Parsing The Latest Evidence That Aspirin And Coffee Keeps Cancer Away

In In The News by Barbara Jacoby

By: Arlene Weintraub


Anyone looking for an excuse to get through the morning staff meeting by popping an aspirin and downing a lot of coffee has reason to cheer this week. The evidence in favor of such a routine flowed freely, first at the closely watched annual meeting of the American Association of Cancer Research (AACR), where Harvard scientists presented data showing that long-term aspirin use decreased the risk of gastrointestinal cancers. A day later Swedish researchers announced results of a study, published in an AACR journal, showing that breast cancer survivors who drank at least two cups of coffee a day greatly lowered their risk of recurrence. Other recently released studies suggest coffee prevents liver tumors, endometrial cancer and melanoma.

This is hardly the first time scientists have touted the potential life-extending attributes of two of the world’s favorite legal drugs—aspirin and caffeine. The benefits of coffee and aspirin have been well documented in cardiovascular disease. In fact, the data in favor of aspirin have prompted an estimated 40 million Americans to take one a day to prevent heart attacks. And Harvard researchers discovered that people who regularly drink coffee have a lower risk of dying from heart disease than those who don’t. They found the evidence so compelling that the website for the university’s school of public health declares coffee to be “one of the good, healthy beverage choices.”

But what about cancer? The evidence suggesting that aspirin and coffee may be “chemopreventative”—the term scientists use for anything that wards off cancer—is promising, but very early. And as is the case with any remedy being recommended for people who are otherwise healthy but looking for potential life-extending panaceas, extreme caution is warranted.

Let’s start with the latest aspirin study. The data came from 82,600 women and 47,651 men participating in two of the largest long-term health research projects: the Nurses’ Health Study and the Health Professionals Follow-up Study. The researchers found that over the 32-year period that was recorded, people who took two or more aspirins per week had a 25% lower risk of colorectal cancer and a 14% lower risk of gastroesophageal cancers. The reduction in risk was similar for men and women and was not affected by body mass index, smoking, or even one’s family history of cancer.

Aspirin may protect against other cancers, as well, past studies have sugested. In 2011, an analysis of eight separate studies comparing aspiring takers with non-aspirin takers found that people who regular took the drug for four years or more lowered their risk of dying from any cancer by 20%, according to the National Cancer Institute.

But there are caveats here. Most of the studies looking at aspirin and cancer risk have been observational rather than the gold-standard blinded, placebo-controlled trials, and many were not originally designed to measure the pill’s effect on the disease anyway. Even the Harvard researchers who presented the GI study at AACR earlier this week were quick to say more research is needed.

The question of whether aspirin should be widely prescribed for preventing either cancer or heart disease is complicated by the fact that it does have side effects, most notably a risk of GI bleeding. Last spring, the FDA reversed its previous stance on aspirin and cardiovascular disease, issuing a consumer alert urging healthy people to stay away. “FDA has concluded that the data do not support the use of aspirin as a preventive medication by people who have not had a heart attack, stroke or cardiovascular problems, a use that is called ‘primary prevention,’” the agency said.

As for coffee and cancer prevention, the data there is similarly unclear. The newest research does make a strong case for the beverage in women who have already had the disease. The study, led by scientists at Lund University in Sweden, showed that among 500 breast cancer survivors who had been treated with the drug tamoxifen, the risk of recurrence in patients who drank at least two cups of coffee a day was half that of those who didn’t. The researchers looked closely at caffeine and caffeic acid, and found that the substances impeded the growth and survival of cancer cells, especially when the coffee was combined with tamoxifen.

It’s promising, to be sure, especially in the context of all the recent studies of coffee consumption in healthy people. In January, the National Cancer Institute published a study showing that people who drank four cups of caffeinated coffee a day had a 20% lower risk of melanoma than non-coffee drinkers. A study published in February in an AACR journal found that women who drink four cups a day have a reduced risk of endometrial cancer. And in late March, U.K. researchers released an analysis of 34 studies conducted around the world and concluded that coffee consumption—even just one cup a day—reduces the risk of liver cancer.

Still, no one has quite figured out how caffeine prevents cancer growth and whether other substances in coffee like polyphenols are playing a role. Furthermore, drinking large amounts of coffee with popular additives like sugar and cream causes weight gain, which likely counteracts all the positive effects of the beverage.

The bottom line: Maintaining a daily coffee-and-aspirin routine probably isn’t harmful, but it’s way too early to say it will protect anyone from cancer.

Perhaps the most promising outcome of all this research is that it has encouraged scientists to dig deeper to try to figure out who might derive the most chemopreventative benefits from coffee and aspirin. Andrew Chan, who discussed the aspirin study at AACR this week, said his team has been looking for genetic biomarkers that might predict which subsets of the population would benefit from regular aspirin use. They recently found that people who regularly took aspirin or other non-steroidal anti-inflammatories (NSAIDs) and who had a particular genotype common among people of European descent, for example, had a significantly lower risk of developing colorectal cancer. As Chan, associate professor in the Department of Medicine at Harvard Medical School and director of the Gastroenterology Training Program at Massachusetts General Hospital, concluded in a statement released at AACR: “This strengthens the case for further research into defining subsets of the population that may obtain preferential benefit from regular aspirin use.”