A new study provides hope that smarter timing of cancer treatments could improve cure rates.
The study's Principal Investigator, Dr Robert Noble , Senior Lecturer at the Department of Mathematics, City, St George's, University of London, sought to tackle a major problem in cancer care.
"Although tumours may at first shrink under therapy," he explains, "in many cases they eventually regrow. These relapses stem from a small number of cancer cells that have gained mutations making the cells resistant to the treatment."
The standard clinical approach is to wait and see if a tumour regrows before trying a different treatment. By this point, some tumour cells are likely to have gained mutations making them resistant to the second treatment, which then also fails.
Evolutionary theory suggests an alternative strategy. Instead of waiting, it might be better to switch to a second treatment while the tumour is still responding to the first one. This "kick it while it's down" approach is most appropriate when doctors know from experience that even the best option for a first treatment often fails due to resistance.
As Dr Noble explains in a podcast about the study , "Evolutionary approaches have been very successful in other contexts, such as combatting antibiotic resistance, or predicting what vaccines we should use in a particular flu season. There is every reason to suppose that similar approaches should work in tumours."
To test this hypothesis, Dr Noble and colleagues adapted mathematical methods more commonly used to understand how plants and animals evolve in response to environmental pressures, such as climate change.
In their study, the team concludes that their findings justify further experimental and clinical testing of this innovative evolutionary treatment strategy. Three small clinical trials are already underway in soft-tissue cancer, prostate cancer, and breast cancer. Further trials are in development.
"Our models predict that this new approach will generally outperform the standard of care," explains Dr Noble. "A sequence of two treatments, even if optimally timed, is likely to succeed only in relatively small tumours. But we have reason to hope that switching between three or more treatments, following the same principle, could eliminate larger tumours."
The full research article is published in the journal Genetics.
