Blog Creating mini tumours Growing a tumour outside the body In an exciting step forward, scientists have been able to predict how cancer patients will respond to therapy by growing miniature versions of their tumours in the laboratory. The study, published in the journal Science, was able to indicate in every single case where a drug given was not effective. This means that in future patients who will not respond to certain drugs could be spared gruelling and aggressive therapies. Developing these structures, known as organoids, in the lab is a relatively new and exciting technique which will help to match the individual's tumour back exactly to them. We know that cancer develops differently in every individual, and finding ways to target the individual's cancer will be hugely important in future. The study Biopsies of 71 patients with advanced colorectal (bowel) cancer were taken and then grown into miniature 3D cancerous organs in the laboratory. Researchers treated each organoid with the same drug doctors gave to the patient in the clinic. The results showed: If the drug worked in the organoids, it worked 88% of the time in the patient If the drug failed in the organoids, it failed 100% of the time in the patient Just sparing patients the brutal side-effects of a drug that will not work would make a huge difference, the researchers said. Dr Nicola Valeri, from the Institute of Cancer Research in London, said: "For the first time we proved these organoids not only resembled the biology of metastatic cancer, but also mirror what we see in the clinic." In one patient, genetic testing had suggested their tumour would respond to a drug, but the treatment failed in both the clinic and the organoid. What does this mean for bowel cancer treatment? If these results can be replicated in a larger study, this is very significant. Patients who will not respond to current therapies will be spared aggressive treatments and alternatives will be sought. The use of organoids to study bowel cancer in the lab will be an important research tool, and more research will develop to make use of these in future.