Primary Chemotherapy Effect in Sentinel Node Detection in Breast Cancer

Sentinel node (SN) biopsy is a reliable method for improved staging of breast cancer, offering an alternative to routine axillary dissection. Perhaps preoperative chemotherapy could increase the rate of false-negative SN because of induced lymphatic changes. The aim of the study was to evaluate the utility of lymphoscintigraphy and of hand-held probe detection in the SN approach after chemotherapy, correlating it with histologic analysis of the axilla.Eighty-three patients (mean age, 53 years; TNM stage I) were studied prospectively. They were separated into two groups: group 1 (G1), 37 patients with preoperative chemotherapy and group 2 (G2), 46 patients without chemotherapy. Mean tumor size was 2 cm in both groups. Lymphoscintigraphy was performed 3 to 4 hours after peritumoral injection of Tc-99m dextran-70 in a 0.2-ml volume and activity of 14.8 MBq (0.4 mCi), performed under ultrasound or mammographic control. On the following day, each patient underwent tumor resection with axillary dissection, included the SN.The SN was detected by scintigraphy in 78 patients (94%). The failure of SN to predict the axillary histologic status was significantly higher (P = 0.01) in G1 than in G2 (7 and 1 false-negative result, respectively).Preoperative chemotherapy seems to impair axillary evaluation by SN biopsy and should be used cautiously in this subset of patients.