The American Cancer Society recently published the results of a study that investigated the causes of various types of cancer and related deaths. Professor Alona Zer Kuch, director of Medical Oncology at the Joseph Fishman Oncology Center of Rambam Health Care Campus (Rambam) in Haifa, Israel comments on the findings.
Professor Alona Zer Kuch. Credit: Rambam HCC.
According to the study, smoking alone causes nearly one in five cancer cases and almost a third of cancer deaths, with lung cancer being the most common culprit. Nearly 40% of cancer cases among people aged 30 and over—and almost half of cancer-related deaths—are attributable to preventable risk factors, with smoking and obesity being the leading contributors.
Professor Alona Zer Kuch, weighs in and explains, “Lung cancer is probably the most preventable cancer we know, because more than 80% of cases are associated with smoking. Moreover, some cases not directly related to smoking can be linked to passive smoking or air pollution, which are also preventable.”
“The risk of a non-smoker developing lung cancer is less than one in a hundred, while a heavy smoker has a risk of one in three or four,” adds Zer Kuch. “This strong correlation between smoking and lung cancer proves the importance of quitting.” She also notes that other preventable risk factors include occupational exposure to smoke, asbestos, and certain dusts, which heighten the risk of lung and other respiratory cancers.
“Smoking is not only a risk factor for lung cancer but also for cancers of the nose, mouth, upper airways, esophagus, and bladder,” says Zer Kuch. “Skin tumors caused by sun exposure are another example of preventable cancers.”
Other significant risk factors presented in the study include obesity, alcohol consumption, physical inactivity, poor diet, and infections like human papillomavirus (HPV. Obesity is the second leading cause of cancer after smoking, linked to about 5% of new cases among men and almost 11% among women. It also contributes to more than a third of deaths from endometrial, gallbladder, esophagus, liver, and kidney cancers.
The researchers analyzed 18 modifiable risk factors across 30 types of cancer. In 2019, these factors were associated with more than 700,000 new cancer cases and over 262,000 deaths. Some cancers, like melanoma and cervical cancer, are highly preventable. Over 90% of melanoma cases are linked to ultraviolet radiation, and almost all cervical cancer cases are linked to HPV, preventable by vaccination.
“HPV vaccination significantly lowers the risk of cervical cancer,” Zer Kuch concludes, “and we believe it also reduces the risk of other malignancies related to the virus, such as tumors of the genitalia, rectum, mouth, and pharynx.”