# Table 2. AMSTAR-2 detailed scoring of the 5 anchor systematic reviews — full-text LLM-augmented scoring

Pipeline: multi-agent local Claude Opus 4.7 (one Sonnet 4.6 fallback). Each agent independently applied the 16-item AMSTAR-2 rubric to the SR with full-text content where the open-access PDF was available; the algorithmic overall confidence per Shea 2017 is reported. Scores reconciled with two human reviewers (S.C., D.D.) by consensus.

**Anchor selection rationale (revised).** Following the strict PICOS eligibility triage (Table 1, Tables 1A/1B, and Supplementary File S4), Yu 2024 was excluded from the 13-SR primary synthesis because its population is restricted to cN0 patients (cN0 → ypN0 path), inverting the protocol's cN+ scope. Yu 2024 has therefore been **replaced** as an anchor SR. The five anchors below were selected from the 13 fully-eligible SRs as the most-impactful for breadth across umbrella outcomes and for representativeness of the contemporary evidence base:
- **Simons 2019** — first MA pooling SLNB + MARI + combination procedures restricted to pathologically confirmed cN+; foundational for marker-based axillary staging.
- **Tee 2018** — high-impact BJS MA in initial biopsy-proven cN+; subgroup analyses by mapping technique and number of nodes removed.
- **Samiei 2021** — largest pooled MA of axillary pCR by molecular subtype (n=57,531); selects de-escalation candidates.
- **Swarnkar 2021** — pooled FNR of MLNB and TAD in cN+ after NACT; intervention-specific quantitative anchor.
- **de Wild 2024** — comprehensive BJS SR of TAD restricted to cN+ (51 studies, 4,512 patients); explicitly excludes cN0.

The pre-triage anchor set (Mocellin 2015, Samiei 2021, Swarnkar 2021, de Wild 2024, Yu 2024) is preserved in the project's audit trail at `_amstar2_toolkit/results/` for reproducibility; Mocellin 2015 (now BORDERLINE — population mixed cN0/cN+ in LABC) and Yu 2024 (now EXCLUDED — cN0-only) appear there only as historical scoring runs and are no longer presented as anchors. Cao 2021 and Abdulla 2026 are also strong anchor candidates (both ELIGIBLE) and their full AMSTAR-2 scoring is available at `_amstar2_toolkit/results/` for sensitivity-analysis use.

| Item | Domain | Critical? | Tee 2018 | Simons 2019 | Samiei 2021 | Swarnkar 2021 | de Wild 2024 |
|---|---|---|---|---|---|---|---|
| 1 | PICO components |  | Yes | Yes | Yes | Partial | Yes |
| 2 | Pre-registered protocol | C | No | No | No | No | No |
| 3 | Justified study designs |  | Yes | Yes | No | No | Yes |
| 4 | Comprehensive search | C | Partial | Partial | Partial | Partial | Partial |
| 5 | Duplicate selection |  | Yes | Yes | Yes | No | Yes |
| 6 | Duplicate extraction |  | Yes | Yes | Yes | No | No |
| 7 | List of excluded studies | C | No | No | Partial | No | No |
| 8 | Detailed description of included |  | Partial | Yes | Partial | Partial | Partial |
| 9 | Risk-of-bias assessment | C | Partial | Yes | No | No | No |
| 10 | Reported funding sources |  | No | No | No | No | No |
| 11 | Appropriate statistical methods | C | Yes | Yes | Yes | No | Partial |
| 12 | Impact of RoB on results |  | No | Partial | No | No | No |
| 13 | RoB in interpretation | C | Partial | Yes | No | No | Partial |
| 14 | Heterogeneity discussion |  | Yes | Yes | Yes | Partial | Yes |
| 15 | Publication bias | C | Yes | Partial | No | No | No |
| 16 | Conflicts of interest |  | Yes | Yes | Yes | Yes | Yes |
| **Critical flaws** | | | **2** | **1** | **4** | **6** | **4** |
| **Overall confidence (LLM full-text)** | | | **Critically Low** | **Low** | **Critically Low** | **Critically Low** | **Critically Low** |
| **MA performed** | | | Yes | Yes | Yes | Yes | Yes |
| **Full-text accessed** | | | ✓ | ✓ | ✓ | ✓ | ✓ |

Codes: Yes / Partial = Partial Yes / No = No / C/T = Cannot Tell / n/a = No meta-analysis (items 11/12/15 do not count toward critical flaws for narrative SRs). **C** marks the seven critical items per the Shea 2017 algorithm.

## Per-anchor narrative notes

**Tee 2018** — High-impact BJS MA of 13 studies (1,921 patients) in initial biopsy-proven cN+. Two critical flaws: item 2 (no protocol/registration) and item 7 (no excluded-studies list). Item 4 Partial Yes (no grey literature). Item 9 Partial Yes (RoB assessed but with single-rater limitation). Subgroup analyses by mapping technique and number of nodes removed strengthen item 11. Methodologically sound but lacks core safeguards.

**Simons 2019** — Anchor SR/MA of 20 studies (2,217 patients) restricted to pathologically confirmed cN+ comparing SLNB, MARI, and combination procedures vs ALND. Strongest of the five anchors with only 1 critical flaw: item 7 (no list of excluded studies). Items 2 (no protocol) and 4 (Partial — no grey literature) preclude a higher rating. Item 9 = Yes (QUADAS-2 applied), item 13 = Yes (RoB explicitly discussed), item 15 = Partial (limited publication-bias check). Highest overall confidence ("Low") in the anchor set.

**Samiei 2021** — Pooled MA of 33 studies (57,531 patients) of axillary pCR by molecular subtype. Critical flaws on items 2 (no protocol), 9 (no RoB), 13 (no RoB discussion), 15 (no publication bias assessment). PRISMA-DTA followed for reporting. Methodologically sound pooling but lacks core AMSTAR-2 critical safeguards.

**Swarnkar 2021** — Pooled analysis of MLNB (9 studies/366 patients) and TAD (13 studies/521 patients) in cN+ after NACT. Six of seven critical items rated No (items 2, 4 partial, 7, 9, 11, 13, 15). Pooled analysis without formal meta-analytic model, no protocol, no RoB assessment, no list of excluded studies, no duplicate selection/extraction, no publication bias test. The lowest overall AMSTAR-2 score in the anchor set, but retained because of unique pooled MLNB/TAD intervention coverage.

**de Wild 2024** — Comprehensive BJS narrative SR of 51 studies (4,512 patients) of TAD restricted to cN+, with random-effects MA of proportions (metaprop) for pooled IR. Four critical flaws: item 2 (no protocol/registration, explicitly stated), item 7 (excluded studies counts only, no reference list), item 9 (NIH tool not satisfactory RoB instrument, single rater), item 15 (no publication bias assessment). High-impact BJS review but methodological reporting gaps drive Critically Low rating.

## Full-cohort frequency of unmet items (n = 33 originally screened SRs)

Across all 33 SRs scored under full-text LLM-augmented review (preserved as the historical audit set; the strict PICOS triage applied to the 23-SR working set yields the same item-level pattern):
- Item 7 (excluded studies list) — "No"/"Cannot tell" in 32/33
- Item 2 (pre-registered protocol) — "No"/"Cannot tell" in 30/33 (Ma 2023 sole explicit PROSPERO)
- Item 16 (review COI/funding) — "No" in 27/33
- Item 9 (RoB tool) — "No"/"Cannot tell" in 26/33
- Item 15 (publication bias) — "No" in 22/28 meta-analyses (Yu 2024 sole funnel+Egger; Yu 2024 now excluded but item-level result preserved for audit)

See Supplementary File S3 for the full per-item × per-SR matrix and Supplementary File S4 for the documented exclusions with per-SR rationale.
