There is some new and very interesting news about aspirin that you probably won’t be hearing about from drug representatives or drug companies. No one but the consumer is going to benefit from these findings, and pharmacists are in a good position to disseminate this information.
In 1988, a large case-control study examined the use of several random medications and the occurrence of colorectal cancer. The study unexpectedly discovered that daily aspirin users had lower rates of colorectal cancer.1
That led to more studies over the subsequent 28 years. Just recently this information was examined by the US Preventative Services Task Force, a volunteer panel of national experts in prevention and evidence-based recommendations about clinical preventive services such as screenings, counseling services, and preventive medications. Their assessment and recommendations. published in JAMA Oncology, was titled “Aspirin for Cancer Prevention, One Step Closer.”2
Years of frequent aspirin use resulted in a reduction in the risk of developing both colorectal and esophageal cancers (19% and 15% respectively,) but had no impact on breast, advanced prostate, lung, or pancreatic cancers.
The task force said 8.0% of all GI tract cancers and10.8% of CRCs could have been prevented with regular aspirin use.2
The Task Force also said that protection against GI tract cancers occurs at relatively low doses of 0.5 to 1.5 standard tables a week. The people in the study used aspirin for various reasons such as cardioprotection, headache, arthritis, and musculoskeletal pain. The greatest risk reduction seen at increasing doses with longer durations of use and 6 years was suggested as the minimum duration of use needed to realize cancer-protective benefits.2
However, various studies have concluded other figures, with one study testing 600 mg/day PO to decrease the risk of developing hereditary colorectal cancer (ie, Lynch syndrome).3 More studies are needed to confirm the exact regimen needed for maximum results and specific risk reductions. It seems like the higher the dose taken and the more consistently the aspirin is taken, the sooner the cancer protection occurs.
But what about people who start taking aspirin after being diagnosed with cancer? The task force did not address that in their report, but past studies have noted that taking aspirin after diagnosis improved survival rate:
- Colon cancer: 50%
- Rectal cancer: 50%
- Esophageal: 50%
- Prostate cancer: 39%
In patients who started taking aspirin after being diagnosed with GI cancer, they lived twice as long as those who didn’t take aspirin. Specifically, after 5 years, survival was 75% among aspirin users, and 40% among nonaspirin users. The people in the study had esophageal, colon, and rectal cancers.3 That study was led by Dr. Martine Frouws. She and her colleagues speculated that aspirin prevents the circulating tumor cells from hiding inside the platelets. Therefore the immune system can attack and kill cancer more easily. 4
Things to note:
All the experts, including the task force, agree that going for a colonoscopy and having polyps removed will do way more to reduce the cancer occurrence than aspirin alone. Don’t use aspirin in place of having polyps removed. Use aspirin in addition to polyp removal. 1,2,3,4
Realize there is an investment period. People need to take aspirin for several years before the protection kicks in. With continuous use, the protection increases and maxes out at 5-6 years. Also, after stopping aspirin, the protection continues for a couple of years. 1,2,3,4
Bleeding is a known side effect. GI bleeds are a concern and brain hemorrhages are even more of a concern. They are painful and deadly. The experts agree that people 70 and older are at the highest risk of bleeding and being that aspirin does not start working for 3 years, they should just skip the aspirin altogether. The risk/benefit ratio is not in their favor.
The people who benefit the most are those in the 50-60 age group. They are the ones less likely to bleed, and they are young and/or healthy enough to put in the initial investment years needed before aspirin starts working.2
Perhaps healthy 60-70-year-olds could also take aspirin successfully, but it’s a judgment call in older people. A personal medical doctor would know best if the person is at high risk of a bleed and if aspirin would benefit them.
For people taking aspirin for stroke or heart attack prevention, I tell them to keep taking it just like the doctor prescribe because they will get the added bonus of GI cancer protection.
For those patients that have GI cancers or express a fear of developing GI cancers, tell them there is new hope in the form of aspirin and to talk to their GI doctor about it.
It’s up to the pharmacist to give good advice on aspirin use. Pharmacists are the consumer’s advocate. We always have been, and we always will be.
1. Kune GA, Kune S, Watson LF. Colorectal cancer risk, chronic illnesses, operations, and medications: case-control results from the Melbourne Colorectal Cancer Study. Cancer Res. 1988; 48:4399.
2. Vilar E, Maresso KC, Hawk ET, et al. Aspirin for Cancer Prevention: One Step Closer. JAMA Oncol. 2016; 2(6): 770-771.
3. Movahedi M, Bishop DT, Macrae F, et al. Obesity, Aspirin, and Risk of Colorectal Cancer in Carriers of Hereditary Colorectal Cancer: A Prospective Investigation in the CAPP2 Study [Published online ahead of print August 17, 2015]. J Clin Oncol. DOI: 10.1200/JCO.2014.58.9952.
4. European Cancer Congress (ECC) 2015: Abstract 2306. Presented September 28, 2015.