WORKPLACE SAFETY AND INSURANCE APPEALS TRIBUNAL DECISION NO. 1557/14

Transcription

1 WORKPLACE SAFETY AND INSURANCE APPEALS TRIBUNAL DECISION NO. 1557/14 BEFORE: M. Crystal: Vice-Chair HEARING: August 20, 2014 at Toronto Written DATE OF DECISION: December 4, 2014 NEUTRAL CITATION: 2014 ONWSIAT 2630 DECISION UNDER APPEAL: WSIB ARO decision dated January 31, 2013 APPEARANCES: For the worker: Mr. J. Patterson, United Steelworkers, Local 6500 For the employer: Interpreter: In house representative N/A Workplace Safety and Insurance Appeals Tribunal Tribunal d appel de la sécurité professionnelle et de l assurance contre les accidents du travail 505 University Avenue 7 th Floor 505, avenue University, 7 e étage Toronto ON M5G 2P2 Toronto ON M5G 2P2

2 Decision No. 1557/14 REASONS (i) Introduction [1] This appeal was considered as a written case in Toronto, on August 20, The worker s estate appeals the decision of Appeals Resolution Officer (ARO) Mark Evans, dated January 31, That decision determined that the worker is not entitled to benefits for lung cancer. [2] The worker s estate was represented by Mr. Jason Patterson, United Steelworkers, Local The employer participated in the appeal, and was represented by its in-house representative. Written submissions, dated April 30, 2014 were provided by Mr. Patterson. The employer s in-house representative provided written submissions, also dated April 30, (ii) The issue under appeal [3] The sole issue to be determined in this appeal is whether the worker, through his estate, is entitled to benefits for lung cancer. (iii) The evidence [4] The worker was employed by the accident employer, a mining company, beginning in According to a Board memo, dated January 10, 2005, prepared by Dr. H. Kabir, the Board s occupational hygienist, the worker began working at the employer s mill as a process labourer, and worked through several positions at the mill, until he became a foreman in The worker retired from his employment with the accident employer in The case materials included a Proof of Death Document, dated April 20, 2003, which stated that the worker passed away on that date. The worker was 81 years old at the time of his death. [5] Dr. Kabir s memo stated that the employer had provided no exposure monitoring data for the worker because the employer only began hygiene monitoring at about the time that the worker retired and it will be nearly impossible to find any co-worker still alive to testify to this worker s possible exposures. The memo went on to provide Dr. Kabir s views concerning the worker s possible occupational exposures, based on his understanding of the past processes and operations at the employer s mill, as well as the worker s smoking history based on information provided by the worker s widow. In this regard, the memo stated: Based on my understanding of the [employer s] mill processes and its operations in the past, I tend to suspect the possibility of this claimant s possible exposure to both asbestos & crystalline respirable silica. It will now be impossible to quantify or substantiate this possibility. Because of the wide-spread use of asbestos in the time period this claimant worked in the mill and his long-term involvement in the crusher operations, I tend to suspect the possibility of his exposure to asbestos and crystalline respirable silica. It is quite possible that the claimant may have had significant exposure to both asbestos and crystalline silica. The widow states that the claimant quit smoking some 27 years ago and prior to that he was a very light smoker. I have indexed and scanned the McMaster University epidemiology report relevant sections on the lung cancer risks of [employer s] mill workers who never worked on the sinter plant. This claimant appears to have solely worked in the mill & did not import any other carcinogenic exposures or risks from other processes and operations of [the accident employer]. Please bring this to the Medical Consultant s attention.

3 Page: 2 Decision No. 1557/14 [6] The case materials included information about medical investigation that the worker underwent in 1976, in connection with a medical issue that had arisen in relation to the worker s larynx. According to a report, dated December 28, 1976, prepared by Dr. P. Andrews, the worker underwent a laryngoscopy and biopsy on that date. The report stated that findings looked like a carcinoma of the left vocal cord. The worker underwent surgery to treat the issue associated with his larynx in January Although some medical information that was prepared in the course of his treatment for this issue suggested a diagnosis of carcinoma, as the Board subsequently pointed out, the worker did not have a clear diagnosis of laryngeal cancer. The issue of entitlement to benefits for laryngeal cancer was not an issue that was before me in this appeal. [7] Beginning in or about late 2000, the worker underwent some further investigation for an issue associated with his lungs. The materials included a report, dated February 18, 2003 on a CT scan performed on the worker s chest, which provided the following conclusion: Multiple left lower lobe nodules and associated lymphadenopathy highly suspicious for malignancy. I suspect there may be an adrenal gland metastasis. [8] The materials included a pathology report, dated March 5, 2003, prepared by Dr. Anna Tomczak-Bojarski, pathologist, which noted that the worker had undergone a core biopsy left lower lung mass, and that the biopsy specimen consisted of three pieces of apparent needle core biopsy measuring up to.9 cm in length which were all submitted in one cassette. The report provided the following diagnosis: DIAGNOSIS LEFT LUNG, LOWER LOBE MASS, CORE BIOPSY: Changes consistent with sarcoma [9] The report also provided the following Comment : The lack of staining for wide spectrum keratin makes less likely that this tumor represents sarcomatoid mesothelioma or sarcomatoid carcinoma. Also lack of actin and desmin staining suggest that this is probably not a leiomyosarcoma or rhabdomyosarcoma. There was no more tissue available for additional special stains. [10] The case materials also included a report, dated March 19, 2003, prepared by Dr. T. David Ewing-Bui, thoracic surgeon. The report noted that the worker s fine needle biopsy of the left lung mass revealed the presence of sarcoma cells but that in view of the fact that the patient has Alzheimer s disease and severe COPD [chronic obstructive pulmonary disease] he would not be a candidate for a surgical resection of his sarcoma. The report stated that treatment options would be discussed with the worker s family but that Dr. Ewing-Bui indicated that it is not unreasonable to treat him conservatively and to treat him symptomatically. As indicated above, the worker passed away on April 20, According to a Board memo, dated September 28, 2004, a claim was established at the Board in relation to the worker s lung cancer and laryngeal cancer. [11] At the request of the Board s Claims Adjudicator (CA), as well as Dr. I. Taraschuk, one of the Board s medical consultants, Dr. David C. F. Muir, the Board s chest consultant was asked to provide a medical opinion on the issue of the whether it was likely that the worker s lung cancer was related to his occupational exposures while employed by the accident employer. Dr. Muir provided his view in a Board memo, dated May 5, 2005, which stated, in part:

4 Page: 3 Decision No. 1557/14 A chest CT scan of 18/02/03 noted a mass in the left lower lobe, which was likely to be a malignant tumor. A needle biopsy was undertaken and the histology was a form of sarcoma. This was not related to the carcinoma of the vocal cord. The tumor was not amenable to surgery and the patient died on 17 April 2003 [sic]. He worked for 35 years in [the employer s mill] and retired in The epidemiological study of lung cancer in the [mill] did not show any evidence of a lung cancer risk and this is included in the report by Dr. H. Kabir. SUMMARY: Lung cancer in a worker employed in the [employer s mill] Not of occupational origin. [12] Again, at the request of the CA and Dr. Taraschuk, Dr. Muir was asked to provide an additional review of the worker s entitlement to benefits for lung cancer. Dr. Muir provided a further memo, dated July 21, 2005, which stated: I have reviewed LUNG SARCOMA in the PUB MED index and also in the textbook by Fraumeni on Cancer Epidemiology. This rare tumor is reported occasionally but no inferences about causation can be derived. Virtually all lung cancers are derived from surface epithelium and this gives rise to various forms of carcinoma. This would be expected since they are exposed to environmental carcinogens. Deep seated tissue gives rise to sarcomas and are not directly exposed. [13] In correspondence from the Board, dated September 8, 2005, the worker s widow was advised that the estate s claim for entitlement to benefits for both laryngeal cancer and lung cancer had been denied. The correspondence indicated that entitlement to benefits for lung cancer was denied, noting that: [the worker] was diagnosed with lung sarcoma which is a very rare form of cancer. Present medical research does not indicate a cause for this form of cancer but it is not expected that it would be caused by any exposure in the work environment. An epidemiological study of lung cancer in [the employer s mills] did not show any increased cancer risk among this group of workers. [14] The letter also stated that entitlement to benefits for laryngeal cancer was being denied because the medical reports on file from 1977 to 1980 indicate that he underwent surgery but was never diagnosed with laryngeal cancer. The letter stated that his diagnosis was atypical cells and because the worker had not been diagnosed with an occupational disease, the claim for laryngeal cancer was denied. As I have noted above, the question of whether the worker was entitled to benefits for laryngeal cancer, was not an issue that was before me in this appeal. [15] The worker s representative objected to the decision letter, dated September 8, 2005, and access to the worker s claim file was requested. The materials disclose that, between 2005 and 2008, there was no significant activity at the Board in relation to the worker s accident claim. It appears that, in or about 2008, the worker s estate, or its representative, requested that OHCOW (Occupational Health Clinics for Ontario Workers Inc.) further investigate the worker s case. The case materials included a Final Surgical Pathology Report dated June 16, 2008, prepared by Dr. Brendan Mullen, pathologist, in relation to the worker s case. The report stated that OHCOW had requested evaluation of the worker s pathology specimen for the possibility of mesothelioma. The report provided the following Comment :

5 Page: 4 Decision No. 1557/14 Interpretation is limited by the relatively small amount of tissue available. The differential [diagnosis] includes both primary and secondary neoplasms. While the diagnosis of mesothelioma cannot be fully excluded, it is unlikely on the basis of the morphology of the tumour and immunohistochemical staining pattern. Prior radiology should be consulted in this regard. In addition, histopathologic evaluation of the patient s primary larynx cancer is necessary to fully exclude this as a possible source of this patient s malignant spindle cell neoplasm. DIAGNOSIS Left (left lower lobe, needle core biopsy): - malignant spindle cell neoplasm. [16] Dr. Abe Reinhartz, a physician with OHCOW, provided a report, dated November 21, 2008, on the worker s case. The report reviewed the worker s history, including the recent pathology report provided by Dr. Mullen, referred to above. Dr. Reinhartz noted that Dr. Mullen had indicated that the best he could come up with was this was a malignant spindle cell neoplasm of some type due to the scantiness of the material in the biopsy specimen but that Dr. Reinhartz believed that clinically [the worker s] disease was typical of a run of the mill epithelial lung cancer in that it was associated with significant mediastinal lymphadenopathy as well as adrenal metastases, typical for lung cancers. The report went on to suggest that the Board s conclusion that the worker s cancer was a sarcoma was not likely. In this regard, the report stated: I believe that a considerable amount of confusion is due to the histological nature of the tumour. Given the extreme rarity of a primary lung sarcoma, in my opinion it is unlikely that this was the diagnosis given the metastatic pattern of disease is more typical for a primary lung cancer. Thurlbeck and Churg describe carcinosarcoma, which is an epithelial tumour with a malignant appearing stromal pattern. Histologically, most of the cancers [are] made up of this stromal component with a small epithelial component, usually, squamous cell carcinoma. The epidemiology follows that of a typical lung cancer in that more than 80% are male and more than 90% are more than 50 and most are smokers. In this case, the fine needle biopsy may likely [have] sampled more of this stromal component than the epithelial component and therefore, the diagnosis was missed. It is unclear if the malignant spindle cell component is truly of mesochymal origin of [sic- or?] epithelial origin as this is a matter of debate. Another possibility is that this was a primary spindle cell carcinoma of the lung which is a variant of squamous cell carcinoma (Pathology of Lung, Thurlbeck and Churg page 518). [17] The report went on to review medical literature related to the relationship of asbestos exposure to the development of cancer. The report concluded by stating: In summary, despite the debate about the histology of the tumour, common things being common and the fact that the clinical pattern of the disease followed a primary lung cancer, this is an epithelial lung cancer, this is the most likely diagnosis that [the worker] had. The WSIB has already acknowledged that [the worker] had significant workplace exposure to both asbestos and silica. These are both Type I lung carcinogens. Therefore, [the worker s] workplace exposures, despite his smoking history, played a significant contributing role to his development of lung cancer. [18] At the further request of Dr. Taraschuk, Dr. Muir considered the worker s case in light of the report provided by Dr. Reinhartz. Dr. Muir responded in a Board memo dated March 17, 2009, which stated: I have previously reviewed this claim on the basis that this was a rare pulmonary sarcoma. (See pathology report by Dr. Tomczak-Bojarski dated 05/03/03). The basis of

6 Page: 5 Decision No. 1557/14 Dr. Reinhartz s letter from the Occupational Health Clinic for Ontario Workers (OHCOW) is that he thinks it was more likely to have been a carcinoma. I am not a pathologist and cannot offer an opinion on the reliability of the biopsy report referral to above. It will be necessary to seek an opinion from a pathologist with a special interest in lung disease. Does the WSIB have a consultant who can assist? I understand that there is a University referral system in Toronto. [19] A further pathology report, dated May 5, 2009, was prepared by Dr. Ming-Sound Tsao, pathologist. Dr. Tsao s report stated, in part: Diagnosis Left lower lobe lung tumor, core needle biopsy (March 5, 2003): - Spindle cell neoplasm, favor sarcoma. Comment The examination of this biopsy material is very limited by the lack of additional materials for further immunohistochemistry studies. Request to the [hospital] for additional unstained sections indicated that the block has been exhausted. Based on the HE and results for the four immunohistochemistry stains, it is not possible to define further the nature of this lesion. The histology is that of a spindle cell neoplasm, consistent with a sarcoma. The differential diagnoses would include primary lung sarcoma such as pulmonary artery leiomyosarcoma, malignant solitary fibrous tumor, sarcomatoid mesothelioma or metastatic sarcoma. All these require additional immunohistochemistry studies to decide. Dr. I. Weinreb has also reviewed the case and agrees with this assessment. [20] The report provided by Dr. Tsao was reviewed by Dr. J. Roos, the Board s consultant respirologist, who provided his view in a memo, dated October 21, 2009, which stated: The worker had significant exposure to both silica and asbestos. The pathologic fine needle biopsy gave only scant tissue; the differential diagnosis involved 4 varieties of sarcoma but not carcinoma, as submitted by the examining pathologist. Dr. Reinhartz in his detailed and commendable review concludes that the ultimate clinical course resembled an epithelial lung cancer and that despite the smoking history the silica and/or asbestos inhalation was the most likely cause of demise, and that perhaps a significant portion of the tumour may have been missed in the biopsy sampling. This is a difficult choice but I favour accepting the pathology of sarcoma, non-occupational being a positive finding, and the missed sample conjectural. (iv) Applicable law [21] The worker was diagnosed with lung cancer in a medical report, dated March 5, Accordingly, the estate s entitlement to benefits in this appeal is governed by the Workplace Safety and Insurance Act, (v) Analysis [22] In this case, following a biopsy of tissue from the worker s left lower lung mass, in keeping with the pathology report, dated March 5, 2003, the worker was diagnosed with sarcoma, a type of lung cancer. In his memo, dated May 5, 2005, which is reproduced above, Dr. Muir referred to the pathology report, and stated that based on the biopsy, the histology was a form of sarcoma. Dr. Muir indicated in the memo that the sarcoma was determined to be not of occupational origin. In a further memo, dated July 28, 2005, Dr. Muir provided an

7 Page: 6 Decision No. 1557/14 explanation for the conclusion that it was unlikely for the worker s sarcoma to have been related to occupational exposures. [23] The memo explained that carcinoma are generally derived from surface epithelium. Since the surface epithelium could be exposed to environmental carcinogens, this explains why carcinoma have the potential to be related to occupational exposure. The memo went on, however, to explain that sarcoma, which were being distinguished from carcinoma, are derived from deep seated tissue which are not directly exposed. It appears that, on this basis, Dr. Muir concluded that the worker s lung cancer, which had been diagnosed as a sarcoma, was not occupationally related. [24] I note that Dr. Kabir s memo indicated that it was likely that the worker had had occupational exposure to asbestos and crystalline respirable silica, and this was a fact that was highlighted both in the report that was prepared by Dr. Reinhartz, and by the estate s representative in the submissions that were provided by the representative in this appeal. I conclude, however, that if sarcoma was the correct diagnosis, the fact that the worker may have been exposed to asbestos and crystalline respirable silica would not be a factor affecting the development of the worker s cancer, because, according to the information provided by Dr. Muir, it is not probable that sarcoma, which is associated with deep seated tissue, is affected by environmental exposures. [25] I note that Dr. Reinhartz sought to refute the conclusion that the worker s cancer was not occupationally induced by advancing the possibility that sarcoma was an incorrect diagnosis. He stated that it was unlikely that the worker s cancer was a sarcoma, first, because sarcoma is rare, and further, because the clinical course of the worker s cancer was more closely related to a typical primary lung cancer, or carcinoma. He also suggested that the result of the needle biopsy process may not have achieved appropriate sampling of the tissue, or that another possibility was that the biopsy tissue, in fact, was a carcinoma. [26] I note that the information provided by Dr. Reinhartz did not suggest, however, that it was likely that sarcoma is an occupationally related disease, and his report did not refute the explanation, provided by Dr. Muir, as to why sarcoma is unlikely to be related to occupational exposures. Accordingly, a threshold question to be determined in the analysis of entitlement in this appeal, is whether it is likely that sarcoma was the correct diagnosis. The majority of Dr. Reinhartz report is related to the risk of lung cancer that has been associated with asbestos exposure, however, if sarcoma is the correct diagnosis, since sarcoma is not an occupationally related disease, the information provided by Dr. Reinhartz concerning the risk associated with asbestos exposure would be less relevant to the issue of entitlement. [27] On the question of whether it is probable that sarcoma was the correct diagnosis, I note that: The original pathology report, dated March 5, 2003 prepared by Dr. Tomczak- Bojarski, concluded that the worker had changes consistent with sarcoma. The report also provided the view that it was less likely that the staining performed indicated that the worker s tumour was a mesothelioma or carcinoma, and also that the tumour was also probably not either leiomyosarcoma or rhabdomyosarcoma. A further pathology report, dated June 16, 2008, prepared by Dr. Mullen, indicated that, while the diagnosis of mesothelioma cannot be fully excluded it was

8 Page: 7 Decision No. 1557/14 unlikely that the tumour represented mesothelioma, based on the morphology of the tumour and the staining patterns. A further pathology report, dated May 5, 2009, prepared by Dr. Tsao, concluded that, based on the tests that had been performed on the biopsied tissue, the histology is that of spindle cell neoplasm, consistent with sarcoma. The report also stated that, another pathologist, Dr. I. Weinreb, agreed with Dr. Tsao s assessment. Dr. Roos, the Board s consultant respirologist, indicated in his memo, dated October 21, 2009, that he favoured accepting the pathology of sarcoma, notwithstanding that it was a difficult choice. He also noted that Dr. Reinhartz suggestion that the biopsy sample was not representative of the tissue from which it was taken, was conjectural. [28] I note that Dr. Muir, who is a highly regarded occupational physician and the author of occupational epidemiology studies, refrained from expressing a view on whether sarcoma was the correct diagnosis. In his memo, dated March 17, 2009, he made the comment that I am not a pathologist and cannot offer an opinion on the reliability of the biopsy report I agree with Dr. Muir that the physicians who would be most qualified to express a view on the reliability of the finding that the worker s tumour represented sarcoma, were the pathologists who considered the matter. Of these physicians, three of the four (i.e., Dr. Tomczak-Bojarski, Dr. Tsao, and Dr. Weinreb) who reviewed the case, concluded that sarcoma was the most probable diagnosis. The fourth pathologist who considered the matter, Dr. Mullen, had been asked to evaluate the biopsy specimen for the possibility of mesothelioma, and he concluded that this was unlikely. Dr. Mullen also suggested that a histopathologic evaluation of the patient s larynx cancer is necessary to fully exclude this as a possible source of this patient s malignant spindle cell neoplasm. His report did not specifically indicate whether or not sarcoma was the probable diagnosis. I note that none of the pathologists who reviewed the worker s case indicated that carcinoma was a probable diagnosis, or that the diagnosis of sarcoma was not probable. [29] I conclude from my review of the medical information on file, that the preponderance of the views expressed by the pathologists who had considered the worker s case indicates that sarcoma is the worker s most probable diagnosis. [30] I also agree with Dr. Roos that Dr. Reinhartz suggestion that the biopsy sample was not appropriate, causing a missed diagnosis, is speculative. Dr. Reinhartz premised his view that sarcoma was unlikely to be the correct diagnosis, in part, on the worker s clinical course, which he stated would more likely be associated with a more common carcinoma. I attribute limited weight to this view, given that the worker s treating physicians would have been well aware of the worker s clinical course, and if this factor strongly affected the reliability of the diagnosis of sarcoma, I would have expected them to raise this in the medical information. Dr. Reinhartz also suggested that sarcoma was not the likely diagnosis because it is a rare form of cancer, however, the reviewing pathologists would also have been well aware that the condition was rare. This fact apparently did not dissuade them from their diagnosis of sarcoma, based on the objective evidence before them. [31] I also note that the pathologists who reviewed the case were apparently not associated with the worker or the Board, and that they would likely be objective in their analysis of the biopsy sample, and disinterested in the outcome of their assessments.

9 Page: 8 Decision No. 1557/14 [32] For these reasons, I conclude that it is probable that the worker s cancer was properly diagnosed as a sarcoma. I accept Dr. Muir s statement that sarcoma is not likely to be an occupationally related disease. This view was not refuted by Dr. Reinhartz. [33] Accordingly, the worker s estate is not entitled to benefits for lung cancer.

10 Page: 9 Decision No. 1557/14 DISPOSITION [34] The appeal is denied. [35] The worker s estate is not entitled to benefits for lung cancer. DATED: December 4, 2014 SIGNED: M. Crystal