A new treatment for breast cancer has completely eradicated tumours in just 11 days, UK doctors have shown.
They said the “surprise” findings, reported at the European Breast Cancer Conference, could mean some women no longer need chemotherapy.
The drugs, tested on 257 women, target a specific weakness found in one-in-ten breast cancers.
Experts said the findings were a “stepping stone” to tailored cancer care.
The doctors leading the trial had not expected or even intended to achieve such striking results.
They were investigating how drugs changed cancers in the short window between a tumour being diagnosed and the operation to remove it.
But by the time surgeons came to operate, there was no sign of cancer in some patients.
Prof Judith Bliss, from the Institute of Cancer Research in London, said the impact was “dramatic”.