Postoperative radiotherapy for breast cancer: UK consensus statements

Cardiac-sparing radiotherapy should be considered the standard of care for patients with left-sided breast cancer.

• The heart should routinely be excluded from the radiotherapy field.
• All UK radiotherapy departments should have a breath-hold technique available.
• A target mean heart dose would help departments to implement breath-hold.

Tumour bed boost

• A tumour bed boost should be considered for all patients with invasive breast cancer who are less than 50 years old.
• Consider the benefit of a tumour bed boost for those over 50 years with higher risk pathological features (especially Grade 3 and/or extensive intraductal component).
• A hypofractionated boost using a similar fraction size as the whole breast is acceptable; it should be equivalent to 16 Gray (Gy) in eight fractions.

Breast-conserving surgery and tumour bed clips

• Tumour bed clips should be considered the standard of care to improve planning (and delivery) of the boost.

Avoidance of radiotherapy should be considered:

• In women deemed to be at very low risk of local recurrence, for example patients ≥70 years out of a research study and ≥60 years in study with T1N0 oestrogen receptor positive (ER+), progesterone receptor positive (PR+), human epidermal growth factor receptor negative (HER2-), Grade 1–2 tumours AND who are willing to take adjuvant endocrine therapy for a minimum of five years AND have regular mammograms for ten years. These criteria are best fulfilled within the UK PRIMETIME bio-marker directed study and participation is recommended.

• Internal mammary chain (IMC) radiotherapy should be considered in patients at high risk of recurrence (that is, T4 and/or N2–3 disease).

• IMC radiotherapy should be considered in patients at intermediate risk of recurrence (that is, 1–3 axillary macrometastases and central/medial disease, who have been recommended locoregional irradiation).

• IMC radiotherapy should be given using techniques which minimise doses to organs-at-risk. Every centre should have a breath-hold technique available for patients undergoing IMC radiotherapy.

• The following dose constraints are recommended for IMC radiotherapy: heart V17 Gray (Gy) <10%, ipsilateral lung V17Gy <35%, mean contralateral breast dose <3.5 Gy; in patients at intermediate risk of recurrence, a mean heart dose <6 Gy is considered a reasonable objective.

There is no indication to use more than 15 fractions for the breast, chest wall or nodal areas for standard adjuvant treatment.

Further local treatment for the malignant sentinel lymph node (SLN) in individuals with early invasive breast cancer:

• Sentinel nodes with isolated tumour cells and/or micrometastases – no further axillary treatment is required in addition to breast-conserving surgery or mastectomy.
• 1–2 sentinel nodes with macrometastases – further axillary treatment is no longer mandatory in breast conservation with whole-breast radiotherapy in patients who are postmenopausal and have T1, Grade 1 or 2, oestrogen receptor positive (ER+) and human epidermal growth factor receptor negative (HER2-) tumours. These patients could also be entered into the POSNOC or equivalent clinical trial.
• Three or more sentinel nodes with macrometastases – patients should usually be recommended to have further axillary treatment.
• Further axillary treatment should usually be recommended for patients undergoing mastectomy or with tumours with one or more of the following features: T3, Grade 3, ER- or HER2+.These patients could also be entered into the POSNOC or equivalent clinical trial.
• No consensus was reached on the management of the axilla for patients with one or more of the following features: premenopausal status, T2 tumours, lymphovascular invasion or extranodal spread.

* These statements were agreed by the Trustees of the Association of Breast Surgery (ABS) following the ABS Multidisciplinary Consensus Meeting on the further management of the malignant axillary node, held in London on 26 January 2015.

• Can be considered for patients ≥50 years, Grade 1–2, ≤3 centimetres (cm), oestrogen receptor positive (ER+), human epidermal growth factor receptor negative (HER2-), N0 with minimum 1 millimetre (mm) radial excision margins for invasive disease, using either (i) external beam radiotherapy with 40 Gray (Gy) in 15 fractions over three weeks or (ii) multicatheter brachytherapy using fractionation schedules as per the Groupe Européen de Curiethérapie and European Society for Radiotherapy and Oncology (GEC-ESTRO) trial.
• Classical lobular cancer and/or lymphovascular space invasion should be excluded.