Researchers have shown that 44.4% of cancer deaths worldwide can be attributed to preventable risk factors, including behavioral and environmental ones .
It is well known that many cancer cases occur due to behavioral and environmental and factors such as smoking and pollution, which makes them theoretically preventable. This is thoroughly confirmed in a new paper published in the venerable journal Lancet. While it lacks astonishing revelations, this research still paints a picture worth contemplating.
The paper, based on the 2019 results from the mammoth Global Burden of Diseases, Injuries, and Risk Factors study (GBD), is probably the most comprehensive account of the contribution of various risk factors to the global cancer burden to date. It encompasses 204 countries and territories, practically the whole world, and it accounts for sex, age, and national development levels.
According to the researchers, in 2019, the total number of cancer deaths in the world attributable to potentially preventable risk factors amounted to 4.45 million, a whopping 44.4% of all cancer deaths. However, sex differences were significant: in males, 50.6% of all cancer deaths were due to preventable risk factors, while in women, only 36.3% were.
What are the risk factors?
Between 2010-2019, the composition of the leading risk factors hardly changed. Tobacco consumption remained the most significant factor for both sexes, accounting for 33.9% of all cancer DALYs (disability-adjusted life years, which is another measure of the burden of disease) in males. In females, however, its contribution was far lower: only 10.7%. In males, the next three major factors were alcohol consumption, dietary risk, and air pollution, with 7.4%, 5.9%, and 4.4% respectively. In females, the second major factor was unsafe sex (8.2%), which increases cancer risk mostly by transferring HPV viruses . Dietary risks and high BMI (body-mass index) were high on the list for both sexes.
Given the huge contribution of smoking, it is not surprising that the leading type of cancer for both males and females around the world was tracheal, bronchial, and lung cancer (36.9% of all attributable cancer deaths). This was followed by colon and rectal cancer, esophageal cancer, and stomach cancer in males and cervical cancer, colon and rectal cancer, and breast cancer in females.
Good news and bad news
The report provides some interesting geographical and socioeconomic insights. Countries with high SDIs (socio-demographic index, a measure of development) seem to suffer from much higher cancer burdens, accounting for 25.4% of all cancer deaths and 26.5% of all risk-attributable cancer deaths, despite hosting only 13% of the global population. However, on the region and country levels, the situation becomes more complex.
While the overall number of cancer deaths grew by 20.4% between 2010 and 2019, which can be attributed to population growth and aging (cancer, after all, is age-related), the global age-standardized rates of risk factor-related cancer deaths actually decreased by 6.9%. This means that in any given age group, the prevalence of cancer declined.
Some risk factors became more prevalent than others. The single highest increase was in deaths related to metabolic risks, especially to high BMI (+4%). On the other end of the spectrum, there was a 10.5% decrease in cancer deaths related to air pollution, including a drastic 35.5% decrease in deaths related to household air pollution from solid fuels. This data is not hard to decipher: particlulate air pollution has been in free fall globally, and poverty has been declining too, enabling millions of people to switch from using solid fuels to less harmful ways of heating and cooking. However, prosperity brings along “the problems of the rich”, such as the availability of unhealthy food and the obesity epidemic .
Occupational risk factors, such as exposure to industrial carcinogens, which disproportionately affect males, declined by 11.4%, indicating improvements in work environments. Behavioral risk factors (mostly smoking, but also alcohol consumption, diets low in vegetables, etc.) took a plunge as well.
Clearly, humanity is doing something right and something wrong. As more people are lifted from poverty around the world, and new technologies spread, some risk factors for cancer are likely to keep declining. On the other hand, due to the same reason, abundance-related risk factors will likely become more prevalent.
Our analysis found that 44·4% (95% UI 41·3–48·4) of global cancer deaths and 42·0% (39·1–45·6) of global cancer DALYs were attributable to estimated risk factors in 2019. These findings highlight that a substantial proportion of cancer burden globally has potential for prevention through interventions aimed at reducing exposure to known cancer risk factors but also that a large proportion of cancer burden might not be avoidable through control of the risk factors currently estimated. Thus, cancer risk reduction efforts must be coupled with comprehensive cancer control strategies that include efforts to support early diagnosis and effective treatment.
While it is tempting to focus on new cutting-edge anti-cancer therapies, this report is a sobering reminder that almost half of the world’s cancer deaths happen due to potentially preventable factors. Some people believe that for the longevity field to be worthy of its name, efforts must be made to address currently preventable deaths alongside research into new treatments.
However, as Dr. Matt Kaeberlein, one of the foremost longevity researchers, wrote on Twitter, “many of those folks [whose deaths from cancer can be prevented] would die from a different cancer or other disease within a few years due to the exponential increase in risk with age. Preventing/curing individual cancer is important. Effectively targeting aging biology is far more important”.
 Tran, K. B., Lang, J. J., Compton, K., Xu, R., Acheson, A. R., Henrikson, H. J., … & Banach, M. (2022). The global burden of cancer attributable to risk factors, 2010–19: a systematic analysis for the Global Burden of Disease Study 2019. The Lancet, 400(10352), 563-591.
 Shepherd, J., Peersman, G., Weston, R., & Napuli, I. (2000). Cervical cancer and sexual lifestyle: a systematic review of health education interventions targeted at women. Health Education Research, 15(6), 681-694.
 Lim, H. J., Xue, H., & Wang, Y. (2020). Global trends in obesity. Handbook of Eating and Drinking: Interdisciplinary Perspectives, 1217-1235.