A groundbreaking global study has revealed that more than one in three cancer cases worldwide could be prevented through simple modifications to lifestyle habits. This comprehensive research, one of the first of its kind, analysed data from nearly 200 countries, including the United States and the United Kingdom, examining 19 million cases across 36 different cancer types.
Modifiable Risk Factors Account for 7.1 Million Diagnoses
Utilising the latest available figures from 2022, the research team discovered that 38 percent of cancer diagnoses, equating to 7.1 million cases, were attributable to 30 distinct modifiable risk factors. This significant finding underscores the substantial potential for cancer prevention through targeted public health interventions and personal behavioural changes.
Tobacco Smoking Remains the Leading Preventable Cause
Despite consistent declines in smoking rates globally, tobacco use emerged as the foremost modifiable risk factor for cancer, responsible for approximately one in six cases. It was identified as the top preventable cause in men, highlighting the ongoing critical need for tobacco control measures and cessation support programmes.
Infections and Alcohol as Significant Contributors
Infections, including human papillomavirus (HPV) – a leading cause of cervical and anal cancer that can be mitigated through vaccination and safe sex practices – were linked to one in ten cancer cases. These infections represented the primary preventable causes for women. Meanwhile, alcohol consumption was responsible for three percent of global cancer diagnoses, adding to the burden of preventable disease.
Regional and Gender Variations in Preventable Cancers
The study uncovered notable disparities when examining data by sex and region. For women, 30 percent of new cancer cases were tied to modifiable risk factors, compared to 45 percent for men. The highest burden for women was observed in sub-Saharan Africa, where 38 percent of new cancer diagnoses were linked to these factors, while in North America, 34 percent of cases in women were deemed potentially preventable.
For men, East Asia exhibited the largest burden, with 57 percent of cancers tied to modifiable risk factors. In North American men, approximately one in three cases met these criteria, indicating substantial regional differences in preventable cancer incidence.
Specific Cancers and Additional Risk Factors
The research identified that lung, stomach, and cervical cancers collectively constituted nearly half of all preventable cancer cases globally. Beyond smoking, infections, and alcohol, other significant modifiable risk factors included:
- Suboptimal breastfeeding practices
- Air pollution and environmental contaminants
- Lack of physical activity and sedentary lifestyles
- Exposure to hazardous chemicals such as asbestos
- High body mass index (BMI) and obesity-related factors
Contextualising the Findings Within Broader Cancer Trends
These revelations arrive alongside recent data from the American Cancer Society indicating that cancer survival rates in the United States have reached historic highs, with seven in ten patients now living at least five years post-diagnosis. This marks a significant improvement from 64 percent in 2000 and approximately 50 percent during the 1970s.
However, concerning trends persist, particularly regarding rising cancer rates among younger populations. Separate research has documented increases in colorectal cancer deaths among individuals under 50, alongside a nearly three percent rise in breast cancer cases among American women aged 20 to 39 between 2004 and 2021. Scientists attribute these upticks largely to lifestyle factors, including diets high in ultra-processed foods, alcohol consumption, obesity, and environmental pollutant exposure.
Detailed Analysis of Leading Risk Factors
The study, published in the esteemed journal Nature Medicine, meticulously examined 30 modifiable risk factors using data from the GLOBOCAN database maintained by the International Agency for Research on Cancer. For women globally, infections accounted for 11.5 percent of new cancer cases, with HPV affecting 40 percent of Americans at any given time and responsible for 90 percent of cervical and anal cancers. Other infections like hepatitis, Epstein-Barr virus, and Helicobacter pylori also contributed significantly to cancer risk.
In the United States, Canada, and the United Kingdom, tobacco smoking remained the leading modifiable cancer risk factor, despite dramatic declines in smoking rates over recent decades. Smoking causes 90 percent of lung cancers in the US and has also been linked to rising colorectal cancer rates among young Americans.
Preventable Lung and Breast Cancer Cases
The research provided detailed breakdowns for specific cancers. For women, nearly half a million lung cancer cases were preventable, with 60.5 percent attributable to smoking, 27.5 percent to pollution, and 12 percent to occupational hazards like asbestos. In men, 1.3 million lung cancer cases stemmed from modifiable factors, with 69 percent from smoking, 16 percent from pollution, and 15 percent from occupational exposures.
Regarding breast cancer, the study linked 33 percent of cases to insufficient physical activity, 29 percent to high BMI, and 18 percent to suboptimal breastfeeding practices, which can reduce estrogen exposure and eliminate damaged cells.
Implications for Public Health and Cancer Prevention
The researchers emphasised that these findings signal a growing imperative to focus on modifiable risk factors in cancer prevention strategies. By addressing behaviours and exposures that can be changed – such as smoking, alcohol consumption, diet, physical activity levels, and vaccination uptake – substantial progress could be made in reducing the global cancer burden.
While the study acknowledged limitations, including uneven data quality across regions and challenges in precisely quantifying exposure levels, its comprehensive scope provides compelling evidence for prioritising prevention alongside treatment in the global fight against cancer. The complete list of 30 cancer risk factors examined underscores the multifaceted nature of cancer causation and the numerous opportunities for intervention.
