Occupational Exposures and Cancer

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Occupational exposures and cancer

Definition

Occupational exposure to cancer occurs at the work-place. Some individuals develop cancer from exposure to certain substances at an indoor workplace such as a factory or a restaurant. Others may be exposed to carcinogenic substances while working primarily outdoors, such as construction or lawn maintenance workers.

Description

About 5% of cancer in men and 1% of cancer in women are a result of exposure to carcinogenic substances in their work environment. The most common cancers associated with occupational exposure are:

Lung and pleura
Bladder
Skin
Laryngeal
Nasal cavity
Leukemia
Throat
Lymphoma
Soft-tissue sarcoma
Liver

Causes

Tobacco smoking is considered the greatest risk factor for lung cancer. Individuals who do not smoke can still develop lung cancer. Employees in smoke-filled environments such as bars, restaurants, casinos, airplanes, bingo halls, and bowling alleys are at greatest risk from second-hand smoke. Second-hand smoke is highly toxic. Non-smokers who live with a smoker are at 30% greater risk of developing lung cancer than if they lived with a non-smoker.

Asbestos is a known carcinogen. Individuals whose work exposes them to asbestos are seven times more likely to die from lung cancer. Asbestos workers who smoke are 50-90 times more likely to develop lung cancer than the average individual. Asbestos affects the lining of the lungs, causing malignant mesothelioma . Mesothelioma is considered incurable and fatal, and may not be detected until as long as 45 years after exposure. Asbestos still exists in schools, offices, factory buildings and homes in the form of insulation. Workers who remove asbestos from buildings need to take special precautionary measures to avoid inhalation of asbestos fibers, and wear special clothing so that they do not bring home the dust on their clothes. Asbestos can affect railroad workers, ship builders, gas mask manufacturers, and workers in insulation factories. Because of the way in which asbestos in inhaled and processed in the body, it can also lead to cancers of the larynx, esophagus, pancreas, kidney, and colon.

Radon is another substance that can cause lung cancer. Houses or commercial properties that are built on soil containing radon may contain radon in gas form. Many inhaled chemicals put workers at risk. This includes uranium and talc miners and workers who are exposed to the chemicals: arsenic, vinyl chloride, nickel chromates, coal products, mustard gas, and chloromethyl ethers. While these industries need to provide safety gear to protect workers from these substances, it is always best if the worker makes sure she or he is properly protected.

Workers who are exposed to diesel fumes, such as railroad crews and truck drivers, may have a 40% greater risk of lung cancer. Diesel fumes contain benzene, formaldehyde, and dioxins. Formaldehyde alone is also implicated in respiratory cancers, and is used as a sterilizing agent in dialysis units, disinfectant in operating rooms, carpet and furniture glues, as well as for embalming.

Painters, printers, and chemists are also at increased risk for lung cancer because of their occupational exposure to certain chemicals. Employees exposed to fine silica particles also have an increased risk for lung cancer. Silica appears in sand, rock, and mineral ores, and is used in sandblasting, masonry work, tunnel construction, ceramics, laying railroad track, soap manufacturing, glass manufacturing, shipbuilding, and agriculture.

Bladder cancer from occupational exposure is most common in individuals working with radiation or dyes that involve the aromatic amine chemicals such as benzidine and beta naphthylamine. Factory workers involved in the production of these dyes, as well as those who use these dyes, such as hair colorists, and possibly even people who apply their own permanent hair dye at least once a month may be at increased risk for bladder cancer.

Chemicals used in the rubber, leather, textile, and paint industries can also be carcinogenic. The risk of bladder cancer rises with age, and smoking increases significantly the risk of developing bladder cancer. Individuals who have taken the herb Aristocholia fangchi as part of an herbal weight loss product may also be at higher risk for bladder cancer. Drinking at least 11 cups of fluid a day can decrease the risk of bladder cancer, as it increases urination and decreases the concentration and the amount of time that carcinogenic substances come into contact with the bladder lining.

There are several types of skin cancer, varying in aggressiveness. Basal and squamous cell cancers are considered very curable. Melanoma is the most serious type, and the most likely to metastasize. Exposure to ultraviolet rays, coal tar, pitch, creosote, arsenic and radium can lead to skin cancer. Individuals whose work is primarily outdoors, such as employees of road and building construction, landscaping, outdoor painting, and beach and boating work are at greater risk. Using sun-screen and protective clothing such as long-sleeved shirt, long pants, and a wide-brimmed hat can decrease exposure, but is unlikely to be used in those professions.

Laryngeal cancer . Individuals whose work includes heavy exposure to wood dust, paint fumes, and asbestos, and workers exposed to certain chemicals in the metalworking, petroleum, plastic, and textile industries are at increased risk for laryngeal and hypopharyngeal cancers. Tobacco and heavy alcohol use can increase the risk for these cancers by as much as 100 times.

Farmers and others who have long-term exposure to herbicides and pesticides are at increased risk for leukemia. Children whose parent has chronic lymphocytic leukemia (CLL) have two to four times greater risk of getting CLL themselves. Long-term exposure to benzene places the employee at greater risk of developing acute leukemia . Herbicides and pesticides are both associated with the development of lymphomas, so workers involved in their production as well as their application are at increased risk. Children exposed to pesticides on a regular basis are significantly more likely to develop non-Hodgkin's lymphoma than children not exposed.

Farmers appear to have an increased incidence of prostate cancer . The reason is not yet clear. While some have suggested it may be due to a diet high in red meat and fatty foods, studies are investigating the link between prostate cancer and pesticides, fertilizers, chemical solvents, and farm equipment fumes. Salivary gland cancer may be linked to working with nickel alloy and silica dust, and exposure to radioactive substances.

Pancreatic cancer appears to be associated with significant exposure to pesticides, certain dyes, and chemicals found in gasoline. Occupational exposure to asbestos, cadmium, and organic solvents (especially trichloroethylene) seems to increase the risk of getting kidney cancer. Dioxin is a known carcinogen, and may be a causative factor in a variety of cancers. It is a byproduct in industrial processing that deals with chlorine and hydrocarbons, such as found in incinerators and paper and pulp factories.

Other chemicals linked with cancer are DDT and PCBs (polychlorinated biphenols). Health care professionals, both human and veterinary, may be exposed to carcinogenic substances in caring for their patients. Body fluid exposure can increase the risk of Hepatitis B, and Hepatitis C can cause liver failure and increase the risk of liver cancer. HIV can cause AIDS and increase the risk of a variety of malignant tumors. Chemicals in paint and paint solvents are also used in ceramic factories.

Electric and magnetic fields surround electric tools and machinery. Studies have been done to investigate whether these fields are harmful to humans. Research findings continue to be controversial, some showing an increased incidence of cancers, other not finding an association. However, federally funded research studies continue.

Special concerns

Cancers that originate in the workplace do not require different treatment than if that same cancer had developed from another source. However, workers who develop cancer through occupational exposure may not be able to return to the same job, perhaps not even the same company. This means that even if the individual has survived the cancer, and gone though all that treatment entails, they cannot pick up their life where they left it at the time of the cancer diagnosis. They may be disabled, and not be able to work at all, or they may have to retrain for work, either a different job within the same company, or a whole new job and environment.

If the person is older, he or she may be less employable after their illness because of age. Depending on the type of cancer, it may be difficult to prove that the work environment was a causal factor in the development of the disease. This can make it harder to obtain benefits that would be work-related. Consequently, financial concerns may be a great burden. Also, certain cancers may have developed from the inhalation of substances that were also brought home on the employee's clothing. Others in the family may have gotten ill as well. Fine dust particles can come home on workers' clothing, shoes, skin, hair, facial hair, tool or lunch box, and on the inside or outside of their car.

Workers in any occupation need to be fully informed of the substances with which they come in contact. Federal regulations are in place to improve employee safety, but the regulations are ineffective if the employees do not utilize the protective clothing, masks, and other safety measures at their disposal. Individuals who learned their trade prior to the installation of many safety measures may find it difficult to retrain themselves with the new equipment. But not doing so may raise their risk of cancer.

While many cancers have an unknown source, cancers due to occupational exposures have known sources. This means that they are preventable, if proper safety equipment is used, used all the time, and always used correctly.

Treatments

Treatments for cancers due to occupational exposure would be expected to be the same as for the same cancer developed from a different source. Treatment will depend on the type and stage of the cancer diagnosed, as well as the age and fertility needs of the patient. Access to treatment may vary, however, depending on the type of insurance the individual holds. Access to experimental treatments, or treatment that a health insurance deems experimental can vary.

Alternative and complementary therapies

Alternative therapy options for cancer due to occupational exposure would be the same as if that cancer had developed from another source. Complementary treatments that improve the functioning of the body's immune system, or that decrease treatment side effects such as nausea, can be helpful. There may be different stresses in the life of the person with a work-related cancer. So, therapies such as meditation, guided imagery, therapeutic touch, yoga, and t'ai chi can help deal with the stress of having cancer, going through treatment, and having to find alternative work options.

See Also Environmental factors in cancer development

Resources

BOOKS

Kimball, Chad T., Ed. Work Health and Safety Sourcebook. Health Reference Series. Detroit: Omnigraphics, 2000.

McGinn, Kerry A., and Pamela J. Haylock. Women's Cancers: How to Prevent Them, How to Treat Them, How to Beat Them. Alameda, California: Hunter House, 1998.

Teeley, Peter, and Philip Bashe. The Complete Cancer Survival Guide. New York: Doubleday, 2000.

PERIODICALS

Michaud, D. S., et al. "Fluid Intake and the Risk of Bladder Cancer in Men." The New England Journal of Medicine. (May 6, 1999): 1390-1397.

ORGANIZATIONS

American Cancer Society. (800) ACS-2345. <http://www.cancer.org>.

United States Department of Labor. Occupational Safety and Health Administration, 200 Constitution Ave., NW, Washington, D.C. 20210. <http://www.osha.gov>.

Esther Csapo Rastegari, R.N., B.S.N., Ed.M.

KEY TERMS

Carcinogen

—A substance, method, or process that has been scientifically shown to be a causative factor in the development of a certain cancer.

Metastasize

—The ability of a cancer to spread from its site of origin to other sites in the body. The more a cancer has metastasized, the worse is the individual's prognosis for cure.