# Table 5. Synthesis of international clinical practice guidelines on omission of completion axillary lymph node dissection (ALND) in cN+ patients converting to ypN0 after neoadjuvant chemotherapy

Twelve guideline documents from seven international organisations (NCCN, ASCO, ESMO, St Gallen, AGO, EUSOMA, EUBREAST) published between 2017 and 2025 are summarised below. Convergence is striking: every body endorses ALND omission in highly selected cN1 patients converting to ypN0 with adequate technique; divergence persists for ITC handling and regional radiotherapy.

| Organisation, year | Marker placement at diagnosis | Dual tracer | Minimum SLNs (or marked-node retrieval) | TAD endorsed | Omit ALND if ypN0? | ITC (ypN0(i+)) handling | Recommendation strength |
|---|---|---|---|---|---|---|---|
| **NCCN Breast v2024-2026** | Recommended | Recommended | ≥2 SLNs or TAD | Endorsed (preferred when feasible) | Yes if cN1 → TAD/SLNB ypN0 | Treated as ypN0 in current version (footnote: clinical judgement) | Category 2A |
| **ASCO 2025 (Park)** | Recommended | Required | ≥3 SLNs or TAD | Preferred option | Yes if FNR <10% documented locally | Cautious — not yet automatically equivalent to ypN0 | RCT + meta-analysis (high) |
| **ASCO/Ontario 2021 (Brackstone)** | Recommended | Acceptable | ≥2-3 SLNs | Acceptable | Yes in selected cN1 → ycN0 | Considered positive | Systematic review |
| **ESMO 2023 (Loibl)** | Recommended (clip mandatory) | Recommended | ≥3 SLNs | Recommended for cN+ initial | Yes, individualised | Counted as positive | IV-A / III-B |
| **St Gallen 2023 (Curigliano)** | Recommended (panel majority) | Recommended | ≥3 SLNs | TAD = best technique (panel consensus) | Yes (majority vote in responders) | Split panel vote — most consider equivalent to ypN0 | Expert vote |
| **St Gallen 2021 (Burstein)** | Recommended | Recommended | ≥3 SLNs | Preferred | Yes | Mixed | Expert vote |
| **St Gallen 2017 (Curigliano)** | Recommended | Recommended | ≥3 SLNs | Mentioned (emerging) | Yes in cN1 → ycN0 | Counted as positive | Expert vote |
| **AGO 2025 (Reimer / Park-Simon)** | **Mandatory (clip pre-NAC)** | AGO++ (recommended) | ≥3 SLNs (TAD preferred) | **AGO++ (preferred standard)** | Yes if TAD/SLNB ypN0 | AGO++ accepts ypN0(i+) as ypN0 | AGO ++ |
| **AGO 2022 (Banys-Paluchowski)** | Mandatory | Recommended | ≥3 | TAD recommended for cN1 converters | Yes | Treated as ypN0 | AGO ++ |
| **EUSOMA 2023 (Rubio)** | Quality indicator | Recommended | ≥3 SLNs | Per institutional algorithm | Yes per algorithm | Per algorithm | Quality standard |
| **EUBREAST 2023 (Weber)** | Majority of survey | Variable internationally | ≥3 SLNs | TAD viewed as preferred | Recognised | Variable | Survey + meta-analysis |
| **EUBREAST 2022 (Gasparri)** | 75-80% use some method | Variable | Variable | Increasing adoption | Variable | Variable | International survey |

## Cross-cutting consensus (high agreement, 2021-2025)

1. **Marker the biopsied node before NAC.** All guidelines either mandate or strongly recommend metallic clip / radioactive seed / magnetic seed / carbon-ink tattoo placement at the time of diagnostic biopsy. This is the technical pre-condition for any de-escalation strategy.
2. **Dual tracer for sentinel mapping.** Technetium plus blue dye, or technetium plus ICG, or blue plus ICG — accepted by ASCO, ESMO, AGO, St Gallen.
3. **Retrieve ≥3 sentinel nodes** to drive FNR below 10%.
4. **TAD (clip + SLNB) is the preferred technique** for patients converting from cN+ to ycN0. AGO 2025, EUBREAST 2023, and St Gallen 2023 explicitly identify TAD as best-in-class.
5. **Omit ALND in TAD-confirmed ypN0** — endorsed by every body listed above for selected cN1 disease.

## Persistent areas of divergence (2025)

- **ypN0(i+) (isolated tumour cells)**: AGO++ accepts as ypN0 → omit ALND. St Gallen 2023 panel split. ASCO 2025 still cautious.
- **Regional nodal irradiation (RNI) in ypN0**: NSABP B-51 (Mamounas 2025; DOI 10.1056/NEJMoa2414859) supports omission of RNI in cN1 → ypN0; Alliance A011202 will inform the ypN+ question. Wang 2021 (PMID 33996002) and Tan 2024 align with the omission strategy in ypN0.
- **cN2-cN3 converters**: most guidelines still recommend ALND, though selected cN2 with full clinical/radiologic conversion is an emerging subset (de Wild 2024; Mukhtar 2025 I-SPY2).
- **Marker technologies (magnetic seed, radar reflector, SPIO)**: AGO 2025 and EUBREAST 2023 incorporate these; NCCN/ESMO use general "marker" language without endorsing specific technologies.

## Practice implication

A cN1 patient with HER2+ or TNBC biology, marked at diagnosis with a clip, treated with modern NAC (anthracycline-taxane backbone ± dual HER2 blockade ± pembrolizumab), and undergoing TAD with dual tracer and ≥3 SLNs retrieved who is ypN0 on final pathology can have ALND safely omitted — a position now shared by NCCN, ASCO, ESMO, St Gallen, AGO, EUSOMA and EUBREAST.
