Aspirin and Colorectal Cancer: A Common Drug’s Potential to Offset Unhealthy Habits

Could a ubiquitous pill, found in nearly every medicine cabinet, hold the key to mitigating colorectal cancer (CRC) risk—especially for those whose lifestyles lean toward the less-than-optimal? A groundbreaking study suggests that regular aspirin consumption might serve as a powerful, albeit underappreciated, shield against this deadly disease, with the most pronounced benefits observed in individuals engaged in unhealthy behaviors.

The study, a colossal undertaking published in JAMA Oncology on August 1, spanned over three decades and scrutinized data from more than 107,000 participants. The findings? A striking reduction in CRC risk among individuals with poor lifestyle choices—think smoking, high body mass index (BMI), sedentary tendencies, and dietary neglect. Intriguingly, the data suggests that aspirin’s protective effects were most evident in those with higher CRC susceptibility due to lifestyle-related factors.

This revelation arrives at a critical juncture. Colorectal cancer rates are climbing, with a particularly alarming uptick among younger generations.

“The rise of early-onset colorectal cancer—cases diagnosed before age 50—is an especially troubling development,” remarked Dr. Tingting Tan, an oncologist at City of Hope Newport Beach, in an interview with Health. “By 2030, colorectal cancer is expected to surpass all other cancers as the leading cause of cancer-related deaths among young adults in the U.S. This underscores an urgent need for enhanced research, awareness, and proactive screening.”

Lifestyle, Aspirin, and Colorectal Cancer: An Interwoven Nexus

Previous studies have cemented the link between lifestyle habits—such as smoking and alcohol consumption—and CRC risk. But could aspirin tip the scales toward prevention? This latest research aimed to answer that question, integrating lifestyle factors into its analysis.

The dataset was formidable: 107,655 participants drawn from two extensive health studies—the Nurses’ Health Study (comprising 63,957 women) and the Health Professionals Follow-Up Study (including 43,698 men). What is the average participant age? 49.

Researchers categorized subjects based on five well-established, modifiable CRC risk factors: BMI, smoking history, alcohol consumption, physical activity levels, and dietary quality. A lifestyle score was assigned, ranging from zero (unhealthiest) to five (healthiest).

“All five of these factors correlate with inflammatory processes known to influence long-term cancer outcomes,” noted Drs. Andrew Chan and Long Nguyen, lead authors of the study and researchers at Massachusetts General Hospital.

Participants self-reported their height, weight, diet, exercise habits, and smoking status through comprehensive questionnaires. Then, over the next three decades, researchers tracked CRC incidence.

The results? Aspirin use—defined as consuming two or more standard tablets weekly—was linked to an 18% reduction in CRC risk compared to non-users. The effect was even more pronounced among individuals with low lifestyle scores (zero or one), yet aspirin conferred benefits across the spectrum, even for those with healthier habits.

“While those with the least healthy lifestyle derived the greatest absolute benefit from aspirin, our findings suggest that even individuals with a lower baseline risk of colorectal cancer may still gain protection,” the study authors concluded.

How Does Aspirin Ward Off Colorectal Cancer?

This isn’t the first study to hint at aspirin’s cancer-fighting prowess.

“For centuries, aspirin has been lauded for its anti-inflammatory and analgesic properties,” Dr. Tan noted. But what makes it particularly intriguing in cancer prevention?

“Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) are believed to reduce colon cancer risk by inhibiting the production of pro-inflammatory proteins called prostaglandins,” explained Dr. Thomas Deas, a gastroenterologist at Texas Health Harris Methodist Hospital. The logic? By suppressing chronic inflammation, aspirin might obstruct the chain of events that culminates in cancer formation.

But its potential doesn’t end there. Aspirin may also interfere with the development of blood vessels that nourish tumors, effectively starving malignancies before they gain momentum. Additionally, the drug appears to modulate immune responses, potentially enhancing the body’s ability to combat rogue cancerous cells.

Moreover, previous studies bolster the case for aspirin’s role in CRC prevention. Research suggests it may inhibit polyp formation—precancerous growths that can evolve into malignancies. A 2016 study linked long-term aspirin use to a reduced risk of gastrointestinal cancers, while a 2020 study found that aspirin appeared to stifle tumor growth and recurrence in CRC patients.

Yet, despite these promising insights, recommendations remain cautious. The U.S. Preventive Services Task Force once advised adults aged 50-59 to take low-dose aspirin for CRC prevention but later retracted this guidance, citing concerns over gastrointestinal bleeding risks and the need for further research.

The bleeding risk presents a notable limitation of Chan and Nguyen’s study as well.

“Our research did not systematically assess the potential side effects associated with prolonged aspirin use, particularly gastrointestinal bleeding, which could limit its viability as a long-term preventive strategy,” they acknowledged.

Dr. Tan echoed this sentiment. “While these findings hold great promise, further research is essential to confirm and strengthen these conclusions”

Consult Your Doctor Before Embracing Aspirin as a Preventive Strategy

Despite the compelling data, experts urge caution before self-prescribing aspirin as a cancer shield.

“It’s plausible that suppressing inflammatory agents in the colon could ultimately prove both safe and effective in reducing CRC risk,” Dr. Deas acknowledged. “But we’re not there yet—more research is needed.”

His advice? Talk to your doctor.

“Patients should assess their individual risk-benefit ratio with their healthcare provider, someone who understands their medical history best,” he advised.

For individuals already on aspirin—perhaps for cardiovascular protection—there may be an added, unintentional benefit: reduced CRC risk. However, for those considering it solely for cancer prevention, medical consultation is paramount.

Dr. Tan reinforced a fundamental truth: aspirin is not a panacea. Lifestyle remains the linchpin of cancer prevention.

“The most effective strategy for lowering CRC risk is adopting a healthy lifestyle,” she emphasized. This means maintaining a healthy weight, prioritizing nutrient-dense foods, staying active, getting quality sleep, and steering clear of tobacco and excessive alcohol.

Ultimately, prevention isn’t just about a pill—it’s about a comprehensive approach. And while aspirin might be a valuable ally in the fight against CRC, it is no substitute for a proactive, health-conscious lifestyle. Regular screenings, including colonoscopies, remain crucial for early detection and prevention.

“This study reinforces the importance of making informed, healthy choices,” Dr. Tan concluded. “The path to cancer prevention starts with lifestyle—and vigilance.”