jueves, 18 de octubre de 2018

Radiotherapy for Breast Cancer

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By Yolanda Smith, B.Pharm.Reviewed by Susha Cheriyedath, M.Sc.

Radiotherapy, also known as radiation therapy, is sometimes used in the treatment of breast cancer, usually in addition to other treatment techniques such as surgery or chemotherapy. It uses high-energy X-rays or particles to destroy cells in a localized area to reduce or eradicate cancerous growth.

There are various types of radiotherapy that may be used, depending on the type and the extent to which the cancer has spread, as well as individual patient characteristics. Some patients may also receive more than one type of radiation therapy.

Radiotherapy may be indicated in the treatment of breast cancer in several different situations. It is most often given after surgery (e.g. breast-conserving surgery or a mastectomy) to help lower the chance of recurrence of cancer in breasts or adjacent lymph nodes. It is also used for advanced stage breast cancer when it has spread to other parts of the body such as the bones or the brain.

Types

There are two main types of radiotherapy that may be used in the treatment of breast cancer: external beam radiation and internal radiation, also known as brachytherapy. Both of these types will be discussed in more detail below.

External beam radiation is the most common type of radiotherapy for patients with breast cancer. This technique involves radiation sourced from a machine outside of the body that is directed towards the chest and the specific region of the breasts that is affected by cancer. For women who have had a mastectomy the radiation is focused towards the chest wall and the regions of draining after the surgical procedure. For women who had breast-conserving surgery, the radiation is usually directed towards the entire area of the breast, with additional focus on the area of the original tumor. The lymph nodes may also be targeted if cancerous cells were found in them.

Brachytherapy is an alternative way to deliver the radiation to the body, involving a device with radioactive material that is placed inside the body. This technique is best for breast cancer that has been detected at an early stage, so it is unlikely that it spreads to other areas of the breast. It helps to reduce side effects to other areas of the breast because the radiation is concentrated in that area.

Administration

Radiotherapy is not usually administered until at least a month after the conclusion of surgery to allow the tissues in the area to heal. In most cases, radiotherapy is also delayed until the completion of treatment with chemotherapy.

Before the beginning of treatment with radiotherapy, it is important for the medical team to identify the areas of the body that should be targeted with the radiation to destroy the cells in the localized area. Ideally, the radiation beams should be angled to concentrate the dose in areas that are most likely to have cells with cancerous growth, with as little exposure as possible to the surrounding tissues. Marking the skin to use as a guide when directing the radiation is often useful.

Patients should be advised to avoid using any lotions, powders, deodorants, antiperspirants, or perfume on their skin before or during treatment because this can interfere with the treatment.

The duration of treatment with radiotherapy will depend on the specific case, but the traditional schedule involves radiation for 5 days a week for 6 weeks. Recently, radiologists have been tending towards accelerated breast irradiation, which involves higher doses of radiation for a shorter period of time.

Adverse effects of radiotherapy

The actual procedure to administer radiotherapy is painless and is similar to an X-ray imaging scan, with higher doses of radiation being given. However, there are some side effects that may present within several days or weeks from the initiation of treatment. These include:

Swelling of the breasts
Heaviness of the breasts
Reddening or blistering of the skin
Fatigue

Most of these changes to the skin and breast tissue will improve within several months of stopping treatment; however, the effects can last longer. Some women may notice permanent changes to the shape of their breasts, reporting that they are smaller and firmer than before treatment.

Radiation therapy can also affect the options available for a breast reconstruction if the woman chooses to have a reconstruction after treatment. It can also increase the difficulty in breastfeeding for women who plan to have children in the future.