APPEALS RESOLUTION OFFICER DECISION
DECISION NUMBER: 20230049
OBJECTING PARTY: worker
REPRESENTED by: worker REPRESENTATIVE)
RESPONDENT: employer
HEARING: HEARING IN WRITING
HEARD by: l. diaz, appeals resolution officer (ARO)
ISSUE
The worker objects to the Adjudicator’s June 2, 2022 decision which denied entitlement to occupationally related colon cancer.
BACKGROUND
The history of this claim is documented in a prior May 10, 2022 appeals decision and will therefore not be repeated at length in this decision. Briefly, the worker is claiming entitlement to colon cancer stemming from their occupational exposures while employed in the rubber industry from 1954 until their retirement in 1989. The worker was 85 years old at the time of their diagnosis in August 2014.
The worker’s file was reviewed by a WSIB Occupational Hygienist (OH) on January 14, 2019, to comment on the worker’s potential for occupational exposure to asbestos, x-ray and gamma-radiation.
The worker’s representative submitted a March 28, 2019 opinion by Dr. Jugnundan of OHCOW (Occupational Health Clinics for Ontario Workers Inc.) for consideration.
At the request of the Adjudicator, an external Occupational Medical Consultant (OMC) then provided a January 30, 2020 opinion with respect to whether the worker’s occupational exposures to asbestos, x-ray and gamma-radiation significantly contributed to the development of their colon cancer.
Following review of the above information and the general file information, the worker’s claim for colon cancer was denied in an April 27, 2020 decision. This decision was upheld in a May 10, 2022 ARO decision. However, the May 10, 2022 ARO decision clarified that their review of the worker’s case was based solely on the worker’s exposure to asbestos and did not have regard for exposure to chemicals in the rubber industry.
The worker’s representative then requested entitlement to colon cancer under the claim based upon the worker’s exposure to chemicals in general at their workplace. The Adjudicator referred the worker’s file to an external OMC provide an opinion on the matter. Dr. Markus, OMC, provided an opinion in a June 1, 2022 review.
Adjudicator’s June 2, 2022 decision
Following a re-review of the file information and the opinion by Dr. Markus, the Adjudicator concluded in the June 2, 2022 decision that the worker’s occupational exposures did not significantly contribute to their condition, and as a result, denied entitlement to colon cancer under the claim.
Worker’s position
In their August 23, 2022 Appeals Readiness Form, the worker’s representative requested that I refer to their prior October 22, 2021 prior submission for consideration. Their submission and arguments will be reviewed in the body of this decision.
AUTHORITY
Workplace Safety and Insurance Act
Section 2(1)
Section 15
Section 119
Operational Policy Manual documents: Published
11-01-02 Decision Making October 12, 2004
11-01-03 Merits and Justice October 12, 2004
ANALYSIS
I find the worker does not have entitlement to occupationally related colon cancer under the claim. In arriving at this decision, I had regard for the arguments presented, the relevant file information, and the applicable policies and legislation.
Occupational disease claims are adjudicated under Section 2(1) and Section 15 of the Act and by Regulations 3 and 4 of the Act. If the disease for which the worker is claiming entitlement to benefits is not listed in the Schedules and a relevant policy has not been developed, initial entitlement is determined based on the merits and justice of the individual claim.
For entitlement to be granted under Policy 11-01-03, it must be shown that it is more probable than not that the circumstances of a worker’s employment and exposure history significantly contributed to the development of the condition being claimed.
Review of file medical information
The file medical information confirms that on August 18, 2014, the worker presented to X Hospital emergency after awakening at night with sharp umbilical abdominal pain, bloating, and nausea. The worker underwent a CT scan following which a colonic mass was identified. The worker was then taken to the operating room that evening for an exploratory laparotomy and underwent a right hemicolectomy. This report noted the worker was a non-smoker and would drink one beer per day. The worker was diagnosed with stage III colon cancer.
The worker underwent a colonoscopy on May 15, 2015, during which time a lesion in the upper rectum was removed endoscopically. Dr. Kilmurry’s June 18, 2015 report confirmed the lesion did have some carcinoma within it. Given the worker’s concurrent medical concerns, the recommendation was to simply monitor the situation. A December 17, 2015 repeat colonoscopy was normal. A repeat colonoscopy was recommended in 3 years.
There was no further medical information submitted to file in relation to the worker’s colon cancer.
Occupational exposures
WSIB OH, A. Nayebzadeh, conducted an occupational hygiene review which provided the following relevant information in relation to the worker’s occupation and potential exposures:
From 1954 until 1959 the worker was employed at Y as a Lead Man / Machine Operator where potential occupational exposures included the following: petroleum-based solvents: hexane, benzene and toluene, rubber process emissions, PVC fumes.
From 1959 until 1989 the worker was employed at Z at the A St. plant. From 1959 until 1982 the worker was employed as a General Relief with duties in Banbury and milling. From 1982 until 1990 the worker was a Calender Operator / Union President. Potential exposures included rubber solvents such as hexanes, cyclododecatriene, gasoline, naphtha, aliphatic and aromatic hydrocarbons such as hexane, toluene, xylene, benzene, MEK. Carbon black, sulphur compounds, zinc oxide, pigments, mineral oil and extender oils, rubber process emissions, talc, etc.
The WSIB OH indicated in their report that the process and job description in their review was based on information obtained by the operating area, along with supporting documentation, the worker’s statements on file, the employer’s submission, government reports, and the OH’s understanding of the process/jobs in question.
The WSIB OH provided the following general information with respect to the business:
The manufacture of tires involves a series of operations, which have the potential for exposing ‘workers to a variety of chemicals. Chemicals used in the manufacturing of these products are added to the rubber either to shorten the time of vulcanization (curing) or to gain certain desired properties in the rubber. A tire consists of five basic parts: tread, sidewall, cord or ply, bead and liner. The processes associated with tire manufacturing are compounding, mixing, milling, extrusion, calendaring, tire building, vulcanizing and inspection and finishing. The available information about the worker’ employment history indicated that he was engaged in various duties at Y and X plant located on A St.
The worker’s job duties included the following:
Y: (approximately 5 years):
The worker stated that the were employed at Y. This was a rubber shoe manufacturing company. They added that the company made mostly plastic overshoes. They were the Lead Person and they oversaw 4-5 staff but they were in charge of running the machine. Part of their duties included removing molds out of the machine. They also added that they were involved in curing plastic components.
Z: (~30 years)
Banbury/Milling relief worker: The claimant worked for approximately 25 years in banbury and milling, compounding area. The employer indicated that the worker was compound helper. The worker noted that they were engaged in various duties in banbury and worked as a relief worker and therefore they were engaged in various duties. Majority of their job was to prepare batches of mixed chemicals and to transfer them to Banbury for mixing. The main tasks performed by the worker involved manual transferring and weighing of various rubber ingredients including powders and oils. The worker placed the ingredients in bags and transported the bags to the Banbury mixing area and placed the bags of chemicals on the conveyor. The worker also placed the slabs of synthetic or natural rubbers on a conveyor which were then loaded into the hopper for a Banbury mixer. In addition, a smaller portion of the worker's shift was spent cleaning and sweeping in the compounding room and assisting with the unloading of rubber ingredients from rails cars and trucks.
It should be noted that the employer’s submission indicated that worker was engaged in duties such as hand cement and elevator truck during the above period (1959-1985). The worker explained that these tasks were short- term duties in the milling area.
Calender Operator (6): As an operator, they were responsible setting-up the various machine parameters, feeding the rolls of rubber into the calender and monitoring the coating process via a control panel located near the calender. The worker also unwrapped rolls of fabric and spliced the ends of the fabric using rubber pieces. The splicing operation involved the application of heat and pressure. The worker noted that they became Union President in 1984. Thus, it is estimated that they performed actual calendaring job for 1-2 years. The rest of their duties during the last 4-5 years of employment were administrative and they were not involved with operation of tire manufacturing equipment. They noted that their office was in the mill area.
Although the WSIB OH then documented the worker’s exposure assessment, it was principally in relation to asbestos exposure. It was noted the worker’s job title did not suggest that they were involved in Quality Assurance testing and use of X-ray testing equipment, and as a result, it was not anticipated the worker had any exposures to ionizing radiation. There was no further evaluation of any additional potential exposures in the OH’s review.
Analysis
In the January 30, 2020 review, Dr. Somerville, OMC, provided the following background information on colorectal cancer:
Colorectal cancer is the third most commonly diagnosed cancer in males in the world. The highest rates are in Australia, New Zealand, Canada, the United States, and parts of Europe (1, 2). These geographic differences appear to be related to dietary and environmental exposures superimposed on a background of genetic susceptibility. The incidence is about 25% higher in men than in women. Age is a major risk factor for sporadic colon cancer. This disease is uncommon before the age of 40, but becomes more prevalent afterwards. The lifetime incidence of this cancer in individuals at average risk is about 5%, with 90% of cases occurring after age 50. The incidence rate is more than 50 times higher in persons aged 60 to 79 years than in those younger than 40 years (2).
Dr. Somerville recorded the following with respect to risk factors associated with this cancer:
Environmental and genetic factors greatly increase the likelihood of developing colon cancer. Inherited susceptibility results in the most striking increases in risk. Several specific genetic disorders, most of which are inherited in an autosomal dominant fashion, are associated with a very high risk of developing colon cancer. Familial adenomatous polyposis (FAP) and Lynch syndrome (hereditary non-polyposis colorectal cancer) are the most common of the familial colon cancer syndromes. The colorectal tumors that develop in patients with Lynch syndrome are characterized by early age of onset and predominance of right-sided lesions. The mean age at initial cancer diagnosis is 48 years, with some patients presenting in their 20s. Nearly 70 percent of first lesions arise proximal to the splenic flexure, and approximately 10 percent will have synchronous (simultaneous onset of two or more distinct tumors separated by normal bowel) or metachronous cancers (non-anastomotic new tumors developing at least six months after the initial diagnosis) (1).
Family history is also an important risk factor even outside of the syndromes with a defined genetic predisposition. Having a single affected first-degree relative (parent, sibling, or child) with colorectal cancer increases the risk about twofold over that of the general population (1).
Aside from hereditary syndromes and family history of sporadic colon cancer, numerous other risk factors exist such as inflammatory bowel disease, abdominal radiation, African-American descent, obesity, cigarette smoking, acromegaly, renal transplantation, diabetes mellitus, heavy alcohol use, physical inactivity, and long-term consumption of red meat (1). Taken together, physical inactivity and excess body weight are reported to account for about a fourth to a third of colorectal cancers (2). It has been estimated that 12% of colorectal cancer deaths are attributable to smoking (3). Diet strongly influences the risk of colorectal cancer as well. Diets high in fat, especially animal fat, are a major risk factor for colorectal cancer (2). For example, it has been estimated that around 21% of colorectal cancers in the UK were linked to consumption of red and processed meat (4).
An association between colon cancer and Barrett's esophagus has been reported. Barrett's esophagus is a condition in which the cells lining the esophagus are replaced by cells similar to the intestinal lining. This more often occurs in a setting of long-term gastroesophageal reflux disease - GERD. Patients with Barrett's esophagus may develop more changes in the esophagus called dysplasia. When dysplasia is present, the risk of getting cancer of the esophagus increases. Some research suggests the risk of developing colon cancer increases in cases of Barrett's esophagus as well, although the data are conflicting (5, 6).
In their January 30, 2020 review, Dr. Somerville also referenced the following with respect to review of related studies:
Some studies have found excess mortality from gastrointestinal (GI) cancer in asbestos-exposed populations; however other studies have found no significantly increased risk for GI or colorectal
cancer. Confounders, such as diet, alcohol, and other chemical exposures were rarely well-controlled. Studies often failed to differentiate between the multiple types of gastrointestinal cancers. Some of the studies that found an association involved very high levels of asbestos fibers in drinking water, which is a route of exposure not often found in industrial settings. Animal studies using the rat model have also shown conflicting results. According to the Agency for Toxic Substances and Disease Registry, "the available data do not support a definitive conclusion about whether the increased risk for gastrointestinal cancer observed in some of the epidemiologic studies is real or not" (7).
A consensus report released in June 2006 from the Institute of Medicine of the National Academies in the United States reviewed the available studies regarding asbestos and risk of colorectal cancer. The consensus report noted that case-control studies with higher quality assessment of asbestos exposure found essentially no association while lower quality studies found a significantly positive association between asbestos exposure and colorectal cancer. For the case-control studies examined, the summary estimate of association was not statistically significant. Furthermore, the case-control studies did not provide evidence of a dose-response relationship, while cohort studies were very modestly statistically significant with slight evidence of a dose-response relationship. The consensus report concluded that the available evidence was suggestive but not sufficient to infer a causal relationship between asbestos exposure and colorectal cancers (8).
Statistically significant evidence demonstrating an association between asbestos exposure and colorectal cancer typically comes from studies in which individuals were heavily exposed to respirable asbestos fibers for prolonged periods of time or ingested high levels in drinking water. There is relatively little consistency in the observed increases across studies though. This finding regarding high level exposure to asbestos is in keeping with the position of the WSIB Occupational Disease and Policy Research Branch Report of May 2009 which noted, "there is suggestive evidence of an increased risk of gastrointestinal cancer for those with high cumulative exposure to asbestos".
Results of studies of solvent exposure and risk of colon cancer largely mirror those of asbestos and colon cancer. Evidence overall is conflicting. Most of the cancer literature focused on benzene, trichloroethylene, tetrachloroethylene, perchloroethylene, methylene chloride, and mixtures of unspecified organic solvents. Many studies did not have accurate exposure data, which diminished the overall quality of the study. Additionally, many studies lacked sufficient size. Furthermore, many were not adjusted for age, diet, body mass and physical activity. A recent study that had better design parameters found no consistent evidence of increased cancer risk including from those with long-term exposure to solvents such as trichloroethylene, perchloroethylene and mixed solvents (9). More robust studies, which would be biomarker studies incorporating body burden of solvents as well as markers of effect, have yet to be done (10).
Dr. Somerville also indicated that the association between ionizing radiation exposure and cancer has been well-documented, mainly from data on atomic bomb survivors and from patients who received high-dose therapeutic radiation for diseases other than cancer. Dr. Somerville confirmed the association has been best established for leukemia as well as cancer of the lung, pancreas and rectum (11). However, the risk of cancer from radiation exposure increases as the dose of radiation increases. Dr. Somerville indicated that epidemiological studies have demonstrated the dose-response relationships for cancer induction and quantitative evaluations of cancer risk following exposure to moderate to high doses of ionizing radiation, but not for low doses of ionizing radiation.
I also had regard for Dr. Jugnundan’s March 28, 2019 consultation report. Dr. Jugnundan reviewed the worker’s medical, family, and work history. Dr. Jugnundan also documented the worker’s occupational exposures, however, I note the exposure information is not as detailed compared to what was provided by the WSIB OH.
In the March 28, 2019 consultation report, Dr. Jugnundan referenced a medical review by Dr. Sarma, WSIAT (Workplace Safety and Insurance Appeals Tribunal) Medical Assessor, which is contained in WSIAT decision xxx/xx dated May 31, 2000 for consideration. However, I note this medical review is more than 20 years old, and more epidemiological studies have been conducted on the subject since that time. As a result, I will lend significantly greater weight to the reviews provided by the external OMCs in the worker’s file as their reviews have also considered more contemporary epidemiological studies. Dr. Somerville referenced more recent medical literature with respect to colon cancer, as did Dr. Jugnundan. Dr. Jugnundan specifically referenced a recent study by Aran et al (2016) which highlighted associations with genetic factors, and lifestyle factors of high alcohol intake, diets rich in meat fat and low fibre, smoking, obesity, and inflammatory bowel disease.
Dr. Jugnundan also referenced the Thrumurthy et al (2016) study which published a review of colorectal cancer and documented the following risk factors: older age; male sex; red meat and processed meat consumption; obesity; alcohol; tobacco smoking; family history; inflammatory bowel disease. Although Dr. Jugnundan reviewed Monograph 100C, 2012 by IARC (International Agency for Research on Cancer), it was principally with respect to the association between asbestos and colon cancer, and not other agents. In summary, although Dr. Jugnundan indicated in this review that the worker’s occupational history indicated a potential exposure, it was in relation to asbestos exposure, which has already been addressed in the ARO decision of May 10, 2022.
With respect to occupational exposures in the rubber industry, Dr. Jugnundan briefly indicated that ‘there was some indication of an association between colorectal cancer and work in the rubber industry’. Dr. Jugnundan’s conclusion was that ‘the rubber industry in general may confer some increased risk of colorectal cancer’.
The worker’s file was more recently reviewed by Dr. Markus, OMC, on June 1, 2022, with respect to a review of chemicals in the rubber industry and any association to colon cancer. Dr. Markus provided the following opinion:
This is the 2ⁿᵈ review of this claim. In the first OMC review, Dr Somerville noted that IARC has not classified any occupational exposures as colonic carcinogens, other than ionizing radiation. Asbestos was listed as a Group 2 carcinogen. The remaining Group 1 carcinogens include alcoholic beverages, processed meat and tobacco smoke. The remaining Group 2 carcinogens included night shift work, red meat, and Schistosoma parasites. There is no indication that rubber industry work is associated with the development of colon cancer. Oddone et al conducted a review and meta-analysis of industries and colon cancer risk. The authors found increased risks of colorectal cancer for labourers occupied in industries with a wide use of chemical compounds, such as leather (RR= 1.70, 95%CI: 1.24- 2.34), basic metals (RR= 1.32, 95%CI: 1.07-1.65), plastic and rubber manufacturing (RR= 1.30, 95%CI: 0.98-1.71and RR = 1.27, 95%CI: 0.92-1.76, respectively), besides workers in the sector of repair and installation of machinery exposed to asbestos (RR= 1.40, 95%CI: 1.07-1.84). The relative risk of 1.27 for rubber manufacturing is in my opinion too weak an association to conclude compatibility on the balance of probabilities and failed to meet significance. Kogevinas et al found inconsistent results in an earlier review study such that 3/6 cohort studies found a modest excess of risk, while the other 3 found none. 1 out of 2 case-control studies found a three-fold excess risk, while the other did not. This inconsistency in the literature is borne out in more recent studies. IARC does not consider rubber industry work as a risk for colon cancer. I do not believe the evidence supports this association.
The worker’s representative indicated the file information did not support the worker had any personal risk factors associated with the development of colon cancer, except for age and sex. It was acknowledged the worker smoked for a period of time around the second World War, however, this smoking history was brief. Although scientific literature confirms that dietary factors are also considered a risk factor, i.e. red meat consumption, low fibre consumption, I note the file information is silent with respect to these risk factors.
The worker’s representative also included several citations of Dr. Demers’ July 8, 2020 report. Dr. Demers report was released on July 8, 2020, and was commissioned by the Ministry of Labour to review how scientific evidence can best be used in determining work-relatedness in occupational cancer claims, to inform best practices in other jurisdictions that Ontario should consider adopting, and to determine what scientific principles should inform the development of occupational disease policy.
The worker’s representative indicated the worker was employed in an atmosphere with multiple chemicals, and that even if the asbestos exposure was not at the level which could result in entitlement being granted, consideration ought to be given to the additive or synergistic effects of all chemicals to which the worker was exposed. The worker’s representative cited the portion of Dr. Demers’ report which indicates “when two or more hazardous substances have a similar toxicologic effect on the same organ or system, their combined effects, rather than that of either individually, should be given primary consideration”.
In response to the above citation, I note that there have not been ‘two or more hazardous substances’ identified by the worker’s representative or in the file information which likely had a similar toxicologic effect on the same organ or system (emphasis added) as a result of the worker’s occupational exposures.
Dr. Markus, Dr. Somerville, and Dr. Jugnundan all made reference to the fact that IARC did not consider that work in the rubber industry was a risk for colon cancer. As a result, based on the opinions above, and the scientific literature referenced, it is more likely than not that the potential ‘additive’ or ‘synergistic’ effects of the chemicals to which the worker was exposed at work had little effect on the development of the worker’s particular cancer.
Although Dr. Jugnundan indicated in their March 28, 2019 consultation report that the worker’s occupational exposures may have played a role in the development of their particular cancer, an opinion that something is possible or conceivable is insufficient for entitlement. To establish entitlement to colon cancer, the evidence must support that it is more probable than not that the circumstances of the worker’s employment and exposure history significantly contributed to the development of the condition being claimed.
In summary, having carefully considered the file information, the medical opinions provided, and the arguments presented, I do not find it has been shown that the worker’s occupational exposures significantly contributed to the development of their colon cancer. As a result, I conclude the worker does not have entitlement to colon cancer in the claim.
CONCLUSION
I conclude the worker does not have entitlement to colon cancer under the claim.
The worker’s objection is therefore denied.
DATED February 13, 2023
L. Diaz
Appeals Resolution Officer
Appeals Services Division