Mice with aggressive breast cancer given a daily low dose of aspirin had tumors 47% smaller than those of a control group.
Conducted by Dr. Sushanta Banerjee, research director of the Cancer Research Unit at the Veterans Affairs Medical Center in Kansas City, MO, and colleagues, the study revealed how low-dose aspirin impaired the ability of breast cancer cells to renew.
The researchers say their findings suggest a daily dose of aspirin - a medication commonly used to relieve pain and prevent blood clots - could prevent breast cancer development and recurrence in women.
After skin cancer, breast cancer is the most common cancer for women in the US. This year, it is estimated that more than 230,000 women will be diagnosed with breast cancer, and more than 40,000 will die from the disease.
This latest study is not the first to hail aspirin for its potential anticancer properties. In July 2014, Medical News Today reported on a study linking regular aspirin use to reduced risk of colon cancer in women, while a 2014 study from the University of Texas in Austin found regular aspirin use may halve breast cancer recurrence in overweight and obese women.
For their study, Dr. Banerjee and colleagues set out to investigate how aspirin would affect incubated breast cancer cells in laboratory dishes and breast cancer tumors in mouse models.
Daily low-dose aspirin almost halved tumor growth in breast cancer mouse models
The team tested the incubated breast cancer cells in 96 separate dishes, exposing each one to various doses of acetylsalicylic acid, or aspirin.
The researchers found that the aspirin killed the majority of breast cancer cells, with those it failed to kill left unable to grow.
Next, the researchers gave five mice with aggressive breast cancer tumors a daily dose of aspirin for 15 days. The dose they received was the equivalent to 75 milligrams in humans, which is considered to be a low dose.
At the end of the 15 days, the team compared the tumor sizes of the treated mice with those of five mice with aggressive breast cancer that did not receive aspirin.
They found that the tumors of the mice that received the aspirin were 47% smaller than those of the untreated mice.
The team then gave a daily dose of aspirin to a group of healthy mice for 10 days, before exposing them to breast cancer cells. Compared with a control group, the mice that received the aspirin had much lower levels of cancerous growth.
According to Dr. Banerjee, the team found that the aspirin blocked the self-renewal activity of the breast cancer cells. "Basically, they couldn't grow or reproduce," he explains.
As such, the researchers believe their findings indicate a daily dose of aspirin could be an effective prevention strategy against breast cancer. Dr. Banerjee says:
"[...] There are two parts here. We could give aspirin after chemotherapy to prevent relapse and keep the pressure on, which we saw was effective in both the laboratory and the mouse model, and we could use it preventatively."
While the team's results are promising, Dr. Banerjee admits that individuals should talk to their doctor before taking a daily dose of aspirin, pointing to the potential side effects of the drug, such as internal bleeding.
However, he believes the benefits of regular aspirin use outweigh the risks, noting that he has been on a daily aspirin regimen for the past 3 years and has experienced no side effects.
"Of course there is a risk," he adds, "but you have to weigh that against the risks of cancer. It's true this is relatively new and we don't know all the side effects yet, but this was a very low dose."
It should be noted, however, that each individual can have different reactions to medication and should seek advice from a health care provider before embarking on any form of drug regimen.