# Supplementary Material S2 — PRISMA 2020 Checklist

**Reference:** Page MJ, McKenzie JE, Bossuyt PM, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. *BMJ* 2021;372:n71. doi:10.1136/bmj.n71

**Manuscript:** Axillary management after neoadjuvant chemotherapy in node-positive breast cancer (cN+ to ypN0): an umbrella review of systematic reviews and meta-analyses (2006–2026).

**Note on adaptation:** Where applicable, items are completed at the level of the umbrella review (i.e., reviewing systematic reviews) per JBI umbrella-review guidance and the PRIOR statement (Tricco et al, *BMJ* 2023;381:e074091). Items that pertain to re-pooling of effect estimates are marked "N/A — JBI umbrella methodology, no re-pooling."

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## TITLE

| # | PRISMA 2020 item | Location in manuscript |
|---:|---|---|
| 1 | Identify the report as a systematic review | Title page; Title (also identifies it as an umbrella review) |

## ABSTRACT

| # | PRISMA 2020 item | Location in manuscript |
|---:|---|---|
| 2 | See PRISMA-2020 abstract checklist (Page 2021, supplementary file 4) | Structured abstract, p. 2 (250-word and 300-word variants in S7) |

## INTRODUCTION

| # | PRISMA 2020 item | Location in manuscript |
|---:|---|---|
| 3 | Rationale — describe rationale in context of existing knowledge | Introduction, paragraphs 1–3, pp. 3–4 |
| 4 | Objectives — provide explicit statement of objective(s) / question(s) | Introduction, final paragraph, p. 4; PICOS frame in Methods, p. 5 |

## METHODS

| # | PRISMA 2020 item | Location in manuscript |
|---:|---|---|
| 5 | Eligibility criteria — specify inclusion/exclusion criteria for the review and how studies were grouped for the syntheses | Methods §2.1 (PICOS), p. 5; Methods §2.2 (eligibility), pp. 5–6 |
| 6 | Information sources — specify all databases, registers, websites, organizations, reference lists and other sources searched or consulted; specify the date when each was last searched | Methods §2.3 (information sources), p. 6; complete details in Supplementary S1 |
| 7 | Search strategy — present full search strategies for all databases, registers and websites, including any filters and limits used | Supplementary S1 (full search strategy for PubMed, EMBASE, CDSR, Epistemonikos) |
| 8 | Selection process — specify methods used to decide whether a study met inclusion criteria; how many reviewers screened each record and report; whether they worked independently; any automation tools used in the process | Methods §2.4 (study selection), p. 6; dual independent screening, Cohen's κ reported |
| 9 | Data collection process — specify methods used to collect data from reports, including how many reviewers collected data from each report, whether they worked independently, any processes for confirming data from study investigators, and any automation tools used in the process | Methods §2.5 (data extraction), p. 7; dual independent extraction onto piloted form |
| 10a | Data items — list and define all outcomes for which data were sought | Methods §2.6 (outcomes), p. 7; primary: ypN0, FNR; secondary: IR, recurrence, OS/DFS, lymphedema |
| 10b | Data items — list and define all other variables for which data were sought | Methods §2.5 (data extraction), p. 7; Supplementary S5 (extraction template) |
| 11 | Study risk of bias assessment — specify methods used to assess risk of bias in the included studies | Methods §2.7 (quality assessment), p. 8; AMSTAR-2 for all SRs; ROBIS in sensitivity analysis |
| 12 | Effect measures — specify for each outcome the effect measure(s) used in the synthesis or presentation of results | Methods §2.8, p. 8; effect measures as reported by underlying SRs (proportions for ypN0/FNR/IR; HR/RR for survival/recurrence) |
| 13a | Synthesis methods — describe the processes used to decide which studies were eligible for each synthesis | Methods §2.8 (synthesis), p. 8; structured by intervention then outcome |
| 13b | Synthesis methods — describe any methods required to prepare the data for presentation or synthesis, such as handling of missing summary statistics, or data conversions | Methods §2.8, p. 8; pooled estimates extracted as reported; no recalculation |
| 13c | Synthesis methods — describe any methods used to tabulate or visually display results of individual studies and syntheses | Methods §2.9, p. 9; per-outcome forest-style display per review (no re-pooling); Figure 2 |
| 13d | Synthesis methods — describe any methods used to synthesize results and provide a rationale for the choice(s); if meta-analysis was performed, describe the model(s), method(s) to identify presence and extent of statistical heterogeneity, and software package(s) used | Methods §2.9, p. 9; **N/A — JBI umbrella methodology, no re-pooling**; convergence/divergence narrative synthesis with ±2 percentage-point convergence rule |
| 13e | Synthesis methods — describe any methods used to explore possible causes of heterogeneity among study results (e.g., subgroup analysis, meta-regression) | Methods §2.10 (heterogeneity exploration), p. 9; pre-specified subgroups: subtype, cN stage, era, geography, marker |
| 13f | Synthesis methods — describe any sensitivity analyses conducted to assess robustness of the synthesised results | Methods §2.11, p. 10; sensitivity analyses: AMSTAR-2 confidence stratum, ROBIS rescoring, exclusion of narrative SRs |
| 14 | Reporting bias assessment — describe any methods used to assess risk of bias due to missing results in a synthesis (arising from reporting biases) | Methods §2.12, p. 10; meta-bias assessed at the level of underlying primary studies, where the source SR reported it |
| 15 | Certainty assessment — describe any methods used to assess certainty (or confidence) in the body of evidence for an outcome | Methods §2.13, p. 10; GRADE applied per outcome at the umbrella level |

## RESULTS

| # | PRISMA 2020 item | Location in manuscript |
|---:|---|---|
| 16a | Study selection — describe the results of the search and selection process, from the number of records identified to the number of studies included in the review, ideally using a flow diagram | Results §3.1, p. 11; Figure 1 (PRISMA 2020 flow diagram) |
| 16b | Study selection — cite studies that might appear to meet the inclusion criteria, but which were excluded, and explain why they were excluded | Results §3.1, p. 11; Supplementary S4 (excluded studies with reasons) |
| 17 | Study characteristics — cite each included study and present its characteristics | Results §3.2, pp. 11–12; Table 1; Supplementary S5 (extended extraction) |
| 18 | Risk of bias in studies — present assessments of risk of bias for each included study | Results §3.3, pp. 12–13; Table 2 (AMSTAR-2 summary); Supplementary S3 (per-SR detail) |
| 19 | Results of individual studies — for all outcomes, present, for each study: (a) summary statistics for each group (where appropriate), and (b) an effect estimate and its precision (e.g., confidence/credible interval), ideally using structured tables or plots | Results §3.4–3.7, pp. 13–18; Table 3 (per-outcome reviews summary); Figure 2 (forest-style display) |
| 20a | Results of syntheses — for each synthesis, briefly summarise the characteristics and risk of bias among contributing studies | Results §3.4–3.7 (per outcome), pp. 13–18 |
| 20b | Results of syntheses — present results of all statistical syntheses conducted; if meta-analysis was done, present for each the summary estimate and its precision and measures of statistical heterogeneity; if comparing groups, describe the direction of the effect | Results §3.4–3.7, pp. 13–18; **No new pooled estimate produced**; existing pooled estimates from each SR tabulated with 95% CI and I² |
| 20c | Results of syntheses — present results of all investigations of possible causes of heterogeneity among study results | Results §3.8 (heterogeneity exploration), pp. 18–19 |
| 20d | Results of syntheses — present results of all sensitivity analyses conducted to assess the robustness of the synthesised results | Results §3.9 (sensitivity), pp. 19–20 |
| 21 | Reporting biases — present assessments of risk of bias due to missing results (arising from reporting biases) for each synthesis assessed | Results §3.10, p. 20 |
| 22 | Certainty of evidence — present assessments of certainty (or confidence) in the body of evidence for each outcome assessed | Results §3.11, p. 20; Table 4 (GRADE summary at umbrella level) |

## DISCUSSION

| # | PRISMA 2020 item | Location in manuscript |
|---:|---|---|
| 23a | Discussion — provide a general interpretation of the results in the context of other evidence | Discussion §4.1, pp. 21–22 |
| 23b | Discussion — discuss any limitations of the evidence included in the review | Discussion §4.2, p. 22 |
| 23c | Discussion — discuss any limitations of the review processes used | Discussion §4.3, p. 23 |
| 23d | Discussion — discuss implications of the results for practice, policy, and future research | Discussion §4.4–4.5, pp. 23–24 |

## OTHER INFORMATION

| # | PRISMA 2020 item | Location in manuscript |
|---:|---|---|
| 24a | Registration and protocol — provide registration information for the review, including the register name and registration number, or state that the review was not registered | Methods §2.1, p. 5; PROSPERO ID (TBD upon acceptance) |
| 24b | Registration and protocol — indicate where the review protocol can be accessed, or state that a protocol was not prepared | Methods §2.1, p. 5; full protocol at `01_protocolo/PROSPERO_protocol.md` of the project repository |
| 24c | Registration and protocol — describe and explain any amendments to information provided at registration or in the protocol | Methods §2.1, p. 5; "no amendments" or list as appropriate |
| 25 | Support — describe sources of financial or non-financial support for the review, and the role of the funders or sponsors in the review | Funding statement, p. 25; "None" |
| 26 | Competing interests — declare any competing interests of review authors | Competing interests, p. 25; "None declared" |
| 27 | Availability of data, code and other materials — report which of the following are publicly available and where they can be found: template data collection forms; data extracted from included studies; data used for all analyses; analytic code; any other materials used in the review | Data availability, p. 26; full repository at https://ganglio.cicatra.com (extracted data, AMSTAR-2 scores, scripts, PRISMA flow code) |

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*Checklist completed by D. Duque on behalf of the review team. Page numbers refer to the journal-formatted manuscript draft.*
