Aspirin lowers the rate of the accumulation of DNA mutations in abnormal cells in at least one pre-cancerous condition, a new study has claimed.

Carlo Maley, PhD, a member of the UCSF Helen Diller Family Comprehensive Cancer Center, said that aspirin and other non-steroidal anti-inflammatory drugs, which are commonly available and cost-effective medications, may exert cancer-preventing effects by lowering mutation rates.

Maley, working with gastroenterologist and geneticist Brian Reid, MD, PhD, of the Fred Hutchinson Cancer Research Center, analyzed biopsy samples from 13 patients with a pre-cancerous condition called Barrett`s esophagus who were tracked for six to 19 years.

In an "observational crossover" study design, some patients started out taking daily aspirin for several years, and then stopped, while others started taking aspirin for the first time during observation. The goal was to track the rate of mutations in tissues sampled at different times.

The researchers found that biopsies taken while patients were on an aspirin had on average accumulated new mutations about 10 times more slowly than biopsies obtained during years when patients were not taking aspirin.

Gender and ethnic distribution of study patients reflected the known demographics of esophageal cancer, which predominantly affects, white, middle-aged and elderly men, he said. Barrett`s esophagus only occasionally progresses to esophageal cancer.

Maley said that less inflammation may result in less production within pre-cancerous tissue of oxidants known to damage DNA, and may dampen growth-stimulating signaling.

For the duration of the study, the rate of accumulation of mutations measured in the biopsied tissue between time points was slow, even when patients were not taking aspirin, with the exception of one patient.

While mutations accumulated at a steady rate, the vast majority of mutations arose before the abnormal tissue was first detected in the clinic, the researchers concluded.

In the one patient who later went on to develop cancer, a population of cellular "clones" with a great number of mutations emerged shortly before he started taking aspirin.

The study has been published online in journal PLOS Genetics.