Radiation Therapy, Explained in Just 2 Minutes

This type of cancer treatment is over a century old.

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Using X-rays to shrink cancer tumors may sound like something from a sci-fi movie, but it’s exactly how radiation therapy works. Radiation is a classic type of cancer treatment, dating back even earlier than chemotherapy.

Radiation therapy, sometimes called radiotherapy, uses high doses of radiation—much higher than what’s used to X-ray your bones. At these doses, the radiation mangles the DNA of the cancer cell, causing it to become damaged and die off.

As these cancer cells are killed, the body can break them down further and eliminate them from the body. This process slows the growth of cancer cells and can shrink and potentially eliminate tumors.

Radiation therapy comes in a few forms. It can be delivered via X-ray beams from a machine, and this is called external beam radiation therapy. This is a local treatment, meaning it attacks cancer cells in a specific area of the body.

Another type of radiation therapy is brachytherapy. This is an internal type of radiation. Doctors place capsules or ribbons containing radiation into the body near the tumor. This is also a local treatment, and it’s especially used for cancers of the head and neck, breast, and prostate, according to the National Cancer Institute.

Another internal type of radiation therapy is called systemic therapy. As the name suggests, this type of radiation therapy travels throughout the body to treat cancer cells that have spread beyond the initial cancer site. These are delivered via injections or IVs.

Like chemotherapy, radiation therapy can damage normal, healthy cells and result in side effects. The adverse effects associated with radiation therapy include fatigue, nausea, hair loss, and changes in the skin. However, side effects can vary depending on what part of the body is being treated by radiation therapy.

Although newer types of treatment—namely immunotherapy and targeted therapy—may be more precise and cause fewer side effects, radiation therapy is still one of the most commonly used treatments against cancer. For people with types of cancer that aren’t response to immunotherapy or targeted therapy, radiation therapy is a life-saving option.