# SUPREMO (BIG 2-04)

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

## TL;DR

For women with one to three involved nodes or a larger node-negative tumour, radiotherapy to the chest wall after mastectomy did not help them live longer. It roughly halved the small chance of the cancer returning on the chest wall, from one in forty to one in ninety.

## Summary

SUPREMO is the trial the postmastectomy radiotherapy question needed, because the meta-analysis that established the practice pooled trials run between 1964 and 1986, before modern systemic therapy. It randomised patients with intermediate-risk disease after mastectomy, an axillary procedure and systemic therapy to chest-wall irradiation of 40 to 50 Gy or to none; the intention-to-treat population was 1,607.

At a median 9.6 years, ten-year overall survival was 81.4 percent with irradiation and 81.9 percent without (hazard ratio for death 1.04, 95 percent confidence interval 0.82 to 1.30, p=0.80). Twenty-nine patients had a chest-wall recurrence, nine (1.1 percent) with irradiation and twenty (2.5 percent) without, a hazard ratio of 0.45 (0.20 to 0.99). Disease-free survival was 76.2 against 75.5 percent (hazard ratio 0.97, 0.79 to 1.18) and distant metastasis-free survival 78.2 against 79.2 percent (1.06, 0.86 to 1.31).

The limits are worth stating because they are being argued over. SUPREMO tested chest-wall irradiation alone, not comprehensive regional nodal irradiation including the internal mammary chain, so it does not speak to the nodal question that MA.20 and EORTC 22922 answered. Its sample size was cut and its eligibility widened during a long accrual, and the population skews to the lower end of intermediate risk. Commentators have made both cases from the same paper: that postmastectomy radiotherapy can be safely omitted in this group, and that the trial does not resemble the way radiotherapy is now delivered.

In England, NICE NG101 recommendation 1.13.10 offers postmastectomy radiotherapy for node-positive macrometastatic disease or involved margins and 1.13.12 says not to offer it to people at low risk of local recurrence; the guideline predates this trial.

## Fields

- Kind: Trial
- Status: negative
- Last checked: 2026-09-25
- Also known as: SUPREMO trial; BIG 2-04; Selective Use of Postoperative Radiotherapy aftEr MastectOmy
- Registry id: ISRCTN61145589
- Phase: 3
- Setting: Intermediate-risk breast cancer after mastectomy, an axillary procedure and systemic therapy, defined as pT1N1, pT2N1, pT3N0, or pT2N0 with grade 3 histology or lymphovascular invasion: chest-wall irradiation of 40 to 50 Gy against no chest-wall irradiation, with overall survival at ten years as the primary endpoint
- Sponsor: University of Edinburgh and the Medical Research Council, within the Breast International Group
- Enrolled: 1607
- Result: Ten-year overall survival 81.4 percent with chest-wall irradiation against 81.9 percent without (hazard ratio 1.04, p=0.80); chest-wall recurrence 1.1 against 2.5 percent (hazard ratio 0.45).
- Outcomes: Overall survival at 10 years: Chest-wall irradiation 81.4% vs No chest-wall irradiation 81.9%, HR 1.04; Chest-wall recurrence: Chest-wall irradiation 1.1% vs No chest-wall irradiation 2.5%, HR 0.45; Disease-free survival at 10 years: Chest-wall irradiation 76.2% vs No chest-wall irradiation 75.5%, HR 0.97
- Replication: The EBCTCG overview of 8,135 women in 22 trials run between 1964 and 1986 found postmastectomy radiotherapy reduced breast cancer mortality in women with one to three positive nodes (rate ratio 0.80, 0.67 to 0.95); SUPREMO tested the same question with modern systemic therapy and found no survival gain.

## Sources

- ISRCTN61145589: https://www.isrctn.com/ISRCTN61145589
- SUPREMO ten-year survival (New England Journal of Medicine 2025): https://doi.org/10.1056/NEJMoa2412225
- Reconsidering postmastectomy radiotherapy after SUPREMO (Radiotherapy and Oncology 2026): https://doi.org/10.1016/j.radonc.2026.111416

## 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: [Hypofractionated radiotherapy](https://onco.cc/technologies/hypofractionated-radiotherapy/), [IMRT / IGRT (modern external beam)](https://onco.cc/technologies/imrt-igrt/)
- companies: [Breast International Group (BIG)](https://onco.cc/companies/big/)
- terms: [Breast reconstruction](https://onco.cc/terms/breast-reconstruction/), [Mastectomy](https://onco.cc/terms/mastectomy/), [Radiotherapy after mastectomy](https://onco.cc/terms/post-mastectomy-radiotherapy/)
- trials: [EORTC 22922/10925](https://onco.cc/trials/eortc-22922/), [NCIC MA.20](https://onco.cc/trials/ma-20/), [NSABP B-51 / RTOG 1304](https://onco.cc/trials/nsabp-b51/)

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