Radiation therapy for cancer involves the use of ionizing radiation, high energy, in order to eliminate cancer cells. It is a type of cancer therapy in which X-rays and other high-energy particles are incised on the tumor or the area where cancer cells are found.
The high energy of said ionizing particles causes the cells that receive them to be destroyed. The goal of radiotherapy treatment is to eliminate aberrant cells, preserving nearby healthy tissues. The treatment is usually administered by a radiation oncologist. On the other hand, it usually consists of several sessions during a certain period of time.
Types of radiotherapy treatments for cancer
Radiotherapy 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 treatment. Radiation therapy can be used as a first treatment for cancer, in order to reduce the size of the existing tumor.
- As adjuvant therapy. In these cases, radiation therapy for cancer is used after surgery or chemotherapy treatment to eliminate possible residual cancer cells.
- As a palliative therapy. Radiation therapy can be used in cases where it is not possible to completely destroy the tumor to reduce its size. Thus their possible symptoms are alleviated.
Also called external beam radiotherapy, this treatment is undoubtedly the most used in radiation oncology. In it, radiation is emitted from a machine external to the body, to the area of the tumor.
In this type of treatment you can adjust the size and shape of the beam.In this way the radiation can be directed precisely to the desired area, avoiding damaging adjacent healthy regions. The types of external beam radiation that exist are:
Three-dimensional conformal radiotherapy (3D-CTR)
In this variant three-dimensional images of the tumor are used to know precisely where the beam of radiation must be directed. 3D images are obtained by computerized tomography or magnetic resonance imaging.
One of the advantages of this therapy is that higher doses of radiation can be used, knowing exactly the area to which to direct the beam. This prevents damage to healthy areas.
Thanks to its high precision, the 3D-CTR can avoid damage to the salivary glands. This eliminates one of the typical side effects of radiotherapy for cancer: dry mouth.
Intensity Modulated Radiation Therapy (IMRT)
The IMRT offers even greater precision when it comes to avoiding healthy tissue than the 3D-CTR. This is achieved because the intensity of each beam can be modified, modulating the radiation specifically for each zone.
Proton beam therapy
This method is relatively new and uses a specific machinery. Therefore, at present it is not available in all types of centers. Instead of X-rays, protons are used in this variant.
Protons are high-energy subatomic particles. Like X-rays, they can destroy the cells on which they radiate. An advantage of this method is that the radiation does not expand to other areas, as it does in the previous ones.
Image guided radiotherapy (IGRT)
In this treatment, the radiation oncologist collects images of the tumor area, both before and after irradiating the area.
In this way, the images before and after each treatment session can be compared. This allows focusing the next sessions towards the irradiation of some areas or others. The IGRT helps evaluate the effectiveness of the treatment and avoid damage to healthy tissues.
In this modality, a system of independent three-dimensional coordinates of the patient is used to accurately locate the lesion. The method allows to direct very precise and very high energy beams towards very small areas.
During the process, the patient must remain completely immobile. They usually use supports for the head or corporal molds that limit the movements.
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.