Using aspirin to lower the risk of colorectal cancer

You’ve probably heard about daily aspirin therapy as a preventative for heart attack and stroke.

But in 2019, a large clinical trial showed that, beyond the age of 70, taking a daily aspirin did not reduce the risk of a first heart attack or stroke. However, it did increase the risk of serious internal bleeding.

Well, now we’re going down a similar research road with colorectal cancer. It’s been long established that daily low-dose aspirin can protect against this deadly form of cancer.

But more recently, scientists are finding that how well this protection works, or if it works at all, has a lot to do with when it’s started.

So, can we still say that aspirin protects against colorectal cancer? The answer, it seems, is “it depends.”

Start taking aspirin before 70

A team of researchers led by Dr. Andrew Chan set out to study whether older adults (beyond age 70) should begin taking aspirin to prevent colorectal cancer.

Dr. Chan is a gastroenterologist and chief of the Clinical and Translational Epidemiology Unit at Massachusetts General Hospital.

The research team analyzed data from The Nurses’ Health Study (January 1980 – June 2014) and the Health Professionals Follow-up Study (January 1986 – January 2014).

In total, these two studies looked at over 94,000 people and their aspirin use over about 35 years, seeking connections between aspirin use and cancer risk.

This is where the “it depends” comes in.

Dr.Chan’s team established that for people who had started taking aspirin in their fifties and sixties, continuing this habit into their seventies was associated with a lower risk of colorectal cancer.

However, for those who started taking aspirin after age seventy, no such benefit was found.

Start aspirin before a cancer diagnosis

According to the American Cancer Society, the five-year survival rate for colorectal cancer that is localized (has not spread at all) is 91 percent. That survival rate drops to 72 percent, once the cancer has spread to organs close to the colon.

By the time it’s metastasized to more distant organs, the five-year survival rate plummets to fourteen percent.

This is why another new study from the American Cancer Society is so important.

“These findings are important because colorectal cancer patients seek guidance on lifestyle factors to improve their prognosis,” says Dr. Peter Campbell.

The study used data from men and women who were enrolled in the American Cancer Society’s Cancer Prevention Study-II Nutrition Cohort. All were cancer-free when the study began in 1992, but were diagnosed later on, up to the year 2015.

The bottom line: If you’re going to take aspirin to prevent colorectal cancer, start before you’re seventy.

If you’re beyond age seventy, Dr. Chan of Massachusetts General says that “a discussion is warranted about whether to start aspirin after weighing the benefits against the risks.”

And even if you do receive a diagnosis of colorectal cancer, if you’ve been taking aspirin in your fifties or sixties, you should continue. It will reduce the likelihood that the cancer will spread, and help add years to your life.

Sources:

Does aspirin lower colorectal cancer risk in older adults? It depends on when they start  – Eureka Alert

Study shows aspirin before a diagnosis may lower colorectal cancer mortality – Medical Express

Daily Aspirin Can Lower Colon Cancer Risk, But Age Matters – US News & World Report

ASPIRIN and HEALTH – aspree.org

Effect of aspirin and NSAIDs on risk and survival from colorectal cancer – Gut

Associations of aspirin and non-aspirin non-steroidal anti-inflammatory drugs with colorectal cancer mortality after diagnosis – Journal of the National Cancer Institute