Controlling blood sugar may improve outcomes for diabetic lung cancer patients

The benefits of controlling a patient’s diabetes are well established. But the consequences of unregulated diabetes on survival rates for lung cancer have been widely debated. 

Now, a retrospective study of people with lung cancer who are diabetic shows they can survive longer if their blood sugar levels are carefully controlled. This holds true across broad socioeconomic and demographic populations that include obese and morbidly obese patients. 

The study examined de-identified health records of 32,642 lung cancer patients from the University of Texas MD Anderson Cancer Center (MDACC) and 17,768 patients from the Louisiana Tumor Registry and Ochsner Health and University Medical Center New Orleans. It drew an association between glycemic (blood sugar) control and improved survival rates among lung cancer patients who also had diabetes. The findings reveal statistically significantly improved overall survival in lung cancer patients having controlled versus uncontrolled blood sugar levels. 

"These findings make a strong case for optimal glycemic control in lung cancer management," wrote the research team led by Xi Liu, Ph.D. of the Frederick National Laboratory for Cancer Research. Results were published in JNCI Cancer Spectrum. 

"These observations provide a rationale for a prospective and randomized trial in lung cancer cases where the survival consequences of improved control of glycemia are explored," the researchers reported. Such a study could demonstrate whether or not blood sugar levels actually cause the improved survival rates in lung cancers.  

The patient population for the study was diverse. The MDACC cohort received care from a National Cancer Institute-designated comprehensive cancer center, while the Louisiana patients included many who lacked health insurance and suffered health disparities.   

The observed health benefit of controlling blood sugar in diabetic lung cancer patients applied regardless of sex, age, smoking status, stage, race, socioeconomic group, body mass index, and histopathology. 

African American/Black, Caucasian/Non-Hispanic White, and Hispanic lung cancer patients with well-controlled glycemia lived longer than did uncontrolled patients. But the health records had too few numbers of American Indian/Alaskan Native, Asian, and Native Hawaiian/Pacific Islanders to draw statistical conclusions for those groups. 

Nonsmokers and current and former smokers all survived longer when their blood sugar levels were well-controlled. Survival rates were substantially improved in lung cancer patients who were impoverished. 

Liu’s laboratory is co-directed by Ethan Dmitrovsky, M.D., President of Leidos Biomedical Research and Director of the Frederick National Laboratory. This collaborative team has been exploring the relationship between metabolic processes and lung cancer. In an earlier association study, they found nonsteroidal anti-inflammatory drugs (NSAIDs) – common drugs for controlling pain and inflammation, such as aspirin and ibuprofen – improved overall lung cancer survival by a statistically significant margin. The study recommended clinical trials to explore cause-and-effect. 

“Because diabetes is a metabolic syndrome that needs management, we wanted to see whether that management would affect lung cancer survival,” Liu said. “We hope to raise awareness among oncologists to pay more attention to diabetes management. Diabetes management is usually done by primary care doctors. We hope this will raise overall awareness.” 

Association studies can provide a rationale for randomized clinical trials in which cause-and-effect can be determined, and that can lead to practice-changing treatments and improved patient outcomes.