Health:High Use Of Acetaminophen, Paracetamol, Linked To Blood Cancers

High use of acetominophen, a high-selling over-the-counter analgesic or nonsteroidal anti-inflammatory drug (NSAID) known in Europe as paracetamol and more commonly in the US as the brand Tylenol, is linked to an almost two-fold increased risk of certain blood cancers, although no such link was found for aspirin, nonaspirin NSAIDs, or ibuprofen, according to a large new study from the US, published online this week in the Journal of Clinical Oncology.

Although the researchers found that prolonged high use of acetominophen (4 or more times per week for four years or more) nearly doubled the risk of certain cancers involving the blood cells (such as lymphoma and myelodysplastic syndrome, or MDS), the risk is still small.
The study sheds no light, however, on mechanisms linking acetominophen to the development of blood cancers, if there are any.

The researchers found no link between high use acetominophen and another group of blood cancers called chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL).

Co-author Emily White, member of the Fred Hutchinson Cancer Research Center, and Professor of Epidemiology, School of Public Health at the University of Washington in Seattle, said the risk of a person aged 50 or over getting one of the blood cancers is about 1% in ten years.

"Our study suggests that if you use acetaminophen at least four times a week for at least four years, that would increase the risk to about 2%," said White, according to a Reuters news agency report.

White and colleagues wrote in their background information that previous studies disagree about whether NSAIDs are linked to "incident hematologic malignancies" or certain types of blood cancer, but tended to agree that there is an increased risk from acetaminophen (paracetamol).

So the researchers decided to take a closer look by examining data from a large prospective cohort study, the Vitamins and Lifestyle (VITAL) study.

From the VITAL study they got demographic, health and history data including daily use of analgesics of 64,839 men and women between 50 and 76 years of age who enrolled between 2000 and 2002. From the Surveillance, Epidemiology and End Results cancer registry they got data on blood cancer incidence in the group and found 577 incident hematologic malignancies through to December 2008.

They used statistical tools like Cox proportional hazards models to look for links between use of analgesics and blood cancers, and adjusted the results for the usual confounders such as age, gender, race/ethnicity, education, smoking, general health (self-rated), various types of pain, fatigue, and also family history of blood cancers such as leukemia/lymphoma.