VA Research Currents

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Researchers with the Miami VA Healthcare System uncovered a mechanism by which some lung cancer cells resist the chemotherapy drug cisplatin. Researchers used cells in the lab, human blood samples, and mouse models to examine cancer cells at a molecular level. They found that cisplatin-resistant cells had higher activity of an enzyme called IDO1 and higher levels of reactive oxygen species, a chemical byproduct found in many cancers. Reactive oxygen species can cause cell breakdown. But IDO1 initiates the metabolization of kynurenine (an amino acid), which helps cancer cells cope with excessive reactive oxygen species. The researchers were able to use drugs to suppress IDO1 activity. This increased reactive oxygen species levels and in turn inhibited cancer cell growth. The results suggest that IDO1 inhibitors may be a suitable treatment in patients whose lung cancer resists cisplatin, say the researchers. (Molecular Cancer Research, January 2020)

Smoking is linked to a higher risk of dying from prostate cancer, found a VA San Diego Health Care System study. Researchers looked at more than 73,000 VA patients diagnosed with prostate cancer. The rate of death from prostate cancer was 5.2% for currents smokers within 10 years of their diagnosis. Past smokers had a 4.8% mortality rate, while those who never smoked had a rate of 4.5%. The study shows that prostate cancer diagnosis may be an important opportunity to discuss quitting smoking. (Prostate Cancer and Prostate Diseases, Oct. 17, 2019)

 Many demographic disparities in colorectal cancer screening seen in the general population do not exist in VA. That is the main finding from a study by VA Greater Los Angeles Healthcare System researchers. In the database study, the overall colorectal screening rate for VA patients ages 50 to 75 was 82%. Rates  were lowest among American Indians/Alaska Natives, those with a history of serious mental illness or substance abuse, and those with the lowest socioeconomic status. However, screening rates even for these groups topped 75%. Older age, Hispanic ethnicity, black race, Asian race, and co-occurring illnesses were all predictors of higher screening rates. Although screening disparities are relatively rare in VA, groups with lower rates might benefit from targeted efforts to increase uptake, say the researchers. (Medical Care, Aug. 14, 2019)

 Low-value prostate cancer screening remains prevalent in the VA health system, found a VA Pittsburgh Healthcare System study. Prior research has shown that screening for prostate-specific antigen—a biomarker of prostate cancer in the blood—does not improve survival of men 70 and older. The screening can lead to anxiety about diagnosis and overly aggressive treatment. Out of more than 200,000 male Veterans 75 or older, 18% underwent prostate-specific antigen screening in the study year. The rates of screening for this age group of men varied across VA medical centers, ranging from 3% to 38%. The results show that more efforts are needed to reduce low-value tests in VA, say the researchers. (Journal of the American Geriatrics Society, July 5, 2019)