If you have been diagnosed with cancer your doctor may recommend radiation therapy or radiotherapy as a treatment option. Radiation uses ionizing radiation to destroy cancer cells and eradicate them from your body. As the radiation passes through your body it forms ions and releases electrons from atoms. Ions are simply atoms that have gained an electric charge by the gain or loss of an electron.

This is called ionization and damages the DNA of both normal healthy cells and cancer cells in the body. This need not be worrisome as these normal cells are able to repair themselves once the therapy is completed. Radiation therapy may be used alone or in combination with chemotherapy or surgery.

What Types of Radiation are Used to Treat Cancer?

Two types of radiation can be used to treat cancer:

1. Photons (x-rays and gamma rays)

2. Particulate radiation (electrons, protons, neutrons, alpha particles, and beta particles).

Certain types of ionizing radiation are more powerful than others and the higher the energy the more deeply the radiation will be able to penetrate into the tissues of the body. Radiation treatments are planned according to how the radiation behaves in the body and your treatment professional will choose the type and energy of radiotherapy that is appropriate for your cancer.

How is Radiation Therapy Given?

There are several different kinds of radiation therapy and these include external beam radiation, Brachytherapy and Radioimmunotherapy. The different types of radiation therapy are given to patients in different ways.

External Beam Radiation

This is a very widely used kind of radiotherapy and uses a machine called a Linear accelerator to produce a high energy x-ray or ‘photon’. It works a little like having an x-ray but for a much longer time. They focus radiation on the area where the cancer can be successfully treated. This form of therapy means large areas of the body can be treated and several areas may be treated at the same time for example the main site of the cancer and lymph nodes nearby. It is generally given in daily treatments over several weeks.

Brachytherapy

This is also known as interstitial radiation and uses small pellets or "seeds" of radioactivity which are directly implanted into a body cavity or tumor or in the tissues of the body. It may be left in place for one to seven days and once removed the body is not subject to any residual radioactivity that can be transmitted outside of the body.

High dose Brachytherapy makes use of needles that contain radioactive material left in place for less than twenty four hours. The radioactive source travels to the tumor via the needles and there may be pain in the area for about a week after insertion of the needles.

Only a small amount of tissue is treated so less normal tissue is destroyed. This means that cancer that is widespread cannot be treated by Brachytherapy. The radioactive substance in an implant may transmit rays outside the body so safety measures must be taken.

Radioimmunotherapy

This kind of radiotherapy makes use of radiolabeled antibodies and delivers doses of radiation directly to the site of the cancer. The antibodies are actually proteins produced by the body target certain proteins or structures on cells. Cancer cells express large amounts of these proteins and the antibodies will concentrate in these areas. In this way the radiation is directed at the site of the cancer. The cancer must produce the right protein and enough of it to be recognized by the antibodies for this type of therapy to be effective.

Proton Beam Radiation

A new form of treatment for cancer that works on the principle that protons cause little damage to tissues as they pass through but are can effectively in kill cells at the end of their path in the targeted tissue. This helps to minimize damage to nearby tissue and reduce side effects. This type of therapy is at present only available at a few treatment centers.

Neutron radiation

This is used for some cancers of the head, neck, and prostate.

Radiopharmaceuticals

These are unsealed sources of radiation that are given intravenously (IV), by mouth or placed into a body cavity. The radiation is taken into parts of the body in doses powerful enough to treat or (when given in smaller amounts), to help diagnose cancer.

What are the Side Effects of Radiation Therapy?

It is not possible to accurately predict how radiation will affect your body’s normal, healthy tissues and side effects will vary from person to person. In general the more rapidly growing cells in your body are likely to be affected of radiation treatment.

With the exception of fatigue, any side effects you may experience are usually confined to the area that is being treated and will probably appear a few days or weeks after treatment starts. They may remain for several weeks once the treatment is over.

As you read through the list of possible side effects bear in mind that not every person will experience all of these side effects and many are temporary or at the very least treatable. Side effects should never be a reason to avoid or discontinue treatment and should always be viewed in light of the effects of the cancer itself.

Fatigue and Weakness

It is not fully understood why many patients undergoing radiotherapy feel very tired. It is possible that the tumor itself may cause the immune system to produce substances that cause fatigue. You may have anemia (low red blood cell count), a poor diet due to surgery or loss of appetite, persistent pain, or be taking medications such as steroids or chemotherapy that could all contribute to your fatigue. Depression and stress may aggravate the problem. Undue tiredness may be addressed by taking moderate exercise and rest breaks.

Skin Changes

These days, radiation therapy causes less damage to the skin than it once did because the bulk of the radiation delivered below the skin’s surface but you may still find that your skin is affected early on, probably during the first 2 weeks of treatment. Your skin may show a short, but lasting redness or dryness and peeling of the skin, dry desquamation, may occur in 3 to 4 weeks.

The skin at the treatment site may darken due to your skin cells producing more pigment and the skin may become dry and itchy. Relief may be obtained by moisturizing the skin with Aloe Vera, lanolin, or vitamin E creams. After about a month of treatment you may experience extreme peeling and weeping areas on your skin and you should alert your treatment professional if this happens.

Inflammation of the Mouth

Mucositis is a temporary side effect of radiotherapy treatments to the head and neck area which usually clears a few weeks after treatment. There may be dryness and a loss of taste as a result of damage to the salivary glands and taste buds. If your mouth gets very sore you may be prescribed pain medication to lessen the discomfort. Paying good attention to mouth hygiene is very important, especially if you get radiation to the head and neck area as it can increase your chances of getting cavities.

Brain Changes

When radiation therapy is given to large areas of the brain there can be changes in brain function like memory loss, lowered sexual desire or a poor tolerance for colder weather but these are minor complaints when compared to the damage that a brain tumor can cause.

Lung Problems

Radiation treatments to the chest area can affect the lungs. The air passages may become restricted and prevent the lungs from expanding properly and you may have shortness of breath or cough. You may be given steroids to decrease inflammation.

Gastrointestinal Tract

Radiation to the abdominal area can cause swelling and inflammation to the esophagus or intestines in turn causing nausea, vomiting, or diarrhea. Taking an antacid combined with Xylocaine (a numbing medication) can help to relieve pain from inflammation of the esophagus and nausea and vomiting can be treated with medications or in severe cases intravenous fluids can be given to avoid or treat dehydration. Avoiding aggravating foods can help.

Reproductive Organs

Both men and women can experience some effects on their reproductive organs such as loss of sperm production or ovarian function or vaginal dryness and difficulty getting or maintaining an erection.

Second Cancers

Radiation therapy has dramatically improved over the past decades and now target cancer cells more accurately and with more precise doses. Thus the number of secondary cancers resulting from radiation therapy is expected to be substantially reduced. This risk should always be weighed against the great benefits of radiation treatment.

To conclude, you may experience some unpleasant side effects and feel unwell for a period of time during your radiation treatments so talk to your family and try to set some limits on your activity and some boundaries for yourself so that you are supported throughout your treatment.

Always follow a healthy diet, get enough rest and relaxation and make sure you talk through any social or psychological issue with an objective person or group. Successful cancer treatment is about the whole person so pay attention to your own needs at this time.

In general, radiotherapy is a highly effective treatment for cancer and it should always be considered if recommended by your health care provider. Many people who have been treated with radiation have been able to continue to live healthy and fulfilling lives thanks to this modern medicine.