INVITED SPEAKERS ABSTRACTS
How much more surgery is necessary after identifying a positive lymph node in melanoma?
Over 20 years ago, elective lymph node dissection (ELND) was abandoned for melanoma patients with clinically negative (cN0) regional lymph nodes, based on three facts: (1)<20% of cN0 intermediate-thickness melanoma patients are found to be pN1; (2) an effective ‘salvage’ strategy, therapeutic lymph node dissection (TLND), exists for patients upon nodal relapse; and (3) there is no compelling evidence that elective node dissection improves survival and regional disease control and/or decreases surgical morbidity sufficiently to offset the large number of patients subjected to the procedure without an expectation of benefit. ELND has now been replaced by sentinel lymph node biopsy (SLNB), and we find ourselves in a parallel situation regarding completion lymph node dissection (CLND) for our sentinel node positive patients. Specifically, (1) <20% of patients with a positive sentinel node have histopathologic involvement of non-sentinel nodes; (2) TLND should be effective ‘salvage’ therapy upon nodal relapse; and (3) to date, there has been no compelling evidence that CLND conveys outcome advantages for sentinel node positive patients (in particular, improved survival) of sufficient magnitude to offset the drawback that all sentinel node positive patients are incurring morbidity including some as yet undefined percentage who would never relapse in the remaining regional nodes. Taken to extreme, the same arguments could be used to justify excisional biopsy of clinically positive nodes without TLND – a practice that most melanoma surgeons would condemn.
Areas that still need to be understood about CLND after positive SLNB are: how often is there tumor involvement of non-sentinel nodes that is not detected by routine histopathology; what is the safety and efficacy of ‘salvage’ TLND at the time of nodal relapse; and how much if any of the curative and palliative potential of lymphadenectomy is lost if patients relapse in their regional nodes. Also yet to be defined is what is the proper surveillance strategy (particularly in terms of frequency but also technology) for patients with positive nodes who have not undergone CLND. Data generated from MSLT-1 and -2 will be highly informative, but because of patient selection not uniformly generalizable to all clinical situations. Furthermore, experience has shown that patients and even physicians don’t always see eye-to-eye when interpreting the results of randomized trials. Conversely, patients are motivated to avoid toxicity (especially lymphedema) without sacrificing disease control. Unfortunately, our own experience and an emerging body of clinical data suggests that nodal failure is common after positive SLNB without CLND, yet the morbidity of CLND is less than that for TLND – especially if extensive recurrent disease mandates postoperative radiation to the nodal basin. For the time being, we continue to urge patients not to forego completion node dissection outside the setting of a prospective clinical trial, and meanwhile we urge all melanoma surgeons to continue to pursue strategies to minimize the morbidity of completion lymphadenectomy.© 2010 Lippincott Williams & Wilkins, Inc.