Radiotherapy for Breast Cancer

For Whom Is Radiotherapy for Breast Cancer Suitable?

The primary purpose of radiotherapy for breast cancer patients is to prevent a recurrence of cancer, a so-called relapse. Nowadays, most affected women undergo breast-conserving surgery, which means only the tumor is removed from the breast, while the remaining healthy tissue is spared. Radiation therapy is used after the surgical removal of the tumor tissue to destroy the remaining cancer cells that may still be present in the former tumor bed and grow again into a tumor by splitting. This procedure is an established guideline in Germany and carried out for all women after breast-conserving surgery. Women whose affected breast has been completely removed are usually not irradiated.

Breast Cancer Radiation or Chemotherapy?

Chemotherapy is a systemic treatment for cancer that works throughout the body, which is not always necessary in all patients and is mainly used when the risk of cancer recurrence is high. This risk can be determined on the cancer cells' surface receptors, which provide information about the type of tumor.

Currently, only a small number of breast cancer patients in Germany are treated with chemotherapy after surgical removal of the tumor. In most cases, the cancer is detected before spreading to other parts of the body, so that local therapy with surgery and radiation is sufficient.

Which Radiation Methods Are Used?

Nowadays, linear accelerators are used almost exclusively for the irradiation of the breast, where the generated rays are explicitly directed to the breast tissue and are individually adjusted to the patient's anatomy. Depending on the tumor's former location and the shape and size of the breast, a radiation plan is created before the first irradiation. The linear accelerators generate radiation at a high dose rate, so the irradiation only takes a few minutes in each session.

A total dose of 50-66Gy is required for irradiation after breast-conserving surgery. The total dose is administered in many single doses, which are kept as low as possible to minimize radiation therapy's side effects. For example, in the standard procedure, it is common to administer 1.8-2.0Gy per session, so the entire radiation therapy lasts 6-7 weeks. During the week, radiation is administered every day from Monday to Friday, while no radiation is administered on weekends.

Hypofractionation

A new form of breast irradiation is the so-called hypofractionation, where the individual dose is increased, and fewer sessions are required to achieve the total dose. This procedure is mainly used in younger women without any previous illnesses, as the duration of treatment can be reduced without additional side effects compared to the standard therapy.

Boost Irradiation

Suppose the distance between the tumor and the incision edge is small (a few millimeters) during breast-conserving surgery. In that case, the former tumor bed is treated with so-called boost radiation, which involves additional radiation doses of about 60-66Gy.

Brachytherapy for Breast Cancer

In brachytherapy, the radiation source is placed directly into the tissue, allowing irradiating the diseased tissue with very high radiation doses without destroying the surrounding tissue. Brachytherapy is mainly used for partial breast irradiation. If the tumor has been surgically removed, only the former tumor region can be irradiated and not the entire breast. This method's advantages are the protection of skin and breast tissue and the short treatment time of 4-5 days.

Procedure and Duration of Breast Cancer Irradiation

A planning CT of the patient is created before the first radiation appointment. Markings are made on the skin to establish the same position in the linear accelerator for the following sessions, as in the planning CT. Then the radiation plan is created in cooperation with the doctors and medical physicists. During the first irradiation session, the settings on the linear accelerator are adjusted to the patient. This appointment lasts approx. 30-45min, and takes considerably longer than the subsequent sessions, which last only 10-15min. The irradiation of the breast is carried out in the dorsal position. After the patient has undressed the upper body, she can lie comfortably on a couch and asked to put the arms over her head. The position is the same for each session, so the patients learn a routine after a few appointments. During the irradiation, the medical staff leaves the room to protect themselves from radiation. The irradiation only lasts a few minutes, and no noise, heat, or visual effects are expected. The patients can only see the linear accelerator rotating around them.

What Should Be Paid Attention to During Breast Cancer Radiation?

Radiotherapy can be carried out in outpatient settings for most breast cancer patients. During the irradiation period of 6-7 weeks, a certificate of inability to work can be issued. The markings on the skin may not be removed during daily hygiene, as these must remain visible from the time of the planning CT until the last radiation session. The skin over the irradiated breast should not be exposed to the sun to prevent radiodermatitis as far as possible. Skin irritation caused by chlorine water in the swimming pool should also be avoided.

What Side Effects and Long-Term Consequences Can Occur?

Acute side effects of irradiation occur more frequently, the more often the patient has already been irradiated. Side effects may be similar to a sunburn, such as dryness and reddening of the skin. In medicine, this condition is called radiodermatitis and is divided into four degrees of severity. In more severe forms, there is detachment of skin scales and pain in the affected areas. After radiotherapy, when the radiodermatitis has healed, residual hyperpigmentation may remain, i.e., darker skin areas with increased skin pigment deposition. The breast may also harden after radiotherapy due to tissue remodeling, so-called fibrosis. Fatigue and general exhaustion can also occur in the course of radiotherapy. Patients are recommended to participate in sports and stay in the fresh air to relieve this symptom.

Which Doctors and Clinics Are Specialized in Radiotherapy for Breast Cancer?

Experts in radiotherapy for the breast are doctors specializing in radiotherapy and radio-oncology. They work in clinics of the same name in close cooperation with gynecologists, who, in most cases, are the first to discover and operate breast cancer. Also, medical physicists play a significant role in the planning of radiation therapy since the medical side of breast anatomy and treatment plans must be brought together with the linear accelerator's technical side. Breast cancer patients can be treated well in outpatient settings, so radiotherapy can usually be carried out in the hospitals or a radiotherapy practice.

Sources

• Piper: Innere Medizin . 2. Auflage. Springer 2012, ISBN 978-3-642-33107-7.
• Hien: Praktische Pneumologie . 2. Auflage. Springer 2011, ISBN 978-3-642-10209-7.
• Wannemacher et al. (Hrsg.): Strahlentherapie . 2. Auflage. Springer 2013, ISBN 3-540-88304-5.
• www.radioonkologie.insel.ch/de/unser-angebot/zentrum-fuer-brachytherapie/