Endoscopic steam ablation of the duodenum shows promise in reducing blood sugar and insulin use in early trials

A novel endoscopic treatment that uses bursts of heated vapor to ablate the lining of the duodenum has produced encouraging results in early clinical studies, with some people with type 2 diabetes reducing medications and a small group stopping insulin injections. Researchers and clinicians say larger, longer trials are required before the therapy can be widely recommended.

Trials published and reported to date include a 2022 multicentre study in Europe and Brazil, published in Diabetes Research and Clinical Practice, which found that two years after duodenal mucosal resurfacing many patients had significantly lower blood-sugar levels and more than half reduced or did not need to increase their diabetes medications. A smaller trial reported in GIE, the journal of the American Society for Gastrointestinal Endoscopy, described 20 patients treated in Chile who were able to stop insulin injections nine months after a newer steam‑based variant of the procedure, although some remained on oral medication.

Investigators say the approach builds on observations from bariatric surgery. Surgeons noted decades ago that gastric bypass often produces rapid improvement in blood-glucose control that cannot be explained by weight loss alone. That led researchers to examine the duodenum — the first part of the small intestine — which appears to play a role in signaling the body’s metabolic responses when nutrients arrive from the stomach.

Clinicians have reported that people with type 2 diabetes frequently have a thickened duodenal mucosa, and researchers hypothesise that chronic high blood sugar and insulin exposure promote tissue changes that reduce the gut lining’s sensitivity to insulin-related signals. Deliberately resurfacing or ablating the duodenal lining allows it to regenerate, and investigators say the regenerated mucosa can restore more normal signalling and improve glycaemic control.

Early approaches used a balloon device to deliver hot liquid along a 15 cm section of duodenum. The newer method under study, described by investigators as radio-frequency vapour ablation, uses a catheter passed through an endoscope to release three-second bursts of steam that ablate a longer segment. In a trial that began in 2023 and is overseen by researchers at the Cleveland Clinic in London, clinicians treated about 60 cm of the duodenum to approximate the portion bypassed by gastric bypass surgery, said Dr. Rehan Haidry, a gastroenterologist and interventional endoscopist leading the work.

Dr. Haidry said the procedure takes roughly 30 minutes, uses liquid heated to about 90 degrees Celsius and that patients typically go home around two hours after treatment. He said the mucosal surface heals in about four weeks and, thus far in the trial, patients have not reported complications, pain or lasting discomfort. Preliminary data cited by investigators indicate an average HbA1c reduction from about 9.3% to 7.6% in treated patients; full results of the study have not yet been published.

Experts caution that the evidence base remains limited. The U.K. National Institute for Health and Care Excellence (NICE) reviewed existing studies of duodenal mucosal resurfacing and recommended that the procedure only be offered within formal research settings. The treatment is not currently available on the NHS, and clinicians involved in the work say regulatory approval and larger trials are needed to confirm efficacy, durability and safety.

Arin Saha, a consultant in general, upper gastrointestinal and bariatric surgery, said the findings are notable because they echo the metabolic effects seen after gastric bypass. "When people underwent gastric bypass surgery to help them lose weight, it can also hugely improve their type 2 diabetes," he said, noting the speed of those improvements suggested mechanisms beyond weight loss. "So researchers began looking at another explanation. We found that nutrients were only now being absorbed in the small bowel, which meant glucose levels were more normal afterwards."

About one in four of the estimated 5.8 million people in the United Kingdom diagnosed with type 2 diabetes relies on insulin injections to manage their condition, according to Diabetes UK. Investigators leading the steam‑ablation trials say they are seeking wider approval to run larger, controlled studies; Dr. Haidry has indicated plans to apply for permission to conduct a U.K. trial in the coming year.

Until larger randomised trials are completed and peer-reviewed results are published, clinicians and regulators say the procedure should remain under investigation. Ongoing studies aim to define which patients may benefit most, how long improvements last and what the long-term safety profile is for duodenal ablative treatments.