Brachytherapy

Generality

Brachytherapy, or internal radiotherapy, consists of placing a radioactive source in direct contact with the tumor. This form of treatment has the advantage of exposing only the affected anatomical area to radiation, thus saving the surrounding healthy tissues. Moreover, it is carried out very quickly and with few therapeutic sessions.

Figure: an interesting diagnostic image of the pelvic area, which shows the radioactive sources (in this case seeds resembling rice grains) inserted into the body, to treat a tumor. From the site: abitarearoma.net

The procedure can be put into practice in different ways, depending on how the tumor appears (location and size) and the patient's health conditions.

What is brachytherapy?

Brachytherapy is a type of radiotherapy in which the placement of radioactive material inside the body, near the tumor to be treated, is expected. This explains why brachytherapy is also referred to as internal radiotherapy .

The radioactive material, composed of radioisotopes, can be applied to cylindrical supports, small spheres or seeds similar to rice grains (the choice depends on the needs), then implanted in the most appropriate location to act as an internal source of radiation . These radiations serve to destroy the cells that make up the growing tumor mass.

ADVANTAGES OF BRACHYTHERAPY

The main strengths of brachytherapy are three.

The first advantage is to guarantee limited exposure to radiation and less damage to healthy tissues: in fact, unlike what happens with external radiotherapy (which affects an extended area of ​​the body), internal radiotherapy "operates" only on area occupied by the tumor.

The second advantage is connected to the first and consists in the possibility of increasing the dose of radioactivity emitted by the source, as this is directed exclusively against the tumor mass. In reality, as we will see later, the quantities of radiation emitted are not always high: in some cases, in fact, we opt for a treatment at lower doses, but very prolonged.

The third advantage, finally, concerns the speed of treatment. While external radiotherapy takes place in many sessions (the time that separates them also allows the tumor residues to resume growth), brachytherapy is immediate and rapid. As will be seen, it does not require special equipment and in some cases allows the patient to undergo treatment and, at the same time, continue in their daily activities.

When you run

Brachytherapy is adopted for the treatment of various cancers, which affect:

• Biliary tract
• Otherwise
• Uterine cervix
• Endometrium
• Eyes
• Brain and, in general, the head and neck
• Lung and respiratory system in general
• Prostate and penis
• Urinary system
• Colorectal
• Skin
• Various soft tissues
• Vagina and vulva

Brachytherapy, like external radiotherapy, is a treatment that can be practiced alone or in association with other anticancer treatments. For example, in cases of tumors accessible to the surgeon, brachytherapy can be adopted to complete a first surgical removal operation; in the case of non-operable tumors, on the other hand, internal radiotherapy can be the only viable solution.

Sometimes, it is possible to have recourse, at the same time, to brachytherapy and external radiotherapy, to obtain a better therapeutic result.

Figure: the anatomical districts, which, affected by a tumor, can be treated with brachytherapy. From en.wikipedia.org

Side effects

Since, albeit to a limited extent, brachytherapy exposes to radiation, it can also produce other side effects, of a general and specific type.

General side effects: they are swelling and pain in the area where the radioactive source is located.

Specific side effects: they depend on the tumor in question and on the area in which it occurs. In order to know the consequences of the treatment in detail, it is advisable to consult your doctor.

Preparation

Before starting brachytherapy, the patient with cancer must undergo several diagnostic tests, such as computerized axial tomography ( CT ) and nuclear magnetic resonance ( NMR ), to define the location and size of the tumor.

Once in possession of this data, an oncologist radiotherapist will plan the most appropriate therapeutic path.

Details of the procedure

As mentioned above, brachytherapy involves placing a radioactive source near the tumor. This procedure can be performed in various ways, depending on the size of the tumor, the location of the latter and the patient 's state of health .

The three parameters below serve to distinguish the various types of brachytherapy, however, as the reader will also notice at the end of the discussion, this distinction is only formal. The only factors that influence the procedure are the characteristics of the tumor and the patient's condition.

• Location of the radioactive source
• Intensity of radioactivity
• Duration of treatment

PLACEMENT SEAT: INTERSTIAL OR CONTACT BRACHYTERAPY

Depending on where the radioactive material is inserted, brachytherapy can be interstitial or contact.

• In interstitial brachytherapy, the radioactive sources are inserted directly into the tumor-affected tissue. Such springs are usually spheres or small seeds, similar to grains of rice; their precise placement is carried out using needles, catheters or special applicators, with the aid of diagnostic imaging equipment (CT or ultrasound). The most suitable time to position the sources depends on the tumor and its severity: in severe neoplasms, in which the surgeon cannot completely eliminate the tumor mass, it is possible to apply seeds or balls at the end of the surgery.

  Examples of tumors for which the so-called interstitial brachytherapy is foreseen are breast and prostate neoplasms.

• In contact brachytherapy, the radioactive sources are inserted in the spaces close to the target tissues, usually cavities of the body but not only, given that this method is also used for the treatment of skin tumors. Radioisotopes are released from cylindrical or tubular supports ( cylinders or tubes ), placed directly by the surgeon's hand or by computerized machinery. Also in this case, for the correct execution of the procedure, the guidance of diagnostic tools is required, such as CT and ultrasound.

  Some examples of cancers treated with contact brachytherapy are those of the uterus, cervix, vagina, skin or digestive system (see table).

Figure: the seeds used for brachytherapy. Similar to rice grains, they are "loaded" with radioactive material and then inserted into the tissue affected by the tumor. From the site: //en.wikipedia.org/

THE RADIOACTIVITY DOSE ?: BRACHYTHERAPY AT HIGH OR LOW DOSE

Based on the radioisotope dose released from the sources, brachytherapy can be distinguished in brachytherapy with a high dose of radioactivity and in brachytherapy with a low dose of radioactivity. Here are the implications of each procedure:

• Brachytherapy with a high dose of radioactivity . In these cases, the positioning of very powerful radioactive sources is foreseen, so that the treatment lasts a few minutes (not more than 20) and is repeated maximum twice a day, for a few days or weeks. There is no real hospitalization of the patient, but an isolation (in a special room of the treatment center) as long as the exposure to radioactive material. At the end of the treatment, the radioactive source is removed and the patient can leave the hospital and return to their daily activities.

  Precautions, during the treatment period: it is important that the patient does not come into contact with anyone (except appropriately protected medical personnel), due to the risk of radiation contamination.

  Pain or discomfort during the treatment period: high dose brachytherapy does not usually cause pain; moreover, the isolation room is equipped with all the comforts. Any inconvenience may arise when the sources are inserted.

• Brachytherapy with a low dose of radioactivity . The use of low-power sources is used and long exposure hours, if not days, are expected. Obviously, the patient must be hospitalized and kept as isolated as possible, despite the low radioactivity. There are rooms with all the comforts, where the patient can feel at ease.

  Once the therapy is finished, the radioactive material is removed and the patient can return to his daily activities.

  Tricks during the treatment period: visits to the patient by family members must be reduced to the essentials. Furthermore, it is good that children and pregnant women avoid making contact with individuals under care.

  Pain or discomfort during the treatment period: in general, low-dose brachytherapy does not cause pain, and if these should occur, medical personnel are still ready to intervene. Some discomfort may appear due to forced isolation or at the time of insertion of radioactive material.

DURATION OF TREATMENT: PERMANENT OR TEMPORARY

Premise: radioactive materials, used for brachytherapy, are not eternal, but undergo the so-called phenomenon of radioactive decay, or the progressive loss of radioactive capacity. This process lasts a few weeks and, once finished, the supports (seeds, cylinders etc.) are "discharged" and without any effect.

Radioactive sources can be left in place in a stable manner or removed and replaced at regular intervals. In the first case, we talk about permanent brachytherapy, while in the second case, temporary brachytherapy . In detail:

• Permanent brachytherapy . This method involves the insertion of seeds with very low radioactivity, which, once properly arranged, are left in place even after their decay. In fact, these sources are in no way harmful to the patient. The dose of radioactive material is so low that the individual treated represents no danger to the people around him on a daily basis.

  Precautions, during the treatment period: although the risk of spreading harmful radiation is very low, it is recommended that the patient be in close contact with children and pregnant women. This restriction lasts a few weeks or a few months, depending on when the source's radioactive charge ends.

  Pain or discomfort during the treatment period: in some areas of the body, the insertion of seeds can be painful. However, once placed in the office, the pain ceases and the patient does not usually feel any particular disturbance.

• Temporary brachytherapy . This therapeutic protocol provides for the placement, replacement (after decay) and the definitive removal of radioactive sources. The dose of radioactivity can be low or high, depending on the tumor that is being treated. The duration of treatment ranges from a few hours to a maximum of 24 hours, based on the radioactive power of the sources. Isolation of the patient at the time of treatment is required.

  Precautions, during the treatment period: they are the same as described for brachytherapy at high doses and at low doses of radioactivity.

  Pain or discomfort during the treatment period: insertion could be painful.

The results

The results and effectiveness of brachytherapy, as it happens with many other anticancer therapies, are an unknown factor. In fact, each patient responds to treatment differently and this depends exclusively on the characteristics of the tumor, ie whether it is severe, infiltrated, benign, malignant, slow growing, etc.

In any case, to understand if there have been benefits after brachytherapy, it is necessary to perform diagnostic tests, such as CT and MRI.