Cancer is not one disease but many, and its causes range from unchangeable, like BRCA1 gene mutations, to fully preventable, like smoking. And in many cases, cancer is triggered by random mutations that accumulate as we age.
Modifiable risk factors are responsible for more than 40 percent of all cancers and cancer-related deaths, according to a recent study from the American Cancer Society (ACS). And while everyone knows that smoking causes cancer, other risk factors may come as a surprise.
The researchers calculated that more than 650,000 new invasive cancer cases (42 percent) and more than 265,000 deaths (45 percent) among people age 30 and older were attributable to about a dozen modifiable risk factors.
As expected, smoking was responsible for the most cancer cases (19 percent) and cancer deaths (29 percent).
Alcohol was blamed for nearly 6 percent of cancer cases and 4 percent of deaths. The American Society of Clinical Oncology recently warned that even light or moderate drinking raises the risk of several types of cancer, including mouth and throat cancers, colon cancer and breast cancer. Yet a survey by the group found that a majority of Americans don’t recognize alcohol as a cancer risk factor.
People who enjoy an occasional beer or glass of wine don’t need to panic, according to Aaron Carroll, MD, of Indiana University School of Medicine. He calculated that if light drinking raises a 40-year-old woman’s 10-year risk of breast cancer by 6 percent, that means one additional cancer case among 1,667 women.
About 8 percent of cancers were linked to being overweight, 3 percent to lack of physical activity and 2 percent to a shortage of fruits and vegetables. This is in line with a recent Centers for Disease Control and Prevention report showing that overweight people are at higher risk for at least 13 types of cancer.
Infections are another underrecognized risk factor. Nearly 2 percent of cancers were attributable to human papillomavirus (HPV), which causes cervical, anal and some oral cancers. However, these cancers can be prevented with a vaccine, which is now recommended for adolescents. Likewise, the hepatitis B vaccine and treatment that cures hepatitis C lower the risk of liver cancer.
Saying a risk factor is modifiable doesn’t mean it’s easy to change—as those who have tried to quit smoking or lose weight can attest! It also doesn’t suggest that people who get preventable cancers should be blamed or shamed. Most people have some less-than-healthy habits, and everyone living with cancer deserves care and compassion.
But knowing the risk factors can empower people to lower their odds of getting cancer.
“These findings underscore the vast potential for reducing cancer morbidity and mortality through broad and equitable implementation of known preventive measures,” the ACS researchers conclude.