Radiotherapy in the treatment of breast cancer

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Breast cancer is one of the most common cancers in women. It can be diagnosed early in women over the age of 40 with regular screening studies including mammography, breast ultrasonography and physical examination. In addition, clinical manifestations such as swelling or mass formation in the breast, discharge from the nipple, and skin discoloration may occur.

Breast cancer can spread throughout the body through lymph and blood. The disease spreads beyond the breast tissue, often to the axillary lymph nodes via lymphatic tissue, and to other organs and tissues in the body, such as the liver, lungs, brain, and spinal cord, via blood. Breast cancer is staged according to the degree of spread of the disease in the body. This staging is divided into two as clinical staging using clinical examination findings or radiological imaging methods (ultrasonography, computed tomography, scintigraphy, magnetic resonance) data or surgical-pathological staging using data obtained from histopathological evaluation of the operation specimen (tissue removed during the operation). The type of treatment to be applied is decided according to the surgical-pathological stage in patients who underwent surgery, and according to the clinical stage in patients who did not undergo surgery.

In the treatment of breast cancer, radiotherapy, surgery, hormone therapy, chemotherapy and receptor-directed treatments can be used together or alone; It is used as a palliative in order to completely cure the disease (to achieve cure) or to reduce and eliminate the patient’s complaints due to the disease.

The necessity of applying radiotherapy in breast cancer varies according to the stages of the disease, whether the patient is operated on, what type of operation is performed, and the histopathological evaluation findings of the operation specimen (tissue removed during the operation).

In this section, the situations in which radiotherapy is required in patients with breast cancer, the ways in which radiotherapy is applied, radiotherapy planning, necessary preparations and possible radiotherapy side effects will be evaluated.

Radiotherapy and application techniques of radiotherapy

Radiotherapy is the use of ionizing radiation for therapeutic purposes. In the simplest terms, radiotherapy, which is the application of high-energy ionizing rays for the treatment of tumors, is one of the most effective methods in the treatment of patients with breast cancer. It inhibits the growth, reproduction of cancerous cells and prevents their spread to normal tissues, in most cases, it can completely destroy the tumor. In addition to preventing the recurrence of breast cancer in the same place (local recurrence), it also contributes to prolonging the life span of patients with breast cancer.

Radiotherapy can be administered externally (externally) or internally (brachytherapy).

Outside irradiation:

High-energy x-rays are passed through the skin and subcutaneous tissues with the help of a device to the area to be treated and applied to the tumor tissues. High-energy rays at megavoltage level are used in external radiotherapy in breast cancer, and electron energies at different levels are used in selected patients. According to the stage of breast cancer (such as tumor size, spread to regional lymph nodes), it can be applied only to the breast, part of the breast, chest wall and breast, chest wall, regional lymph nodes (Figure 1). Radiotherapy to the chest wall and regional lymph nodes may also be required in cases where the entire breast is removed (Figure 2).

Treatment Planning:

A patient-specific treatment planning is made in the computerized planning device so that organs such as the lungs and heart, which are in the vicinity of the target (breast, chest wall and regional lymph nodes) to be radiotherapy in breast cancer, are minimally exposed to the effects of radiation.

In this planning process, computed tomography images are used to identify target tissues and organs that need radiation protection. It uses devices or body fixation devices specially made for the patient in order to ensure that the body remains stable throughout the treatment, and that the treatment is applied in the same position and with precision accuracy every day.

In external planning, 3-dimensional conformal radiotherapy and intensity modulated radiotherapy, which is a more advanced technique of conformal radiotherapy, can also be used. In 3D conformal radiotherapy, a combination of many beam fields is used to limit the radiation dose in the breast and to protect the surrounding normal tissues (Figure 1-2). In the intensity modulated radiotherapy technique, which is a more advanced technique of conformal radiotherapy, a sharper radiation dose distribution to the treatment volume is obtained by changing the intensity of the beam fields across the area (Figure 3).

In selected patients in whom only the tumor was removed from the breast and the whole breast was not removed, instead of irradiating the entire breast, irradiation of a limited volume around the tumor can be used as “partial breast irradiation”. Partial breast irradiation can be applied intraoperatively (in the operating room immediately after surgery) in a single session with external radiotherapy or brachytherapy or technique. In addition, it can be applied between one and 5 days after the surgery with external radiotherapy or brachytherapy methods. External radiotherapy can be administered with conformal radiotherapy or intensity modulated radiotherapy (IMRT) techniques (Figure 4). Brachytherapy, on the other hand, can be applied with interstitial brachytherapy technique through balloon-shaped mamosite or catheters.

In the computerized planning device, the most appropriate treatment planning is made and the treatment time is calculated. Marks that can be erased if desired can be drawn on the skin with some special pens and markers in the area to be treated.

In patients with left breast cancer, respiratory-controlled radiotherapy technique is applied to protect the heart and coronary arteries from the effects of radiation.

Treatment

External radiotherapy is usually administered once a day, five days a week, for 5-6 weeks. The treatment process is similar to a film or photo shoot, no pain is felt during the treatment. However, during the treatment session, it is necessary to remain completely still and in the position applied in the planning. Each treatment takes about 2-3 minutes.

During the period of external radiotherapy, the patient does not have the risk of radiating to those around him, and he can continue his normal social life.

At certain intervals throughout the treatment process, without additional radiation dose, the treatment volume is verified with the portal imaging method and the planned treatment is applied correctly.

Possible Side Effects

During the radiotherapy process, there may be a feeling of sensitivity on the skin, varying from very mild to moderate skin redness, mild swelling of the breast, and fatigue, varying from patient to patient. In addition, especially in patients whose regional lymph nodes are irradiated, mild fatigue, anorexia, and nausea may be experienced due to the increase in the irradiated volume. During the treatment period, it will be beneficial for the patient to follow the skin care recommendations suggested by the doctor and not to use synthetic, nylon, tight clothing. It is important for the patient to take care of his health during radiotherapy in order to continue the treatment without interruption. Balanced diet, maintaining body weight throughout the treatment will reduce side effects such as fatigue that may occur due to treatment. Protein foods such as meat, yogurt, legumes, milk, fish are necessary.

In addition to continuing his normal life as much as his strength allows, light exercises such as short walks are useful if the doctor does not have any other recommendations.

It is appropriate for the patient to continue to take the drugs that he uses for the treatment of diseases other than cancer (heart, kidney or diabetes, etc.), unless his doctor informs him otherwise.

Internal Irradiation (Brachytherapy):

Brachytherapy or internal irradiation is the placement of small radioactive (implants) inside the body or cavities in order to give radiation directly to the cancerous cells. Brachytherapy has been used successfully since the early 1900s. Initially, radium and cesium were widely used, but today iridium, cobalt and cesium are preferred. Today, brachytherapy is applied with remote afterloading and remote controlled devices. Medical personnel do not come into contact with radioactive materials, exposure to radioactivity is reduced to a negligible level. Brachytherapy devices contain small needles or pellets that contain a radioactive source measured in millimeters. During the treatment, these sources pass through the catheters and the applicator, apply radiation to the limited area where the tumor is located, at the positions calculated and determined in the planning device and for the specified time, and return to the device again.

After irradiation of the entire breast with external radiotherapy, additional dose to a limited area around the tumor or partial breast irradiation can be applied alone in selected patients.

It can be applied with interstitial brachytherapy technique by means of balloon-shaped mamosite applicator or catheters in brachytherapy application for partial breast irradiation in selected breast cancer patients. In the mammosite technique, the treatment is completed in 3-4 days in 8-10 fractions, twice a day. Interstitial brachytherapy is applied in 8-10 fractions in 3-4 days with the high-dose rate brachytherapy technique, while it is applied in a single fraction lasting 36-72 hours in the low-dose rate brachytherapy technique.

Application (Placement) operations:

In the application of brachytherapy with the Mamosite technique, a special applicator (catheter with a balloon around it) can be placed on the tumor area immediately after the operation, or the applicator can be placed in a separate session after the operation. In interstitial brachytherapy, special needles are applied around the tumor area with a separate application process.

Preparation for treatment:

Resting the patient the day before the treatment and sleeping well at night will be beneficial for the comfortable toleration of the treatment. In some cases, pre-treatment anesthesia may be required. For this reason, nothing should be taken by mouth, food or liquid after midnight.

Treatment Planning

It is important to define the target tissues (tumor or organ) and surrounding healthy tissues in detail, to limit the high radiation dose to the target and to protect the healthy tissues. For this reason, after the placement of the applicators, the images of the area to be treated are taken with computerized tomography and magnetic resonance imaging, and treatment planning is made by means of these images in the computerized radiotherapy planning device. During the treatment planning process, the patient waits in the treatment room, while the nurse is accompanied.

Treatment

After the calculation and planning processes are completed, the high dose rate brachytherapy to be administered is between a few minutes and 30 minutes. There is no one else in the room other than the patient during the treatment. However, the doctor and nurse watch the patient from outside via closed-circuit TV and talk when necessary. At any stage of the treatment, the treatment can be stopped and the patient can be controlled.

Possible side effects:

In the early period, sensitivity, pain, bleeding and edema may develop due to the applicator inserted during the application. In the late period, thickening, narrowing and enlargement of the skin vessels can be seen in the tissues that are applied brachytherapy.

Radiotherapy requirement according to breast cancer stage and cell type

Ductal carcinoma in situ

In its treatment, removal of the entire breast or removal of only the tumor region and applying radiotherapy to the entire breast are equally successful.

Lobular carcinoma in-situ

In its treatment, removal of the entire breast is applied.

Stage I, II, IIIA, operation applicable IIIC

In patients at these stages, removal of only the tumor tissue and axillary lymph nodes and radiotherapy to the whole breast, removal of the entire breast and axillary lymph nodes are used with equal success. Radiotherapy to regional lymph nodes is related to the spread of the disease to the lymph nodes.

Stage IIIB, inoperable IIIC, IV and metastatic breast cancers

Systemic chemotherapy followed by radiotherapy should be applied to the chest wall and regional lymph nodes after the operation in which the breast and axillary lymph nodes are completely removed, if applicable.

IV and metastatic breast cancers

Although systemic treatment is the main treatment, radiotherapy or surgery may be required in some complaints and clinical conditions of the patient. For example, radiotherapy may be needed to treat brain metastases or painful, fracture-prone bone metastases. In addition, in the presence of bleeding, pain and pressure complaints on the skin that are too advanced to be operated on, the application of radiotherapy reduces these complaints.

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