Sentinel lymph node biopsy

Editor—Kell and Kerin wrote about sentinel lymph node biopsy in breast cancer and melanoma. This is a staging procedure with a well established role in breast cancer, reducing the need for dissection of the axillary node. The indications and advantages for sentinel lymph node biopsy in melanoma are not confirmed, and it is certainly not the established treatment implied in the editorial. Sentinel node status in melanoma is indeed the best staging and prognostic indicator: patients with negative results have a better prognosis then those with positive results. However, there is no evidence from randomised clinical trials that completion lymphadenectomy (sometimes known as selective lymphadenectomy) in patients with positive sentinel node biopsies offers any survival advantage. Neither is there any adjuvant therapy that can influence the natural history and benefit patients who are sentinel node positive. Concern has recently been raised about the possible increased incidence of local and in-transit recurrence in patients with positive sentinel nodes who undergo completion lymphadenectomy. This iatrogenic complication carries an ominous prognosis and is probably explained by lymphatic obstruction and entrapment of melanoma cells in transit to the regional nodes. The final decision for or against sentinel lymph node biopsy in melanoma must await the result of a multicentre selective lymphadenectomy trial, which will not be published before 2006. Until then, patients deserve to be informed that sentinel lymph node biopsy in melanoma is an investigational procedure with an unknown outcome; the significance of a possibly increased incidence of local or in-transit recurrence should be included when obtaining informed consent. A degree of editorial balance in the literature should be encouraged, rather than the present unbridled enthusiasm for an attractive but unproved concept.