Cancer remains our number two killer, just behind heart disease. Far too many people die each year from cancer of the breast, prostate, colon and lung. What can be done to prevent tumors or keep cancer from spreading?
What if an inexpensive aspirin tablet could not only prevent many cancers but also reduce the risk of metastases after treatment? A new study suggests that aspirin may indeed help keep cancer from spreading. A review of the world’s research suggests that aspirin lowers the likelihood that there will be metastatic spread and death from colorectal, breast and prostate cancer (PLOS ONE, April 20, 2016). Although data remain scanty, there is a hint that aspirin might also improve survival against lung and esophageal cancers as well as lymphatic leukemia.
The Greatest Challenge of Treatment Is to Keep Cancer from Spreading:
The greatest fear of cancer survivors is that one day their cancer will return. For reasons that remain mysterious, sometimes seemingly successful treatments can eventually fail. That is to say, breast, prostate and many other cancers can recur 10 or 15 years after surgery, radiation or chemotherapy.
The goal of most current cancer treatment is prolonged survival, turning a malignancy into a chronic condition after the acute emergency has been overcome. Can surgery, chemo or radiation keep cancer from spreading and/or produce long-lasting survival? Sometimes they do, but not always.
Even the latest immunotherapy agents can’t guarantee a cure. Some of the hottest new drugs offer median “progression free-survival” of only several months. Translating from medicalese, that means about half the patients getting the treatment live longer than three or four months. In some cases, that is significantly longer than they would live without treatment. But it also means that about half the patients get less than three or four months.
A TV commercial for Opdivo (nivolumab) promotes the idea that this immunotherapy drug will provide some lung cancer patients “A Chance to Live Longer.” The message is that by taking this very expensive medication patients “significantly increased the chance of living longer versus chemotherapy.” What the commercial does not say, though, is that the average improvement in lifespan on Opdivo was about three months more than with chemo alone. The cost: roughly $14,000 per month. Side effects can be severe.
How Long Have We Known that Aspirin Could Keep Cancer from Spreading?
Although the latest overview of aspirin research was published in PLOS ONE on April 20, 2016, researchers have long been suggesting that this old and inexpensive drug might have anti-cancer activity. In August, 1977, researchers writing in the Journal of the National Medical Association offered the following hypothesis that aspirin might keep cancer from spreading:
“Aspirin for Reducing Cancer Metastases?
“Distant metastases are the principal cause of death from cancer. Many animal experiments in the last 25 years have shown consistently that distant metastases can be significantly reduced by anticoagulants and fibrinolytic agents. Since aspirin inhibits platelet function and increases fibrinolytic activity in humans, it may be effective in preventing metastases in cancer patients. It is suggested that aspirin be offered as an option to cancer patients who are at risk for distant metastases.”
Oncologists are often quick to adopt the latest advances in cancer treatment. We understand their desire to extend the lives of their patients, even when the cost of the new drugs is prohibitive.
What we do not understand, however, is their reluctance to consider aspirin as a potential addition to traditional treatment. We find it intriguing that 39 years after researchers suggested “aspirin be offered as an option for cancer patients who are at risk for distant metastases,” a surprisingly similar message is offered by the authors of the April 20, 2016, PLOS ONE article in their conclusions:
“It appears likely that low-dose aspirin has a beneficial role as an adjunct treatment of cancer. Reductions in mortality are shown in colon cancer, probably in prostate cancer and possibly in breast and individual studies of several other cancers also suggest benefit.”
The researchers analyzed 42 observational studies and five randomized controlled trials and called for more research:
“Nevertheless, despite the need for randomised trials, we believe the evidence of benefit from aspirin is sufficiently persuasive that physicians should engage with patients in a presentation and discussion of aspirin as an additional treatment. Furthermore, we hold that patients should be given this evidence within the context of a healthy lifestyle, they should be allowed to make their own decision about aspirin therapy, and should then be supported in whatever decision they make.”
Preventing Cancer with Aspirin:
So far, we’ve been discussing the possibility that taking aspirin could keep cancer from spreading. What about preventing cancer in the first place? There is a substantial amount of evidence that regular aspirin use can help people from developing colorectal cancer in the first place. A review in JAMA Oncology (March 3, 2016) notes that people taking aspirin were 19 percent less likely to develop this kind of malignancy. The authors also note:
“Secondary analysis of randomized clinical trials (RCTs) of aspirin for the prevention of cardiovascular disease (CVD) supports a potential role of aspirin in reducing overall cancer incidence. In 6 trials of daily low-dose aspirin therapy (≥75 mg), aspirin use was associated with a relative risk (RR) of 0.76 (95% CI, 0.66-0.88) for overall cancer after 3 years, with the benefit increasing with longer duration.”
That means a 24 percent lower risk of cancer in general. To learn more about how aspirin might affect the risk of other cancers here is a link.
What About Aspirin Side Effects?
Whenever aspirin’s potential benefits are mentioned, there are some health professionals who downplay the good news and focus on the dangers. There is no doubt that aspirin can pose risks: stomach irritation, bleeding or perforated ulcers. The same risk holds for all NSAIDs, including diclofenac, ibuprofen and naproxen. Bleeding ulcers can be deadly.
The PLOS ONE authors offer intriguing insights about the harms:
“Shortly after aspirin taking commences the risk of a gastrointestinal (GI) bleed is high but the risk falls rapidly thereafter, and in short-term trials the additional risk of a bleed from low-dose aspirin amounts to perhaps one or perhaps two patients in every 1,000 on low-dose aspirin. After about three years of aspirin taking however, there appears to be no evidence of any excess GI bleeds attributable to the drug…
“The most serious bleeds are those that lead to death, and despite frequent references to fatal bleeds attributed to aspirin, there appears to be no valid evidence that deaths from GI bleeds are increased by low-dose aspirin…
“Cerebral bleeds attributable to aspirin are rare, about one or two per 10,000 patient-years. Hypertension is the major factor in such bleeds and in a randomised trial of aspirin based upon patients with hypertensive disease all of whom were adequately treated with anti-hypertensive drugs, there was the same number of cerebral bleeds in ten thousand patients on aspirin (19 patients) as in ten thousand on placebo (20 patients).”
Regardless of the risk, no one should ever start taking aspirin on a regular basis without medical supervision. Aspirin can interact with many other drugs and requires oversight.