In a recent article published in The Lancet Global Health, researchers presented the findings of a population-based study conducted across 185 countries to estimate premature deaths due to 36 different types of cancers in 2020, a leading cause of premature deaths worldwide.
They categorized premature cancer deaths as preventable (via primary or secondary public health interventions) and treatable (via curative treatment) deaths.
The Organisation for Economic Co-operation and Development (OECD) estimates that ~1.9 million preventable and >1 million treatable premature deaths occurred across 38 OECD member countries in 2017. Of these, ~31% of preventable and 27% of treatable premature deaths occurred due to cancers.
The global burden of cancer incurs significant societal and financial costs. For instance, in Brazil, Russia, India, China, and South Africa (BRICS) countries, estimated productivity losses due to premature cancer deaths are 46.3 billion USD.
While timely public health interventions could prevent premature deaths from some cancers, it isn't a feasible approach for many cancer types. Cancer is an umbrella term encompassing many diseased states arising from genetic mutations, environmental factors, or lifestyle choices. Moreover, growth rate, the likelihood of metastasis, and response to treatment vary for different cancers, raising the need for a personalized approach to manage cancer.
About the study
In the present study, researchers extended the OECD work to a global scale to explore the multifaceted variations in premature cancer deaths. They presented the burden of preventable and treatable premature deaths and estimated crude and age- and cancer-type-adjusted years of life lost (YLLs) for 36 cancer types in 2020 for 185 countries. Further, they stratified their findings by country (world region) and their Human Development Index (HDI), sex, and age groups.
In 2020, over 50% of 9.96 million cancer deaths occurred prematurely, i.e., before the age of 70, equating to 182.8 million YLLs. The proportion of premature YLLs in low HDI countries was higher compared to high HDI countries (68.8% vs. 57.7%). Moreover, women in low HDI countries had to bear a higher burden of premature cancer deaths than men, most of which were due to cervical cancer caused by the human papillomavirus (HPV).
Thus, increasing HPV vaccination coverage and cancer screening in low HDI countries could potentially eliminate cervical cancer.
Owing to high levels of tobacco use among men in many middle-income countries, they bear a higher burden of premature deaths from lung cancer. The prevalence of lung cancer in women is also high in high HDI countries, indicating changing cancer profiles among women.
Higher smokeless tobacco use among men in medium HDI countries, such as India, Bangladesh, and Nepal, has led to increased dominance of head and neck cancers in men, both of which are preventable. Other preventable cancers are attributable to alcohol use, such as liver and esophagus cancers, commonly affecting the populations of Central-eastern Europe and Eastern Asia.
Together, tobacco and alcohol use, as well as environmental (air pollution) and occupational risks (asbestos exposure), impact the variability in premature, preventable cancer deaths. Moreover, people in each country experience varying cancer risk factors; thus, the preventable proportion of premature YLLs due to cancer varies by country.
Furthermore, the study estimates suggested that nearly one-third of premature YLLs from cancer(s) were preventable with equitable access to effective treatment. In high HDI countries, the quality of cancer care systems and therapeutic capacities are superior to middle- and low-income countries. Moreover, they have better infrastructure for providing essential cancer care services, such as radiotherapy, chemotherapy, and surgery.
The inequities in the distribution of radiotherapy machines across low-income and high-income countries are enormous, with the former having an average of 0.06 machines per million inhabitants compared to more than seven per million in the latter, contributing to a substantial variation in premature cancer mortality.
Surprisingly, treatable premature cancer deaths due to colorectal and breast cancer remained comparable across all countries. In high-income countries, screening programs have also helped reduce premature deaths by treatment of colorectal and breast cancers in their early stages. In low- and middle-income countries, these screening programs have remained ineffective. Thus, these countries need screening guidelines customized to their specific situations to give people more access to effective cancer treatments.
The right combination of primary and secondary prevention measures and more accessible and cost-effective treatments translate into multimodal quality cancer care. Low HDI countries have a larger population in premature age groups (30-69 years) and a lower life expectancy in general, resulting in a higher proportion of premature YLLs. In addition, they have weaker and fragmented health systems.
On the contrary, high HDI countries, through the cost-effective implementation of public health programs and high-quality cancer screening programs with high population coverage, have ensured that their citizens have equitable access to quality cancer care, including care for cancer survivors.
To summarize, the current study examined preventable and treatable cancer deaths worldwide and their impact on global and national health systems.
They found that the burden of these deaths and YLLs was the highest in transitioning countries, raising the need for prioritizing national cancer planning and implementation, with greater emphasis on primary and secondary prevention of premature deaths due to cervical, colorectal, breast, and lung cancers, and building therapeutic capacity. More importantly, cancer control strategies should be tailored to the country's needs.
Global and national efforts for higher investments in cancer risk factor(s) reduction and vaccination [for prevention of specific cancers (e.g., cervical cancer)] are needed. Moreover, in global initiatives advocating universal health coverage, nations should appeal to address disparities in access to cancer care.
Furthermore, since premature cancer death rates vary by cancer type and gender, there is a need for monitoring cancer-specific deaths in a sex-disaggregated manner.
Overall, the study data could help implement, monitor, and tailor national health policies concerning cancer prevention and treatment to minimize premature deaths worldwide.