# EORTC 10801

Source: https://onco.cc/trials/eortc-10801/  
OnCo record `eortc-10801` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The third of the big conservation trials, and the one that deliberately included larger tumours. After twenty-two years there was still no difference in how long women lived, which is why keeping the breast became standard rather than optional.

## Summary

EORTC 10801 recruited between 1980 and 1986 in eight centres in the United Kingdom, the Netherlands, Belgium and South Africa, and included tumours up to 5 cm, larger than Milan I allowed. 448 patients were randomised to breast-conserving therapy and 420 to modified radical mastectomy. The primary endpoint was time to distant metastasis.

After a median follow-up of 22.1 years, 175 patients (42 percent) in the mastectomy arm and 207 (46 percent) in the conservation arm had distant metastases, and 506 patients (58 percent) had died. Neither difference was significant: the hazard ratio for time to distant metastasis was 1.13 (95 percent confidence interval 0.92 to 1.38, p=0.23) and for time to death 1.11 (0.94 to 1.33, p=0.23). Twenty-year overall survival was 44.5 percent after mastectomy and 39.1 percent after conservation, and the trial reports these as not significantly different. There was no interaction with age.

The record is marked mixed rather than positive because the point estimates favour mastectomy on both endpoints while the confidence intervals include no difference, and because the earlier reports found better local control after mastectomy. What the trial establishes is that conservation costs nothing in survival, not that the two operations are identical.

## Fields

- Kind: Trial
- Status: mixed
- Last checked: 2026-09-25
- Also known as: EORTC breast conservation trial
- Phase: 3
- Setting: Stage I and II breast cancer up to 5 cm, node-negative or node-positive: breast-conserving therapy with lumpectomy, complete axillary clearance, breast radiotherapy and a tumour-bed boost, against modified radical mastectomy, with time to distant metastasis as the primary endpoint
- Sponsor: European Organisation for Research and Treatment of Cancer
- Enrolled: 868
- Result: At a median 22.1 years, time to distant metastasis hazard ratio 1.13 (0.92 to 1.38) and time to death 1.11 (0.94 to 1.33) for conservation against mastectomy; twenty-year overall survival 39.1 against 44.5 percent, not significantly different.
- Outcomes: Time to distant metastasis: Breast-conserving therapy vs Modified radical mastectomy, HR 1.13; Overall survival at 20 years: Breast-conserving therapy 39.1% vs Modified radical mastectomy 44.5%, HR 1.11
- Replication: NSABP B-06 and Milan I reached the same conclusion on survival, with twenty-year follow-up in both.

## Sources

- EORTC 10801 twenty-year follow-up (Lancet Oncology 2012): https://doi.org/10.1016/S1470-2045(12)70042-6

## Connected records

- 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/)
- technologies: [IMRT / IGRT (modern external beam)](https://onco.cc/technologies/imrt-igrt/)
- companies: [EORTC](https://onco.cc/companies/curie-nki-eortc/)
- terms: [Breast conservation or mastectomy](https://onco.cc/terms/breast-conserving-surgery-versus-mastectomy/), [Lumpectomy (breast-conserving surgery)](https://onco.cc/terms/lumpectomy/), [Lymphadenectomy (lymph node dissection)](https://onco.cc/terms/lymphadenectomy/), [Mastectomy](https://onco.cc/terms/mastectomy/), [Tumour bed boost](https://onco.cc/terms/tumour-bed-boost/)
- trials: [EORTC 22881-10882 (boost against no boost)](https://onco.cc/trials/eortc-22881-boost/), [Milan I (quadrantectomy against radical mastectomy)](https://onco.cc/trials/milan-i/), [NSABP B-06](https://onco.cc/trials/nsabp-b06/)

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