Vaccination, behavior changes could prevent 40% of U.S. cancer cases, study finds

July 11 (UPI) -- Lifestyle choices such as smoking, drinking and other avoidable factors are responsible for 40% of cancers and about half of all U.S. cancer deaths in adults over age 30, new research published Thursday suggests.

A new study led by a team at the American Cancer Society found that 713,340 cancer cases and 262,120 cancer deaths in 2019 were caused by modifiable risk factors, including cigarette smoking, excess body weight, alcohol consumption, physical inactivity, diet and infections, the organization said in a news release.

Cigarette smoking was by far the leading risk factor, contributing to nearly 20% of all cancer cases and 30% of all cancer deaths, according to the study, which appears in the ACS's flagship journal, CA: A Cancer Journal for Clinicians.

"Despite considerable declines in smoking prevalence during the past few decades, the number of lung cancer deaths attributable to cigarette smoking in the United States is alarming," said lead author Dr. Farhad Islami, ACS senior scientific director for cancer disparity research.

"This finding underscores the importance of implementing comprehensive tobacco control policies in each state to promote smoking cessation, as well as heightened efforts to increase screening for early detection of lung cancer, when treatment could be more effective," Islami said.

Islami also called for interventions to help people maintain healthy body weight and diet, especially given the increasing incidence of several cancer types linked to excess body weight, particularly among young people, saying these actions could cut the number of cancer cases and deaths in the United States significantly.

The proportion and number of cancer cases and deaths attributable overall to risk factors seen as mutable was estimated for 30 cancer types (excluding non-melanoma skin cancers) using nationally representative data on cancer incidence and mortality and risk factor prevalence.

Risk factors included current or past smoking; secondhand smoke; excess body weight; alcohol consumption; consumption of red and processed meat; low consumption of fruits and vegetables, dietary fiber and calcium; physical inactivity; and sun exposure.

Also highlighted were seven viral infections: Epstein-Barr virus; Helicobacter pylori; hepatitis B; hepatitis C; human herpes virus-8 (Kaposi sarcoma herpesvirus); human immunodeficiency virus; and human papillomavirus.

Smoking had by far the highest proportion of cases attributable to risk factors in the population at almost 1 in 5 of a total of 1.78 million cancer cases -- or equivalent to 344,070 cases -- and was responsible for 56% of 368,600 potentially preventable cancers in men and 39.9% of 344,740 preventable cases in women.

Trailing some way behind were being overweight with a population attributable fraction of 7% was excess body weight; alcohol consumption at 5.4%; and UV radiation exposure and physical inactivity at 4.6% and 3.1%, respectively.

The study determined that all cervical and Kaposi sarcoma cancers were caused by elevated risk factors that had the potential to be modified, as well as more than 50% in 19 of the 30 cancer typesat which researchers looked.

The percentages for skin melanomas and cancers of the lung, pharynx, trachea, esophagus and mouth were all above 85%. By contrast, the figure for ovarian cancer was just 4.9%.

However, lung cancer accounted for the most cancer attributable to risk factors among both sexes -- 104,410 cases in men and 97,250 cases in women.

With other cancers, there was a disparity among men and women, with men more prone to skin melanoma, 50,570 cases; colorectal cancer, 44,310 cases; and bladder cancer, 32,000 cases, while women had more breast cancer at 83,840 cases' corpus uteri, 35,790 cases; and colorectal, 34,130 cases.

"These findings show there is a continued need to increase equitable access to preventive health care and awareness about preventive measures," said senior author Dr. Ahmedin Jemal, ACS senior vice president for surveillance and health equity science.

"Effective vaccines are available for hepatitis B virus, which causes liver cancer and HPV, which can cause several cancer types, including cervical, other anogenital and oropharyngeal cancers,"

"Vaccination at the recommended time can substantially reduce the risk of chronic infection, and consequently, cancers associated with these viruses. HPV vaccination uptake in the United States is suboptimal."