Aspirin: A Blockbuster Therapy for Breast Cancer Survivors?

Aspirin’s anti-inflammatory effects appear to cut the risk of a breast cancer recurrence.

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"Has it spread?" "Am I going to die?" These are the heart-sinking questions that invariably run through the minds of women who have been told that they have breast cancer. They courageously take on surgery, long and arduous chemotherapy, and radiation treatments, hoping to fend off the fate of the 40,000 women whose breast cancer will take a deadly turn this year, reappearing and relentlessly spreading throughout their body.

The report just released from the Nurses' Health Study, in a rather understated way, offers 2 million American women who have had breast cancer some vital and actionable information. Taking a single aspirin tablet—a baby aspirin or one adult pill—every other day can be lifesaving. (In fact, were these aspirin tablets a hot new biotech drug, we would be popping champagne right now.) The long-term, low-dose aspirin program was initiated a year or more after the cancer diagnosis as an add-on to treatment, not as a substitute for it, to control the fate of tumor cells silently left behind. For some women, this post-treatment phase is one in which the cancer has gone underground and not entirely disappeared. It can lead to unexpected recurrence with the cancer spreading sometimes 10 to 20 years after diagnosis. Scientists seem to have stumbled upon an easy way to cut that risk.

The study followed 4,164 breast cancer survivors over a period from 1976 to 2006, assessing in detail their use of aspirin. The women studied initially presented with tumors ranging from small early invasive cancers confined to the breast to more advanced ones that had spread into surrounding lymph nodes. Over more than three decades of follow-up, 400 women had a cancer recurrence with distant tumor spread, which had killed 341 of them by the time the study ended.

The power to spread is the power to kill, and what aspirin seems to be doing is interfering with that process. It was by coincidence, not by design, that almost half of the medically smart women in the NHS were diligently taking aspirin. The surprise finding: Those who made aspirin a regular habit, consuming low doses two to five times a week (mostly to help their hearts), were 71 percent less likely to have a deadly recurrence of their breast cancer compared to those who were taking little or no aspirin.

A similar trend was found with regular use of other nonsteroidal anti-inflammatory drugs, but the numbers of users over the study time were insufficient for statistical certainty. The findings are nonetheless provocative, reinforcing the notion that the beneficial effects of aspirin on cancer survival may rest with its anti-inflammatory effects. We do know that deadly cancers hijack the inflammatory system to spread and invade distant organs, but we understand woefully little about the process for any given cancer and how to treat it. Figuring out the underlying secrets of this aspirin effect will open up neglected fields of cancer study: why and how cancers ultimately claim lives.

But what does this mean for breast cancer survivors now? A lot. Aspirin has proved itself as a safe, effective, and inexpensive preventive medicine that cuts the risk for colon and prostate cancer and for years has served as a way to prevent heart disease and stroke. Here the Nurses' Health Study shows, for the first time, that breast cancer survivors can substantially lower their risk of a recurrent, deadly tangle with this cancer in the future.

The big caveat is that the study was "observational" and not a blue-chip randomized trial, making many hesitant to crow about its results. I'd say crow nonetheless. The heart disease and stroke benefits are indication enough for any woman to start a low-dose aspirin program—with her doctor's oversight. For the patients of tomorrow, a randomized study can be started of the group of anti-inflammatory agents, which will take way more than a decade to carry out. For the 2 million breast cancer survivors of today, the NHS is compelling enough to ask your doctor, "Why wait?"