Cancer treatment is not a one-size-fits-all approach. Different types of cancer may be better treated with one treatment—or perhaps a combination approach. Treatments for the same type of cancer may even vary from patient to patient. One of the most common treatments is radiation, also referred to as radiation therapy, radiotherapy, irradiation, and x-ray therapy. This therapy uses high doses of radiation to kill cancer cells and shrink tumors. More than half of patients with cancer undergo radiation therapy, either alone or in conjunction with other treatment(s).
Therapy teams may include a radiation oncologist, physicist, therapist/therapy technologist, and therapy nurse, as well as a dosimetrist.
According to the American Cancer Society (ACS), the goals of this treatment are often one of the following:
- To cure or shrink early-stage cancer. Radiation can sometimes shrink the cancer or make it go away entirely. Sometimes, patients may receive chemotherapy or other anti-cancer drugs first. Other patients may undergo treatment before surgery to shrink the tumor—which would be referred to as neoadjuvant therapy—or they may receive radiation postoperatively to prevent the cancer from coming back—which would be referred to as adjuvant therapy.
- To stop cancer from coming back somewhere else. There is a possibility of cancer spreading to other parts of the body, even if it doesn’t show up on imaging scans. Radiation may then be used as a cautionary treatment, to kill cancer cells that may have spread to an area of the body commonly associated with the spot of the primary cancer before they become tumors.
- To treat symptoms caused by advanced cancer. It may also be used as part of palliative cancer treatment in patients whose cancer cannot be cured. In these cases, the goal is to shrink the tumors to help relieve some of their associated symptoms, in order to make the patient more comfortable.
- To treat cancer that has returned. Patients with recurrent cancer may undergo this therapy to either treat the cancer or its symptoms. This depends on where the recurring cancer is, however. If it’s in an area of the body that previously underwent radiation treatment, repeating radiation may not be possible.
What Types of Radiation Are There?
Even among the patients who undergo radiation, not all treatments are the same.
The most common type is external radiation, or external beam radiation, which utilizes a large machine that aims high-energy rays (beams) into the tumor from outside the body. Many cancers may be treated with external radiation.
Different options also exist under the external umbrella:
- Three-dimensional conformal radiation therapy (3D-CRT)
- Image guided radiation therapy (IGRT)
- Intensity modulated radiation therapy (IMRT)
- Photon beam radiation therapy
- Proton beam radiation therapy
- Stereotactic radiosurgery
- Intraoperative radiation therapy (IORT)
External radiation is often performed in the outpatient setting, with many patients requiring sessions five days a week—in some cases, twice in the same day. The off days allow the normal cells time to recover. Treatment often spans five to eight weeks, depending on how much total radiation is needed and how much is given in each session. Both of these factors will be determined based on the size, location, and type of the cancer; other treatments; the patient’s health in general; the reason for treatment; and more.
Internal radiation, as the name states, is a treatment that goes on inside body. Also known as brachytherapy, internal radiation involves placing a radioactive implant inside the body, either in or around the tumor to protect as many healthy cells as possible. The implant is usually placed in a hospital operating room to contain the radiation.
There are different types of implants that are placed for different amounts of time. Some implants are only placed for a few minutes, others for a few days, and some are permanent. This, like with external, depends on factors such as the type and location of the cancer, the patient’s general health, and other treatments being received.
High-dose-rate (HDR) brachytherapy is the type that is typically left in the body for shorter periods of time. HDR brachytherapy is performed by placing the implant for 10 to 20 minutes at a time in multiple sessions over the course of several weeks. The applicator may be left in the patient’s body, but the radioactive material is not.
Low-dose-rate brachytherapy is a bit different. In this case, patients receive an implant that gives off lower doses of radiation but for a longer length of time. These implants may be placed for one or several days. Typically, patients receiving this type of brachytherapy are required to stay in the hospital during the course of treatment.
For patients who receive permanent implants, radiation may be given off for several weeks or months, but once it’s all been given, the implant is no longer considered active.
Brachytherapy may be used to treat head and neck, breast, cervix, prostate, and eye cancers.
Systemic radiation is a completely different option that does not target one area of the body but instead focuses on the whole body. It may be used to treat thyroid, bone, and prostate cancers. Systemic therapy involves the use of liquid, radioactive drugs given either orally or intravenously. Two types of radiopharmaceuticals include radioimmunotherapy and peptide receptor radionuclide therapy.