The Difference Between Chemo and Radiation

The Difference Between Chemo and Radiation

When you or a loved one is diagnosed with cancer, it’s normal to have many thoughts running through your head — how bad is it, what does this mean for my future, and what is the treatment actually like?

When referring to treatment, you may hear the words “chemotherapy” or “radiation.” Maybe, you’re told about a combination of both. So, what exactly is the difference between chemo and radiation?

Chemotherapy and Radiation Therapy? What Are the Differences?

What Is Chemotherapy?

Chemotherapy, or chemo, is a process in which drugs are used to treat cancer.

It is a “systemic” treatment — working through the whole body to prevent the spread of the disease. The drug(s) used will vary depending on the type and stage of cancer as well as the patient’s age and health. The goal of chemotherapy is to stop the spread of cancer to other parts of the body.

Chemotherapy is administered by a medical oncology (cancer) health professional, typically a nurse or doctor. Chemo can be delivered as an outpatient procedure, in a hospital, a doctor’s office, or even at home in any of the following ways:

  • Injection into muscle, vein, or artery
  • Orally
  • Injection into the body (such as the abdomen)
  • Direct skin application

Chemotherapy side effects

Chemo side effects vary depending on the type and amount of chemotherapy drug used and how the body reacts to it. Because chemotherapy drugs travel through the body, they can also impact healthy cells, leading to a variety of side effects.

Chemo is designed to kill fast-growing cancer cells, but this can sometimes lead to side effects involving the body’s other, healthy fast-growing cells.

  • Blood forming cells in the bone marrow (anemia, increased risk of infection, bruising)
  • Hair follicles (temporary hair loss)
  • Cells in the mouth, digestive and reproductive tract (nausea, loss appetite, constipation, diarrhea)

Some chemo drugs can damage cells in the heart, kidneys, bladder, lungs, and nervous system. Your doctor monitors you closely and may prescribe medicines to protect your body’s normal cells. There are also medicines to help relieve side effects.

What Is Radiation Therapy?

Radiation therapy is the use of high-energy particles or waves to destroy or damage cancer cells.

Radiation is delivered using special equipment that sends high doses of radiation to the cancer cells or tumor. Radiation can also affect healthy cells, however, normal cells can repair themselves, while cancer cells cannot.

Sometimes radiation is used to treat cancer, or it may be used to help you feel better, such as to minimize bone pain, for example. Radiation therapy can take place on its own, but it’s frequently combined with chemotherapy as a comprehensive cancer treatment program.

Radiation therapy differs from chemotherapy — it is used to treat just the tumor, so it affects only the part of the body that has cancer.

Types of radiation therapy

Radiation can be administered in two ways: internally or externally:

External: External beam radiation is delivered from a machine. It is very similar to receiving a chest X-ray. Most people are treated five days a week for one to 10 weeks, depending on the type and location of cancer, their overall health, and other factors. The treatment only takes a few minutes, and is not generally given over the weekend.

You will be asked to lie flat on a treatment table, under the radiation machine. Other parts of your body may be protected with special shields or blocks to prevent the radiation from going to those areas.

External treatments include:

  • 3D conformal radiation therapy after the tumor is mapped through imaging, beams of radiation treat the cancerous tumor.
  • Intensity-modulated radiation therapy (IMRT) gives the radiation oncologists the ability to more precisely “custom sculpt” the shape of the tumor. This helps deliver the right amount of radiation more accurately, as well as helps to preserve healthy tissue surrounding the tumor.

Internal: Radiation that is placed inside of the body is called internal radiation therapy or brachytherapy. A radioactive source, called an implant, is placed directly to the tumor or near the tumor. This delivers large doses of radiation to directly to the source of your cancer. These implants may look like a wire, pellet, or seeds.

If the implants are left in your body, you may be given special instructions such as to limit your time with and/or avoid children or pregnant women. After a few weeks to a few months, the implants stop giving off radiation, and you can return to normal activities. The implant, however, will remain in your body forever.

Some implants may be removed after a period of hours or days. Most often, they are administered in a hospital private room, and visitors will only be allowed to stay with you for short periods of time.

This article is from UPMC Hillman Cancer Centre -


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