What this means
CFS was most strongly associated with elevated risk of NHL (especially DLBCL and MZL) , kidney cancer , and pancreatic cancer , and there was an inverse association with breast cancer and cancers of the oral cavity and pharynx . We did not find an association between CFS and risk of brain tumors
The cause of chronic fatigue syndrome (CFS) is unknown but is thought to be associated with immune abnormalities or infection. Because cancer can arise from similar conditions, we examined associations between CFS and cancer in a population-based case-control study among the U.S. elderly.
Using linked SEER-Medicare registry data, we evaluated approximately1.2 million cancer cases and 100,000 controls (age 66 to 99 years, 1992 to 2005). CFS was identified in the period more than one year prior to selection using linked Medicare claims. We used unconditional logistic regression to estimate the odds ratios (ORs) comparing the CFS prevalence in cases and controls, adjusting for age, sex, and selection year. All statistical tests were two-sided.
CFS was present in 0.5% of cancer cases overall and 0.5% of controls. CFS was associated with an increased risk for non-Hodgkin lymphoma. Among NHL subtypes, CFS was associated with diffuse large B cell lymphoma, marginal zone lymphoma , and B-cell NHL not otherwise specified. CFS associations with NHL overall and NHL subtypes remained elevated after excluding patients with medical conditions related to CFS or NHL, such as, autoimmune conditions. CFS was also associated (although not after multiple comparison adjustment) with cancers of the pancreas , kidney , breast , and oral cavity and pharynx . Not with brain cancer.
Chronic immune activation or an infection associated with CFS may play a role in explaining the increased risk of NHL.