# Tumour bed boost

Source: https://onco.cc/terms/tumour-bed-boost/  
OnCo record `tumour-bed-boost` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

An extra dose of radiotherapy aimed at the small area the lump came from, given after the whole breast has been treated. It cuts the chance of the cancer coming back in that breast by about a third, does not help anyone live longer, and triples the chance of the breast becoming hard and scarred.

## Summary

EORTC 22881-10882 randomised 5,318 patients after complete excision and 50 Gy of whole-breast irradiation to a further 16 Gy to the tumour bed or to nothing more, and followed them for a median 17.2 years. Twenty-year overall survival was 59.7 percent with the boost and 61.1 percent without (hazard ratio 1.05, 99 percent confidence interval 0.92 to 1.19, p=0.323). The twenty-year cumulative incidence of recurrence in the treated breast was 12.0 percent with the boost against 16.4 percent without (hazard ratio 0.65, 0.52 to 0.81, p<0.0001). Severe fibrosis at twenty years was 5.2 percent with the boost against 1.8 percent without (p<0.0001).

The trial's own reading of its data is that the absolute benefit is largest in young patients and that the extra dose can be avoided in most patients over 60, because the recurrence risk they start from is low enough that a one-third reduction saves few events while the fibrosis is the same for everyone.

NICE NG101 recommendation 1.13.17 offers an external beam boost to women with invasive breast cancer and a high risk of local recurrence following whole-breast radiotherapy, and 1.13.18 requires that the risk of side effects be explained. Neither recommendation defines high risk numerically, so the judgement is local and usually rests on age, grade, margin width and lymphovascular invasion.

## Fields

- Kind: Term
- Last checked: 2026-09-25
- Also known as: boost; breast boost; radiotherapy boost; boost to the tumour bed

## Sources

- EORTC boost trial at twenty years (Lancet Oncology 2015): https://doi.org/10.1016/S1470-2045(14)71156-8
- NICE NG101 recommendations 1.13.17 and 1.13.18, breast boost: https://www.nice.org.uk/guidance/ng101

## Connected records

- terms: [Hypofractionation (fewer, larger radiotherapy doses)](https://onco.cc/terms/hypofractionation/), [Leaving radiotherapy out](https://onco.cc/terms/radiotherapy-omission-early-breast-cancer/), [Lumpectomy (breast-conserving surgery)](https://onco.cc/terms/lumpectomy/), [Partial-breast irradiation](https://onco.cc/terms/partial-breast-irradiation/), [Resection margins (R0 / R1 / R2)](https://onco.cc/terms/resection-margins/)
- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [HER2-positive breast cancer](https://onco.cc/cancers/breast-her2-positive/), [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- fronts: [Radiation Therapy](https://onco.cc/fronts/radiation/)
- technologies: [IMRT / IGRT (modern external beam)](https://onco.cc/technologies/imrt-igrt/)
- trials: [EORTC 10801](https://onco.cc/trials/eortc-10801/), [EORTC 22881-10882 (boost against no boost)](https://onco.cc/trials/eortc-22881-boost/), [IMPORT LOW](https://onco.cc/trials/import-low/)

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