South Korea Study: Diabetes Linked to Higher Death Risk in Rare Lymphoma

A study from South Korea has uncovered important findings about a rare but serious cancer called MALT lymphoma — and diabetes plays a surprisingly significant role in patient outcomes. For the estimated 38 million Americans living with diabetes, these findings add another reason to prioritize blood sugar management as part of overall cancer risk awareness.

What Is MALT Lymphoma?

Extranodal marginal zone B-cell lymphoma, commonly called MALT lymphoma, is a slow-growing cancer that develops in mucous membrane tissues — most often in the stomach, but also in the lungs, eyes, and thyroid. It accounts for roughly 7–8% of all non-Hodgkin lymphomas diagnosed in the United States each year. While it is considered one of the more treatable lymphomas, survival varies widely depending on patient factors.

What the South Korean Researchers Found

Researchers at Kyungpook National University in Daegu, South Korea analyzed data from 11,730 MALT lymphoma patients captured in the South Korean National Cancer Registry — one of the largest and most comprehensive cancer databases in the world. Using Kaplan-Meier survival analysis and multivariable statistical modeling, they identified key factors that increased or decreased the risk of dying from this cancer.

Factors that significantly raised mortality risk included:

• Being male (hazard ratio 2.00 — meaning men were twice as likely to die)
• Advanced age, especially 80 years and older (hazard ratio 33.92)
• Metastatic (spread) disease (hazard ratio 2.77)
• Diabetes, cardiovascular disease, and cerebrovascular disease

Factors that significantly reduced mortality risk included:

• Higher household income (hazard ratio 0.63)
• Regular physical activity (hazard ratio 0.60)
• Higher body mass index within a healthy range (hazard ratio 0.95 per unit)

Women made up 54.6% of cases and demonstrated meaningfully better survival outcomes than men across all age groups studied. The comorbidity effects — including diabetes — were most pronounced in patients aged 60 to 79.

What This Means for US Guidelines

The American Diabetes Association (ADA) recommends maintaining fasting blood glucose below 100 mg/dL (5.6 mmol/L) for healthy adults, and below 130 mg/dL (7.2 mmol/L) before meals for people managing diabetes. Current US cancer care guidelines already acknowledge diabetes as a comorbidity that complicates cancer treatment, but this large-scale Korean national registry data provides some of the strongest population-level evidence yet that diabetes directly worsens lymphoma survival odds — reinforcing why comprehensive diabetes management matters far beyond blood sugar control alone.

Why This Matters for US Patients

The United States and South Korea share remarkably similar trends in rising type 2 diabetes rates, aging populations, and increasing lymphoma diagnoses. South Korea's national cancer registry system — which tracks nearly all cancer cases nationwide — provides a statistical power that is difficult to achieve in the fragmented US healthcare system. That makes this data particularly credible and applicable to American patients.

If you have diabetes and are also navigating a MALT lymphoma diagnosis, this research strongly suggests that actively managing your blood sugar, staying physically active, and working with your care team to address cardiovascular risk factors could meaningfully improve your prognosis. Physical activity alone showed a 40% reduction in mortality risk in this study.

Talk to your endocrinologist and oncologist together. Integrated care — where your diabetes management is coordinated with your cancer treatment — is not just beneficial; this research suggests it may be life-saving.

Study Citation

Nam, Jo. "Prognostic outcome of extranodal marginal zone B-cell lymphoma: a nationwide cohort." Scientific Reports (2025). DOI: 10.1038/s41598-025-32259-5. PMID: 41402369.