Radiation therapy boost after breast-conserving surgery

A tumor bed boost is recommended for patients with invasive breast cancer who meet any of the following criteria: age ≤50 years with any grade, age 51 to 70 years with high grade, or a positive margin (Quality of evidence – moderate)

Offer an external beam boost to the tumour bed for women with invasive breast cancer and a high risk1 of local recurrence, following whole‑breast radiotherapy

Boost RT is recommended to reduce the risk of in-breast relapse in patients at higher risk of local recurrence [I, A]

Consider omitting radiotherapy for women who (a) have had breast‑conserving surgery for invasive breast cancer with clear margins and (b) 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 (c) are willing to take adjuvant endocrine therapy for a minimum of 5 years

When considering omitting radiotherapy discuss the benefits and risks, including those in Table 5 (see NICE 2018 guideline for more details) , and explain that: (a) 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 year; (b) overall survival at 10 years is the same with or without radiotherapy; (c) there is no increase in serious late effects if radiotherapy is given (for example, congestive cardiac failure, myocardial infarction or secondary cancer)

A strong recommendation indicated the task force was confident the benefits of the intervention clearly outweighed the harms, or vice versa, and “all or almost all informed people would make the recommended choice.”

Strong evidence for efficacy with a substantial clinical benefit, strongly recommended