For patients navigating both stomach cancer and type 2 diabetes, the surgical method used to reconnect the digestive tract after partial stomach removal may play a pivotal role in managing post-operative blood sugar levels.
Korea University Anam Hospital announced on July 23 interim findings from the STARDOM study—a prospective, multicenter clinical trial investigating blood sugar improvements across different intestinal reconstruction methods following gastrectomy. The research team, led by Professor Park Sung-soo and Professor Kwon Young-geun of the Department of Gastrointestinal Surgery, presented their six-month interim analysis at the American Society of Clinical Oncology (ASCO) Breakthrough meeting in Singapore.
The trial enrolled 60 patients with early-stage lower stomach cancer and type 2 diabetes undergoing distal gastrectomy—a surgical procedure that removes the lower portion of the stomach. When part of the stomach is removed, surgeons must perform an intestinal reconstruction to restore the digestive pathway. Patients were randomly assigned to one of three reconstruction techniques: traditional Billroth II reconstruction; standard Roux-en-Y reconstruction; or long small-intestine bypass Roux-en-Y reconstruction, which extends the segment of the small intestine bypassed by food.
Long bypass method yields significantly higher target blood sugar rates
Six months post-surgery, complete follow-up outcomes were analyzed for 44 patients: 14 in the Billroth II group, 13 in the standard Roux-en-Y group, and 17 in the long small-intestine bypass Roux-en-Y group.
The proportion of patients reaching the target glycated hemoglobin (HbA1c) level below 6.5% differed markedly among the three approaches. In the long small-intestine bypass Roux-en-Y group, 70.6% of patients achieved target blood sugar control—approximately 2.5 times higher than the 28.6% target attainment rate observed in the Billroth II group. Meanwhile, 53.8% of patients in the standard Roux-en-Y group reached the target. Average HbA1c levels at six months stood at 6.17% for the long bypass group, 6.55% for standard Roux-en-Y, and 6.50% for Billroth II.
Crucially, all three groups demonstrated comparable levels of weight loss and post-operative complication rates, indicating that the superior glycemic control in the long bypass group cannot be attributed to weight reduction alone.
"This study is significant because it demonstrates that post-operative blood sugar changes are difficult to explain by weight loss alone," said Professor Kwon Young-geun. "We plan to conduct a more precise analysis of metabolic changes by reconstruction method to build clinical evidence that can improve long-term diabetes management and metabolic health after cancer treatment."
Lower blood sugar does not equal complete diabetes remission
Researchers cautioned that the interim six-month findings reflect target HbA1c attainment rates and should not be interpreted as full diabetes remission or a cure. The trial's primary endpoint is defined as maintaining an HbA1c level below 6.5% without the aid of diabetes medications 12 months after surgery.
"This prospective clinical trial provides the final stage of evidence needed to apply 'cancer metabolic surgery'—a concept our team has pursued since 2013—to real-world clinical practice," said Professor Park Sung-soo. "Confirming that the degree of diabetes improvement varies by reconstruction method is highly meaningful, and we anticipate that the final 12-month analysis will help reshape stomach cancer treatment guidelines for patients with co-existing diabetes."
The authors noted that long small-intestine bypass reconstruction may not be suitable for every stomach cancer patient with diabetes, as surgical choices must account for tumor location, resection extent, nutritional status, and complication risks. However, the findings offer patients and clinicians a crucial evidence-based foundation when discussing surgical strategies that address both cancer removal and long-term metabolic health.
