When we think about radiation as carcinogens, the cause is cellular: higher energy radiation has enough energy to remove an electron from (or ionize) an atom or molecule. These forms of radiation are called ionizing radiation. Ionizing radiation has the ability to damage cell DNA, which may in turn, lead to cancer.
Media reports tend to play off the latest reports of a new or insidious source of radiation that may or may not be the next big cancer link. Smartphones, microwaves and other devices in our day-to-day lives have come under fire, although there are no studies that show conclusive evidence of a link between, say, regular smartphone use and brain tumors. In fact, many major cancer research organizations in the U.S. do not find a definitive link between smartphones and other technological devices and cancer.
However, there are many sources of radiation in our everyday lives that DO, in fact, put us at risk for developing cancer. Among them:
UV Rays
Radiation is the emission (sending out) of energy from any source.
Ultraviolet (UV) radiation is a form of electromagnetic radiation. The main source of UV radiation (rays) is the sun, although man-made sources such as tanning beds and welding torches also emit it. UV rays have more energy than visible light but not as much as x-rays and gamma rays. There are three types of UV rays:
UVA rays are the weakest of the UV rays. They can cause skin cells to age and can cause some indirect damage to cells’ DNA. UVA rays are mainly linked to long-term skin damage, such as wrinkles.
UVB rays are slightly stronger. They are mainly responsible for direct damage to the DNA and are the rays that cause sunburns. They are also thought to cause most skin cancers.
UVC rays are the strongest UV rays. Fortunately, because of their strength, they react with ozone high in our atmosphere and do not reach the ground. Therefore, UVC rays are not present in sunlight and are not normally a risk factor for skin cancer. But they can be found in some manmade sources, such as arc welding torches and mercury lamps. In the past, sunbeds also were a source of UVC rays.
Do UV Rays Cause Cancer?
Yes. Most skin cancers are direct results of exposure to the UV rays in sunlight. In-transit, basal cell and squamous cell cancers of the body -- the most common types of skin cancer, tend to be found on sun-exposed parts of the body, and they are linked to lifetime sun exposure. Melanoma, a more serious but less common type of skin cancer, is also related to sun exposure.
Cancer Treatments
Some cancer treatments such as chemotherapy and radiation therapy may increase a person's risk of developing a different type of cancer later in life. Advances in radiation therapy, a common cancer treatment, increase the chances of survival for many cancer patients.
Cancer is a common disease, and not all second cancers are due to cancer treatment. For example, certain inherited gene changes can increase a woman's risk for both breast and ovarian cancer. Also, being exposed to certain cancer-causing substances, like tobacco smoke, can put a person at higher risk for several different cancers, such as cancers of the lung, larynx (voice box), throat and mouth.
Does Radiation Therapy Cause Cancer?
As these treatments become more common and more successful, studies are being conducted on the long-term effects they have on the patients. Of the possible long-term complications of radiation therapy, developing a second cancer is one of the most serious.
Radon Exposure
Radon is a colorless, odorless, radioactive gas that is present both outdoors and indoors. It’s typically found in very low levels in the air in our homes, office buildings and other structures, as well as in ground water and well water. As radon breaks down, or decays, into solid radioactive elements (radon progeny), they can attach to dust and other particles in the air, and can be breathed into the lungs. Once inside the body, they can give off alpha particles, a form of high-energy radiation that can damage cell DNA.
Most exposure to radon comes from being indoors in our homes, commercial buildings, schools, malls and other structures. Levels of radon vary depending on the characteristics of the soil in the area, as does radon exposure. While elevated radon levels have been found in every state in the U.S., radon levels vary from town to town. Small amounts of radon also can be released from the water supply into the air, especially if the water source is underground. As the radon moves from the water to air, it can be inhaled. Water that comes from deep, underground wells in rock may have higher levels of radon, whereas surface water (drawn from lakes or rivers) usually has very low radon levels. For the most part, water does not contribute much to overall exposure to radon.
Does Radon Cause Cancer?
While most people associate cigarette smoking with lung cancer, radon exposure is actually the second-leading cause of lung cancer in the US, claiming about 20,000 lives annually. Radon progeny can lodge in the lining of the lungs, where they continue to break down into other radioactive elements by releasing radiation. The radiation released in this process can lead to lung cancer. Long-term exposure to radon can cause a skin tumor to spread through a lymph node and begin growing more than 2 centimeters away from the primary tumor.