Five-week therapy helps four in five rectal cancer patients keep their rectum

Four in five patients kept their rectum. That is the central result from STAR-TREC, an international clinical trial coordinated by the Cancer Research UK Clinical Trials Unit at the University of Birmingham, with researchers from UCL and the University of Leeds. After 12 months, patients with earlier-stage rectal cancer who received five weeks of chemoradiotherapy were less likely to need radical surgery than those given five days of radiotherapy.

The trial enrolled more than 500 patients in the United Kingdom, the Netherlands, Denmark, Belgium and Sweden. One group received the current standard treatment: surgery removing the whole rectum. Two other groups tested organ-preserving strategies, using radiotherapy first and reserving major surgery for tumors that did not shrink enough.

The approach is response-led. If small areas of cancer persisted, surgeons removed them through a smaller, local operation that preserves the rectum. Researchers say the more targeted treatment produced a relatively low level of severe short-term side effects, though the trial report does not establish that avoiding radical surgery is safe over the long term.

The stakes are practical rather than abstract. Around 4,100 people in England are diagnosed with early-stage rectal cancer each year, and radical treatment can leave patients with bowel dysfunction, sexual and urinary problems or a permanent colostomy bag. For patients whose tumors respond, the trial points to a route that may avoid those consequences while still treating the cancer.

And so what, concretely? The five-week regimen could become an additional treatment option for eligible patients if the results hold up. That is not settled yet: researchers are following participants for the next three years to see whether cancer is more likely to return without radical surgery and whether survival differs. The findings are published in The Lancet Oncology; the longer-term evidence will determine how far the approach can move into routine care.