Considerations for surgery in melanoma

I am Dr. Jeffrey Weber, Deputy Director of the Laura Cancer Center and Isaac Perlmutter, and Professor of Medicine at NYU Langone Medical Center in New York. Dr. Robert Andtbacka, Professor in the Department of Surgery of the University of Utah School of Medicine and a researcher at the Huntsman Cancer Institute in Salt Lake City, Utah, participates today. to our distinguished panel. Dr. Omid Hamid, Head of Research and Immuno-Oncology at the Angeles Clinic and Research Institute and co-director of the Cutaneous Malignancy Program at Cedars-Sinai Medical Center in Los Angeles, California; Dr. Jason Luke, Assistant Professor of Medicine and Medical Oncologist at the University of Chicago in Chicago, Illinois; Dr. Michael Postow, Assistant Physician, Department of Oncology, Melanoma and Immunotherapies, Memorial Sloan Kettering Cancer Center, New York; and Dr. Hussein Tawbi, Associate Professor and Director of Clinical Research and Early Drug Development at the Department of Medical Melanoma in Oncology and a member of the Cancer Oncology Research Department at the UT MD Anderson Cancer Center in Houston, Texas. Thank you all for joining us. Let's start

There has been a tremendous amount of action and research and development in the field of adjuvant melanoma treatment over the last year, with three very impressive trials and multiple new approvals. This raises a lot of problems. One of the first problems we think about is: who is operated on and who does not work? So, who receives adjuvant therapy? Robert, how do you decide? What are the criteria for resecting a patient with stage 3 or 4 melanoma? Who is resectable and who is not?

Robert Andtbacka, MD, CM: This is a very good question, Jeff, and it's something we deal with daily with our patients. In stage 3, we really need to divide patients into those who have microscopic disease in their lymph nodes compared to patients with large disease and macroscopic disease. First of all, if we look at patients with microscopic disease a year ago, we would have recommended that almost all patients – if they had microscopic disease in a ganglionic pelvis – get a complete dissection of the lymph nodes.

There are two important studies that have produced results asking the question: do we really need to do that? In these studies, patients were randomized to have complete lymph node dissection, which would have been the standard of care, or ultrasound follow-up, if they had a disease in the lymph node pool. Both of these studies focused on survival in these patients, and there were slightly different types of survival. The MSLT-II study, which was the largest study, examined specific survival for melanoma. There was really no difference in patients who had partial dissection of sentinel lymph nodes, who underwent lymph node dissection completion, versus ultrasonographic follow-up of melanoma-specific survival in this patient population.

We must remember that the only patients who actually benefit from a surgical procedure – as a result of additional surgery, if they have a positive sentinel lymph node – are patients with an additional disease in their ganglionic pelvis. They represent about 25% of all patients. This means that 75% of patients will not have benefited from this operation at all. The second study was a German study. This was a slightly smaller study, also looking at survival without distant metastases for these patients. The study examined a similar patient population. Again, there was no difference in survival for these patients. One of the caveats with these two studies was that the amount of tumor in the sentinel lymph node was quite low. When we think of these patients, we must remember that most patients had just one positive sentinel lymph node. When we completed a lymph node dissection, we did not necessarily find additional lymph nodes with melanoma. The burden of the tumor in these sentinel lymph nodes was also very low.

In my practice, in these patients, following these patients with an ultrasound is a very viable option. I would say that more than half of the patients just want to follow with an ultrasound.

Jeffrey S. Weber, MD, Ph.D .: How often do you do it?

Robert Andtbacka, MD, CM: In my practice, we probably do it about 20%, 30% of the time, when we do dissection of the lymph nodes completion. This tends to be for patients who have a large amount of disease in the lymph node pool and also for patients with multiple lymph nodes with melanoma. I still think it remains … controversial. We know that in these patients, after completing the dissection of the lymph nodes, they are at high risk of local recurrence but also of distant recurrence. These are patients with whom we will always discuss adjuvant therapy. In the adjuvant studies that were done, all patients who went into adjuvant studies had to have a lymph node dissection completion. I think one of the controversies is that we do not fully know what the benefit of adjuvant therapy is, if the patient has not had a complete dissection of the lymph nodes. That said, I still think the minority of our patients now get a complete dissection of the lymph nodes

Jeffrey S. Weber, MD, Ph.D .: And, interestingly, I do not think so that it's going to be an adjuvant study in patients in this category, because we have a number of positive studies that we'll talk about in a few minutes. I do not think that will ever happen. So, as often happens in medicine, we use the best data we have, and we're going to extrapolate.

Transcription edited for clarity