Breast radiotherapy – FAQS

The size, grade, stage and type of your breast cancer, which operation and other treatments you have had and how many lymph nodes were affected will determine if you need radiotherapy and which area(s) require treatment.

Post-operative radiotherapy is given to reduce the risk of breast cancer cells recurring in the breast, chest wall or lymph node regions.

Most patients require post-operative radiotherapy to the remaining breast tissue following breast-conserving surgery (removal of the breast cancer and an area of normal tissue around it, also known as a ‘lumpectomy’).

Some patients who have had breast conserving surgery may be at higher risk of the cancer returning in the breast, for example:

  • Younger patients with larger tumours
  • Patients where only a narrow rim of normal tissue was taken around the cancer (also known as ‘close margins’)
  • Patients who required pre-operative chemotherapy.

These patients require an extra ‘boost’ dose to the area where the original tumour developed.

Following a mastectomy (removal of the whole breast) radiotherapy to the scar and chest area may be considered if the tumour:

  • Was large
  • Was deep in the breast and close to the chest wall
  • Had spread to some or all of the lymph nodes.

Sometimes the lymph nodes under the arm and / or in the lower neck might need radiotherapy, depending on the type of surgery and how many lymph nodes contained cancer cells.

Most patients have radiotherapy after surgery. It is important the wound(s) are fully healed before treatment starts, so typically the radiotherapy commences about four to eight weeks post-operatively.

If you also require chemotherapy, this is given first; the radiotherapy usually starts about one month after the chemotherapy is complete.

Sometimes, fluid collects around the breast or armpit scar after the surgery (known as a ‘seroma’). This may require drainage and needs to settle before the radiotherapy can be planned. Occasionally the treatment may need to be delayed until the fluid stops reaccumulating.

It’s important that you’ve regained your arm movement after surgery and can comfortably raise your arms above your head before treatment planning starts. Exercises and physiotherapy can help; talk to your breast care nurse if you need further information.

Most courses of radiotherapy to the breast or chest wall (+/- lymph nodes) are delivered once daily (Monday – Friday) for three weeks (a total of fifteen consecutive weekday visits).

Patients who need a ‘boost’ dose usually require an additional one week (5 extra days) of treatment.

Interruptions during a course of radiotherapy are not recommended as the treatment is known to be less effective if given over a prolonged period of time.
DIBH uses state-of-the-art technology to minimise the radiation dose to the heart and eliminate organ movement caused by breathing in patients being treated for left sided breast cancers.

Patients receive a short breathing training session before their radiotherapy planning CT scan and breathe through a mouth piece (like a snorkel) during the treatment.

All left breast cancer patients treated at GenesisCare are offered DIBH.

A full description and patient information film is available here.

Yes. All medication can be continued safely during radiotherapy. Please let the doctors and nurses know which medicines you are taking.

Practical tips for skincare during and after breast radiotherapy

In addition to the general skincare advice given patients often find it helpful to:

  • Wear a soft cotton bra or vest
  • Some patients find it more comfortable to go without a bra
  • Avoid underwired bras or tight clothes until the skin is healed.

Skin reactions usually heal within three or four weeks of completing radiotherapy.

Breast radiotherapy information film


Read more from


“The support I’ve received has been invaluable and
made the journey easier”