GLOBAL CANCER BURDEN DUE TO OCCUPATIONAL EXPOSURES
Authors: Weiderpass Elisabete , Schubauer-Berigan Mary , Schüz Joachim 
Published: July 2024

According to the estimates of the International Agency for Research on Cancer (IARC), in 2022 there were 20.0 million new cancer cases and almost 10 million cancer deaths worldwide. Lung cancer was the most commonly diagnosed cancer worldwide in 2022 (12.4% of the total cases), followed by cancers of the female breast (11.6%), colorectum (9.6%), prostate (7.3%), and stomach (4.9%). Lung cancer was also the leading cause of cancer death (18.7% of the total cancer deaths), followed by colorectal (9.2%), liver (7.8%), female breast (6.9%) and stomach cancer (6.8%). Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development and implementation of effective prevention and mitigation strategies.

Occupational carcinogens represent a significant threat to workers’ health, notably when they are simultaneously exposed to several carcinogens. Understanding the global scope of cancer burden specifically related to occupational exposures is crucial for implementing effective workplace safety policies and minimizing the associated health risks. Studies of cancer in workers have been instrumental in identifying causes of cancer in humans, often with direct relevance to the general population and public health.

The IARC Monographs programme plays a crucial role in identifying the carcinogenic hazards posed to humans by various chemicals, physical and biological agents, complex mixtures, personal habits, and occupational exposures. Over the years, the programme has observed a notable increase in the number of Group 1 agents, classified as carcinogenic to humans, with occupational relevance. From 28 of 89 total Group 1 agents identified through 2003, this figure rose to 47 out of 119 Group 1 agents by 2017. Additionally, there were 12 more broadly defined occupations, industries, or processes classified in Group 1 with "sufficient" evidence in humans.

3.5-5% of all cancer deaths, varying by country in high-income countries with less precise data for low-and-middle countries, were estimated due to occupational carcinogens. Occupational carcinogens are the exposures where still today the resulting cancer burden is much higher in men than in women. Lung cancer is the main occupational cancer in terms of absolute numbers. Mesothelioma, on the other hand, which is a rare cancer is mostly caused by occupational exposure to asbestos.

However, there remains a notable gap in epidemiological evidence for many workplace exposures of concern. Addressing this gap requires ongoing research on the occupational causes of cancer, particularly in low- and middle-income countries, to enhance our understanding of quantitative exposure and exposure–response data. This imperative research will not only fill crucial gaps but also inform effective preventive measures to safeguard workers' health globally.

In her lecture, Dr. Weiderpass will highlight IARC’s epidemiological research on occupational cancers and on occupational carcinogens identified by the IARC Monographs programme.