SHORT REPORT Sentinel lymph node biopsy in impalpable breast cancer S. A. McIntosh, 1 D. Ravichandran, 1 K. K. Balan, 2 L. Bobrow, 3 G. C. Wishart 1 and A. D. Purushotham 1 Departments of 1 Surgery, 2 Nuclear Medicine and 3 Pathology, Addenbrooke’s Hospital, Cambridge, UK SUMMARY. Sentinel lymph node biopsy has been investigated using combined radioactive colloid and supra vital blue dye in 27 patients with impalpable breast cancers. Sentinel nodes were identified in 25 cases (93%). Seven patients had involved nodes of whom all had a positive sentinel node. Sentinel node biopsy is ideally suited for use in impalpable breast cancers. # 2000 Harcourt Publishers Ltd INTRODUCTION Axillary lymph node status remains the most important prognostic feature in breast cancer patients. 1 Tradition- ally, the ‘gold standard’ method for obtaining this information has been by axillary clearance. This procedure carries an associated morbidity. 2 The techni- que of sentinel lymph node (SLN) biopsy has been proposed as a method of staging the axilla whilst avoiding the morbidity of axillary clearance. 3 This technique would appear to be of particular value in patients at low risk of nodal metastasis. It would therefore seem logical that it be applied to patients with screen-detected impalpable tumours. There is little published literature specifically addressing the role of SLN biopsy in impalpable lesions. This study describes a series of patients with impalpable lesions who under- went SLN biopsy using a combination of vital blue dye and radiocolloid for lymphatic mapping. PATIENTS AND METHODS Between October 1998 and October 1999, patients with an impalpable breast lesion histologically proven to be invasive carcinoma, were considered eligible for entry into this study (part of a larger study evaluating a combined technique of SLN biopsy in tumours less than 30 mm in diameter). After obtaining written informed consent, a dose of 40 MBq of technetium 99 m labelled nanocolloid (Nanocoll, Sorin Biomedica, Vercelli, Italy) was injected peritumourally down the localization needle. Where practical, a preoperative lymphoscinti- gram was taken 2 h following isotope injection. The operating surgeon was blinded to the scintigram results. After induction of anaesthesia, 2 ml of 2.5% patent blue-V dye (Laboratoire Guerbet, Aulney-Sous-Bois, France) diluted to 5 ml in 0.9% NaCl was injected around the tip of the localization wire. This was followed by massage of the breast for 5 min. A standard axillary incision was then made as for routine axillary clearance. The SLN was then identified, using the hand- held gamma detection probe (C-Trak, Care-Wise Medical Products, Morgan Hill, California), in combi- nation with direct visualization of blue-stained lympha- tic channels and nodes. All blue-stained nodes were removed from the axilla, as were all radiolabelled or ‘hot’ nodes. After excision of the SLNs, the axilla was re-examined with the gamma probe to ensure that there was no residual activity remaining. The primary tumour was then excised widely and a standard level 2 axillary clearance performed. All retrieved lymph nodes were examined by routine haemotoxylin and eosin staining. RESULTS A total of 27 patients with impalpable breast tumours underwent SLN biopsy using the above technique. The SLN was detected in 25 cases (93%), and the false negative rate was 0%. In 71% of cases where the axilla contained metastatic disease, the SLN was the only Address correspondence to: A. D. Purushotham, Cambridge Breast Unit, Box 201, Addenbrooke’s Hospital, Hills Road, Cambridge CB2 2QQ, UK. Tel.: þ 44 (0) 1223 586627; Fax: þ 44 (0) 1223 586932 The Breast (2001) 10, 82–83 # 2000 Harcourt Publishers Ltd doi:10.1054/brst.2000.0200, available online at http://www.idealibrary.com on 82