Radiotherapy in breast cancer: what you should know

Dr Cattleya Gaspar educates us on radiotherapy in breast cancer to clear up any misinformation and underling fears.

The number of women being diagnosed with breast cancer is unfortunately on the rise, making breast cancer one of the most common types of cancer worldwide. Breast cancer can affect women of all ages and races. In South 

Africa, the lifetime risk of developing breast cancer is 1 in 27.¹ Even men can develop breast cancer, albeit low, it was noted that 1% of all breast cancers are found in men.²  

The treatment of breast cancer is a broad topic and can be overwhelming to newly diagnosed patients. In general, the management plan will depend on several factors including: the patient’s stage, cancer type, family history, age, co-morbidities and function. Treatment options for patients with breast cancer vary but broadly consist of surgery, systemic therapy and radiotherapy. 

In certain patients, the addition of radiotherapy is a crucial adjuvant treatment option. Randomised trials have shown that the addition of radiotherapy reduces local tumour recurrence rates and increases subsequent overall survival.³ 

What is radiation? 

• Radiation occurs when there is a release of energy caused by an electromagnetic wave or a moving sub-atomic particle. 

• Radiation can be ionising or non-ionising.  

– Ionising radiation has high energy and causes the ionisation of molecules whereby a moleculegains a negative or positive charge. If this happens in human tissue, DNA damage is the end result.⁴ 

What is external beam radiotherapy (EBRT)? 

Ionising radiation is produced by a machine known as a linear accelerator and is delivered to a focused area, such as the breast, in the form of external beam radiotherapy. The ionising radiation released destroys cancer cells by causing DNA damage. DNA damage will prevent the cancer cell from dividing successfully and will subsequently cause cancer cell death. 

Is EBRT safe?⁵ 

Yes, if given correctly and if the well-established safety protocols are carefully followed. The radiotherapy team is responsible for a patient’s radiation treatment. The team consists of doctors, radiotherapists and medical physicists who all work together to ensure that the patient’s radiotherapy is delivered safely and accurately. 

Patients often ask if they will become radioactive during EBRT. After receiving EBRT, you do not become radioactive.

Which breast cancer patients benefit from radiotherapy?⁶ 

• A patient who has undergone breast conservation therapy.  

• A patient who has undergone a mastectomy and lymph node dissection with one or more of the following characteristics: 

– A tumour measuring 5cm or more or tumours that invade the overlying skin or underlying muscle.

– Positive surgical margins.

– If the cancer has moved to the local draining lymph nodes.

– Certain features on pathological histology.

• A patient who is inoperable but still needs adequate pain relief and bleeding control. 

• A patient whose cancer has spread to other parts of the body, such as the bones, spinal cord, or brain. Radiotherapy assists with reducing the tumour burden as well as with pain control.

Radiotherapy course and expected side effects 

Radiotherapy can either be delivered to the whole breast (post lumpectomy) or to the chest wall and scar (post mastectomy). In some patients, radiotherapy is also delivered to the axilla (armpit) and the supra-clavicular area (above the clavicle and lower neck). Treatment can only be started once the patient’s surgical wounds have healed or once chemotherapy has been completed. 

Patients are treated on a daily basis and, in most cases, are treated over a period of time which can range from three to six weeks. The patient is aligned in the same position every day and treatment is delivered over a 10-to-15-minute period. This procedure is not painful.

However, gradually over the course of treatment, the patient’s skin over the treated area may become sensitive and may resemble sunburn. Commonly, skin changes include redness with itching and darkening of the skin. In rare cases, a patient’s skin may blister and peel. 

Other side effects

  • Tiredness.
  • Changes to the breast: shape, numbness or swelling.
  • Late skin changes such as pigmentation and/or appearance of tiny blood vessels over the treated area. 
  • Effects on the breast: hardening of the breast, especially in patients with prostheses.
  • Swelling of the arm, fingers, and breast due to lymphoedema.
  • Heart or lung problems (uncommon). 
  • Secondary cancer (rare complication in adults). 

Skincare during radiotherapy

When bathing, lukewarm water should be used and the use of harsh, fragranced soaps should be avoided. Patients should rather opt to use a soap for sensitive skin, preferably with an added moisturiser. Patients should not rub/scrub over the treated area. 

It is important that patients keep their skin moisturised. Non-fragranced, gentle, hypoallergenic creams can be applied to the treated area before and after a radiotherapy session. Deodorant should not be used on the side that is being treated.

Patients should avoid rough or tight clothing around the treatment area. Loose garments are more comfortable. Patients should also avoid skin-on-skin contact which may lead to friction.

Patients should always protect the skin over the treated area from the sun and should also avoid the use of heating pads and ice packs. 

When a patient develops a skin reaction, they should let their oncologist know. The oncologist will prescribe the most appropriate medication to alleviate the symptoms and prevent further worsening of the symptoms. If a patient is unsure about which skin product to use, then they should rather ask for assistance.

Undergoing radiotherapy may feel like a daunting process but the correct information and mindset will go a long way.


  1. 2019 National Cancer Registry
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  3. Handbook of Evidence-Based Radiation Oncology 3rd Edition, Kindle Edition by Eric K. Hansen, Mack Roach III. Chapter 17: Breast Cancer.
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Dr Cattleya Gaspar is a radiation oncologist and practices at the Groenkloof Radiation Oncology and Mûelmed Radiation Oncology Centres. Her special areas of interest include gynaecological-, gastro-intestinal-, genito-urinary- and breast cancers.

MEET THE EXPERT – Dr Cattleya Gaspar

Dr Cattleya Gaspar is a radiation oncologist and practices at the Groenkloof Radiation Oncology and Mûelmed Radiation Oncology Centres. Her special areas of interest include gynaecological-, gastro-intestinal-, genito-urinary- and breast cancers.