It has long been suggested that regular use of aspirin might lower the risk of developing cancer. For one cancer—colorectal—the idea is clearly supported by research evidence. For others like melanoma, ovarian cancer, pancreatic cancer, and a kind of liver cancer called hepatocellular carcinoma, the evidence is mixed. A recent paper with Huntsman Cancer Institute ties adds to the evidence that regular aspirin use decreases the risk of ovarian cancer.

Mollie Barnard is a postdoctoral fellow at Huntsman Cancer Institute. This is a stage of education when someone who holds a doctoral degree receives additional mentoring and training before they begin running their own research as a primary investigator. She led the work into aspirin and ovarian cancer while finishing her doctoral schooling at the Harvard School of Public Health.

The Data

Barnard's paper analyzed data from a famous study called the Nurses' Health Study, which collected data on a great deal of information from over 205,000 women about health habits, diet, exercise, and medication use (among other things) over a period of more than 25 years in an effort to understand the factors that contribute to development of disease. Hundreds of papers have been published from the data collected in the study, with very diverse findings:

• Smoking increases the risk of heart disease. That risk falls within 2-4 years of quitting smoking.
• Women who currently use oral contraceptives are at increased risk of developing breast cancer and coronary heart disease. That risk disappears once use is discontinued.
• Eating more green leafy vegetables reduces the risk of cognitive impairment. Eating a lot of red and processed meat increases the risk of colon cancer.

When Barnard analyzed the data on aspirin use and ovarian cancer from the Nurses' Health Study, she saw that taking 100mg of aspirin regularly (this is slightly more than the 81mg of baby aspirin) was associated with lower risk of developing the cancer. Taking the regular dose of aspirin regularly—325mg—wasn't.

Barnard says, “Our research suggests that low-dose aspirin use is associated with a lower risk of ovarian cancer, but more research is needed to confirm that finding [...] It is important for women to discuss the risks and benefits of extended aspirin use with their doctors. If future research confirms our findings, the benefits of low-dose aspirin use may expand to include ovarian cancer prevention.”

Research in the Pipeline

Currently, colorectal cancer is the only type of cancer for which medical professionals recommend vulnerable patients start taking aspirin regularly, according to the National Cancer Institute. Evidence is building that it may help for other types of cancer, but that evidence is mostly from the type of studies that simply observe people's behavior rather than directly changing it. This type of study is called observational research, and doesn't provide evidence as strong as that from clinical trials which do directly change people's behavior.

According to the National Cancer Institute, there are currently 3 major clinical trials underway into aspirin and cancer risk. They say the trials will be critical in the medical world's decision as to whether aspirin actually works to reduce the risk of cancers other than colorectal, and whether the risks that come from long-term use of the drug—a blood thinner—are worth it. Those studies are expected to be completed in January 2019, October 2026, and September 2027.

Sources

Add-Aspirin: A Trial Assessing the Effects of Aspirin on Disease Recurrence and Survival After Primary Therapy in Common Non Metastatic Solid Tumours - Full Text View. (2017, November 22). Retrieved from https://clinicaltrials.gov/ct2/show/study/NCT02804815?show_locs=Y#locn 

Aspirin in Reducing Events in the Elderly - Full Text View. (2018, July 11). Retrieved from https://clinicaltrials.gov/ct2/show/NCT01038583 

Aspirin to Reduce Cancer Risk. (2017, February 23). Retrieved from https://www.cancer.gov/about-cancer/causes-prevention/research/aspirin-cancer-risk 

S. (n.d.). Aspirine macro shot[Photograph found in Wikimedia Commons]. Retrieved from https://commons.wikimedia.org/wiki/File:Aspirine_macro_shot.jpg 

Barnard, M. E., Poole, E. M., Curhan, G. C., Eliassen, A. H., Rosner, B. A., Terry, K. L., & Tworoger, S. S. (2018). Association of Analgesic Use With Risk of Ovarian Cancer in the Nurses’ Health Studies. JAMA Oncology. doi:10.1001/jamaoncol.2018.4149 

Finding the Best Dose of Aspirin to Prevent Lynch Syndrome Cancers - Full Text View. (2016, August 25). Retrieved from https://clinicaltrials.gov/ct2/show/NCT02497820 

Ingram, I. (2018, October 04). Aspirin Use Tied to Reduced Risk of Liver, Ovarian Cancers. Retrieved from https://www.medpagetoday.com/hematologyoncology/ovariancancer/75511 

Key contributions to scientific knowledge. (n.d.). Retrieved from http://www.nurseshealthstudy.org/about-nhs/key-contributions-scientific-knowledge 

Low-Dose Aspirin May Lower Risk of Ovarian Cancer. (2018, October 16). Retrieved from https://huntsmancancer.org/circle-of-hope/2018/10/low-dose-aspirin-may-lower-ovarian-cancer-risk.php 

Postdoctoral Fellows. (2018, October 15). Retrieved from https://medicine.utah.edu/population-health-sciences/faculty/postdoctoral-fellows.php