Rx Effects Could Be in Your Genes

NSAIDs may reduce colorectal cancer risk for those with certain genes but not others

(RxWiki News) Medications are not one-size-fits-all. They can affect people differently. Even simple NSAIDs like aspirin can have varying effects.

Those varying effects may also apply to how NSAIDs affect cancer risk. In a new study, the use of aspirin or other NSAIDs (nonsteroidal anti-inflammatory drugs) was shown to reduce the risk of colorectal cancer. This effect was related to certain genetic markers.

An editorial written by Richard C. Wender, MD, of the American Cancer Society in Atlanta, GA, reviewed the merits of the recent study.

"The study illustrates that interventions can be genetically targeted not just to direct treatment but also to direct preventive interventions," Dr. Wender wrote.

In other words, medications should be chosen with a person's genetic makeup in mind, Dr. Wender said.

NSAIDs can have negative effects like liver or stomach damage if taken for a long time. However, in the case of colorectal cancer, the use of NSAIDs as a preventive measure may provide an important benefit.

This study was conducted by a large team led by Hongmei Nan, MD, PhD, of the Richard M. Fairbanks School of Public Health and Bren Simon Cancer Center in Indianapolis, IN. The study looked at more than 8,600 patients with colorectal cancer and nearly the same number of patients who did not have colorectal cancer (the control group).

Genetic SNP (single nucleotide polymorphism) data was compared for those taking aspirin or NSAIDs and those not taking them. SNP data can be used to identify genetic similarities or differences between people.

Dr. Nan and team found that taking NSAIDs may reduce the risk of colorectal cancer. The study also discovered a location on a gene that was related to the reduction.

The authors speculated that this genetic location may be tied to a gene involved in tumor growth. Perhaps NSAIDs are helping or preventing the gene product from doing its job, they said.

Individuals can have differences in their sequences of DNA. At this particular genetic location, 96 percent of the population has a particular sequence. This study found that these people had a reduced cancer risk after NSAID use. However, for the 4 percent of the patients with a different sequence at this genetic location, NSAID use was shown to actually increase the risk of cancer.

The general conclusion is still that NSAIDs reduce colorectal cancer risk. Yet, for the subgroup with the abnormal gene sequence, taking preventive NSAIDs could be risky, Dr. Nan and team said.

Of course, without a genetic test, patients will not know which gene sequence they have. Patients should discuss NSAID use with a doctor.

The editorial by Dr. Wender concludes that, "In the not-too-distant future it will be possible to affordably and efficiently conduct genetic testing in healthy individuals to more accurately define benefits and risks of interventions intended to decrease risk of disease."

At that time, this information will be invaluable for selecting the most effective preventive care, Dr. Wender wrote.

The study and editorial were published in the March 17 issue of JAMA.

The study was funded by many sources, such as the National Cancer Institute of the National Institutes of Health.

Study author Dr. Baron held a use patent for aspirin as a colorectal chemopreventive agent. Dr. Zanke held a patent licensed to Arctic Dx. Dr. Chan received fees from Bayer Healthcare, Pozen and Pfizer.

Review Date: 
March 16, 2015