White Cell Counts Predict Cancer Mortality

Researchers in Singapore found that inflammation, as measured by significantly high white blood cell (WBC) counts, appears to be an independent predictor of cancer mortality. Their finding was reported in the January 2006 issue of Archives of Internal Medicine.

The study population consisted of 3,189 Australian men and women (mean age 65.9), who were all free of cancer at the time of baseline examinations, which were conducted from the beginning of 1992 through 1993. The main study recorded all mortality due to cancer as of December 31, 2001. For the analysis, proportional hazards models were created that were adjusted for variables, including age, gender, body mass index, serum hematocrit levels, alcohol consumption, smoking, weekly aspirin use, and diabetes.

Dr. Anoop Shankar and colleagues at the National University of Singapore found that the multivariable risk of all cancer mortality was significantly higher in the highest quartile of WBC counts compared with the lowest quartile. In subgroup analyses, the relative risk of cancer mortality, when comparing the highest WBC counts with the lowest, was higher among participants with diabetes or fasting hypoglycemia than among those with normoglycemia. There was also evidence that aspirin, with its anti-inflammatory action, might have a protective effect for people at highest risk. The association between high WBC counts and cancer mortality was also present among people who had never smoked, suggesting that the observed association cannot be fully explained by smoking.

WBCs occur in large numbers in stromal tissue stages of tumors, and the quantity of inflammatory cells and their production by pro-inflammatory cytokines correlate with tumor stage production. Indirect evidence linking inflammation and cancer comes from data implicating some infectious agents in the etiology of specific cancers, the association of malignant disease and noninfectious inflammatory bowel disease, and the preventative effect of aspirin and other anti-inflammatory agents against cancer.

The authors noted several limitations of the study. Although they excluded people with cardiovascular disease at baseline, the association between WBC count and cancer mortality might be explained by time-dependent confounding comorbidities such as incident cardiovascular disease. Also, the results might be explained by undiagnosed cancer or subclinical disease at the baseline examination, and the findings may not be applicable to other age groups.






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