Nearly 50% of cancer deaths in US may be preventable, study finds: ScienceAlert

Modifiable risk factors, from smoking to lack of exercise, may be responsible for nearly half of cancer deaths among American adults over age 30, according to a new study that analyzed 1.78 million cases from 2019.

The message of the research, led by a team from the American Cancer Society (ACS), could not be clearer: Individually and collectively, the risks of developing cancer and dying from the disease can be significantly reduced by making simple decisions to live healthier lives and improving access to health care.

“A large number of cancer cases and deaths in the United States are attributable to potentially modifiable risk factors, highlighting the potential to substantially reduce the cancer burden through broad and equitable implementation of preventive initiatives,” the researchers write in their published study.

In 19 of the 30 types of cancer studied, more than half of the cases and deaths were due to potentially modifiable risk factors.

The study authors highlighted three areas in particular where there are strong links between cancer rates and factors we can largely control: smoking, excess body weight and cancer-related viruses (such as hepatitis B) that can be vaccinated against.

Smoking is the leading cause of death from this disease: 19.3% of all cases. Being overweight comes second with 7.6%, followed by alcohol consumption (5.4%), exposure to UV rays (4.6%) and physical inactivity (3.1%).

Of course, there are always a number of complex factors at play with cancer, and the extent to which lifestyle choices can mitigate risk varies across cancer types.

The team found that the proportion of cases caused by modifiable risk factors was 100 percent for cervical cancer, because the risk can be essentially eliminated by vaccination.

Topping the list in terms of number of cases is lung cancer: in 2019, 104,410 cases in men and 97,250 cases in women were linked to modifiable risk factors.

“This finding underscores the importance of implementing comprehensive tobacco control policies in every state to promote smoking cessation, as well as increased efforts to increase screening for early detection of lung cancer, when treatment may be more effective,” said ACS cancer epidemiologist Farhad Islami.

“Interventions aimed at maintaining healthy body weight and diet can also significantly reduce the number of cancer cases and deaths in the country.”

Genetic and environmental factors may also play a role in the likelihood of developing cancer. The disease is characterized by uncontrolled cell division, causing abnormal growth that can directly damage organs or create dangerous imbalances in biological functions.

Although treatment options are improving over time and cure rates are increasing, this new study is an important reminder of how many cancers could be prevented in the first place – by quitting smoking, watching our weight, using sun protection measures or drinking less, for example.

“These results show that there is a continued need to increase equitable access to preventive health care and awareness of preventive measures,” said Ahmedin Jemal, a cancer epidemiologist at the ACS.

The research was published in CA: A Cancer Journal for Clinicians.