# NSABP B-06

Source: https://onco.cc/trials/nsabp-b06/  
OnCo record `nsabp-b06` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

This is the trial that ended the routine mastectomy. Twenty years on, women who kept their breast lived exactly as long as those who lost it, and the radiotherapy that went with breast conservation cut the chance of the cancer coming back in that breast from about two in five to about one in seven.

## Summary

Bernard Fisher opened NSABP B-06 in 1976 to ask a question the surgical profession regarded as settled: whether removing the lump was as good as removing the breast. 1,851 women with tumours of 4 cm or less were randomised three ways, to total mastectomy, to lumpectomy alone, or to lumpectomy followed by breast irradiation; all node-positive women received chemotherapy.

At twenty years the cumulative incidence of a recurrence in the treated breast was 14.3 percent after lumpectomy with irradiation against 39.2 percent after lumpectomy alone (p<0.001). That gap is the case for radiotherapy. The case for conservation is what did not differ: there was no significant difference between the three groups in disease-free survival, distant-disease-free survival or overall survival. The hazard ratio for death after lumpectomy alone against total mastectomy was 1.05 (95 percent confidence interval 0.90 to 1.23, p=0.51), and after lumpectomy with irradiation 0.97 (0.83 to 1.14, p=0.74).

One detail is easy to miss and matters for how radiotherapy is discussed today. Among women with tumour-free margins, irradiation gave a hazard ratio for death of 0.91 (0.77 to 1.06, p=0.23): a marginally significant fall in breast cancer deaths that was partly offset by a rise in deaths from other causes. The benefit of breast radiotherapy is real, and it is not free.

The condition Fisher attached to the conclusion is still the condition today: conservation is appropriate provided the margins are clear and an acceptable cosmetic result can be obtained.

## Fields

- Kind: Trial
- Status: positive
- Last checked: 2026-09-25
- Also known as: National Surgical Adjuvant Breast and Bowel Project B-06; NSABP B06
- Phase: 3
- Setting: Invasive breast cancer up to 4 cm, node-positive or node-negative: total mastectomy against lumpectomy alone against lumpectomy with breast irradiation, with disease-free, distant-disease-free and overall survival as the endpoints
- Sponsor: National Surgical Adjuvant Breast and Bowel Project
- Enrolled: 1851
- Result: Twenty-year recurrence in the treated breast 14.3 percent with lumpectomy and irradiation against 39.2 percent with lumpectomy alone; no difference in overall survival between any of the three operations.
- Outcomes: Cumulative incidence of recurrent tumour in the ipsilateral breast at 20 years: Lumpectomy plus breast irradiation 14.3% vs Lumpectomy alone 39.2%; Death from any cause at 20 years, lumpectomy alone against total mastectomy: Lumpectomy alone against total mastectomy 1.05 hazard ratio, HR 1.05; Death from any cause at 20 years, lumpectomy with irradiation against total mastectomy: Lumpectomy plus irradiation against total mastectomy 0.97 hazard ratio, HR 0.97
- Replication: The Milan quadrantectomy trial, EORTC 10801 and three smaller European trials reached the same conclusion in different populations and with different operations; the EBCTCG overview of radiotherapy after breast-conserving surgery quantified the radiotherapy effect across 10,801 women in 17 trials.

## Sources

- NSABP B-06 twenty-year follow-up (New England Journal of Medicine 2002): https://doi.org/10.1056/NEJMoa022152

## 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: [NRG Oncology](https://onco.cc/companies/nrg-oncology/), [NSABP Foundation](https://onco.cc/companies/nsabp-foundation/)
- terms: [Breast conservation or mastectomy](https://onco.cc/terms/breast-conserving-surgery-versus-mastectomy/), [Leaving radiotherapy out](https://onco.cc/terms/radiotherapy-omission-early-breast-cancer/), [Lumpectomy (breast-conserving surgery)](https://onco.cc/terms/lumpectomy/), [Mastectomy](https://onco.cc/terms/mastectomy/), [Resection margins (R0 / R1 / R2)](https://onco.cc/terms/resection-margins/)
- trials: [EORTC 10801](https://onco.cc/trials/eortc-10801/), [Milan I (quadrantectomy against radical mastectomy)](https://onco.cc/trials/milan-i/), [NSABP B-04](https://onco.cc/trials/nsabp-b04/)

---
JSON: https://onco.cc/api/v1/entities/nsabp-b06.json