Gamma probe sentinel node localization and biopsy in breast cancer patients treated with a neoadjuvant chemotherapy scheme

The aim of this study was to analyse the accuracy of scintigraphic and gamm a probe sentinel node (SN) localization in breast cancer patients who have been submitted to neoadjuvant chemotherapy (NC). Seventy-six patients with single breast cancer were included in the study, and were classified into t wo groups. Group 1 consisted of 40 women who had received NC, and Group 2 c onsisted of 36 women who did not receive NC. All patients received 111 MBq (3 mCi) of Tc-99(m)-nanocolloid in 3 ml, by peritumoural injection. Anterio r and lateral thoracic scans were obtained 2 h post-injection. The followin g day (18-24 h post-injection) the patients underwent surgery and sentinel nodes were localized by using a gamma probe. Complete axillary lymph node d issection was performed in all patients. Histological analysis included hae matoxylin-eosin in all cases and immunohistochemistry in 10 cases. In Group 1, SNs were localized in 36/40 patients, histological analysis was perform ed in 34 and there were four false negatives (22%). In Group 2, SNs were lo calized in 32/36 patients, histological analysis was performed in 29 and th ere were two false negatives (9%). Predictive negative values were 78% and 90% in Groups 1 and 2, respectively. In summary, sentinel node localization in breast cancer patients submitted to previous neoadjuvant chemotherapy i s less accurate than in patients who do not receive this therapy. The proce dure is not sufficiently accurate to localize the sentinel node, thus it ca nnot be recommended in these patients. ((C) 2001 Lippincott Williams & Wilk ins).