Researchers used cells taken from 71 patients with colon and rectal cancer and grew miniature 3-D tumors that were specific to each person.

What they did: Scientists tested 55 different drugs—some currently available and others experimental—on all the mini-tumors (also known as “organoids”).

The findings: The technique was better at predicting whether a drug would work against a patient’s cancer than simply sequencing a tumor’s DNA. The organoids were 88 percent successful at forecasting whether a patient would respond well to a given drug and were always correct when it came to predicting that a therapy would not be effective, according to results published in the journal Science.

Why it matters: Nicola Valeri, one of the study authors and an investigator at the Institute of Cancer Research in London, says patient-derived organoids can be used to craft ideal individualized treatment plans. He says they would be particularly useful in sorting cancer patients into the right clinical trials, making it more likely that a drug would succeed.