Sentinel lymph node biopsy

Editor—Kell and Kerin report on the current status of sentinel lymph node biopsy in the surgical treatment of breast cancer and melanoma.¹ They say that the detection of occult malignancy in lymph nodes in breast cancer signifies a worse prognosis and that the rapid intraoperative detection of malignant cells by immunocytochemistry will vitalise sentinel node biopsy—both assertions may be premature. Although a number of earlier studies have shown a worse prognosis, a more recent study using multivariate analysis has indicated that occult metastases are of no independent prognostic importance.²

The optimum method by which lymph nodes removed in the course of breast cancer surgery should be examined, including the utility of immunocytochemistry, remains to be determined. Touch imprint cytology is a reliable method for the detection of carcinoma cells, but may not reliably discriminate between macrometastases (deposits > 2 mm), micrometastases (deposits < 2 mm), and small numbers of individual tumour cells affecting the peripheral sinus of a lymph node.³ Further studies, preferably with large numbers of patients and adequate follow up, will be required before these techniques enter routine practice.