What Is Cancer?
Cancer is a group of diseases in which abnormal cells divide uncontrollably. As the cells divide, they form a tumor, which is an abnormal lump or mass of tissue. Cancerous tumors can invade and destroy healthy tissue. They can also spread to other parts of the body, forming new tumors or metastases.

Cancer specialists usually treat cancer with radiation therapy, surgery, chemotherapy, hormonal therapy and/or biologic therapy, either alone or in combination. As you cope with the disease and weigh your treatment options, it is important to remember that your cancer specialists are the best, most qualified people to help you determine the best treatment plan for your cancer.

If you have a type of cancer that can be treated with radiation, you will be referred to a radiation oncologist – a physician who specializes in treating patients with radiation therapy. Your radiation oncologist will work with your doctor and other cancer specialists, such as surgeons and medical oncologists, to oversee your care. He or she will discuss the details of your cancer with you, the role of radiation therapy in your overall treatment plan and what to expect from your treatment.

What Is Radiation Therapy?
Radiation therapy, sometimes called radiotherapy or irradiation, is the use of various forms of radiation to safely and effectively treat cancer and other diseases. Radiation oncologists may use radiation therapy to try to cure cancer, to control the growth of the cancer or to relieve symptoms, such as pain.

Radiation therapy works by damaging the DNA within cancer cells and destroying the ability of the cancer cells to reproduce. When these damaged cancer cells die, the body naturally eliminates them. Normal cells are also affected by radiation, but they are able to repair themselves in a way that cancer cells cannot.

Sometimes radiation therapy is the only treatment a patient needs, and other times it is only one part of a patient’s treatment. For example, prostate and larynx cancer are often treated with radiation alone, but a woman with breast cancer may be treated with surgery, radiation therapy and chemotherapy.

Sometimes radiation therapy is used as adjuvant therapy to make your primary treatment more effective. For example, you can be treated with radiation therapy (the adjuvant treatment) before surgery (the primary treatment) to help shrink the cancer and allow less radical surgery than would otherwise be required, or you may be treated with radiation after surgery to destroy microscopic cells that may have been left behind.

A radiation oncologist may choose to use radiation therapy in a number of different ways. Sometimes the goal is to cure the cancer. In this case, radiation therapy may be used to:

• Destroy tumors that have not spread to other parts of your body.
• Reduce the risk that cancer will return after you undergo surgery or chemotherapy by killing tiny cancer cells that may remain.

In other cases, the goal is to reduce the symptoms caused by growing tumors and to improve your quality of life. When radiation therapy is administered for this purpose, it is called palliative care or palliation. In this instance, radiation may be used to:

• Shrink tumors that are interfering with your quality of life, such as a lung tumor that is causing shortness of breath.
• Alleviate pain by reducing the size of your tumor.

It is important for you to discuss the goal of your treatment with your radiation oncologist.

Is Radiation Therapy Safe?
Some patients have concerns about the safety of radiation therapy. Radiation has been used successfully to treat patients for more than a century and in that time, many advances have been made to ensure that radiation therapy is safe and effective.

Before you begin treatment, your radiation oncology team will carefully tailor the treatment plan to make sure that you receive safe and accurate treatment. Throughout your treatment, members of your team check and re-check your plan. Sophisticated computers are also used to monitor and double-check the treatment machines to make sure that the proper treatment is given.

If you undergo external beam radiation treatment, you will not be radioactive following treatment because the radiation does not stay in your body. However, if you undergo brachytherapy, tiny radioactive sources will be implanted inside your body, in the tumor or in the tissue surrounding the tumor, either temporarily or permanently. Your radiation oncologist will explain any special precautions that you or your family and friends may need to take.

What Are the Different Kinds of Radiation?
The goal of radiation therapy is to get a high enough dose of radiation into the body to kill the cancer cells while sparing the surrounding healthy tissue from damage. Several different radiation therapy techniques have been developed to accomplish this. Depending on the location, size and type of your tumor or tumors, you may receive one or a combination of these techniques. Your cancer treatment team will work with you to determine which treatment and how much radiation is best for you.

Radiation therapy can be delivered in two ways, externally and internally. During external beam radiation therapy, the radiation oncology team uses a machine to direct high-energy rays at the cancer. Internal radiation therapy, also called brachytherapy, involves placing radioactive sources (for example, radioactive seeds) inside the patient.

External Beam Radiation Therapy
During external beam radiation therapy, a beam of radiation is directed through the skin to a tumor and the immediate surrounding area in order to destroy the main tumor and any nearby cancer cells. To minimize side effects, the treatments are typically given every day for a number of weeks.

The radiation beam comes from a machine located outside of your body that does not touch your skin or the tumor. Receiving external beam radiation is similar to having an X-ray taken. It is a painless, bloodless procedure. The most common type of machine used to deliver external beam radiation therapy is called a linear accelerator, sometimes called a “linac”. It produces a beam of high-energy X-rays or electrons. Using sophisticated treatment planning software, our radiation oncology treatment team plans the size and shape of the beam, as well as how it is directed at your body, to effectively treat your tumor while sparing the normal tissue surrounding the cancer cells.

Several special types of external beam therapy are discussed in the following sections. These are used for particular types of cancer, and your radiation oncologist will recommend one of these treatments if he or she believes it will help you.

Three-Dimensional Conformal Radiation Therapy (3D-CRT)
Tumors usually have an irregular shape. Three-dimensional conformal radiation therapy, or 3D-CRT, uses sophisticated computers and computer assisted tomography scans (CT or CAT scans) and/or magnetic resonance imaging scans (MR or MRI scans) to create detailed, three-dimensional representations of the tumor and surrounding organs. Your radiation oncologist can then shape the radiation beams exactly to the size and shape of your tumor. The tools used to shape the radiation beams are multileaf collimators or blocks. Because the radiation beams are very precisely directed, nearby normal tissue receives less radiation exposure.

Intensity Modulated Radiation Therapy (IMRT)
Intensity modulated radiation therapy, or IMRT, is a specialized form of 3D-CRT that allows radiation to be more exactly shaped to fit your tumor. With IMRT, the radiation beam can be broken up in to many “beamlets”, and the intensity of each beamlet can be adjusted individually. Using IMRT, it may be possible to further limit the exact amount of radiation that is received by normal tissues that are near the tumor. In some situations, this may also allow a higher dose of radiation to be delivered to the tumor, increasing the chance of a cure.

Brachytherapy
Also known as internal radiation, brachytherapy involves placing radioactive material into a tumor or its surrounding tissue. Because the radiation sources are placed so close to the tumor, your doctors can deliver a large dose of radiation directly to the cancer cells with minimal exposure to normal tissue.

The radioactive sources used in brachytherapy, such as thin wires, ribbons, capsules or seeds, come in small sealed containers. Some sources are placed permanently and are referred to as implants. These radioactive sources remain in the body after their radiation has been expended and the source is no longer radioactive. Other sources are placed temporarily inside the body, and the radioactive sources are removed after the prescribed dose of radiation has been delivered.

MEMBERS OF THE TREATMENT TEAM

A team of highly trained medical professionals will be involved in your care during radiation therapy. This team is led by a radiation oncologist, a doctor who specializes in using radiation to treat cancer.

Radiation Oncologists
Radiation oncologists are the doctors who will oversee your radiation therapy treatments. These physicians work with the other members of the radiation therapy team to develop and prescribe your treatment plan and make sure that each treatment is accurately given. Your radiation oncologist will also monitor your progress and adjust the treatment as necessary to make sure you get the best care throughout the course of treatment. Radiation oncologists help identify and treat any side effects that may occur due to radiation therapy. They work closely with other physicians, including medical oncologists and surgeons, and all members of the radiation oncology team.

Radiation oncologists have completed at least four years of college, four years of medical school, one year of general medical training, then four years of residency (specialty) training in radiation oncology. They have extensive training in cancer medicine and the safe use of radiation to treat disease.

Medical Radiation Physicists
Qualified medical physicists work directly with the radiation oncologist during treatment planning and delivery. They oversee the work of the dosimetrist and help ensure that complex treatments are properly tailored for each patient. Medical physicists are responsible for developing and directing quality control programs for equipment and procedures. Their responsibility also includes making sure the equipment works properly by taking precise measurements of the radiation beam and performing other safety tests on a regular basis.

Dosimetrists
Dosimetrists work with the radiation oncologist and medical physicist to carefully calculate the dose of radiation to make sure the tumor gets enough radiation. Using computers, they develop a number of treatment plans that can best destroy the tumor while sparing the normal tissues.

Radiation Therapists
Radiation therapists work with radiation oncologists to administer the daily radiation treatment under the doctor’s prescription and supervision. They maintain daily records and regularly check the treatment machines to make sure they are working properly.