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Radiotherapy or radiation treatment uses high-energy rays or ionizing radiation to treat the cancer. Although X-ray is principally used, other high-energy rays can also be utilized. Radiation damages the genetic material of quickly dividing and growing cancer cells, resulting in cessation of cellular division and death of neoplastic cells.

Today, external radiotherapy is the most commonly used option of radiation treatment. High-dose radiation is generated by an external (extracorporeal) device and delivered to the location of tumor.

On the other hand, brachytherapy implies a radiotherapy modality, wherein the source of radiation is placed into the body.

The destructive effects of radiation are not felt only by cancer cells or in other words, healthy cells are also exposed to radiation. Therefore, radiotherapy is a local treatment and the principle is to focus the high-dose radiation precisely on the target tissue. At this phase, a plan is made before the treatment is initiated in order to minimize the damage to healthy cells. For treatments with the new generation radiotherapy devices, the target area is first visualized in detail with imaging studies and thus, the target area is drawn with reference to type and location of the tumor using special software installed to the radiotherapy device in order to determine total dose of radiation and the number of sessions required to deliver the total dose. Thus, both healthy tissues are conserved and the treatment can precisely target the location of cancer (targeted therapy)

Why is it performed?

Radiotherapy can be the first-line treatment option for certain cancers. In this case, the aim should be complete elimination of cancerous cells. This option is also called stereotactic radiosurgery or radiation surgery.

As a definition, stereotactic radiosurgery is a treatment option that combines highly advanced radiation therapy, imaging method, image processing programs and robotic systems. Although the term “surgery” is expressed in the definition, it does not require incision and anesthesia. After the location of the target is determined and three dimensional images are created, high-dose radiation is delivered. Since CyberKnife can deliver radiation beams with very high precision, healthy tissue around the diseased area is exposed to minimal dose.

Although Cyberknife is more commonly used in the treatment of brain and spinal tumors (primary or metastatic), stereotactic body radiotherapy can be planned for tumors of liver, adrenal glands, prostate, lung and other organs.

On the other hand, radiotherapy can be instituted to support another anti-cancer treatment that was already started and continues. Here, the aim is to increase efficiency and success of the primary anti-cancer treatment by killing as much cancer cells as possible.

For cancers that are decided to be surgically removed, your doctor may decide radiation treatment to kill postoperative cancer residues.

Radiation treatment can be combined with chemotherapy, if required, and in this case, the treatment is called chemoradiotherapy.

The last indication of radiation treatment is to relieve signs and symptoms of the cancer, such as pain.


The side effects of radiotherapy take place in a very wide range depending on the body region where the radioactive rays are transmitted and the dose of radiation. Most side effects are transient in nature and they will spontaneously disappear after the treatment ends.

The most common side effects of radiotherapy are listed below:

Hair loss

Redness and irritation of skin and desquamation

Tiredness and fatigue

Dry mouth

Difficulty swallowing

Mouth sores

Sores in pharynx and esophagus

Change in the sense of taste

Nausea and vomiting


Shortness of breath

Frequent urination

Sexual dysfunctions

Predisposition to infections

Dental caries

You should follow instructions of your doctor on management of potential risks in order to face less side effects during or after the radiation treatment or cope with side effects more easily.


As it is mentioned above, your radiotherapy team will plan your treatment in advance. This plan aims minimizing the number of healthy cells that can be affected by the radiation exposure.

Computerized tomography will be scanned depending on the location of tumor and your position on the table of radiotherapy device will be adjusted and the area is marked, where the radiation is focused on. Simulation is completed using software of the device. Simulation aims to keep you immobilized strictly at same position in each treatment session. Thus, the pre-determined dose of radiation is precisely delivered to the target.

Surgery and early postoperative period

After your radiation treatment is planned, the start date is determined. Radiotherapy is an outpatient treatment and you may receive radiation treatment for five days of the week, excluding weekends. Duration of the treatment will be determined and notified to you by your doctor according to your health condition, type of cancer, location, stage, total dose and number of sessions that the total dose will be delivered. Moreover, your doctor may extend the treatment over weeks in order to provide healthy cells with the chance of self-repair. You may think that radiotherapy usually lasts 5 to 7 weeks.

Each radiotherapy session takes 10 to 30 minutes in average. Since you will need to lie on a table and not to move at this interval, it is reasonable to wear comfortable clothes. Moreover, healthy eating and drinking plenty of water will help you cope with side effects of radiation treatment.

After you are placed on the radiotherapy table, the device will turn around you to reach the target area. Meanwhile, you may hear strange noise. It is very important to stay strictly immobile while radiation rays are delivered. Sometimes, your doctor may even instruct you hold your breath. The device will continue turning around you and deliver the strictly pre-determined dose to the cancer at various angles.

You can communicate with radiotherapy team through a sound and vision transmission system that is equipped in the room, while radiotherapy is done. Thus, you can communicate any complaint to our team.


You may need regular examinations and imaging studies to reveal out the response of cancer to the radiation treatment. Your doctor will make
necessary reviews and inform you about the outcomes of your radiation treatment.