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Interim DeCOG results provide reassurance for patients who delay CLND after positive sentinel node
The majority of patients with stage III melanoma present with a positive sentinel lymph node in a clinically negative regional basin.
Because nodal disease is being diagnosed earlier, surgical treatment of the lymph node basin by completion lymph node dissection (CLND) is able to be done earlier. This often results in fewer side effects of surgery than when it is done for larger-sized nodal metastases.
On the other hand, if the nodal disease has been diagnosed early enough, it may be the case that only the sentinel node — already removed in the initial sentinel node biopsy procedure — has melanoma in it, meaning that CLND likely is unnecessary in a percentage of patients who already are cured by sentinel node biopsy.
Finally, some patients eventually will die of distant metastatic tumors that already have been seeded before the CLND can take place, meaning that the more radical surgery could not impact their survival.
DeCOG results
We do not know which patients already are cured by their sentinel node biopsy procedure, which ones are destined to die no matter what surgery is done, and which ones might be saved from recurring and dying — or at least from extra surgical side effects — by early use of lymph node dissection.
Randomized trials — such as the randomized, phase 3 DeCOG trial and the much larger phase 3 Multicenter Sentinel Lymphadenectomy Trial II (MSLT-II) — will help answer these important questions over the next few years.
In the DeCOG trial, Leiter and colleagues assessed whether surgical removal of the lymph nodes after a positive sentinel lymph node biopsy extended survival for patients with melanoma.
At ASCO, the researchers presented preliminary results based on approximately 3 years of follow-up. At this interim time point, no differences in survival had been detected between patients who underwent CLND after positive sentinel node biopsy and those who did not.
As expected, more nodal recurrences within the sentinel node-positive basin occurred in patients who did not undergo the completion dissection.
These results are not unexpected, and they should not change current practice regarding the management of the sentinel node-positive nodal basin. Improving survival is just one reason why a CLND should be done for a patient who has a positive sentinel node biopsy, and it is not necessarily the main reason.
Regional control of disease is an important goal, and we know that completion node dissection does this well and with lower morbidity than is seen with node dissection after development of recurrent disease.
Obviously, if we could tell all patients with a positive sentinel node that CLND would improve their chances of cure by 5% or even 10%, they surely would want to have the surgery. For stage III melanoma, however, 3 years of follow-up is not long enough to assess the long-term impact of lymph node surgery.
For now, this information provides a degree of reassurance to patients who went onto randomized trials like DeCOG and MSLT-II that delaying lymph node surgery after a positive sentinel node is not harmful in the short run. This information also will provide some data for patients who face the decision of what type of surgery — if any — to have after a sentinel node biopsy has demonstrated that they have stage III melanoma.
CLND still has a role
It is worth emphasizing that there are patients who still should undergo CLND after a positive sentinel node biopsy procedure.
Patients and physicians should take note of the fact that more than 1,250 patients were evaluated for the DeCOG study, yet fewer than 500 actually took part, and half of them had the completion lymph node surgery. It is likely that many of those patients who refused to go into the study had a lymph node dissection, and many of them are glad they did.
In our center, we still strongly recommend CLND to those patients we believe are at highest risk for having additional positive nodes in their nodal basin — especially patients whose melanoma was thicker than 2 mm and ulcerated or had a high mitotic rate, and patients who had multiple positive sentinel nodes or a large tumor and/or extracapsular tumor extension detected in one sentinel node. We also try to judge whether patients may not have had full removal of all sentinel nodes initially, meaning that CLND is even more likely necessary.
Finally, it should be emphasized that any patient with a positive sentinel node who does not have a CLND needs close and careful follow-up, which initially means visits to the surgeon at least 3 times a year. For us, this includes ultrasound of all nodal basins that had a positive sentinel node.
European centers — such as those participating in the DeCOG trial — have a long history of using ultrasound to check lymph nodes, and many of them do it quite well. But in the United States, lymph node ultrasound is not used nearly as frequently, so it is important that we increase our awareness of the importance of nodal ultrasound in melanoma and train more people to do the procedure well.
When my patients grapple with the decision about CLND after a positive sentinel node biopsy, I always remind them about one thing: We have many patients on the MSLT-II trial who were randomly assigned to have CLND, and many others who decided to have the surgery out of an abundance of caution. Most of these patients have done very well and experienced minimal or no long-term side effects of their surgery.
Every patient with a positive sentinel node biopsy should have a conversation with their surgeon about the pros and cons of CLND, and every patient who decides not to have the surgery should be fully committed to a program of careful follow-up lasting many years — at least a decade — and to returning to their surgeon promptly if they feel an enlarged lymph node.
Finally, it is critical to emphasize that nothing about the DeCOG study — or the MSLT-II trial, results of which we are still waiting for — changes the standard recommendation for patients with macroscopic stage III melanoma. All of those patients should have a radical lymph node dissection; they should not have observation of their nodal basin. That is a completely different clinical situation in which the benefits of surgery far outweigh the risks.
Many patients with macroscopic stage III melanoma also will be good candidates for adjuvant therapy clinical trials with promising new anti-melanoma drugs, and we believe that kind of treatment has a real chance to increase survival. Right now, those clinical trials require patients to have a CLND as a condition of eligibility, although it is possible that could be modified in the future for carefully selected patients who agree to be followed closely.
Reference:
Leiter U, et al. Abstract LBA9002. Presented at: ASCO Annual Meeting; May 29-June 2, 2015; Chicago.
For more information:
Vernon K. Sondak, MD, is chair of the department of cutaneous oncology and director of surgical education at Moffitt Cancer Center, and professor of surgery in the departments of oncologic sciences and surgery at USF Health Morsani College of Medicine. He also is a HemOnc Today Editorial Board member. He can be reached at Department of Cutaneous Oncology, Moffitt Cancer Center, 12902 Magnolia Drive, Tampa, FL 33612; email: vernon.sondak@moffitt.org.
Disclosure: Sondak reports consultant/advisory roles with Bristol-Myers Squibb, Merck, Navidea and Novartis.