A new study by the American Cancer Society found that about 40% of cancer cases among people age 30 and over - and almost half of the deaths - are attributed to preventable risk factors. That is, these cases can be prevented through lifestyle changes.
According to the study, smoking remains the biggest risk factor, causing almost one in five cancer cases and almost one-third of cancer deaths. Other factors in cancer cases for about 40% of people over 30 and almost half of the cancer death cases include alcohol consumption, physical activity, diet and infections. In other words, the majority of cancer cases are preventable.
Professor Alona Zer-Koch, director of medical oncology in the oncology department at Rambam Hospital, explains that "lung cancer is probably the most preventable cancer we know because more than 80% of cases are related to smoking. Moreover, we believe that some of the cases that are not directly related to smoking are related to passive smoking or air pollution, which are also considered preventable factors."
"The risk of an adult who does not smoke getting lung cancer is less than 1 in 100, while a heavy smoker has a risk of 1 in 3 or 4. This proves the correlation between smoking and lung cancer," according to Zer-Koch, who adds: "Studies that were recently published show a link between lung cancer and air pollution. The link to passive smoking is much more difficult to assess in studies because not many people report it. We believe that some of the lung cancer cases among non-smokers were caused this way."
She says other risk factors for lung cancer can be prevented. These risk factors include occupational exposure, such as people who are exposed to smoke at work - for example, working with engines, or people who are exposed to asbestos - such as electricians or people who work in construction, and people who work with dust and polishing, may be at a higher risk for lung cancer and other respiratory malignancies.
"Smoking not only causes lung cancer but is also a risk factor for other cancers, such as those of the nose, mouth, esophagus and bladder," adds Zer-Koch. "Of course there are other cancers that can be prevented, such as skin tumors caused by exposure to the sun."
Other risk factors presented in the study were being overweight, alcohol consumption, physical inactivity, diet and infections such as the papilloma virus (HPV). Being overweight is considered the second cause after smoking, and is linked to about 5% of new cases among men and almost 11% among women. Moreover, this factor has been linked to more than a third of deaths from several types of cancer such as gallbladder, esophagus, liver and kidneys.
In total, the researchers analyzed 18 modifiable risk factors across 30 types of cancer. The researchers found that in 2019 these lifestyle factors were associated with more than 700,000 new cancer cases and more than 262,000 deaths.
Professor Alona Zer-Koch, director of medical oncology at Rambam HospitalPhoto: Rambam HospitalThe research findings suggest that some types of cancer are more preventable than others. The risk factors tested contributed to more than half of the new cancer cases, in 19 of the 30 types tested. In 10 cancers examined in the study, modifiable risk factors were linked to at least 80% of new cases, including more than 90% of melanoma cases linked to ultraviolet radiation and almost all cervical cancers linked to HPV infection, which can be prevented by vaccination.
Zer-Koch clarified that "HPV vaccination significantly lowers the risk of cervical cancer, and we believe that it also lowers the risk of other malignancies related to the virus, such as penal tumors as well as in the anus, mouth and the pharynx."
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