Carcinogens

Any substance or exposure that causes cancer is referred to as a carcinogen. Carcinogens can be exposed to people on the job, in the environment, through certain foods, through the use of certain consumer products, and through lifestyle factors.

Carcinogens can cause cancer by altering the DNA of cells or causing them to divide more quickly. This increases the likelihood of developing one or more types of cancer. According to the American Cancer Society, even the most potent carcinogen does not increase a person’s risk of all cancer types.

Some carcinogens cause cancer after a long period of exposure, while others cause cancer after a brief period of exposure. However, because several factors influence cancer development, being exposed to a carcinogen does not guarantee that a person will develop cancer. These factors include the intensity of a carcinogen’s exposure, the length of exposure, and a person’s DNA make-up.

Common Cancer-Causing Agents

People can come into contact with common carcinogens in a variety of ways throughout their lives, including at work, in the environment, through medical treatments, and through their lifestyle.

It is critical to understand that exposure to carcinogens does not guarantee cancer. Chemicals and carcinogens cause the body to react in three ways. It may repair exposed cells, cause some to die, and cause DNA changes in others. Cancer is most likely to be caused by cells that mutate and undergo DNA changes.

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Occupational Exposure

People who work in certain industries that expose them to known carcinogens are at higher risk for developing cancer. These jobs include miners, shipbuilders, certain factory or chemical plant workers and nuclear industry workers.

For example, people who work in jobs that expose them to asbestos — a known carcinogen — are at risk of developing an aggressive type of cancer called mesothelioma. It’s rare to get mesothelioma without asbestos exposure.

Carcinogens and Cancers Associated with Occupational Exposure

Source: Agency for Toxic Substances and Disease Registry

ZANTAC & CANCER

The antacid Zantac was recalled after it had been contaminated with NDMA, a possible carcinogen. Read about the cancers that have been linked to Zantac use.

Environmental Exposures

Several man-made and natural carcinogens exist in the environment. Air pollution is one of the biggest contributors to cancer risk. This can happen indoors or outdoors. For example, indoor air pollution from burning fuels causes about 16,000 lung cancer deaths per year, according to the IARC.

Diesel engine exhaust, solvents, metals and dusts are some of the carcinogens present in air pollution. For people who live in more industrialized areas, these exposures can be higher.

Drinking water is another potential source of carcinogen exposure. Chemical by-products of chlorinating drinking water increase cancer risk, though the chemical concentration is low, according to The National Cancer Institute.

One of these byproducts is N-nitrosodimethylamine, or NDMA, a potential cancer-causing agent. NDMA is found in small amounts in the air, water and some types of food.

Environmental exposures include:

• Agricultural chemicals
• Arsenic
• Asbestos
• Benzene
• Gasoline
• Nickel
• N-nitrosodimethylamine (NDMA)
• Radon gas
• UV radiation

Medical Treatments and Tests

Some medical treatments and tests are carcinogenic because they increase the risk of cancer.

Hormone-related drugs, such as oral birth control and hormone replacement therapy (HRT) may increase the risk of certain cancers in women. Some cancer drugs and treatments such as chemotherapy and radiation are known to increase a patient’s risk for developing another bout of cancer.

Drugs that suppress the immune system and treat inflammatory conditions such as Crohn’s disease and rheumatoid arthritis may increase the risk of cancer. These include Humira, Enbrel, Remicade and prednisone.

In 2019, some drugmakers recalled blood pressure and heartburn medications because of NDMA contamination. Blood pressure drugs included in recalls include valsartan and losartan. After the valsartan recalls, an independent pharmacy found NDMA in Zantac (ranitidine) and manufacturers issued recalls.

Before receiving a medical treatment or taking a medication, talk to your pharmacist or doctor about the risk and benefits of certain medications.

Lifestyle Exposures

Lifestyle factors such as what you eat and whether or not you smoke tobacco or drink alcohol may also affect your cancer risk.

Some foods that contain potential cancer-causing agents include processed and smoked meats, meats cooked at high temperatures or charred, Chinese-style salted fish, very hot beverages and alcoholic beverages.

Many forms of tobacco exposure are carcinogenic. This includes smoking and chewing it as well as inhaling second-hand tobacco smoke.

Contrary to what many smokers believe, nicotine itself is not a carcinogen. While nicotine can be found in both tobacco leaves and e-cigarette liquid and is an addictive substance, it doesn’t cause cancer. Cigarettes and chewing tobacco contain dozens of other chemicals that are known carcinogens, including tar, the chemical responsible for their flavor.

Some cosmetic products such as makeup and talc-based baby powder contain potential carcinogens. Formaldehyde is used in many beauty products as a preservative and antibacterial agent. Talc-based baby powder or makeup contaminated with asbestos is carcinogenic.

People who don’t practice safe sex can expose themselves to the human papillomavirus (HPV) which is known to cause cancer.

TALC & CANCER

Studies have linked talcum powder to ovarian cancer and mesothelioma. Read about talc’s connection to cancer.

Who Classifies Carcinogens?

The National Toxicology Program (NTP) and The International Agency for Research on Cancer (IARC), a part of the World Health Organization (WHO), are the two main agencies that classify cancer in the United States.

International Agency for Research on Cancer (IARC)

One of IARC’s major goals is to identify cancer causes. Its carcinogen grouping system is the most widely used system. The organization has evaluated more than 1,000 likely cancer-causing agents and grouped them into one of four groups.

IARC Carcinogen Classifications

• Group 1: Carcinogenic to humans
• Group 2A: Probably carcinogenic to humans
• Group 2B: Possibly carcinogenic to humans
• Group 3: Not classifiable as to its carcinogenicity in humans

Limiting Exposure

Not all carcinogens are avoidable. Regulations in the workplace reduce people’s exposure to known carcinogens. People can educate themselves on cancer-causing agents and try to avoid them.

Tips for limiting carcinogen exposure include:

• Eliminate or lower alcohol consumption
• Avoid smoked or processed meats
• Avoid eating meats charred or cooked at high temperatures
• Get vaccinated against HPV
• Know your family’s cancer history
• Stop smoking or chewing tobacco
• Avoid second-hand cigarette smoke exposure
• Take precautions in the sun
• Weed your garden manually instead of using pesticides
• Avoid idling your vehicle
• Check ingredients in consumer products for carcinogens
• Ask your doctor about the cancer risk in medical treatments and medicines

Hunain Ali

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