Aspirin: a new option for breast cancer?

Aspirin has been around about as long as anyone has been writing about health. Hippocrates, who was born in 460 BC and is frequently referred to as “The Father of Western Medicine”, used willow bark and leaves – which contain the active ingredients found in aspirin – to help ease pain and fevers. Now a new study says it may also be able to help people battling breast cancer.

A study in the journal Laboratory Investigation looked at the ability of acetylsalicylic acid (the chemical name for aspirin) to block the replication of cancer stem cells in breast cancer. Cancer stem cells are thought to be able to evade chemotherapy or other anti-cancer therapies and help the disease spread or metastasize throughout the body.

Sushanta Banerjee and his team at the Cancer Research Unit at the Kansas City (Mo.) Veterans Affairs Medical Center isolated breast cancer cells and then exposed half of them to varying doses of aspirin. The cells exposed to aspirin either stopped growing or died.

Working in the lab is one thing, working in animals can be something completely different, so the researchers next took 20 mice that had aggressive breast tumors. Half were given the human equivalent of a “low dose” aspirin, half received nothing. After 15 days the mice on aspirin had tumors that were almost half the size of the tumors on the non-treated mice.

But the researchers still weren’t done. They also wanted to see if aspirin could help prevent the spread of the cancer in the first place. So they worked with another group of mice: half got aspirin for ten days, the other half got nothing. The entire group was then exposed to cancer cells. After 15 days the mice on aspirin had considerably less cancer than the untreated group.

Banerjee talked about the significance of their findings in an article in Drug Discovery & Development:

“Our studies, for the first time, showed that aspirin can block the self-renewal capacity of breast cancer stem cells, and growth of breast tumor-initiating cells (BTICs)/breast cancer stem cells (BCSCs), which are also considered breast cancer residual cells, under tissue culture conditions. In addition, we found that aspirin-pre-exposed cells delay the formation of a palpable tumor in a xenograft mice model.  These studies suggest aspirin can prevent disease relapse, and enhance long-term survival of breast cancer patients.”

The article does discuss some of the limitations of the study – such as the dose involved, the length of follow-up and our ability to extrapolate the findings to people. And of course because of the risk of internal bleeding it’s not recommended that people just start taking aspirin without first consulting their own doctor.

Even so, Ricardo Fodde, Ph.D. an Erasmus Medical Center expert on the use of aspirin to treat cancer, says the findings are important:

“I find the general idea of using aspirin in a cancer therapeutic setting quite exciting.” Aspirin is “an extremely cheap and relatively innocuous—at least when compared with conventional cytotoxic drugs—non-steroid anti-inflammatory drug (NSAID) that possibly targets what is nowadays regarded as the beating heart of the tumor mass: cancer stem cells.”

Last November we wrote about a study showing aspirin might also be useful in fighting colon cancer. You can read about that work here.