Identifying subgroups of ypN1 breast cancer patients who may exempt from axillary lymph node dissection after neoadjuvant chemotherapy: insights from a large cohort study.

Background

In patients with breast cancer staged ypN1 after neoadjuvant chemotherapy (NAC), there is limited evidence-based guidance regarding exemption from axillary lymph node dissection (ALND).

Methods

This study analyzed ypN1 breast cancer patients post-NAC from the Surveillance, Epidemiology, and End Results databases. Patients were categorized into the breast-conserving surgery (BCS) group and the total mastectomy (TM) group, and further divided by the number of positive lymph nodes (LNs). The effects of three axillary management strategies, ALND, sentinel lymph node biopsy combined with radiotherapy (SLNB + RT), and ALND + RT were compared. The overall survival (OS) and breast cancer-specific survival (BCSS) of all subgroups and their independent risk factors were analyzed. Independent prognostic factors selected from multivariate Cox analysis were utilized to create nomograms for predicting OS and BCSS.

Results

A total of 3641 patients were involved, with 1331 in the BCS group and 2310 in the TM group. In the TM group, patients with 3 residual positive LNs exhibited significant improvements in OS and BCSS when treated with ALND + RT. For patients with 1 or 2 residual positive LNs in the TM group and all BCS patients, no significant survival differences in survival outcomes were observed among the three axillary management methods. The accuracy of the nomograms was validated via calibration curves, receiver operating characteristic curves, and decision curve analysis curves.

Conclusion

For TM group patients with 3 residual positive LNs after NAC, ALND + RT is recommended. For other subgroups of ypN1 patients, SLNB + RT can be considered an alternative to ALND. The nomogram developed to predict OS and BCSS in ypN1 breast cancer patients demonstrated excellent predictive ability.

COI Statement

Declarations. Conflict of interest: All authors declare that they have no conflicts of interest to disclose. Ethical approval and informed consent. As the SEER database used in this study does not contain personally identifiable information, patient informed consent is not needed. The study received an exemption from the Ethics Committee of the Second Affiliated Hospital of Xi'an Jiaotong University. Consent for publication: All the authors declare that this manuscript is original work and has not been published previously, nor is it under consideration for publication elsewhere. All sources of funding and potential conflicts of interest have been disclosed.

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