Does neoadjuvant systemic therapy in clinical T1-2 N0 human epidermal growth factor receptor 2-positive breast cancer increase the extent of axillary surgery?

BACKGROUND

For patients with human epidermal growth factor receptor 2-positive breast cancer, an upfront surgery or neoadjuvant systemic therapy approach can influence the need for axillary lymph node dissection depending on pathologic nodal status. This study aimed to evaluate the impact of an upfront surgery versus neoadjuvant systemic therapy approach in women with cT1-2 human epidermal growth factor receptor 2-positive breast cancer on pathologic nodal status and odds of axillary lymph node dissection.

METHODS

This retrospective study used the National Cancer Database and included female patients aged ≥18 years, diagnosed between 2016 and 2021, with cT1-2 N0 M0 human epidermal growth factor receptor 2-positive breast cancer. Demographic, clinicopathologic, and treatment data were collected. Analyses included analysis of variance, Kruskal-Wallis, χ2, Fisher exact tests, and multivariable logistic regression analysis.

RESULTS

A total of 62,927 women met inclusion criteria: 66.6% (n = 39,024) underwent upfront surgery, and 33.4% (n = 19,562) received neoadjuvant systemic therapy. The neoadjuvant systemic therapy cohort was younger (mean age: 53.8 vs 59.9 years, P < .001), had fewer comorbidities (86.9% vs 82.7% with a Charlson-Deyo score of 0, P < .001), and more frequently had cT2 tumors (71.7% vs 21.7%, P < .001). On multivariable analysis, patients with upfront surgery were more likely to be pN+ (1-3 nodes: 14.7% vs 6.8%, odds ratio: 3.19, 95% confidence interval: 2.96-3.45 and ≥4 nodes: 2.0% vs 0.7%, odds ratio: 5.48, 95% confidence interval: 4.43-6.80); however, there was no difference in the odds of axillary lymph node dissection (odds ratio: 0.96, 95% confidence interval: 0.86-1.08).

CONCLUSION

Patients who underwent upfront surgery had a greater likelihood of being pN+; however, there was no difference in the likelihood of axillary lymph node dissection. Therefore, neoadjuvant systemic therapy use should be based on current systemic therapy guidelines and patient-centered shared multidisciplinary decision-making.