# IMPORT LOW

Source: https://onco.cc/trials/import-low/  
OnCo record `import-low` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

IMPORT LOW showed that treating only the part of the breast around the tumour bed, with the same simple technique and schedule, is as safe as whole-breast radiotherapy and causes fewer changes to the breast.

## Summary

IMPORT LOW randomised 2,018 women with low-risk breast cancer to whole-breast radiotherapy, whole-breast with reduced dose outside the tumour bed, or partial-breast radiotherapy only, all 40 Gy in 15 fractions with standard tangential fields. Five-year local relapse was 1.1 percent after whole-breast and 0.5 percent after partial-breast treatment, non-inferior, with fewer reported changes in breast appearance (Coles and colleagues, Lancet 2017).

## Fields

- Kind: Trial
- Status: positive
- Last checked: 2026-09-16
- Tags: radiation-wave2
- Phase: 3
- Setting: Low-risk early breast cancer: partial-breast or reduced-dose radiotherapy versus whole-breast radiotherapy, 40 Gy in 15 fractions
- Sponsor: Institute of Cancer Research (UK)
- Enrolled: 2018
- Result: 5-year local relapse 0.5% (partial breast) vs 1.1% (whole breast), non-inferior; fewer breast changes.
- Outcomes: Local relapse at 5 years: Partial-breast radiotherapy 0.5% vs Whole-breast radiotherapy 1.1%

## Sources

- ISRCTN12852634: https://www.isrctn.com/ISRCTN12852634
- Lancet 2017: https://doi.org/10.1016/S0140-6736(17)31145-5

## Connected records

- cancers: [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/)
- technologies: [Hypofractionated radiotherapy](https://onco.cc/technologies/hypofractionated-radiotherapy/), [IMRT / IGRT (modern external beam)](https://onco.cc/technologies/imrt-igrt/)

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