# Margins after breast-conserving surgery, and second operations

Source: https://onco.cc/terms/breast-margins-and-re-excision/  
OnCo record `breast-margins-and-re-excision` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

After conserving surgery a pathologist measures how close the cancer came to the edge of the tissue removed. Cancer at the inked edge means another operation is offered; within 1 mm it is considered; and the threshold was lowered in 2024 specifically to spare people a second operation.

## Summary

NICE NG101 says to offer further surgery, re-excision or mastectomy as appropriate, where invasive cancer or DCIS is present at the radial margins (tumour on ink, 0 mm); to consider further surgery after conserving surgery for invasive cancer with or without DCIS if tumour cells are present within 1 mm of but not at the radial margins; and to use 2 mm rather than 1 mm as the threshold for DCIS alone. The 2024 committee explained its reasoning plainly: a 1 mm margin is likely to achieve better breast preservation and result in fewer additional surgeries, repeated surgeries negatively affect breast appearance and can have a negative effect on self-esteem, and they are traumatic and can lead to stress, infection, pain and complications. It also noted that rates of further surgery currently vary across the country, and asked units to audit radial margins alongside recurrence. This is orientation from public patient pages, guidelines and the trials themselves, not advice for your case: your own team's instructions and 24-hour number come first, and no figure on this page is a prediction about you.

## Fields

- Kind: Term
- Last checked: 2026-09-25
- Also known as: clear margins; tumour on ink; re-excision; further surgery after lumpectomy

## Sources

- NICE NG101: early and locally advanced breast cancer, recommendations (updated 2025): https://www.nice.org.uk/guidance/ng101/chapter/Recommendations
- Macmillan: breast-conserving surgery: https://www.macmillan.org.uk/cancer-information-and-support/treatments-and-drugs/breast-conserving-surgery-for-breast-cancer
- Breast Cancer Now: surgery for primary breast cancer: https://breastcancernow.org/about-breast-cancer/treatment/surgery-for-primary-breast-cancer

## Connected records

- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/)
- terms: [Lumpectomy (breast-conserving surgery)](https://onco.cc/terms/lumpectomy/), [Mastectomy](https://onco.cc/terms/mastectomy/)

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