After breast conservation surgery all patients should receive local radiotherapy, usually receiving a dose of 40-50Gy in daily fractions over 3-5 weeks. Patients may also receive a boost dose direct to the scar.
Radiotherapy administered after local excision with axillary node dissection is associated with an improved 8 year disease-free survival, and reduced local and regional recurrence. There is no effect however of these treatments on overall survival.
After mastectomy radiotherapy is only required for patients at high risk of local recurrence.
Radiotherapy is contraindicated if the area has previously been irradiated.
NICE suggest that (1):
- radiotherapy after breast conserving surgery
- whole-breast radiotherapy should be offered to women with invasive breast cancer who have had breast-conserving surgery with clear margins
- consider partial-breast radiotherapy as an alternative to whole-breast radiotherapy for women who have had breast-conserving surgery for invasive cancer (excluding lobular type) with clear margins and who:
- have a low absolute risk of local recurrence (defined as women aged 50 and over with tumours that are 3 cm or less, N0, ER-positive, HER2-negative and grade 1 to 2), and
- have been advised to have adjuvant endocrine therapy for a minimum of 5 years
- when giving partial-breast radiotherapy, use external beam radiotherapy
- consider not using radiotherapy for women who:
- have had breast-conserving surgery for invasive breast cancer with clear margins and
- have a very low absolute risk of local recurrence (defined as women aged 65 and over with tumours that are T1N0, ER-positive, HER2-negative and grade 1 to 2) and
- are willing to take adjuvant endocrine therapy for a minimum of 5 years
- when considering not using radiotherapy, discuss the benefits and risks with the woman (see table 5) and explain that:
- without radiotherapy, local recurrence occurs in about 50 women per 1,000 at 5 years, and with radiotherapy, occurs in about 10 women per 1,000 at 5 years
- overall survival at 10 years is the same with or without radiotherapy
- there is no increase in serious late effects if radiotherapy is given (for example, congestive cardiac failure, myocardial infarction or secondary cancer).
- adjuvant radiotherapy should be considered for women with DCIS following breast-conserving surgery with clear margins
- radiotherapy after mastectomy
- adjuvant postmastectomy radiotherapy should be offered to people with node-positive (macrometastases) invasive breast cancer or involved resection margins
- consider adjuvant postmastectomy radiotherapy for people with node-negative T3 or T4 invasive breast cancer
- do not offer radiotherapy following mastectomy to people with invasive breast cancer who are at low risk of local recurrence (for example, most people who have lymph node-negative breast cancer)
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