Thursday, January 15, 2009

How much of the Cancer Burden is Work Related?

Everyone knows someone with cancer. About 4 in every 10 of us will be diagnosed with a cancer in our lifetimes regardless of gender. How much of this has to do with the work we do? Estimates vary. The Health and Safety Executive in Britain quotes 4% (range 2% to 8%). A Queensland publication suggests 11% of cancers in males and 2% in females are work related. Whatever the true level, the recorded number of cases that present as claims for workers' compensation are consistently low and those allowed are much lower.

Since the causes of cancer are many, the attribution of work being the cuase is difficult. On a population basis, statistics and very large sample sizes can attribute much or most of the cause to occupation, materials or agents in the workplace, or some other work-related exposure. Unfortunately, this is much harder to do on an individual basis, yet that is what workers' comp systems are asked to do.

The standard of proof on an individual claim is often very high. Some jurisdictions require work to be 'the predominant cause' while others set the bar lower with work being of 'causitive significance'. And the burden of proof often rests with a worker who may have imperfect information on exposures, have other risk factors for a particular cancer, or may have already succumbed to the disease before a claim is even decided.

To overcome these issues, many workers' compensation jurisdictions create schedules or include provisions in their legislation (often called 'presumptions'). Rather than requiring each worker and adjudicator to labour over a particular set of facts, the existance of a presumption allows the claim to be adjudicated quickly. A diagnosis of Asbesosis and Mesothelioma may be presumed to be work-related if associated with a history of work exposure to asbestos, for example.

As the science around the 'work-relatedness' of a particular cancer develops, authorities like IARC, the International Agency for Research on Cancer, provide guidance that may help prevent future work-related cancers and increase vigilance regarding cancer to those exposed to the cuasative agent. IARC uses a four-level classifcation system regaring carcinogenicity to humans with Group 1 representing those agents that are carcinogenic.

About a year ago, IARC published a mongraph that found the following:

How ought workers' compensation/prevention agencies react to this information? The compenstion side will always be difficult and will ultimately require each case to be determined on its own merits. The designation of exposure to a substance, occupation or other agent as a Group 1 carcinogen may assist in claim decision-making. For all Group 1 and 2 categories, prevention is high priority. Identification of those at risk may be straightforward (as it is in these examples where occupations or shiftwork are identified) but the next task is to reach the workplaces where these carcinogens are present. How to do that is a subject I would like to hear from you about? Feel free to email me or make a post!

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