How important is the axillary nodal status for adjuvant treatment decisions at a breast cancer multidisciplinary tumor board? A survival analysis

Background: Tumor board recommendations for breast cancer are mainly based on patient characteristics and prognostic tumor parameters. In the era of potential avoidance of axillary surgery we evaluate the impact of pathologic nodal status for adjuvant treatment decisions. Methods: Postoperative tumor board records of 207 patients over a 1-year period were rediscussed without knowledge of pathologic nodal status. Differences were classified as major (chemotherapy and/or radiotherapy: present/absent) or minor (different chemotherapeutic protocols) discrepancies. The survival rates among subgroups were calculated using Adjuvant! Online tool. Results: The tumor board without information of pathologic nodal status resulted in treatment changes in 72 of the 207 patients studied (34.8%). Major discrepancies were observed in 37 patients (17.9%). The survival rates were not significantly different due to a balanced overtreatment and undertreatment in this subgroup. Lymphovascular invasion (LVI) was an independent parameter used to predict the subgroup with major discrepancies (P = .001; RR = 4.9 [95% CI, 1.9-12.7]). Conclusions: The knowledge of pathologic nodal status is important for postoperative chemotherapy and postmastectomy radiotherapy indications. There is a risk for one-third of all patients when avoiding axillary surgery to get an adjuvant therapy that differs from the current guidelines especially in carcinomas with present LVI.