Aspirin Inhibits Metastatic Cancer Spread, Reducing Mortality by 21 Percent: Study

A comprehensive review found that patients who take aspirin have a relatively lower risk of developing various types of cancer.

Freepik

Aspirin is a long-established and widely used medication with a long history. In addition to its well-known uses for pain relief and its anti-inflammatory and anticoagulant properties, a recent study indicates that cancer patients who take low-dose aspirin daily experience a 21 percent reduction in mortality.

There’s also evidence of aspirin’s role in preventing cancer metastasis.

Cancer is one of the leading causes of global mortality. In 2020 alone, there were about 19.3 million new cancer cases worldwide and almost 10 million deaths. According to statistics, 1 in 6 reported deaths are attributed to cancer. The most common types of cancer include breast, lung, colorectal, prostate, and stomach.

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In November 2023, researchers from Cardiff University in Wales published a comprehensive review in the British Journal of Cancer (BJC) outlining aspirin’s potential to reduce cancer mortality, prevent metastatic cancer spread, and minimize vascular complications. The review encompassed both favorable and unfavorable evidence, thoroughly analyzing the rationale behind using aspirin in cancer treatment.

Aspirin’s Impact on Cancer Mortality

The study compiled results from 118 observational studies involving about 1 million cancer patients. It revealed that daily intake of low-dose aspirin (75 milligrams or 81 milligrams) was associated with a 21 percent reduction in all-cause mortality.

A study involving pancreatic cancer patients undergoing surgery indicated that patients who took aspirin had a three-year survival rate of 61.1 percent, compared to 26.3 percent for those who didn’t take it.

Aspirin’s Role in Reducing Metastatic Cancer Spread

The primary mechanism of action for aspirin is the inhibition of the cyclooxygenase (COX) enzyme. COX is responsible for forming prostaglandins, a critical pathway in cancer signaling. However, the anti-cancer effects of aspirin extend beyond this. Recent research has revealed that aspirin’s mechanisms of anti-cancer action also involve energy metabolism associated with cancer cell proliferation, cancer-related inflammation, and platelet-driven pro-carcinogenic activity.

The metastasis or spread of cancer is a major cause of death in cancer patients, and platelets play a significant role in this process. Aspirin can inhibit platelet aggregation, thereby reducing the spread of cancer cells. The comprehensive review in the BJC found that aspirin can lower the risk of cancer metastasis by 38 percent, to 52 percent.

Additionally, aspirin plays a role in promoting DNA repair. Errors may occur during the replication of DNA, and the human body possesses a mechanism for DNA mismatch repair. Once this function is compromised, it can lead to the development of cancer. Research has demonstrated that aspirin can enhance DNA repair mechanisms, thereby preventing hereditary non-polyposis (Lynch syndrome) colorectal cancer and potentially other cancers.

The Controversy Surrounding Aspirin in Cancer Treatment

The role of aspirin in cancer studies remains controversial, primarily because of concerns about increased bleeding risks. A study published in the Lancet in 2017, suggested that daily aspirin usage causes 3,000 deaths from bleeding in Britain every year.

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However, researchers noted that this prospective study, involving 3,166 older patients, lacked a control group, making it challenging to assess the independent impact of aspirin on fatal bleeding accurately.

The researchers pointed out that an increased risk of bleeding in elderly and frail cancer patients does pose a real danger. However, instead of solely focusing on the frequency of bleeding, greater consideration should be given to its severity, as the most severe instances of bleeding are the ones responsible for death.

The researchers consolidated data from 11 randomized controlled trials, encompassing more than 100,000 participants, that included fatal bleeding events. The data indicated a 55 percent increase in the risk of bleeding because of aspirin. However, among patients who experienced bleeding after taking aspirin, only 4 percent died. In contrast, the control group, who took a placebo, had a death rate attributed to bleeding of up to 8 percent. This suggests that bleeding caused by aspirin is predominantly mild.

The conclusion drawn by researchers is that considering the relative safety of aspirin, it should be considered as a preventative measure for cancer. While there’s evidence indicating that aspirin can reduce the spread of metastatic cancer and that starting aspirin therapy early after a cancer diagnosis enhances its effectiveness, more randomized trials are needed.

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Peter Elwood, honorary professor at Cardiff University, said in a statement that “given its relative safety and its favorable effects, the use of aspirin as an additional treatment of cancer is fully justified.” He added that aspirin is inexpensive and available in nearly every country, and its widespread use could be beneficial worldwide.

Aspirin Lowers Risk of Various Cancers

A comprehensive review published in the journal Annals of Oncology in 2020 indicated that patients who take aspirin have a relatively lower risk of developing various types of cancer.

The researchers conducted a comprehensive analysis of all observational studies on aspirin and digestive tract cancers published until March 2019, encompassing more than 150,000 cases. The results revealed that, compared to patients not using aspirin, those who regularly took aspirin had a 27 percent reduced risk of colorectal cancer, a 33 percent reduced risk of squamous cell esophageal cancer, a 39 percent reduced risk of adenocarcinoma of the esophagus and gastric cardia, a 36 percent reduced risk of stomach cancer, a 38 percent reduced risk of hepatobiliary tract cancer, and a 22 percent reduced risk of pancreatic cancer. However, there was no significant change in the risk of head and neck cancer.

For colorectal cancer, taking a daily dose of aspirin of 75 milligrams to 100 milligrams can reduce the risk by 10 percent, while a daily dose of 325 milligrams can reduce the risk by 35 percent.

Potential Risks of Taking Aspirin

Aspirin is a nonsteroidal anti-inflammatory drug (NSAID) used to treat mild to moderate pain, inflammation, or arthritis. It can also reduce the risk of heart attacks, strokes, and blood clots.

However, it’s essential to note that long-term use of aspirin may pose additional risks for some individuals. According to the UK National Health Service (NHS), children younger than age 16 shouldn’t take aspirin without a doctor’s prescription, since there’s a potential link between aspirin and Reye’s syndrome in children.

For individuals with a history of allergy to aspirin or similar pain relievers, stomach ulcers, high blood pressure, indigestion, heavy menstrual bleeding, recent stroke, asthma or lung disease, blood clotting problems, liver or kidney problems, and gout, it’s essential to consult a doctor before taking aspirin.