In my words
I associate cancer prevention with education. It means continuing to educate the public about the benefits and ease of screening, and scientifically proven cancer causing activities (e.g. smoking) and agents (e.g. asbestos). These messages need to be sensitive and reach a broad audience, including those who may be uncomfortable (or unaware) of screening procedures, or who may not speak/read English.
From 1981 to 2012, the number of newly diagnosed cases of mesothelioma among Ontario men rose steadily at an average of 5.5% per year, from about 30 cases in 1981 to about 180 in 2012. Incidence rates rose from 0.81 per 100,000 to 2.23 per 100,000 over the same period. Since mesothelioma takes a long time to develop, the current burden of disease is associated with asbestos exposure that occurred from 10 to 50 years ago. The number of new cases of mesothelioma is expected to plateau and decline based on the pattern of decreased asbestos use. It is difficult, however, to predict when this will happen.
What is mesothelioma?
Mesothelioma is a rare but highly fatal cancer1. It affects the protective lining covering many of the body’s internal organs, but most commonly the pleura, which cover the lungs. Almost all mesothelioma is caused by exposure to asbestos2, the commercial term for a group of 6 naturally occurring mineral fibres. Asbestos also causes lung, ovarian and laryngeal cancer, as well as asbestosis (scarring of the lungs)3.
Asbestos has been used for many commercial applications, including insulation, textiles, roofing, brake pads and cement pipe. Use of asbestos peaked in the 1960s and 1970s, but it has declined significantly due to regulations and restrictions surrounding its use that were created because of the adverse health effects4. Most exposure today occurs when asbestos-containing materials in older buildings or other products deteriorate or are disturbed during maintenance, repair or remediation. New uses in Canada currently are limited to friction materials contained in some products such as brake pads, cement and a small number of other specialized products. Approximately 52,000 Ontarians are still exposed to asbestos in the workplace, most in the construction, automotive repair, remediation and ship-building industries5.
What do the results show?
- Since mesothelioma takes a long time to develop, the current burden of disease is associated with asbestos exposure that occurred from 10 to 50 years ago.
- From 1981 to 2012, the number of newly diagnosed cases of mesothelioma among Ontario men rose steadily at an average of 5.5% per year, from about 30 cases in 1981 to about 180 in 2012 (Figure 2). Incidence rates rose from 0.81 per 100,000 to 2.23 per 100,000 over the same period.
- The number of newly diagnosed cases of mesothelioma in Ontario women has also increased from 1981 to 2012, but there were fewer total cases. In 1981, there were 13 cases of mesothelioma diagnosed in Ontario women, and in 2012 there were 42. (Figure 2).
- Mesothelioma rates in Ontario are highest in Lambton County due to heavy historic use of asbestos in Sarnia’s so-called Chemical Valley7. Despite this, Ontario’s incidence rate for mesothelioma was lower than the national average from 1981 to 20126, and the number of new cases of mesothelioma is expected to plateau and decline based on the pattern of decreased asbestos use. It is difficult, however, to predict when this will happen.
- Patients with mesothelioma generally have a poor prognosis. The 5-year relative survival for mesothelioma is 7%1. Mesothelioma often is not diagnosed until the later stages, and it can be an aggressive disease, making it more difficult to treat.
- Providing statistics for prognosis for mesothelioma patients in Canada is difficult, partly because mesothelioma is not very common. According to the Canadian Cancer Society, the approximate median survival for mesothelioma can depend on its location:
- patients with pleural mesothelioma have an approximate median survival of 4 to 18 months;
- patients with peritoneal mesothelioma have an approximate median survival of 5 to 12 months;
- patients with pericardial mesothelioma have an approximately median survival of 6 months; and
- patients with mesothelioma of the tunica vaginalis testis have an approximate median survival of 23 months.
- The vast majority of mesothelioma cases are in the pleura (70% to 80%). Peritoneal mesothelioma accounts for about 25% of all mesothelioma cases, and mesothelioma of the pericardium or the tunica vaginalis testis are considered very rare”1“.
- Patients with mesothelioma are often treated by managing their pleural effusion (the buildup of fluid in the pleura) using a surgical procedure called pleurodesis. This procedure is used to reduce the pleural space to prevent fluid build-up.
- Additional surgical options for patients with pleural mesothelioma are a pleurectomy decortication (which removes the pleura) or an extrapleural pneumonectomy (which removes the pleura, an entire lung, a portion of the diaphragm and the pericardium). Patients with peritoneal mesothelioma can undergo a peritonectomy (which removes the peritoneum).
- Some patients may receive chemotherapy or radiation treatment in order to reduce the chance of mesothelioma recurring or to help relieve the symptoms that it causes.
Asbestos and worker’s compensation
- Approximately 85% of mesothelioma cases in men and 40 % of cases in women are attributable to work-related asbestos exposure2,8,9. Most of the remainder are caused by other kinds of environmental asbestos exposure8, such as exposure to insulation containing asbestos in the home or family members’ exposure to trace asbestos on the clothing of workers.
- Despite the high percentage of mesothelioma cases that are caused by work-related asbestos exposure, workers’ compensation rates for mesothelioma are generally less than 50%, primarily due to claims not being filed10,11. This under-reporting obscures the true medical costs, since sick workers are supported by the provincial public health insurance plan instead of being provided with income replacement, extended healthcare coverage rehabilitation and survivor benefits through the workers’ compensation system12.
- Besides covering healthcare expenses, eligible workers may be entitled to some healthcare equipment and expenses for supplies, prescription drug expenses, personal care allowances and some travel expenses13. If a worker is diagnosed before the age of 65, loss of earnings benefits are available13. If the patient dies as a result of the work-related injury or illness, dependents may be eligible for survivors’ benefits, which may include lump sum or monthly payments, employment assistance for spouses, funeral and transport expenses, bereavement counselling and, in some cases, educational benefits for dependent children13.
- When filing a claim for occupational disease, a physician’s opinion is often a crucial first step, and his or her opinion on whether an injury or illness was caused or exacerbated by work carries considerable weight in the compensation process. The physicians (or other healthcare practitioners) play an important role for all injured workers, because they not only recognize work-related diseases, they provide treatment for sick and injured workers, and supply information to workers’ compensation boards about the nature of injuries or illnesses. This process, however, is complex, for chronic diseases with long latency like mesothelioma.
- Canadian Cancer Society [Internet]. Toronto: the Canadian Cancer Society; c2016. Mesothelioma. Available from: http://www.cancer.ca/en/cancer-information/cancer-type/mesothelioma/.
- Rake C, Gilham C, Hatch J, Darnton A, Hodgson J, Peto J. Occupational, domestic, and environmental mesothelioma risks in the British population: a case-control study. Br J Cancer. 2009; 100:1075–83.
- International Agency for Research on Cancer (IARC). Arsenic, metals, fibres and dusts [Internet]. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. 2012; 100C:219–94. Available from: http://monographs.iarc.fr/ENG/Monographs/vol100C/mono100C-11.pdf.
- CAREX Canada [Internet]. CAREX Canada; c2016. Asbestos: profile; 2015 Aug. Available from: http://www.carexcanada.ca/en/asbestos/.
- CAREX Canada [Internet]. CAREX Canada; c2016. Asbestos: occupational estimate. Available from: http://www.carexcanada.ca/en/asbestos/occupational_estimate/.
- Statistics Canada. CANSIM Table 103-0553. New cases and age-standardized rate for primary cancer (based on the May 2015 CCR tabulation file), by cancer type and sex, Canada, provinces and territories [Internet]; 2015 Oct 22. Available from: http://www5.statcan.gc.ca/cansim/a26?lang=eng&retrLang=eng&id=1030553&pattern=mesothelioma&tabMode=dataTable&srchLan=-1&p1=1&p2=-1 .
- Kramer D, McMillan K, Gross E, Kone Pefoyo AJ, Bradley M, Holness DL. From awareness to action: the community of Sarnia mobilizes to protect its workers from occupational disease. New Solut. 2015; 25(3):377–410.
- Lacourt A, Gramond C, Rolland P, Ducamp S, Audignon S, Astoul P, et al. Occupational and non-occupational attributable risk of asbestos exposure for malignant pleural mesothelioma. Thorax. 2014; 69:532–9.
- Spirtas R, Heineman E, Bernstein L, Beebe GW, Keehn R, Stark A, et al. Malignant mesothelioma: attributable risk of asbestos exposure. Occup Environ Med. 1994; 51:804–11.
- Payne JI, Pichora E. Filing for workers’ compensation among Ontario cases of mesothelioma. Can Respir J. 2009; 16:148–152.
- Kirkham TL, Koehoorn MW, McLeod CB, Demers PA. Surveillance of mesothelioma and workers’ compensation in British Columbia, Canada. Occup Environ Med. 2011; 68:30–35.
- WSIB Ontario [Internet]. Toronto: Workplace Safety and Insurance Board Ontario; c1998–2016. Occupational disease and survivors benefits program. Available from: http://www.wsib.on.ca/WSIBPortal/faces/WSIBDetailPage?cGUID=WSIB014540&rDef=WSIB_RD_ARTICLE&_afrLoop=268482415876000&_afrWindowMode=0&_afrWindowId=null#%40%3FcGUID
- WSIB Ontario [Internet]. Toronto: Workplace Safety and Insurance Board Ontario; c1998–2016. WSIB benefits. Available from: http://www.wsib.on.ca/WSIBPortal/faces/WSIBArticlePage?fGUID=835502100635