A recent study says that half of all cancers are preventable if people adopt healthier behaviors.
Smoking is blamed for a third of all US cancer cases and being overweight leads to another 20 percent of the deadly burden that costs the United States some $226 billion per year in health care and lost productivity.
For instance, up to three quarters of US lung cancer cases could be avoided if people did not smoke, said the review article in the US journal Science Translational Medicine.
Science has shown that plenty of other cancers can also be prevented, either with vaccines to prevent human papillomavirus and hepatitis, which can cause cervical and liver cancers, or by protecting against sun exposure, which can cause skin cancer.
Society as a whole must recognize the need for these changes and take seriously an attempt to instill healthier habits, said the researchers.
"It's time we made an investment in implementing what we know," said lead author Graham Colditz, an epidemiologist at the Siteman Cancer Center, Washington University School of Medicine in St. Louis, Missouri.
Exercising, eating right and refraining from smoking are key ways to prevent up to half of the 577,000 deaths from cancer in the United States expected this year, a toll that is second only to heart disease, according to the study.
But a series of obstacles to change are well enshrined in a society that will see an estimated 1,638,910 new cancer cases diagnosed this year.
They include skepticism that cancer can be prevented and the habit of intervening too late in life to stop or prevent cancer that has already taken root.
Also, much of the research on cancer focuses on treatment instead of prevention, and tends to take a short-term view rather that a long-term approach.
"Humans are impatient, and that human trait itself is an obstacle to cancer prevention," said the study.
Complicating those factors are the income gaps between the upper and lower social classes that mean poor people tend to be more exposed to cancer risk factors than the wealthy.
"Pollution and crime, poor public transportation, lack of parks for play and exercise, and absence of nearby supermarkets for fresh food hinder the adoption and sustained practice of a lifestyle that minimizes the risk of cancer and other diseases," said the study.
"As in other countries, social stratification in the United States exacerbates lifestyle differences such as access to health care, especially prevention and early detection services.
"Mammograms, colon screening, diet and nutrition support, smoking cessation resources and sun protection mechanisms are simply less available to the poor."
That means any bid to overcome deep social imbalances must be supported by policy changes, said co-author Sarah Gehlert, professor of racial and ethnic diversity at the Brown School of Social Work and the School of Medicine.
"After working in public health for 25 years, I've learned that if we want to change health, we need to change policy," she said.
"Stricter tobacco policy is a good example. But we can't make policy change on our own. We can tell the story, but it requires a critical mass of people to talk more forcefully about the need for change."