Paper title: Regional recurrence rates with or without axillary dissection for breast cancer patients with node positive disease on sentinel lymph node biopsy after neoadjuvant chemotherapy

Aim(s): Outcomes for SLNB(+) patienst after NAC with and without ALND/ Can ALND be safely omitted in a selected group of this patients? Patterns of recurrence Rates of lymphoedema with and without ALND

DOI:https://doi.org/10.1016/j.adro.2019.09.006

The article is informative and provide a novel and relevant data for the field. Considering current standard of care, presented results may have great influence on clinical practice as well as the impact on ongoing and future research. The aim and methodology are clear and well presented. The results section could be improved by excluding the repetitive text and by replacing some text by additional tables and charts in order to improve readability and clarity. Some results need to be rechecked, omitted and corrected (typing error). The results gained from this study are something completely novel in the field, therefore I suggest the authors to retype the discussion section, e.g. instead of reviewing the results of previous trials this new knowledge, its importance and possible impact in practice should be discussed. The conclusion should be based on the results of this trial as well.

The straight of the article is decreased by its retrospective nature and groups inequalities (number of patients, follow up period and the aggressiveness and stage of the disease). However, the results are novel in this field and may have a great impact on current clinical practice and future research.

Major points in the article which needs clarification, refinement, reanalysis, rewrites and/or additional information and suggestions for what could be done to improve the article:

1. Discussion of the results of this study in context of previous and ongoing trials and its relevance for the current clinical practice and future researches, instead of reviewing and discussing the results of previous trials (the fact that regional, local and distant recurrence rates as well as specific survival and overall survival rates are not statistically significant different between selected SLNB-only and SLNB+ALND groups of patients; the fact that failure rates are not correlated to volume of disease in sentinel node (p=0,8) nor to delivery of nodal radiotherapy (p=0.49); the fact that no predictive factor for regional recurrence was identified in this study and its impact on future researches; the fact that regional recurrence has great impact on survival (p=0.002)
2. Conclusions should be made upon the results of this study and not speculated (the fact is that recurrence rates in this study were not correlated to the delivery of nodal irradiation)
3. While discussing FNR of SLNB after NAC, I suggest to include also the following reference:Tee SR, Devane LA, Evoy D, Rothwell J, Geraghty J, Prichard RS et al. Meta-analysis of sentinel lymph node biopsy after neoadjuvant chemotherapy in patients with initial biopsy-proven node-positive breast cancer. Br J Surg. 2018;105(12):1541-1552) as well as the procedure of targeted axillary dissection, instead of claiming that FNR is unacceptable high (in my opinion that is historical argument, not acceptable anymore).
4. The authors may suggest several proposals for new/ongoing trial; to determine predictive factors for recurrence, to determine the role of nodal irradiation, to determine factors relevant for patient (SN positive patients after NAC) selection for omission of ALND or/and nodal irradiation

Minor points like figures/tables not being mentioned in the text, a missing reference, typos, and other inconsistencies:

1. Suggested references to include: -Tinterria C, Canavesea G, Bruzzib P, Dozinb B. NEONOD 2: Rationale and design of a multicenter non-inferiority trial to assess the effect of axillary surgery omission on the outcome of breast cancer patients presenting only micrometastasis in the sentinel lymph node after neoadjuvant chemotherapy. Contemp Clin Trials Commun. 2019;17:100496

-ClinicalTrials.gov [Internet]. Bethesda (MD): National Library of Medicine (US).2000 [citirano 2020 Mar 27] Identifier:NCT04109079, Axillary Management in Breast Cancer Patients With Needle Biopsy Proven Nodal Metastases After Neoadjuvant Chemotherapy (ATNEC); 2019 Sep 30 available from: https://clinicaltrials.gov/ct2/show/record/NCT04109079

-Tee SR, Devane LA, Evoy D, Rothwell J, Geraghty J, Prichard RS et al. Meta-analysis of sentinel lymph node biopsy after neoadjuvant chemotherapy in patients with initial biopsy-proven node-positive breast cancer. Br J Surg. 2018;105(12):1541-1552).

1. No. of SLN involved in SLNB-ony group=1, No. of SLN involved in SLNB+ALND group=1, p=0.002?; I think this calculation should be recheck.
2. Typing error (Number of patients who received regional node irradiation is different in table and text (numbers 40 and 90 are replaced in text).
3. Replacing text of section “Regional control” with the tables and charts would contribute to readability and clarity, because it is difficult to follow so many results in the text
4. Most of the result section “Patients and treatment characteristic” is already presented with table 1, therefore should not be repeat in text.
5. RCB score is unavailable for over 70% of patients, therefore should not be included in the analysis.