Surgery
PREPEC
ForSkin/nipple-sparing mastectomy, implant reconstruction, prevention/therapeutic
Δ4.8 pts (79.2 vs 74.3)
95% CI 1.0-8.7, p=0.01; 24mo, pre- vs sub-pectoral
TL;DRPre-pectoral implant improved 2yr chest well-being +4.8 pts (BREAST-Q, p=0.01) vs sub-pectoral, but more unplanned implant loss (21% vs 15%).
In pts undergoing skin- or nipple-sparing mastectomy (therapeutic or risk-reducing) who choose implant reconstruction, this supports pre-pectoral placement for better 2yr patient-reported chest well-being, weighed against numerically higher unplanned implant loss (21% vs 15%).
| Endpoint (24mo) | Pre-pectoral (N=191) | Sub-pectoral (N=189) | Difference |
|---|---|---|---|
| Physical well-being, chest (BREAST-Q) | 79.2 (75.5-82.8) | 74.3 (70.7-78.0) | 4.8 (1.0-8.7), p=0.01 |
+1 more figure
| Unplanned implant loss/replacement (24mo) | Pre-pectoral | Sub-pectoral | Adj. difference (95% CI) |
|---|---|---|---|
| Crude % (n/N) | 21.1% (41/194) | 14.5% (27/186) | 5.7% (-2.4 to 13.8) |
8 details 3 trials watching
International randomized phase 3 trial (OPBC-02): pre- vs sub-pectoral implant reconstruction after skin- or nipple-sparing mastectomy. Open-label; patient-reported primary endpoint analyzed by multiple imputation and linear mixed models.
Women undergoing skin- or nipple-sparing mastectomy for cancer treatment or risk reduction, opting for implant reconstruction. Primary QoL analysis N=191 pre- vs 189 sub-pectoral.
Primary: long-term patient-reported physical well-being (chest), BREAST-Q, at 24 months. Main secondary safety: unplanned loss or replacement of expander/implant.
BREAST-Q chest well-being 79.2 vs 74.3 at 24mo, difference 4.8 (95% CI 1.0-8.7, p=0.01), favoring pre-pectoral. Longitudinal completion 83-95%.
Point estimate showed more implant loss with pre-pectoral (21.1% vs 14.5%), failing the trial's non-inferiority safety hypothesis; the adjusted-difference 95% CI (-2.4 to 13.8) crosses zero.
Open-label with a patient-reported primary endpoint, so awareness of implant type could bias PROs. The 4.8-point gain is significant but modest, and the safety signal trended against pre-pectoral.
A major RCT in an area of genuine equipoise. It supports pre-pectoral for patient-reported chest well-being while flagging a higher implant-loss signal, so the choice reads as a real trade-off, not a clean win.
Randomized phase 3, primary endpoint met, but a modest patient-reported surrogate and an unmet non-inferiority safety endpoint keep it short of practice-changing.
- Durability of the QoL benefit and implant-loss gap beyond 24 months n=300 · primary completion 2024-12 · prepectoral vs subpectoral head-to-head, n=300n=88 · primary completion 2025-03 · prepectoral vs subpectoral breast satisfaction
- Do outcomes differ in patients receiving post-mastectomy radiation? n=104 · primary completion 2027-03 · prepectoral recon in adjuvant RT patients
- Which patients accept higher implant-loss risk for better chest well-being?
📚 Sources · 🐦 1 tweet
📌 Surgical de-escalation of implant-based breast reconstruction after mastectomy for breast cancer treatment or prevention: The international randomized phase I|I
— Elisabetta Bonzano MD, PhD (@to_be_elizabeth) May 30, 2026
PREPEC trial (ОРBC-02).
Presented by Walter Weber ✨#ASCO26 @OncoAlert #OncoAlertAF #BreastCancer pic.twitter.com/WE20JcBQG0
SENOMAC NCT02240472
ForcN0 T1-T3 breast cancer, 1-2 sentinel-node macrometastases
HR 0.89
95% CI 0.66-1.19, NI met (margin 1.44); primary OS not yet reported
TL;DR5-yr RFS 89.7% vs 88.7%, HR 0.89 (0.66-1.19): omitting completion ALND noninferior, with nodal RT given in ~90% of both arms.
Nodal RT with nodal target volumes reached ~90% in both arms (89.9% vs 88.4%), so SENOMAC validates dropping completion ALND within regional nodal irradiation, not omitting axillary treatment. For the RT reader it positions nodal RT as the axillary treatment when SNB shows 1-2 macromets; it does not test omitting both surgery and RT.
8 details 4 trials watching
Phase 3 noninferiority RCT, 1:1, N=2766 enrolled (2540 per-protocol), 67 sites across 5 countries; median follow-up 46.8 mo. Reports the prespecified secondary RFS; primary OS not yet reported.
cN0 T1-T3 breast cancer with 1-2 sentinel-node macrometastases (>2mm). Extends eligibility beyond Z0011 to mastectomy, T3, extracapsular extension, and men.
Nodal RT including nodal target volumes reached 89.9% (SNB-only) and 88.4% (cALND). ALND omission was therefore tested within regional nodal irradiation, not as omission of axillary treatment.
Primary: overall survival (not reported in source). This analysis: prespecified secondary recurrence-free survival, per-protocol and modified ITT.
Noninferiority met: the upper confidence bound stayed below the prespecified 1.44 margin (P<0.001) across 191 recurrence-or-death events.
| Endpoint | SNB only | cALND |
|---|---|---|
| 5-yr RFS | 89.7% (87.5-91.9) | 88.7% (86.3-91.1) |
| HR recurrence/death | 0.89 (0.66-1.19) | ref |
Consistent with Z0011 (breast-conserving + whole-breast RT) and AMAROS (axillary RT replacing ALND), both null for ALND benefit at 10 yr. SENOMAC adds the macromet-only, mastectomy/T3/ECE/male groups in a larger cohort.
This is the secondary RFS endpoint, not the OS primary, at a 46.8-mo median follow-up short for ER+ biology. The HR 1.44 noninferiority margin is generous, and ~90% nodal RT confounds attribution to surgical omission alone.
Randomised phase 3 noninferiority; prespecified secondary RFS met, extends Z0011/AMAROS de-escalation to mastectomy/T3/ECE/men. Primary OS not yet reported.
In cN0 breast cancer with 1-2 sentinel-node macrometastases who receive regional nodal RT, this supports omitting completion ALND, including mastectomy, T3, extracapsular extension, and men; it does not extend to patients treated without nodal radiotherapy.
- Overall survival (primary endpoint) result still pending
- Can nodal RT be omitted alongside ALND in this population? recruiting Evaluating Omitting of Internal Mammary Irradiation Among Early Stage Intermediate Risk (N1) Breast Cancer Phase NAn=214 · primary completion 2025-10 · randomized omit internal mammary RT in N1active Postmastecomy Internal Mammary Nodal Irradiation for High-risk Breast Cancer Patients Phase 3n=2400 · primary completion 2025-11 · phase 3 IMN RT vs no IMN RT, DFS endpointrecruiting The T-REX Trial: Tailored Regional External Beam Radiotherapy in Clinically Node-negative Breast Cancer Patients With 1-2 Sentinel Node Macrometastases. Phase NAn=1350 · primary completion 2028-12 · omit regional RT, 1-2 SN macromets, ER+/HER2-recruiting RecurIndex Guided Avoidance of Regional Nodal Irradiation for Node Positive Breast Cancer Phase NAn=540 · primary completion 2029-08 · RecurIndex-guided RNI avoidance in N1
- Durability beyond 5 years in ER+ disease