What Is Radiation Therapy For Cancer?

Radiation therapy for cancer involves the use of high-energy, ionizing radiation to kill cancer cells. It is a type of cancer therapy in which X-rays and other types of high-energy particles are incident on the tumor or the area where cancer cells are found.

The high energy of these ionizing particles causes the cells that receive them to destroy themselves. The goal of radiation therapy treatment is to eliminate aberrant cells, preserving nearby healthy tissues.

Treatment is normally administered by a radiation oncologist. On the other hand, it  usually consists of several sessions during a certain period of time.

Types of radiation therapy treatments for cancer

Radiation therapy can be used in different cases and at different stages of cancer. In each of them you will have a different objective:

• As a first measure of treatment. Radiation therapy may be used as the first cancer treatment to shrink the existing tumor.
• As adjuvant therapy. In these cases, radiation therapy for cancer  is used after surgery or chemotherapy treatment to kill any residual cancer cells.
• As palliative therapy. Radiation therapy may be used in cases where the tumor cannot be completely destroyed to shrink it. In this way, your possible symptoms are alleviated.

External radiation therapy

Also known as “external beam radiotherapy”, this treatment is undoubtedly the most widely used in radiation oncology. In it, radiation is emitted from a machine outside the body, towards the area of ​​the tumor.

In this type of treatment, the size and shape of the beam can be adjusted. In this way the radiation can be directed precisely to the desired area, avoiding damaging the surrounding healthy regions. The types of external beam radiation that exist are:

Three-dimensional conformal radiation therapy (3D-CTR)

In this variant  , three-dimensional images of the tumor are used to know precisely where to direct the radiation beam. 3D images are obtained by computed tomography or magnetic resonance imaging.

One of the advantages of this therapy is that higher doses of radiation can be used, by knowing exactly the area to which the beam is directed. In this way, damage to healthy areas is avoided.

Thanks to its high precision, the 3D-CTR can prevent damage to the salivary glands. This eliminates one of the typical side effects of radiation therapy for cancer: dry mouth.

Intensity Modulated Radiation Therapy (IMRT)

IMRT offers even greater precision in avoiding healthy tissue than 3D-CTR. This is achieved because the intensity of each beam can be modified, modulating the radiation in a specific way for each area.

Proton beam therapy

This method is relatively novel and uses specific machinery. For this reason, it is currently not available in all types of centers. Instead of X-rays, this variant uses protons.

Protons are high-energy subatomic particles. Like X-rays, they can destroy the cells on which they are radiated. An advantage of this method is that the radiation does not spread to other areas, as it does in the previous ones.

Image Guided Radiation Therapy (IGRT)

In this treatment, the radiation oncologist collects images of the tumor area, both before and after having irradiated the area.

In this way, images from before and after each treatment session can be compared. This allows the next sessions to be focused on the irradiation of some areas or others. IGRT helps evaluate the effectiveness of treatment and prevent damage to healthy tissues.

Stereostatic radiation therapy

In this modality, a three-dimensional coordinate system independent of the patient is used to precisely locate the lesion. The method allows very precise and very high energy beams to be directed into very small areas.

During the process, the patient must remain completely still. Head supports or body casts are often used to limit movement.

Due to the high intensity of the radiation used, this therapy usually requires few or even a single session. However, some patients may need several treatments.