Cancer: Nearly half of all deaths could be prevented

In 2024, 20.6 million new cancer cases and 9.8 million deaths were estimated worldwide, according to the latest GLOBOCAN data from the International Agency for Research on Cancer (IARC), published with the American Cancer Society in the journal CA: A Cancer Journal for Clinicians.[1]. A considerable portion of this burden could nevertheless be avoided: according to studies cited by the authors, nearly half (48,130) of cancer deaths are potentially preventable, primarily through the prevention of modifiable risk factors, and to a lesser extent through early detection and access to treatment. Tobacco plays a central role among these factors: it is notably responsible for nearly 60,130 lung cancers in men, lung cancer remaining the leading cause of cancer death worldwide. With the number of new cancer cases projected to reach 34.4 million by 2050, the authors call for placing primary prevention, and first and foremost the fight against smoking, at the heart of health policies.

GLOBOCAN estimates cover 34 types of cancer in 186 countries and territories. They are based on data from cancer registries, which record new diagnoses, and on national mortality statistics. Where this data is missing or outdated, researchers supplement it with statistical models. To allow for comparison between countries with different average ages, rates are calculated as if all countries had the same age distribution. The projection for 2050 assumes that the incidence rates observed in 2024—209.6 new cases per 100,000 men and 185.8 per 100,000 women each year—remain unchanged, and only considers population growth. The proportions of preventable cancers and deaths are based on other epidemiological studies that determine relative risks and risks attributable to risk factors. The authors point out that the quality of the data remains uneven: only one in three countries has reliable incidence data, and one in four has reliable mortality data.

Nearly half of cancer deaths are potentially preventable

According to the Langselius study[2] As cited by the authors, 48% of cancer deaths worldwide are potentially preventable: 33% through primary prevention of modifiable risk factors and 15% through early detection and improved access to treatment. This proportion varies considerably by region. In sub-Saharan Africa, it exceeds 60%, as the region has a high concentration of cancers that are either largely preventable, such as cervical cancer, or highly curable when detected early, such as breast cancer. These deaths occur despite the existence of effective prevention and treatment methods, which remain largely inaccessible: HPV vaccination and screening are still very inadequate, and 50% to 90% of breast cancers are diagnosed at an advanced stage, compared to approximately 30% in the United States. This last factor alone is responsible for approximately 15,130 deaths worldwide that could be prevented with appropriate treatment.

The proportion of cases attributable to known risk factors varies depending on the location. Approximately 80% of stomach cancers are linked to modifiable factors, the most prominent being infection with Helicobacter pylori, and 91% of cervical cancers are attributable to infections, primarily human papillomavirus (HPV). Approximately 20% of breast cancers are linked to known non-genetic factors, such as physical inactivity, smoking, excess weight, or alcohol. Worldwide, about 10% of new colorectal cancer cases are attributable to modifiable risk factors; in men, smoking accounts for half, followed by alcohol, excess weight, and physical inactivity. This proportion only considers a limited number of factors: a US study incorporating a broader range of established factors estimates that up to 55% of colorectal cancers could be prevented.

Tobacco, the leading preventable risk factor for cancer

Tobacco is implicated in numerous cancers. In 2022, nearly 60% of lung cancers in men and 32% in women were attributable to smoking. Lung cancer is projected to account for 12.8% of new cancer cases and 19.1% of cancer deaths worldwide by 2024, representing nearly 2.6 million cases and 1.9 million deaths. It is the leading cause of cancer death in men in 89 countries and in women in 26 countries, including China and the United States. Smoking also accounts for half of the preventable proportion of colorectal cancers in men and, combined with excess weight, more than 30% of pancreatic cancers in men and more than 20% in women. It is among the risk factors for stomach, liver, and cervical cancers, for which it accounts for the proportion of cases not attributable to infections. In high-income Western populations, up to 85% of esophageal cancers are thought to be attributable to tobacco, excess weight, and alcohol, while non-combustible tobacco (chewing tobacco, snuff, or snus) is associated with head and neck cancers.

The differences observed between countries largely reflect the stage of the tobacco epidemic. In high-income countries where smoking took hold in the early 20th century, such as the United Kingdom, the United States, and Australia, lung cancer rates among men have been declining since the 1980s and 1990s, some 20 to 40 years after the peak of consumption. In most low- or middle-income countries, where the tobacco epidemic is more recent, smoking prevalence has recently peaked or continues to rise, and lung cancer rates are expected to increase over the coming decades. The authors are concerned about a significant increase in the global burden, with several highly populated countries having some of the highest daily smoking prevalence among men, such as Indonesia (71 %) and China (45 %) in 2022. Among women, whose smoking epidemic is later, rates continue to rise in many countries, and the incidence among young or middle-aged women is approaching, or even exceeding, that of men in several European and North American countries.

The authors note that the measures of the World Health Organization's (WHO) MPOWER program protect approximately 6.1 billion people in 155 countries, each benefiting from at least one of these measures, but that their implementation remains uneven. In 2024, only 40 countries met the WHO's recommended tobacco tax level (at least 75% of the retail price). A model cited in the study estimates that more than 1.6 million lung cancers could be prevented in the European region over twenty years through the full implementation of tobacco control policies.

A burden expected to grow by 2050

At constant incidence rates, the annual number of new cancer cases is projected to increase from 20.6 million in 2024 to 34.4 million in 2050, a rise of 67 million per 1,000,000 inhabitants, primarily due to global population growth and aging, with the number expected to increase from 8.2 billion to 9.7 billion. To ensure that the number of new cases in 2050 does not exceed that of 2024, incidence rates would need to decline by 2 million per 1,000 inhabitants per year.

The projected increase would not affect all countries equally. The most developed countries would see the largest number of additional cases. This anticipated increase stems primarily from their aging populations and the still high prevalence of risky behaviors. The rise would thus be 4.5 million more in countries with a high HDI, including China, and 3 million more in countries with a very high HDI. However, it is in the least developed countries that the number of cases is expected to increase most rapidly due to the growing prevalence of risky practices: it would more than double in countries with a low HDI (from 0.9 to 2 million, or +122 per 100 million) and increase by 85 per 100 million in countries with a medium HDI, including India (from 2.6 to 4.8 million).

The authors argue that reducing exposure to avoidable risk factors, particularly tobacco, certain infections, alcohol, excess weight, and physical inactivity, is the most effective and sustainable approach to limiting cancer progression, with the potential to prevent millions of cases and deaths. They also call for expanded vaccination, organized screening, and equitable access to care, as well as increased national investment in epidemiological surveillance.

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[1] Sung H, Filho AM, Laversanne M, et al. Global cancer statistics 2024: GLOBOCAN estimates of incidence and mortality worldwide for 34 cancers in 186 countries. CA: A Cancer Journal for Clinicians, 2026. Accessed September 16, 2026.

[2] Langselius O, Rumgay H, Vignat J, et al. Avoidable deaths through the primary prevention, early detection, and curative treatment of cancer worldwide: a population-based study. The Lancet Global Health, 2026;14(3):e356‑e366.

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