Researchers at Edinburgh University said a review of the technology suggests new approaches would make it easier to identify the most promising new drugs to take forward for patient testing.
Recent advances mean scientists can check how experimental drugs are working inside living cells and in real time.
Using automated microscopes to track fluorescent dyes, researchers can rapidly test thousands of drugs in different cancer cell types.
This technique - known as phenotypic drug discovery - monitors the effect of a trial drug on the disease as a whole rather than its impact on an individual target protein, which has been the approach until now.
Applying it early in the drug discovery process could improve the success rate of new medicines by helping to rule out drugs that are unlikely to work.
Writing in the journal Nature Reviews Cancer, they argue it will help to better predict how a drug will work in real life - not just in the test tube.
Author, Dr Neil Carragher said: "The drug discovery process is hugely expensive and inefficient. In Edinburgh we are leading the way in using biological imaging to streamline the process. allowing us to better select drug candidates with the lowest risk of side effects and the best chances of success in treating patients."