Headlines about ‘backfiring’ chemotherapy are misleading

Some of today’s headlines about chemotherapy missed the point

We spotted some worrying headlines today claiming that chemotherapy can ‘backfire’ and ‘encourage cancer’, making it “tougher to tackle”. We want to make it clear that cancer patients don’t need to be distressed by these unnecessarily alarming headlines, or consider stopping their treatment.

In fact, the research from US scientists that sparked the coverage categorically does not show chemotherapy makes cancer harder to beat. Instead, the work gives scientists a vital insight into one way that the body can develop resistance to chemotherapy, and it could help explain why treatment sometimes stops working.

But it doesn’t tell us anything new about current chemotherapy treatments – we already know that some cancers respond to chemo while other don’t, or start growing again after treatment.

So it won’t change how doctors treat cancer patients today.

Read our own news piece about the research for the main facts, and read on for more detailed analysis of the research.

This is a ‘good news’ story

We know from the boost in calls to our Cancer Information Nurses that cancer patients can be unnerved and upset when they spot news like this.

This is a tremendous shame – particularly in this case, as the oversimplified headlines mask what is actually a ‘good news’ story. The researchers, led by Peter Nelson at the Fred Hutchinson Cancer Research Centre in Seattle, have uncovered how healthy cells surrounding tumours can help fuel resistance to chemotherapy.

Such work is crucial if we’re to find ways to make chemotherapy better.

The team focused their attention on something known as the tumour microenvironment – the ‘neighbourhood’ around a cancer that supports it and helps it to grow. This includes lots of normal tissues, such as blood vessels and immune cells that have been co-opted by a tumour to serve its own needs.

This research shows that healthy cells around a tumour called fibroblasts (which normally help to repair wounds) can be damaged by particular types of chemotherapy. This causes them to pump out a molecule called WNT16B, which triggers tumours to grow. Such fibroblast damage could therefore work against the positive tumour-killing effects of chemotherapy.

The scientists found this effect in action in samples of prostate, breast and ovarian cancers, in response to a handful of commonly used chemotherapy drugs including docetaxel and mitoxantrone.

This research doesn’t show that these drugs don’t work – we already know from clinical trials and years of use in patients that they can slow tumour growth and increase survival. But it does explain why they don’t always work, meaning that some tumours aren’t always completely eradicated by chemotherapy.

And – more importantly – now we know the molecular identity of the culprit responsible for this effect, scientists can work on ways to boost the cancer-killing effects of chemotherapy by blocking or interfering with it.

Surprising? Not really

Contrary to what some news outlets claim, this is not a particularly surprising finding either. We’ve known for many years that chemotherapy, like all drugs, can affect healthy tissues. And other scientists, including Cancer Research UK researchers such as Professor Fran Balkwill, are also working to understand how healthy cells are affected by treatment and interact with tumour cells.

We spoke to Professor Balkwill about this latest research. She points out that while the ultimate aim of treatment is to only kill cancer cells, it’s inevitable that other healthy cells that surround tumours are also affected. Sometimes this can be good – for instance, chemotherapy can trigger healthy immune cells around a tumour to attack it.

On the flipside, the effects of chemotherapy on healthy cells in the tumour’s microenvironment can also be negative, as shown by this latest research.

This doesn’t affect current treatment

It’s an important message, so it’s worth repeating. Cancer patients do not need to be alarmed by today’s headlines and should not stop treatment. Decades of clinical trials have proved the effectiveness of chemotherapy in treating cancer and extending life, so this research doesn’t make it stop working overnight. It’s just one project among countless studies ongoing across the globe looking in minute detail at the effects of chemotherapy on the body, with the ultimate aim of making treatment more effective in future.

But while chemotherapy has its share of success stories, anyone who has been through the heartache of losing someone to cancer knows only too well that at some point there’s a chance that treatment will fail and the cancer comes back. Understanding why this happens is of utmost importance if we are to beat cancer, and it’s something that many Cancer Research UK scientists are focusing on.

This important new study has pinpointed one potential mechanism behind resistance. But it’s only based on experiments in the lab, using a limited range of cancer types and drugs, so it’s a long way from yielding anything that could change how patients are treated in the clinic.

Chemotherapy is one part of the picture

Radiotherapy and surgery – not to mention other strategies like healthy living, early diagnosis and screening – are crucial, but chemotherapy plays a big part too. And work to improve it must be welcomed.

But while we applaud the media’s interest in this important scientific paper, we want to calm the nerves of anyone worried by some of the headlines, which by themselves don’t paint an accurate picture of the research.

• To find out more detail about this research, head over to the NHS Choices blog, which has looked at the paper in depth. (link added 07/08/12)

Reference:

• Sun, Y., Campisi, J., Higano, C., Beer, T.M., Porter, P., Coleman, I., True, L. & Nelson, P.S. (2012). Treatment-induced damage to the tumor microenvironment promotes prostate cancer therapy resistance through WNT16B, Nature Medicine, DOI: 10.1038/nm.2890