WORKPLACE SAFETY AND INSURANCE BOARD
APPEALS RESOLUTION OFFICER DECISION
DECISION NUMBER: 20090027
OBJECTION BY: Worker
EMPLOYER: Participating
REPRESENTATIVES: Worker
HEARING DATE: July 14, 2009
ATTENDEES: Worker, Worker Representative
ISSUE
The worker objects to the March 12, 2007 and April 11, 2008 claims adjudicator decisions denying entitlement for prostate cancer.
HOW THE ISSUE ARISES
The worker is now 66 years of age. He was employed as a welder with the accident employer from 1971 until his retirement in 2000. In December 2005 he was diagnosed with prostate cancer for which he had surgery March 15, 2006. This claim was established to consider entitlement to WSIB benefits.
The employer was unable to provide personal exposure monitoring records for the worker but confirmed exposure to mixed welding fumes containing various metals. Entitlement was considered on the basis of possible cadmium exposure. While exposure to high levels of cadmium was considered possible a WSIB medical consultant noted prostate cancer is very common and despite extensive research major critical reviews do not find that occupational exposures can be identified as significant contributory factors.
AUTHORITY
11-01-01 – Adjudicative Process
11-01-02 – Decision Making (Weighing Evidence, Natural Justice)
11-01-03 - Merits and Justice (Decisions related to occupational disease)
ASSESSMENT OF THE EVIDENCE
I have reviewed the record and considered the evidence and submissions. Prior to the hearing the employer representative confirmed the employer would not be attending. The employer representative elected to provide written submissions by fax. These submissions were shared with the worker representative prior to the hearing. The worker representative did not provide a specific response but rather provided the worker perspective on similar issues in her closing arguments.
Submissions
The worker representative suggests entitlement is in order for prostate cancer based on exposure to cadmium and other metals resulting from the worker’s 29 years of employment as a welder. The representative notes the WSIB Occupational Hygienist confirmed elevated arsenic exposure and possible high cadmium exposure. The representative notes the September 2007 OHCOW report suggested studies connect prostate cancer and cadmium. The representative notes the employer confirmed there are co-workers suffering from similar conditions. In the absence of other identified risk factors and noting the worker’s 29 year employment history as a maintenance welder the representative suggests it is reasonable to conclude the workers prostate cancer developed as a result of his work exposures. The representative requests benefit of doubt be applied and entitlement for prostate cancer be accepted. The representative notes the claim at present is limited to payment for health care and travel expenses.
The employer representative suggests the operations division conclusion the workplace exposures were not a significant contributing factor in the development of prostate cancer is correct. The representative suggests benefit of doubt is not in order as the evidence is not equal in weight. The representative suggests the weight of evidence supports the prevailing adjudicative decision and requests the decision to deny entitlement be affirmed.
Analysis
The worker provided testimony describing the nature of his employment from 1971 to 2000. The worker confirmed the general evidence already on record. However, he reports he was employed as a maintenance welder throughout his career with the accident employer. He reports he worked at the met site until the smelter came on line in 1981 or 82 and he then worked in the smelter until retiring in 2000. He reports that throughout his career 90% of his work was maintenance and repair. He reports in the early years limited protective breathing gear was worn and he would frequently be inhaling various fumes while welding and cutting. The worker reports he submitted his claim initially when a former co-worker with whom he was visiting indicated he had a similar condition and suggested he should put in a claim. The worker reports his doctor’s never provided him with a specific opinion as to the cause of his condition.
In assessing entitlement for industrial diseases which are not defined either by regulation or a specific policy, decision makers must condition possible entitlement based on the merits of the case. Under these circumstances the evidence must establish that on the balance of probability the employment exposure was a significant contributing factor in the development or progression of the condition.
In assessing the evidence and worker testimony I accept as fact the worker would have experienced high levels of cadmium and other metal fumes exposure during his period of employment. I further accept it is probable the exposure exceeded recommended levels. I further accept as fact that the worker was diagnosed with adenocarcinoma of the prostate.
The presenting issue is therefore whether there is sufficient evidence to establish this exposure is shown to be a significant contributing factor in the development of this condition.
While the worker representative has suggested benefit of doubt be applied and entitlement allowed I would only consider entitlement in order on this basis should the evidence be accepted as approximately equal in weight. The primary concern therefore becomes whether the medical evidence is sufficient to establish that on the balance of probability the condition would be accepted as arising from the employment exposure.
In this instance I note the worker was diagnosed with a primary prostate cancer and the evidence confirms a number of former co-workers developed similar conditions.
A WSIB occupational hygienist reviewed the employer records and confirmed probable exposures to cadmium and arsenic above exposure limits. The case was then reviewed by the WSIB medical consultant Dr. Muir who in February 2007, noted prostate cancer is very common and despite extensive research, major critical reviews do not indicate occupational exposures can be identified as significant contributory factors.
In response to this opinion the worker representative arranged for an OHCOW review in September 2007. In this report Dr. Jugnunden reviewed the medical records and conducted a further literature review. This review led to the doctor suggesting there is strong evidence showing an association between cadmium exposure and other metal fumes and prostate cancer. The doctor opined that in the absence of other risk factors, exposure to cadmium and other metal fumes was the most likely cause or a significant contributing factor in the development of the prostate cancer.
In light of this reporting Dr. Muir was again asked to review the claim. In his April 2008 review Dr. Muir suggested that despite much research and interest in relation to prostate cancer and cadmium exposure, there is at present insufficient evidence to support a causative effect.
In considering the expressed medical opinions I note two areas of concern.
The first is the difficulty in assessing causes for such a relatively common cancer. The record confirms the condition with which the worker was diagnosed is a relatively common cancer given his age and gender.
The second is the discrepancy in the medical literature in terms of identifying the causes of prostate cancer. The deficiency noted in the OHCOW report is the conflict between the epidemiological and laboratory evidence concerning carcinogenicity of cadmium in the prostate. This report did go on to indicate there is strong evidence of an association between cadmium and other metal fumes exposure and prostate cancer. Dr. Muir’s review places this analysis in context by noting the WSIB use of the Bradford Hill criteria when adjudicating entitlement based on occupational exposures which includes demonstration of statistically significant and increased risk in association with exposure and a dose response where possible. In this response Dr. Muir noted the major reviews did not conclude the evidence supports a link between prostate cancer and cadmium exposure.
Having reviewed the available evidence and relevant medical opinions, I consider it appropriate to ascribe greater weight to the opinion of Dr. Muir than the OHCOW report. I base this conclusion on the nature of the review conducted by Dr. Muir and the fact the suggestion of a probable relationship in the OHCOW report would appear to be based on laboratory evidence suggesting cadmium as a carcinogen rather than epidemiological evidence identifying this exposure as a specific risk factor for prostate cancer.
In summary, while there is no question as to the significant and serious nature of the worker’s diagnosed condition I do not find the evidence sufficient to establish the workplace exposure as a significant contributing factor in the development of prostate cancer. In the absence of the evidence being approximately equal in weight I also do not consider it appropriate to extend entitlement based on the benefit of doubt.
CONCLUSION
The objection is denied.
DATED July 23, 2009
M. Evans
Appeals Resolution Officer
Appeals Branch