The purpose of this study is to investigate the difference in fatigue, quality of life and radiation morbidity between hypofractionated and conventional radiation to the breast, chest wall and regional lymph nodes post mastectomy or lumpectomy

Breast cancer is the most commonly diagnosed cancer in Australia. Radiotherapy to the breast, chest wall and regional lymph nodes for breast cancer after surgery can reduce the risk of local recurrence by 50% and reduce breast cancer mortality. Traditionally, radiotherapy is delivered in a large number of small doses i.e. 25 treatment sessions over 5 1/2 weeks. Another approach is to give a lower number of larger doses i.e. 15 sessions over 3 1/2 weeks (hypofractionated radiotherapy).

Several studies in Europe and Asia have investigated hypofractionated radiotherapy to the chest wall, breast and regional lymph nodes following surgery for breast cancer, and found that it is equally effective to standard treatment, with similar side effects. These two approaches have not been directly compared in Australia.

This trial is to compare these two approaches, to determine whether hypofractionated radiotherapy is better tolerated by patients.

Inclusion Criteria:

• Age 18 years and older
• ECOG performance status 0-2
• Ability to understand and willingness to sign a written informed consent document
• Stage pT1-3, pN0-3, M0 histologically proven breast cancer no matter the status of ER/PR/HER2 receptor testing
• Managed with either mastectomy or breast conserving surgery
• Suitable for radiation therapy to the breast/chest wall and regional lymph nodes
• Neoadjuvant and adjuvant systemic therapy with chemotherapy, endocrine therapy and anti-HER2 therapy is accepted
• Neoadjuvant radiotherapy (reverse sequencing) accepted
• Breast implants and expanders are accepted
• Patients with connective tissue disease are allowed if the treating radiation oncologist finds radiation therapy indicated
• Life expectancy minimum 10 years
• Patients with non-breast malignancies are accepted if the patient has been disease free for five years and/or has a low risk of recurrence as estimated by the treating radiation oncologist (to be determined at initial patient appointment)

Exclusion Criteria:

• Prior radiotherapy to the ipsilateral breast or chest wall
• Pregnancy or lactation
• Radiosensitivity syndrome
• Permanent pacemaker/defibrillator within radiotherapy field
• Oncoplastic surgery where boost volume unacceptable (clinician discretion)
• Conditions indicating that the patient cannot go through radiation therapy or follow up, or a condition where the treating oncologist thinks the patient should not participate in the trial (for example, language barriers)

Patients will be randomised to one of the arms and will be notified for the randomization results. Randomisation ratio 2:1 (hypofractionation : standard)