Omitting Regional Nodal Irradiation after Response to Neoadjuvant Chemotherapy
Mamounas EP, Bandos H, White JR, Julian TB, Khan AJ, Shaitelman SF, Torres MA, Vicini FA, Ganz PA, McCloskey SA, Lucas PC, Gupta N, Li XA, McCormick B, Smith B, Tendulkar RD, Kavadi VS, Matsumoto K, Seaward SA, Irvin WJ, Lin JY, Mutter RW, Muanza TM, Stromberg J, Jagsi R, Weiss AC, Curran WJ, Wolmark N.
- DOI
- 10.1056/nejmoa2414859
- Record issued
- 2026-08-10
- Engine
- 7.29.0
- Exported
- 2026-09-22
Prepared by Alpha1. This document is confidential: it is intended for the recipient it was shared with and must not be redistributed. The live record at alpha1science.com/verify/cd8b61ed-f143-4d77-9fd2-c043c9c721fa is authoritative.
How this rating was calculated
- IntegrityIntegrity concern−0.5★
- ClaimsOverstated claim−0.5★
- ReportingBiological variables not met−0.5★
- ReportingData & code availability not met−0.5★
- ReportingEthical approvals partially met−0.25★
- 01Biological variables not reported
The paper does not report the sex of participants, and age/weight/health status are incompletely reported.
“Median age was 52 years (IQR 44–60) with 40% being <50 years; 17% were Black/African American, and 14% were of Hispanic/Latino ethnicity.”
ResultsFind in source - 02Data and code not shared
No data availability statement is provided, and no data repository deposit is mentioned. This is a significant omission for a clinical trial funded by NIH.
- 03Conclusion reaches beyond the evidence
Our study results demonstrate that pCR in axillary lymph nodes is predictive of lack of benefit from regional nodal irradiation.
“Our study results demonstrate that pCR in axillary lymph nodes is predictive of lack of benefit from regional nodal irradiation.”
Discussion ¶2Find in source
This Kaimen Rigor review uses Kaimen Rigor reviewers trained on a curated corpus of high-fidelity and retracted papers, with expert supervision and curation. It can still make mistakes; verify each finding against the source before relying on it.
This is a rigorously designed and transparently reported phase 3 randomized trial (NSABP B-51/RTOG 1304) with a strong scientific premise, detailed methods, prespecified power analysis, ITT analysis, disclosed limitations/funding, and conservative conclusions. Its main weaknesses are reporting gaps: no data availability statement, no sex/health-status reporting, no named ethical-framework compliance statement, and an under-specified randomization method, plus a numerical inconsistency (1,802 vs 1,602) and an overstated predictive claim.
Both independent reviewers agreed on 7 of 8 dimension statuses and diverged only on key resources (pass vs not applicable), which was resolved as applicable-and-pass because the trial's investigational radiation intervention is a scored resource. The statistics component recomputed only 1 test/estimate (consistent); all other statistics are unverified, not confirmed. Citation screening found 0 retracted and 0 not-found references. Copyedit flagged one major internal-contradiction typo (1,802 vs 1,602).
Numerical inconsistencies
1 finding · worst lowValues that contradict each other or are impossible for the stated sample: recomputed p-values and test statistics, GRIM/GRIMMER checks on summary numbers, percentages against their own counts, totals against their parts, and estimates against their own confidence intervals.
- Internal contradictions in the reported numbersAssessed
Recomputed 1 test: 1 consistent, 0 inconsistent; 1 recomputed directly from the reported test statistics.
- CONSISTENTreported p = .510 · recomputed p = .508Recomputed hazard ratio 0.88 (95% CI 0.60–1.28), reported p=0.51
“hazard ratio 0.88; 95% confidence interval [CI], 0.60 to 1.28; P = 0.51”
Taken as given: 0.60–1.28 is a two-sided 95% confidence interval for the hazard ratio of 0.88, not a range, an IQR, or a different interval level; the hazard ratio is a RATIO measure, so the interval is symmetric on the log scale; p=0.51 is the p for THIS estimate, not for another comparison in the same sentenceMethod: back the two-tailed p out of the log-scale CI width and compare it against the printed pHow we recomputed it: pCI(0.88, 0.6, 1.28, 1)
- lowinternal contradictionThe text states '1,802 evaluated for the overall survival endpoint' but Table 2 shows survival analysis n=802 and n=800, totaling 1,602. This appears to be a typographical error.
“A total of 94 patients died of 1,802 evaluated for the overall survival endpoint”
ResultsFind in source
Overstated conclusions
1 finding · worst mediumConclusions that reach past what the paper's own results support — including a significance claim that no longer holds when the statistic is recomputed, and efficacy resting on an unvalidated surrogate endpoint.
- Conclusions overstated beyond the evidenceAssessed
8 major claims checked against the paper's own evidence: 1 not fully backed by the presented evidence (unsupported or overstated).
- overstatedReviewer 2Our study results demonstrate that pCR in axillary lymph nodes is predictive of lack of benefit from regional nodal irradiation.The trial enrolled only patients who achieved ypN0; it did not include a ypN+ comparator group, so it cannot directly demonstrate a predictive (interaction) effect. The claim extends beyond the study design.Evidence: The null result in this ypN0 population shows lack of benefit in this subgroup, but no direct comparison with non-pCR patients is made.
“Our study results demonstrate that pCR in axillary lymph nodes is predictive of lack of benefit from regional nodal irradiation.”
Discussion ¶2Find in source - supportedReviewers 1, 2Regional nodal irradiation did not significantly increase the invasive breast cancer recurrence–free interval.The presented HR, 95% CI, and p-value directly support this claim.Evidence: HR = 0.88, 95% CI 0.60–1.28, p = 0.51
“Regional nodal irradiation did not significantly increase the invasive breast cancer recurrence–free interval (hazard ratio, 0.88; 95% confidence interval, 0.60 to 1.28; P=0.51).”
AbstractFind in source - supportedReviewer 1Regional nodal irradiation did not increase the locoregional recurrence–free interval, the distant recurrence–free interval, disease-free survival, or overall survival.The reported HR and CIs for these endpoints are all consistent with no benefit.Evidence: HR for locoregional recurrence-free interval: 0.57 (0.21–1.54); DRFI: 1.00 (0.67–1.51); DFS: 1.06 (0.79–1.44); OS: 1.12 (0.75–1.68)
No reduction in locoregional recurrence-free interval with regional nodal irradiation was observed (hazard ratio, 0.57; 95% CI, 0.21 to 1.54)... No difference between treatment arms was noted in DRFI (HR=1.00, 95%CI 0.67–1.51) or DFS (HR=1.06, 95%CI 0.79–1.44)... 94 patients died... (hazard ratio, 1.12; 95% CI, 0.75 to 1.68).
Resultsreviewer’s wording - supportedReviewer 1No deaths related to the protocol-specified therapy were reported, and no unexpected adverse events were observed.The safety data reported confirm this claim.Evidence: No study-related deaths; grade 4 toxicity rare (0.5% vs 0.1%); no unexpected toxicities.
There were no study-related deaths and no unexpected toxicities. Grade 4 toxicity was rare (No regional nodal irradiation: 0.1%, vs. regional nodal irradiation: 0.5%).
Discussionreviewer’s wording - supportedReviewers 1, 2The addition of adjuvant regional nodal irradiation did not decrease the risk of invasive breast cancer recurrence or death from breast cancer in patients who had negative axillary nodes after neoadjuvant chemotherapy.The primary endpoint result and the overall pattern of null findings support this conclusion.Evidence: Primary endpoint: HR 0.88, 95% CI 0.60–1.28, p=0.51; all secondary endpoints also show no significant benefit.
“The addition of adjuvant regional nodal irradiation did not decrease the risk of invasive breast cancer recurrence or death from breast cancer in patients who had negative axillary nodes after neoadjuvant chemotherapy.”
ConclusionFind in source - supportedReviewer 1Exploratory subgroup analyses suggest potential differences in effect by breast cancer subtype, but these should be interpreted with caution.The paper explicitly cautions about the exploratory nature and wide confidence intervals.Evidence: HR for TNBC: 2.30 (1.00–5.25); HR for HR+/HER2-: 0.41 (0.17–0.99). The discussion states these should be viewed with caution.
“The results of the exploratory subset analysis according to breast cancer subgroups should be viewed with caution because the number of patients in each subgroup represents roughly a quarter of the overall patient population, resulting in wide confidence intervals around the estimates.”
DiscussionFind in source - supportedReviewer 2Regional nodal irradiation did not improve locoregional recurrence-free interval, distant recurrence-free interval, disease-free survival, or overall survival.All secondary endpoint HRs have 95% CIs that include 1.0, supporting no significant benefit.Evidence: Reported HRs: LRRFI 0.57 (0.21-1.54), DRFI 1.00 (0.67-1.51), DFS 1.06 (0.79-1.44), OS 1.12 (0.75-1.68).
“Regional nodal irradiation did not increase the locoregional recurrence–free interval, the distant recurrence–free interval, disease-free survival, or overall survival.”
ResultsFind in source - supportedReviewer 2The exploratory subgroup finding of increased risk in triple-negative patients is likely spurious.The authors appropriately caution that this subgroup analysis has wide confidence intervals and is exploratory.Evidence: Exploratory analysis HR 2.30 (95% CI 1.00 to 5.25) in triple-negative subgroup.
“For patients with triple-negative breast cancer, it is hard to explain results indicating greater risk of recurrence among patients who received regional nodal irradiation, likely supporting a spurious finding.”
Discussion ¶4Find in source
Data authenticity concerns
None foundAn adversarial read for patterns associated with data that may not be genuine: results that look too clean, implausibly large effects, duplicated data or images, and methods that do not match the results reported.
Checked — nothing surfaced.
Reporting gaps
3 findings · worst highRequired detail the manuscript never states — study design, biological variables, ethics approval and consent, key resources, statistical reporting, data and code availability, and overall transparency.
- Biological variables not reportedAssessed
- Data and code not sharedAssessed
- Ethics/consent reporting incompleteAssessed
The introduction cites relevant trials and retrospective analyses, acknowledges the gap in knowledge, and provides a logical rationale for the study. The limitations of prior research are addressed, and the hypothesis follows from the cited evidence.
“Adjuvant regional nodal irradiation has been shown to reduce the risk of locoregional recurrence, distant recurrence, and death from breast cancer among patients with early-stage breast cancer who undergo surgery first and have pathologically involved axillary lymph nodes.”
“For such patients, no prospective outcome data show benefit from regional nodal irradiation. This lack of data has led to clinical uncertainty and variability in practice with respect to the use of regional nodal irradiation due to positive axillary nodes at diagnosis or its omission due to negative axillary nodes after neoadjuvant chemotherapy.”
“Retrospective studies have shown that patients with clinically positive axillary nodes whose nodes convert to ypN0 after neoadjuvant chemotherapy have better outcomes compared to those whose nodes remain pathologically node-positive, creating uncertainty regarding the need for regional nodal irradiation.”
“For such patients, no prospective outcome data show benefit from regional nodal irradiation.”
“Retrospective studies have shown that patients with clinically positive axillary nodes whose nodes convert to ypN0 after neoadjuvant chemotherapy have better outcomes compared to those whose nodes remain pathologically node-positive, creating uncertainty regarding the need for regional nodal irradiation.”
“We conducted the NSABP B-51/RTOG 1304 trial to evaluate whether regional nodal irradiation would significantly improve the interval of freedom from recurrence of invasive breast cancer in patients with clinically node-positive breast cancer whose nodes reached ypN0 status after neoadjuvant chemotherapy.”
Randomization is stated but the method of sequence generation is not specified. Blinding is not mentioned, which is common in radiation trials but not justified. Power analysis and inclusion/exclusion criteria are adequately reported. The intent-to-treat analysis is defined.
“The trial was designed to have 80% power to test the hypothesis that treatment with regional nodal irradiation would reduce the annual hazard rate of invasive breast cancer recurrence-free interval events by 35%.”
“Eligible patients had breast cancer that was clinical stage T1 to T3 (tumor size, T1, ≤2 cm; T2, >2 cm but ≤5 cm; T3, >5 cm), N1, and M0 (indicating spread to movable, ipsilateral level I and II axillary lymph nodes but no distant metastasis) and operable at diagnosis, with pathological confirmation of the involvement of axillary nodes by either fine-needle aspiration or core-needle biopsy.”
“The trial was designed to have 80% power to test the hypothesis that treatment with regional nodal irradiation would reduce the annual hazard rate of invasive breast cancer recurrence-free interval events by 35%.”
“Eligible patients had breast cancer that was clinical stage T1 to T3 (tumor size, T1, ≤2 cm; T2, >2 cm but ≤5 cm; T3, >5 cm), N1, and M0 (indicating spread to movable, ipsilateral level I and II axillary lymph nodes but no distant metastasis) and operable at diagnosis, with pathological confirmation of the involvement of axillary nodes by either fine-needle aspiration or core-needle biopsy.”
“The primary analysis was based on the intent-to-treat principle.”
Age is reported but sex is not mentioned. Weight and health status are not provided. Race and ethnicity are reported. For a human trial, sex is a critical biological variable. The omission is a significant gap.
“Median age was 52 years (IQR 44–60) with 40% being <50 years; 17% were Black/African American, and 14% were of Hispanic/Latino ethnicity.”
“Median age was 52 years (IQR 44–60) with 40% being <50 years; 17% were Black/African American, and 14% were of Hispanic/Latino ethnicity.”
The paper states the protocol was approved by each institution's IRB or the NCI Central IRB, and written informed consent was required. However, an explicit statement of adherence to the Declaration of Helsinki, ICH-GCP, or another named regulatory framework is absent. This is a reporting gap, not evidence of an ethical violation.
“The protocol was approved by either the Institutional Review Board at each participating institution or by the NCI Central Institutional Review Board.”
“Written informed consent was required for enrollment.”
“The protocol was approved by either the Institutional Review Board at each participating institution or by the NCI Central Institutional Review Board. Written informed consent was required for enrollment.”
The investigational product (radiation therapy) is described with dose, fractionation, and technique. No other biological resources are applicable. No bespoke analysis software is reported, so software identification is not applicable.
“Patients assigned to receive regional nodal irradiation received 50 Gy in 25 fractions delivered to the retained portion of level I to III axillary nodes after sentinel-lymph-node biopsy or axillary-lymph-node dissection, supraclavicular nodes, and internal mammary nodes within the first three to four intercostal spaces, along with the chest wall after mastectomy or the whole breast after lumpectomy.”
The statistical methods are appropriate and described. The proportional hazards assumption is tested. The primary p-value is exact. All secondary analyses report HR and 95% CI. No arithmetic inconsistencies were detected.
“Differences between treatment arms were assessed by stratified log rank test, controlling for stratification factors.”
“The stratified Cox proportional hazards model was used to estimate the hazard ratios and confidence intervals.”
The paper reports the trial registration number but does not include a statement about where the data can be accessed. Given NIH policies, this is a major gap.
“Trial Registration: NCT01872975 (https://clinicaltrials.gov/ct2/show/NCT01872975)”
The paper mentions trial registration, funding, and conflicts. The methods are detailed. The limitations are discussed. The only missing element is reference to a reporting guideline like CONSORT.
“Trial Registration: NCT01872975 (https://clinicaltrials.gov/ct2/show/NCT01872975)”
“Trial Registration: NCT01872975 (https://clinicaltrials.gov/ct2/show/NCT01872975)”
“Our trial has some limitations. The observed rate of the primary end point (8.2%) was around one third lower than the rate projected on the basis of the combined analysis of the NSABP B-18 and B-27 trials”
“Supported by grants from the National Institutes of Health, U10CA180868, U10CA180822, UG1CA189867, and U24CA196067”
Registered (1 ID: ClinicalTrials.gov). No reporting guideline cited.
Broken references and links
None foundReferences checked against Crossref, OpenAlex and Retraction Watch for retractions and resolvability, plus declared data and code links probed for whether they resolve to content matching the paper.
Checked — nothing surfaced.
Checked 29 references by DOI: 27 verified — 2 no DOI (shown, not verified).
- NO DOIFavourable and unfavourable effects on long-term survival of radiotherapy for early breast cancer: An overview of the randomised trialsNo DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
- NO DOIChecking the Cox model with cumulative sums of martingale-based residualsNo DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
1 data/code link checked; 1 live.
- datahttps://clinicaltrials.gov/ct2/show/NCT01872975LIVEHTTP 200Resolves, but the content could not be matched to the paper.
Copyediting
1 finding · worst lowWording, consistency and formatting errors that need correcting before submission.
- Wording or formatting errors that need correctingAssessed
7 copyedit issues flagged (1 major): mostly typo, other, grammar.
- MAJORtypoResults, Efficacy Analyses“A total of 94 patients died of 1,802 evaluated for the overall survival endpoint”→ Change 1,802 to 1,602 to match the n values in Table 2 (802+800).This number contradicts Table 2 where survival analysis n=802 and n=800 sum to 1,602.
- MINORotherBeginning of paper text“pmc 1 Omitting Regional Nodal Irradiation in Responders to Neoadjuvant Chemotherapy Mamounas Eleftherios P. M.D. ...”→ Remove the 'pmc 1' prefix, which appears to be a formatting artifact.The text starts with 'pmc 1', likely a PMC identifier inadvertently included.
- MINORgrammarResults, Safety“There were no study-related deaths and no unexpected toxicities.”→ Consider rephrasing to 'There were no study-related deaths and no unexpected toxicities were observed.'Minor inconsistency in verb tense between the two clauses.
- MINORtypoFunding/Acknowledgments“interpretation of the date”→ Change 'date' to 'data'.Typo in the funding statement.
- MINORtypoMethods, Radiation Therapy Regimens“A twostep radiation quality-assurance process”→ Change to 'A two-step radiation quality-assurance process'.Missing hyphen and space.
- MINORconsistencyResults, Trial Dates and Timing of Analyses“with 1,641 patients (100.3%)”→ Consider clarifying that 1,641 is 100.3% of the planned 1,636 target.100.3% may confuse readers if not clear that it refers to target accrual.
- MINORclarityResults, Efficacy Analyses“Regional nodal irradiation did not increase the locoregional recurrence–free interval, the distant recurrence–free interval, disease-free survival, or overall survival.”→ Use 'improve' instead of 'increase' for these time-to-event outcomes.The verb 'increase' is ambiguous for negative outcomes (e.g., survival intervals).
As a published trial, the work is robust and its null conclusion is appropriately conservative; an informed reader should weigh the missing IPD data-access route, the absence of sex/health-status baseline reporting, and the unverifiable (not merely unverified) bulk of the statistics. The internal numerical inconsistency (1,802 vs 1,602 for the overall-survival analysable population) warrants a correction/erratum, and the claim that ypN0 is 'predictive of lack of benefit' should be tempered because the trial had no ypN+ comparator to demonstrate an interaction. No ethics or integrity violation is indicated; the gaps are reporting and framing issues rather than validity threats.
- 1.HIGHdata codeAdd a Data Availability Statement to the end of the manuscript naming the managed-access route for individual patient data (e.g., via the NRG Oncology/NSABP data-access committee) with conditions and expected timeframe.An NIH-funded data-driven trial with no data-access statement is a major reporting gap that reviewers and readers will flag.
- 2.HIGHcopyeditCorrect 'A total of 94 patients died of 1,802 evaluated for the overall survival endpoint' to '1,602' in Results, Efficacy Analyses, to match the Table 2 analysable counts (802 + 800).This is an internal contradiction with Table 2 and an impossible published number that warrants an erratum.
- 3.HIGHrigorReport the sex distribution of participants in Table 1/Results; if only women were enrolled (as expected for this breast cancer trial), state this explicitly with any justification.Sex is a critical biological variable for a human trial; its omission is the principal biological-variables failing.
- 4.HIGHrigorTemper the claim that 'pCR in axillary lymph nodes is predictive of lack of benefit from regional nodal irradiation,' since the trial enrolled only ypN0 patients with no ypN+ comparator and cannot demonstrate a predictive (interaction) effect.The claim extends beyond the study design and overstates what a single-arm-in-population comparison can establish.
- 5.HIGHrigorReport health status/comorbidities (e.g., ECOG performance status, relevant cardiovascular/comorbidity history) in the baseline characteristics table.Comorbidities are relevant confounders for survival and toxicity endpoints and are currently absent.
- 6.MEDIUMethicsAdd an explicit statement of compliance with the Declaration of Helsinki or ICH-GCP in the Methods/Ethics section alongside the existing IRB approval statement.A named ethical-framework statement is expected for a human randomized trial and is currently missing.
- 7.MEDIUMotherDescribe the randomization allocation sequence generation (e.g., central web-based randomization, permuted blocks) in the Methods.The randomization method is currently under-specified, which weakens confidence in allocation concealment.
- 8.MEDIUMotherState that the trial was open-label (blinding not feasible for a radiation intervention) and provide the rationale.Blinding status is not reported at all; declaring and justifying open-label design is standard for radiation trials.
- 9.MEDIUMreportingReference the CONSORT reporting checklist or state adherence to CONSORT for this randomized trial.A reporting-guideline reference is expected for a randomized trial and is currently absent.
- 10.MEDIUMstatisticsIdentify the statistical software and version used for analyses (e.g., SAS 9.4, R version) in the Statistical Analysis section.Software/version identification aids reproducibility and is currently missing.
- 11.LOWcopyeditRemove the 'pmc 1' formatting artifact at the very beginning of the paper text.This appears to be an inadvertent PMC identifier prefix that should not appear in the article text.
- 12.LOWcopyeditFix the typo 'interpretation of the date' to 'interpretation of the data' in the funding/acknowledgments statement.A misspelling in a funding statement is an avoidable error.
- 13.LOWcopyeditFix 'A twostep radiation quality-assurance process' to 'A two-step radiation quality-assurance process' in Methods, Radiation Therapy Regimens.Missing hyphen/spacing is a minor typographic error.
- 14.LOWcopyeditClarify 'with 1,641 patients (100.3%)' to state that this reflects 100.3% of the planned 1,636 target accrual, and consider using 'improve' rather than 'increase' for time-to-event outcomes in the efficacy paragraph.The percentage could confuse readers and 'increase' is ambiguous for survival/recurrence-free intervals.
The star rating is the report’s one-glance summary. Every paper starts at 5★ and loses stars for the concrete problems the review finds — so a rating is never a vague average, it’s a running total you can read line by line under “How this rating was calculated.”
- Reporting — 8 dimensionseach dimension that fully fails−½★
- each dimension partially met−¼★
- Statistics · Integrity · Claimseach serious problem−1★
- each medium problem−½★
- Citationseach retracted or unverifiable reference−¼★
- Copyeditonly when the manuscript needs a full edit−½★
The rating never drops below 1★, and a demonstrable critical failure (an impossible statistic, a proven ethics violation) caps it at 1★ on its own — so the stars can never look healthy when the verdict is CRITICAL.
The rating draws on a panel of agents. Three independent Kaimen Rigor reviewers grade the eight dimensions below across several independent passes (the shown verdict is their majority vote — steadier than any single run), isolate the paper’s major claims and check its own evidence backs them, and flag integrity concerns. Alongside them, a citation agent resolves every reference against Crossref, OpenAlex, and Retraction Watch; a statistics agent recomputes reported tests; and rule-based checks verify that declared data/code links actually resolve. Full text is required — an abstract-only submission is not analyzed.
Graded against NIH, MDAR, ARRIVE 2.0, CONSORT, EQUATOR, and RRID guidelines. A dimension that doesn’t apply to the study type is skipped, never penalized.
This Kaimen Rigor review is model-assisted and is not a substitute for formal expert review. It complements human evaluation by surfacing potential methodological concerns — verify each finding against the source.