Christopher M. Booth

For colon cancer survivors, a prescribed, supported exercise programme is now an evidence-based treatment with a survival benefit comparable to many drugs. Health systems will need to fund exercise consultants as they fund chemotherapy. The trial does not tell us whether unsupervised advice achieves the same.

A drug that shrinks tumours or delays progression on scans has not necessarily been shown to help patients live longer or better. Patients and clinicians should ask what the endpoint was; regulators should insist on timely confirmatory trials; and trialists should validate surrogates before relying on them.