Preventing Cancer Is Not a Game of Chance

Preventing Cancer Is Not a Game of Chance

January 4, 2023

Originally published on EWG’s EnviroBlog
By Curt DellaValle, Senior Scientist

Today is World Cancer Day, a perfect time to raise awareness and spur action in the fight against cancer. It’s a day to reflect on a very important question: What is the main cause of cancer? Is it driven by avoidable lifestyle and environmental factors or is it largely due to chance?

That question is particularly relevant in light of President Obama’s call in his final State of the Union address for a cancer “moonshot” to “make America the country that cures cancer once and for all.” Investing in innovative and promising treatments certainly will, and should, be a critical focus of the “moonshot” initiative, but we shouldn’t lose sight of the other side of the cancer fight – preventing it in the first place.

How much do we need to focus on prevention? Is cancer largely avoidable or not?

Early in 2023, a pair of scientists at Johns Hopkins University in Maryland tackled this question and concluded the majority of cancer is due to “bad luck.” They observed that the faster the stem cells in an organ divide and replicate, the more likely cancer is to develop. (Cell division is the body’s way of growing and replacing old or damaged cells). The premise makes sense. Every time a cell divides into new cells it’s a roll of the dice, because there is a chance – a very, very small chance – of a spontaneous error in the new cells’ DNA, such as a mutation, that could cause cancer. The more times you roll the dice, the more likely you are to come up with a bad number.

Their conclusion that about 65 percent of all cancers are a result of “bad luck” sparked a lot of debate, because the study was limited in how it accounted for external factors such as lifestyle and the environment – which can greatly influence cell division and mutation rates. Plus, we see the powerful effect of lifestyle and environment in the real world. Cancer rates vary substantially worldwide and cancer rates among immigrants more closely match the rates in their new country than in their country of origin.

This led a group at Stony Brook University in New York to reexamine the question using the same data. They concluded that cell division rates are responsible for only a baseline risk, accounting for about 10-30 percent of cancers. The remaining 70-90 percent of our risk is due to external factors including lifestyle and environmental exposures.

Whether external factors account for 90 percent or 35 percent of cancer risk, or somewhere in between, both studies point to the same thing: A substantial number of cancers are preventable.

Prevention starts with us. Living a healthy lifestyle, not smoking, eating a nutritious diet, staying physically active and avoiding sexually transmitted disease are all things within our control. We can also reduce our exposures to toxic substances.

EWG has compiled a list of 10 simple steps you can take in and around your home to further reduce cancer risk for you and your family.

When it comes to cancer, we can’t stop rolling the dice, but a healthy lifestyle and clean environment certainly shift the odds in our favor.