aspirin, which is based on old remedies extracted from plants, has shown promise in preventing the disease.

Evidence, not anecdotes

But using the power of plants to beat cancer isn’t about brewing up herbal tea or collecting leaves from the wild. Scientists and doctors are a scrupulously accurate bunch, so when they notice that a particular plant extract might be helpful in treating disease they aim to find out exactly which molecule, at what dose, can actually help patients.

This process of testing and standardisation is absolutely vital – not only to make sure patients are protected from harmful side effects, but also to prove that the potential treatment really does offer clear benefits. Modern medicine is built on evidence – and anecdotes aren’t enough to go on.

Testing curcumin

So how can we investigate whether turmeric could help to treat bowel cancer? The scientific approach is to find the key ingredient – in this case curcumin – and test its effects against bowel cancer in the lab, and then in patients.

Professor Will Steward has been investigating curcumin, and in this latest trial (known as CUFOX) he’ll be finding out if it’s safe and acceptable to patients when taken alongside chemotherapy.

The researchers suspect that the curcumin may make bowel cancer cells more sensitive to the effects of the standard chemotherapy treatment offered to bowel cancer patients – a combination of drugs called FOLFOX. This could be extremely useful. At the moment, six in every 10 patients have to either be given a reduced dose or, in some cases, stop chemotherapy altogether because of serious side effects like nerve pain.

Anything that allows them to continue treatment for longer, or increases the effectiveness of lower doses, could mean treatment is more successful. And because we already know that curcumin is generally safe for consumption, it should be able to be taken long-term without causing severe side effects.

The CUFOX trial will involve around 40 patients with advanced bowel cancer. The first phase will help researchers to work out the best dose of curcumin, as higher levels can sometimes cause side effects like diarrhoea and nausea.

The next phase will involve two groups of patients – one group will receive the standard chemotherapy treatment, while the other group will be given chemotherapy and curcumin capsules. They will then be monitored for two years.

The results initially aim to show that adding curcumin to the standard FOLFOX treatment doesn’t have any negative effects, but the researchers will also be looking for any sign of beneficial effects. This is a small, early-stage trial, so by itself it can’t tell us if curcumin could help people with bowel cancer.

But if the results are promising, the research will ramp up to larger trials that will help to answer this question.

Curry doesn’t cure cancer

A few years ago, early reports of research into turmeric spawned a range of ‘curry cures cancer’ headlines – claims like this are misleading and not helpful for people coping with the disease.

We said it earlier, but it’s worth repeating, the evidence doesn’t justify eating more curry or taking turmeric supplements.

Curries aren’t always the healthiest of meals, and in general there isn’t any evidence that supplements can help to reduce the risk of cancer. And worryingly, there have been reports of contamination in certain turmeric supplements in the past.

Step by step towards better treatments

Our excitement at this new trial has to be tempered with patience. Better treatments for cancer can’t be developed overnight. Research advances our knowledge step by step, not through single breakthroughs.

But we’re making progress – bowel cancer survival rates have doubled in the last 40 years, and research like this will help to save more lives in the future. Researchers will be monitoring participants in this for years to come – and we’ll be awaiting the results.

Nell

Find out more

• 2008 post about Professor Will Steward’s work
• UK clinical trial investigating whether curcumin can help treat Barrett’s oesophagus (please note – this trial is no longer recruiting)
• The American Cancer Society’s page about turmeric and curcumin