Nonaspirin NSAIDs increase renal cell cancer risk
MedWire News: Nonsteroidal anti-inflammatory drugs (NSAIDs), excluding aspirin, are associated with an elevated risk for renal cell cancer, reports research published in the Archives of Internal Medicine.
This finding comes from data from two large prospective cohort studies; the first enrolled 121,700 female nurses aged 30 to 55 years in 1976, and the second involved 51,529 male health professionals aged 40 to 75 years in 1986.
NSAIDs are known to help protect against cardiovascular disease and colorectal cancer, by reducing inflammation, inhibiting cyclo-oxygenase 2 and cell proliferation, and inducing apoptosis in cancer cells. However, results from several case-control studies and small prospective studies suggest that this is not the case for renal cell cancer (RCC).
Eunyoung Cho (Harvard University, Boston, USA) and colleagues examined the impact of these drugs on RCC, which accounts for 85% of all kidney cancer cases.
Regular use of aspirin, nonaspirin NSAIDs, and acetaminophen was assessed using a series of follow-up questionnaires in both cohorts. Information was collected on dose and reasons for use. Regular use was defined as taking one type of analgesic two or more times a week.
Inquiries about occurrence of cancer were included on each questionnaire and physicians reviewed the medical records of patients reporting kidney cancer. RCC was defined according to the World Health Organization classification.
Follow-up over 16 years identified 153 cases of RCC in 77,525 women, and the 20-year follow-up in men identified 180 cases from a total of 49,403 patients. In these large studies, nonaspirin NSAIDs were associated with a significantly increased risk for RCC, especially if they were taken for long periods. There was a dose-response relationship between duration of regular use of nonaspirin NSAIDs and RCC risk; the relative risks compared with nonregular use were 0.81 for less than 4 years use, 1.36 for 4 to 10 years, and 2.92 for 10 years or longer.
There was no association between RCC risk and aspirin or acetaminophen use.
The researchers say that this goes against results from past epidemiological studies on aspirin and acetaminophen, which have linked both to an increased risk of RCC.
"A potential explanation for the discrepancy in findings for aspirin and acetaminophen in our studies versus previous studies may be that most of the previous studies were retrospective, which might be susceptible to biased recall of use of analgesics and reverse causation (ie, individuals might have taken analgesics to treat symptoms related to RCC)," they write.
Noting that fewer studies exist on nonaspirin NSAIDs compared with aspirin and acetaminophen, Cho et al conclude that "risks and benefits should be considered in deciding whether to use analgesics; if our findings are confirmed, an increased risk of RCC should also be considered."
By Chloe McIvor