Cancer is not one disease—it’s more than 200 different diseases. Cancer doctors can treat cancer with radiation therapy, surgery or medications, including chemotherapy, hormonal therapy and now biologic treatments, either alone or in combination.
Radiation, either alone or given along with other cancer therapies, can be used to successfully treat many different types of cancer. Like a surgical treatment, if you know where the cancer is, then you can treat it with radiation therapy. When cancer can be treated with radiation therapy, the patient will be seen by a radiation oncologist—a doctor who specializes in treating patients with radiation therapy.
Radiation oncologists work with primary care doctors and cancer specialists, such as surgical and medical oncologists, to oversee patient care. For each patient, the cancer team works together to figure out the best course of treatment, based on the tumor type, size, shape and location of the cancer. In collaboration with our colleagues who specialize in surgery and chemotherapy, the radiation oncologist will create a unique plan to deliver a specific amount of radiation to the tumor, which protects the surrounding normal tissue.
Radiation therapy, or radiotherapy, is the use of various forms of radiation to safely and effectively treat cancer and other diseases. Radiation therapy works by damaging the genetic material within cancer cells. Once this happens, the cancer cells are not able to grow and spread. When these damaged cancer cells die, the body’s immune system naturally removes them. Normal cells are also affected by radiation, but they can repair themselves in a way that cancer cells cannot.
Radiation oncologists may recommend using radiation therapy in a number of different ways. Often, the goal is to cure the cancer. In this case, radiation therapy may be used on its own to eliminate tumors. It can also be used before surgery to shrink tumors or after surgery or chemotherapy to reduce the risk that tumors may recur.
Sometimes, the goal is to reduce the symptoms caused by growing tumors, improving the patient’s quality of life. This type of treatment can dramatically relieve pain, reduce swelling, improve breathing and treat other symptoms even when cure is not possible.
Radiation therapy can generally be delivered in three ways:
1. External beam radiation therapy
The treatment team uses a machine outside the body to direct radiation beams, such as high-energy X-rays, at the cancer. The radiation beam is usually generated by a machine called a linear accelerator, or linac, and is the most common approach. Using the powerful treatment planning computers and software now available, the treatment team controls the size and shape of the beam, as well as how it is directed at the body, to effectively treat your tumor while sparing the surrounding normal tissue.
There are many kinds of external beam radiation therapy that may be used depending on the location and size of the tumor. Working with a medical physicist, the radiation oncologist can decide whether an individual patient will benefit from conventional X-ray treatments, or beams of electrons, protons or occasionally neutrons.
This involves placing radioactive sources (for example, radioactive seeds) in or near the tumor. These seeds can be embedded and left in the tumor, or they may be inserted into the tumor during a procedure and then removed. These techniques are commonly used in prostate cancer, breast cancer and gynecologic cancers. Whatever the tumor type, placing the radiation directly into the cancer allows for cure with much less radiation to the surrounding healthy tissues.
3. Systemic radiation therapy
Some radioactive drugs are given to the patient and travel through the bloodstream to treat cancer throughout the body. These can be used to relieve symptoms, prolong life and often to help cure the cancer.
David C. Beyer, M.D., Chair, American Society for Radiation Oncology, Cancer Center of Northern Arizona, [email protected]