Deaths from esophageal cancer were reduced by 60% in the aspirin-takers (who took the drug for at least five years), compared with the placebo group. Lung cancer deaths were reduced by 30%, colorectal cancer deaths were cut by 40% and prostate cancer deaths were lowered by 10%, compared with the patients who got placebo. What’s more, the longer people took aspirin, the greater their reduction in cancer risk. . . . those cancer reduction numbers represent a more profound effect than the one aspirin has on heart disease and stroke, which are the main reasons lots of people now take a low-dose aspirin regimen.
This is even more amazing when one considers that this is the opposite of what one would expect knowing only that the asprin was effective in reducing cardiovascular disease. Cardiovascular diseases are major killers late in life, at essentially the same part of the life cycle where cancer is the other biggest cause of death. Naiively, one would expect that people who were at a greatly reduced risk of death from heart attacks and strokes would be more likely as a result to die instead from the other biggest killer for people in that age range, which is cancer. In other words, you'd think that people who otherwise would have died of a stroke would have lived long enough to die of cancer instead.
But, this isn't what happened. Asprin dramatically reduces incidence of both of the biggest categories of diseases that killed middle aged and older people. And, you can buy it over the counter for peanuts, while you have to pay large sums of money for brand name drugs that don't deliver results nearly as impressive.
According to the study author, "the “sensible time” to start taking aspirin “would be before the risk of cancer starts to rise, at about 45.” He says prophylactic aspirin is “worth thinking about” for people with a family history of early cancers."
The studies involved 25,000 people over 20 years, and produced very intense effects. The mechanism appears to be a connection between chronic inflamation which is reduced by asprin and cancer risk, but honestly, it doesn't really matter if the actually mechanism is that asprin attracts cancer cell eating aliens who abduct you at night and remove it without you knowing about it. What matters is that a cheap, simple preventative measure is incredibly effective at reducing many of the main causes of death in older adults.