Purpose: 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.
Methods: 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.
Results: 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).
Conclusion: Preoperative chemotherapy seems to impair axillary evaluation by SN biopsy and should be used cautiously in this subset of patients.