Does the result of completion axillary lymph node dissection influence the recommendation for adjuvant treatment in...

The Hungarian National Institute of Oncology has just closed a single-center randomized clinical study. The Optimal Treatment of the Axilla-Surgery or Radiotherapy (OTOASOR) trial compares completion axillary lymph node dissection (cALND) with regional nodal irradiation (RNI) in patients with sentinel lymph node-positive (SLN+) primary invasive breast cancer. In the investigational treatment arm, patients received 50 Gy RNI instead of cALND. In these patients we had information only about the sentinel lymph node (SLN) status, but the further axillary nodal involvement remained unknown. The aim of this study was to investigate whether the result of cALND influenced the recommendation for adjuvant treatment in patients with SLN+ breast cancer.

Patients with SLN+ primary breast cancer were randomized for cALND (arm A, standard treatment) or RNI (arm B, investigational treatment). Adjuvant systemic treatments were given according to the standard institutional protocol, and patients were followed according to the actual institutional guidelines.

Between August 2002 and June 2009, 474 SLN+ patients were randomized to cALND (arm A, standard treatment = 244 patients) or RNI (arm B, investigational treatment = 230 patients). The 2 arms were well balanced according to the majority of main prognostic factors. However, more patients were premenopausal (34% vs. 27%; P = .095) and had pT2-3 tumors (57% vs. 40%; P = .003) in the completion axillary lymph node dissection (ALND) arm. On the other hand, there were more patients with known human epidermal growth factor receptor type 2 positive tumor (12% vs. 17%, P = .066) in the RNI arm. In the ALND and RNI arms, 78% (190/244) and 69% (159/230), respectively, received chemotherapy (P = .020). Endocrine therapy was administered in 87% (213/244) of the patients in the ALND arm and 89% (204/230) of the patients in the RNI arm (P = .372). Six patients (2.5%) on arm A and 13 patients (5.7%) on arm B received adjuvant trastuzumab treatment (P = not significant). Subgroup analyses explored that more frequent administration of adjuvant chemotherapy in arm A was associated with the higher percentage of premenopausal patients and patients with larger (pT2-3) tumors.

The result of cALND after positive SLN biopsy seems to have no major impact on the administration of adjuvant systemic therapy.