Radiation Oncology

WHAT IS RADIOTHERAPY?

Radiation is a special kind of energy carried by waves or particles. It can be produced by special devices or released by substances called radioactive material. This energy has been used in medicine for imaging purposes since a long time. Lung x-rays are an example for this. These type of x-rays used for such imaging which can be used at much higher energy levels in order to treat cancer and some other diseases. Special devices are needed to direct the radiation to the diseased organ. The use of high-dose radiation energy for treatment purposes is called "radiotherapy" or "radiation therapy".

WHAT KIND OF EFFECT HAS RADIOTHERAPY?

High-dose radiation can kill cells or prevent them from dividing and multiplying. Since cancer cells divide and multiply faster than normal cells, radiotherapy is more effective on cancer cells than normal cells. In addition, normal cells recovered much easier and faster than cancer cells. In the so-called planning stage, physicians direct the treatment by drawing necessary drawings to expose the diseased tissues to the maximum and normal tissues to the minimum amount of radiation.

WHAT ARE THE BENEFITS AND GOALS OF RADIOTHERAPY?

Radiotherapy is used in many cancer types in almost every region of the body.

Nearly half of cancer patients are also undergoing radiotherapy. In some types of cancer, radiotherapy is the only treatment. Radiotherapy can be applied alone or in combination with surgery and/or medication therapy ("Chemotherapy") in order to completely cure many patients.

Radiotherapy is sometimes performed with the aim of reducing the tumor size prior to surgery. In some tumors, it is performed for the purpose of cleaning the cancer cells that may have remained after surgery. There are also methods of radiotherapy used during surgery. Cancer type are present as well in which radiotherapy and chemotherapy is directly administered without any surgery.

In some cases where it is not possible to fully cure the disease, radiotherapy may be used to reduce the patient's complaints such as pain and bleeding. This type of treatment is called "palliative treatment".

ARE RISKS PRESENT?

As with many methods of treatment, there are some radiotherapy related risks. Radiation at doses that will destroy cancer cells may damage normal cells and tissues. In this case, the patient may experience side effects. How to deal with side effects is described in the later sections of the booklet booklet. The risk of side effects is generally much lower than the benefits of killing cancer cells.

Your physician will recommend that you receive radiotherapy if the benefit expected from treatment is much greater than the possible risks.

How is radiotherapy administered?

Radiotherapy can be administered in two ways: External (external) and internal (internal). In some patients, these two forms can be administered in many cases.

In most patients, radiotherapy is performed externally. It is generally performed in outpatient treatment centers and it is carried out by directing rays to the diseased tissue by using radiotherapy devices. External treatments were carried out in recent years with devices called cobalt-60 or linear accelerators. In two-dimensional treatments, normal tissue damage and side effects were more common because large margins of safety used to provide the target with a sufficient dose of radiation. However, in recent years, with the dramatic changes in radiotherapy devices, three-dimensional conformal radiotherapy, IMRT (intensity-adjusted radiotherapy), sterotactic radiotherapy (linak-based, gammaknife, cyberknife) are administereed and the maximum dose is applied to the target volume while normal tissue only receives a minimal amount of radiation. Your physician will also decide which device is best for you when you are being administered radiation therapy.

In the internal radiation therapy treatment, the radioactive material or the source is placed either in a thin wire or in the tubes, either directly into the tumor or in a body cavity. Occasionally, placement can be performed in the remaining space after a surgery.

Who Administers Radiotherapy?

The “Radiation oncologist", a physician who specializes in the treatment of diseases with radiation, determines the type of treatment you need and carries out the planning. This physician will be called "your doctor" throughout the booklet.

During your treatment, radiation oncologists work with a special team. The following professionals are present in this team:

• Radiation physicist: Checks devices are working properly and delivering appropriate doses of radiation
• Dosimetrist: Determines the number and duration of sessions in treatments
• Radiotherapy nurse: Provides nursing services during treatment and helps you to deal with side effects.
• Radiotherapy technician: Performs your pre-treatment preparations ensures the operation of the treatment devices.

Apart from this team, you may also get help from a dietitian, physiotherapist, social service worker and other health professionals.

External Radiotherapy: What to Expect? How Does Your Doctor Prepare a Treatment Plan?

Radiation sources used in radiotherapy are various. Your doctor may use an X-ray or electron beam. The choice of source of radiation to be used is determined by the type of tumor, its location in the body and in particular, its depth. High energy X-rays are used for treatment of many types of cancer. Electron bundles can treat some skin diseases.

Before starting the treatment, a preparatory session is performed with computerized tomography. The aim is to personalize the treatment and determine the irradiation technique which should be chosen according to the type and prevalence of your cancer. The details of this preparatory session and the treatment itself (especially the frequency and duration of sessions) will be reported to you by your radiation oncologist during the initial examination. Firstly, during the radiotherapy sessions, the position that you have to take in the device is determined, then the computerized tomography is obtained in this position. Performing a treatment plan with computed tomography allows detection of the most risky areas related to tumor and/or tumor spread, as well as the detection of normal tissues that need to be protected. During tomography, an intravenous injection, or sometimes a urinary catheter on the area to be imaged may be required, depending on the area to be displayed. The radiation therapist marks your skin from one radiotherapy session to the other in order to ensure that the target volume is irradiated under the same conditions. For this purpose, ink pens that do vanish easily can be used or temporary tattoos may be applied. However, it is necessary to take care not to wash out these marks when showering, because these signs will be needed until your treatment is finished. In case of vanishing, you must inform your therapist. Please do not try to complete the vanished marks yourself.

After the target volume and normal tissue are determined by your doctor via tomography sections, your doctor will discuss with the dosimetrist and radiation physicist how much radiation dose you need and how many sessions will be administered. This usually takes a few days.

Once your treatment has begun, your doctor will monitor your response to treatment, your general condition and possible side effects. This is usually performed once a week, but the frequency may vary depending on your needs. It is important that you receive scheduled treatments on time. Disruptions in the plan may reduce the expected efficacy of treatment.

What happens during the treatment session?

You may need to take off your clothes and wear an apron before the treatment begins. Therefore, it is useful to use clothes you can easily change.

In the treatment room, the radiotherapy technician uses the previously marked lines on your skin to determine the treatment area. You need to sit in a special chair or lie down on the treatment table. Although each treatment session lasts 15 to 30 minutes in the treatment room, the administration of the radiation dose takes place in a period of 1 to 5 minutes. External radiotherapy is painless as it is in an X-ray procedure.

You don't need to hold your breath, you just need to breathe normally. It is important to ensure that the dose defined in the radiotherapy sessions is administered in the most sensitive way and the rays reach the correct place in the body, the position of the patient is not distorted throughout the treatment, the same position is used in each treatment and the environment provides the best possible comfort to the patient. In this process, which we call immobilization, accessories such as head-neck masks, vacuum beds, knee fixators or shoulder pullers can be used.

The radiotherapy technician leaves the room before the beam is emitted. The devices are controlled from a small area nearby. You are being watched via a monitor or window. During this time, even if you are alone, your voice can be heard from the speaker and the technician can contact you when you speak. Radiotherapy devices are quite large and can produce noise when rotating around the treatment area at different angles. Initially, the size and noise of the devices may sound frightening. It should be noted that the devices are operated by professional technicians and their proper operation is continuously checked. Ask the technician or your doctor about any questions you might have about your treatment room or devices.

You cannot see, hear or feel the radiation in any way. If you feel very uncomfortable during the treatment session, inform the technician immediately. The operation of the devices can be stopped immediately if necessary.

What Does Hyperfractional Treatment Mean?

Radiotherapy is administered by dividing the treatment into daily doses according to tumor type and location. In hyperfractional radiotherapy, the daily dose is divided into several small parts. If an area is to be divided into several treatments a day, the treatment is usually performed in 4-6 hour intervals.

What is Intraoperative Radiotherapy?

Intraoperative radiotherapy is simultaneously applied during surgery. The surgeon removes the tumor tissue as much as possible and radiotherapy is administered to the tumor bed immediately after surgery to clear the tumor cells that may have remained in the area.

What are the effects of treatment?

External radiotherapy does not make your body radioactive. For this reason, there is no need to avoid contact with other people because of this treatment. Even in contact situations such as hugging, kissing, there is no risk of negatively affecting other people.

The side effects of radiotherapy are generally related to the treated area. Your doctor and nurse will inform you about these side effects and how to deal with them. If you have symptoms such as coughing, fever, sweating or unusual pain during treatment, inform your doctor or nurse. Although most of the side effects are uncomfortable, they can be controlled via medication or diet. These usually disappear within a few weeks after the end of treatment. However, some side effects may last longer. Most patients do not experience any side effects. More detailed information is available in the "coping with side effects" section of this booklet.

The effectiveness of your treatment will be monitored by your doctor. After your treatment, you may notice pain, bleeding, and other similar complaints. Over time, you will also feel other signs of improvement. Your doctor will probably request some tests while monitoring the treatment effects. Examples for this are routine blood tests with which white counts of blood cells and platelets (clotting-related cells) are monitored. It is common for these numbers to be low during treatment.