Researchers at The Institute of Cancer Research, London, and The Royal Marsden NHS Foundation Trust found testing mini tumours predicted whether a drug would work between 88 per cent and 100 per cent of the time. The approach found a drug that had a chance of shrinking a patient's tumour in nearly 9 in 10 cases.
Scientists have been able to predict how cancer patients will respond to therapy by growing miniature versions of their tumours in the laboratory.
The trial helped medics from the Institute of Cancer Research, London, and Royal Marsden pick out drugs which shrank the tumours in nearly nine out of 10 cases.
Mini tumours grown in dishes couldn't be used to test treatments that work by targeting the environment around the tumour, such as the drug regorafinib which restricts blood supply to the tumour.
They took cells from these biopsy samples - taken before and after treatment from metastatic sites once the disease had progressed - and placed them inside a gel so they were free to form a 3D shape.
Researchers treated each organoid with the same drug doctors gave to the patient in the clinic.
It will also limit exposure to ineffective drugs and potentially toxic side-effects.
Personalised mini-tumours were able to predict in every case when a drug would be useless and were nearly as good at showing which drugs would be most effective, scientists said.
But if mini-tumours accurately reflect their "parent" cancer then they could be a powerful new tool for testing drugs and for understanding the biology of why cancers can resist treatment.
The trial was carried out on 71 patients with advanced bowel and throat cancers. We looked at tumours from patients with cancers of the digestive system, but the technique could be applied to a wide variety of cancer types.
"It could predict whether a cancer will be drug resistant before a person ever receives the treatment - which is especially important for those with advanced cancers where time is so precious. Having a better model for how tumours may respond to treatment could help accelerate drug discovery and even reduce reliance on animal experiments". "We know that cancers evolve over treatment and change between the primary and the secondaries", says Valeri.
Professor David Cunningham of the Royal Marsden and Institute of Cancer Research said: "This promising research moves us forward in the field of personalised medicine and should ultimately lead to smarter, kinder and more effective treatments for patients".
Given the replicas are based on a patient's DNA the consequent treatment will be completely personalised. But the approach could be used in the future to help choose treatment.