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Katie Rose

Katie Rose

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Fairchild crumble? Mesothelioma and radiotherapy

AWARE22/03/2013
Disease Aware Issue 2

Asbestos exposure is the most commonly known risk factor for the development of malignant mesothelioma. The precise mechanism of causation for the disease remains outside the current state of medical and scientific knowledge, thus preventing the victim from proving which exposure was causative. The victim will be unable to satisfy the standard 'but for' test. Even on a balance of probabilities, he cannot prove which fibres caused the disease.

Current test for causation

The Fairchild exception was created to modify the test for causation and fill the gap created by scientific limitations. The exception creates 'a several and joint liability to every party who has, in breach of duty, been responsible for exposing the victim to a significant quantity of asbestos dust and thus creating a 'material increase in risk' of the victim contracting the disease.'

In the case of Barker, the House of Lords considered the application of the Fairchild exception where a defendant was responsible for only a part of the exposure. The Lords readdressed the position confirming that a defendant should only be severally liable for a share of the damage. This part of the judgement was later reversed by s3 of the Compensation Act 2006. Lord Hoffman held that, “the standard rule is that it is not enough to show that the defendant's conduct increased the likelihood of damage being suffered and may have caused it. It must be proved on a balance of probabilities that the defendant's conduct did cause the damage in the sense that it would not otherwise of happened.”

The current position therefore dictates that a victim must show a defendant materially contributed to the risk of the disease. The existence of the 'material contribution' must be proved on a balance of probabilities by the victim.

A competing cause

The Fairchild exception deals with a singular cause of the disease, a concept unique to mesothelioma. Where the evidence demonstrates separate potential causes, which is the correct test of causation to be applied? The time for an answer may have arrived.

Several recent studies have suggested a link between radiation therapy for primary cancers and the subsequent development of malignant mesothelioma. Travis conducted a study in 2005 involving the examination of 40,576 testicular cancer patients to attempt to quantify risks of the development of secondary tumours in long-term survivors. The patients reviewed were diagnosed with a primary cancer of the testis between January 1 1943 and December 31 2001 and had survived at least 1 year.

The study observed statistically significantly elevated risks, for the first time, for cancers of the pleura i.e. malignant mesothelioma. The relative risk (the ratio of risk in testicular cancer patients to that in the general population) was 3.4 with a 95% confidence interval of 1.7 to 5.9. These increased risks were considered to persist for at least 30 years after the initial diagnosis/treatment (a latency period parallel with mesothelioma). The results relate to the chest radiotherapy for Hodgkins Lymphoma, breast cancer and testicular cancer. The results demonstrate evidence that very high doses of radiation might be causally related to cancers at the chest site - including malignant mesothelioma.

The American Cancer Society recently published a paper dealing with the risk of secondary cancers caused by radiotherapy treatment. The paper concludes that radiotherapy is associated with a two to threefold increased risk for secondary tumours. The cancers tend to develop near the area that was treated with radiation. If the radiation field includes the chest, the risk of both lung cancer and mesothelioma are increased.

Even more interesting is the increased risk after radiation if the individual is a smoker. The two factors are thought to act synergistically, as smoking does with asbestos exposure in asbestos lung cancer cases.

The correct test for causation?

The standard position in a mesothelioma claim would be that there is no argument but that mesothelioma is caused by asbestos inhalation. On the state of the present law, there must be proof of material exposure alongside reasonable forseeability of harm as proof of breach and significant exposure to asbestos dust to create a material contribution to the indivisible cancer.

The position is arguably different when a competing cause of the mesothelioma is discovered. If a claimant has a history of a previous cancer, for which he received radiation therapy to the chest site, he is at an increased risk of mesothelioma from that source. Medical research states that asbestos and the radiation treatment will probably have a synergistic effect. This set of variables would not fit within the Fairchild exception dealing with a singular cause for the disease. Arguably the correct test to be applied would be that set out by Lord Hoffman in Barker dealing with lung cancer, which has separate potential causes acting synergistically.

If the above analysis is correct, then the approach on causation may be as set out by Lord Phillips in Sienkiewicz - namely that proof of more than a doubling of the risk from the asbestos must be proved. Lord Phillips at paragraph 93 of the judgement stated:

“Where there are competing alternative, rather than culmative, potential causes of a disease or injury, such as in Hotson, I can see no reason in principle why epidemiological evidence should not be used to show that one of the causes was more than twice likely as all the others put together to have caused the disease.”

If the 'doubling of the risk' test is applicable in these circumstances, the court would need to be satisfied by a determination of fibre type and the amount ingested by the claimant during his employment. Such an analysis then begs the question; in circumstances of light exposure to asbestos alongside a competing cause, would the claimant be able to prove causation?

A step further is to ask the question that, where the cause is unascertainable and all that can be shown is a statistical chance that the breach has caused the injury, is there a claim at all?