Bad genes, bad luck and bad habits are frequently blamed for cancers, but stronger evidence of the occupational and environmental origins of our cancers is much more likely to be disputed or dismissed.
A December 2014 paper in journal Science, concluded two-thirds of the cancer types analysed were caused just by chance mutations. It noted: “These results suggest that only a third of the variation in cancer risk among tissues is attributable to environmental factors or inherited predispositions. The majority is due to ‘bad luck,’ that is, random mutations arising during DNA replication in normal, noncancerous stem cells. This is important not only for understanding the disease but also for designing strategies to limit the mortality it causes.”
The mention of ‘bad luck’ being the root cause of most cancers attracted blanket coverage in the popular press. In December 2014, Cancer Research UK (CRUK) said more than four in 10 cancers could be prevented by changes to lifestyle. According to CRUK, nearly 600,000 cancer cases in the UK could have been avoided in the last five years if people had healthier lifestyles.
However the tendency to blame genes, personal habits or just plain bad luck, steers the blame from many of the major environmental and occupational factors where regulatory and other interventions could eliminate the risk. ‘Chance mutations’ are frequently the product of exposure to carcinogens, with benzene exposure a particularly well documented example.
Ted Schettler, science director of the Collaborative on Health and the Environment (CHE), criticising the “bad luck” paper, noted: “By drawing conclusions that go beyond their data, the authors may deflect attention from the critical need to expand public health cancer prevention programs in our homes, communities, and workplaces. That would truly be an unfortunate outcome.”
Hazards magazine points to the 100 per cent mortality from bladder cancer in workers exposed to beta-naphthylamine in one US plant (Hazards, 2008). Or the conservative 2009 study that concluded one in 10 UK carpenters born in the 1940s would die of asbestos-related lung cancer or mesothelioma (Peto, 2009).
Other examples like nasal cancer in leather workers or mesothelioma hotspots in areas with high concentrations of dockwork or chemical production show that the working and living environment is frequently the difference between being at risk and being killed. Almost all causes of lung cancer, the biggest cancer killer, were identified in workplace studies (Infante, 1975).
Cristian Tomasetti and Bert Vogelstein. Variation in cancer risk among tissues can be explained by the number of stem cell divisions, Science, volume 347, number 6217, pages 78-81, 2 January 2015.
Lifestyle behind more than half a million cancers in five years, CRUK news release, 26 December 2014.
Ted Schettler. Cancer, stem cells and bad luck, critical online commentary from the Collaborative on Health and the Environment, 6 January 2015.
Silent Spring commentary. BBC News Online on the ‘bad luck’ and ‘lifestyle’ cancer stories. Risks 685.