Lab-grown mini tumours offer hope for personalised cancer treatment

"Mini tumours created to battle cancer," BBC News reports on a study in which scientists created lab-grown "mini tumours" to test responses to different treatments.

The research involved taking tumour samples (biopsies) from 71 people with advanced bowel or stomach cancer that had spread to other parts of their body, and who had had already tried lots of other cancer treatments.

Researchers used these samples to grow mini replica tumours in the lab and then tested different cancer drugs on them. They wanted to see if the replica tumours responded in the same way as tumours in the human body had.

Overall, they found the mini tumours' responses were very accurate in predicting which cancer treatments would and wouldn't work. Prior identification of which treatments are likely to be effective could save valuable time and improve the outlook for people with cancer.

These are promising early findings that could open a whole new area of personalised cancer treatment. However, it's important to remember that this research is in its early stages – much more work is needed.

Where did the study come from?

The study was conducted by researchers from The Institute of Cancer Research and The Royal Marsden Hospital, London. It was published in the journal Science. Funding came from numerous sources, including Cancer Research UK, the National Institute for Health Research, the Biomedical Research Centre at The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research.

The media coverage was largely accurate, although it's far too early to say this development "could save lives". For instance, even if an advanced cancer that has spread to other parts of the body responds to a treatment, it's still unlikely to mean it can be completely eradicated and cured.

What kind of research was this?

This was a laboratory study aiming to see whether it's possible to test cancer treatments on miniature replicas of a patient's tumour in the lab and thus know in advance which treatments may be effective.

Previous research has shown it's possible to take cells from organs or tumours and grow mini replicas, or "organoids", in the lab. However, most research to date has involved growing organoids from cells from the original cancer site rather than from tumours that had spread to other parts of the body (metastases). Researchers had also not previously been able to use these organoids to test how patients may respond to treatment.

This study had two aims: to look at organoids grown from stomach or bowel cancer metastases in people who had tried many different cancer treatments, and to see if the organoids' responses to different treatments in the lab reflected what actually happened in the patient.

What did the research involve?

The participants were 71 patients with metastatic cancers of the bowel, stomach, food pipe (oesophagus) or bile ducts, all of whom had taken part in clinical trials and received heavy treatment from various therapies.

Biopsies were taken from the patients' metastases and placed in a gel. About 70% grew into 3D organoids, and the cells in them were shown to closely resemble those in the original tumours.

Using 55 different cancer treatment drugs that were either already established or being used in clinical trials, the researchers then tested the possibility of using the organoids to determine which treatments a person would respond to.

Finally, they compared the organoids' responses with how the patients had actually responded in clinical trials.

What were the basic results?

The organoid tests didn't miss any potentially effective drugs. If the organoids didn't respond to a particular drug you could be 100% certain the person wouldn't respond to it in reality.

The organoid tests were slightly less reliable for identifying drugs that would work: on average, the person would respond to 88% of the drugs the organoid responded to. This meant that around 1 in 10 treatments that were effective in the organoid hadn't worked in the patient.

How did the researchers interpret the results?

The researchers said: "Our data suggest that patient-derived organoids can recapitulate patient responses in the clinic and could be implemented in personalised medicine programs."

Conclusion

This is a valuable study that opens a potential new area of cancer treatment. It's often hard to know which drugs a person may respond to, particularly when they have already tried several treatments.

This work suggests it may be possible to replicate patients' tumours in the laboratory, and so be able to test in advance which treatments they're likely to respond to and which ones they won't.

Researcher Dr Nicola Valeri said: "[The study] has the potential to help deliver truly personalised treatment and avoid the reliance on trial and error for many patients when clinicians give them a new cancer drug."

This could help to make sure effective treatment is given sooner, therefore slowing tumour progression and improving the person's outlook.

However, it's important to remember this research is still in its early stages.

It involved a relatively small sample of people with advanced-stage digestive system cancers that had spread to other parts of the body. It's difficult to know whether researchers would be able to grow replica organoids of other types of tumour and would be as reliable at showing which drugs a person would respond to.

Also, replica mini tumours haven't yet been used to guide treatment, so it's completely unknown whether doing so would lead to more cancers being cured and better survival rates.

The findings are very promising but much more research is needed.