July 10, 2012 — Which patients with newly diagnosed melanoma should undergo sentinel lymph node biopsy (SLNB) and which patients can skip this procedure?
This question is addressed in a new guideline issued jointly by the American Society of Clinical Oncology (ASCO) and the Society of Surgical Oncology (SOS), and published online July 9 in the Journal of Clinical Oncology.
In SLNB, the lymph node situated closest to the site of the melanoma is removed; the presence or absence of cancer cells in this sentinel lymph node determines the course of treatment.
This clinical practice guideline was developed by a multidisciplinary panel of 14 experts who reviewed 73 studies involving more than 25,000 patients.
The panel of experts concluded that routine SLNB can be skipped in the majority of patients who present with the most common form of melanoma.
"When used for the right patients at the right time, sentinel lymph node biopsy is one of our best tools for personalizing melanoma treatment and for sparing patients from unnecessary procedures or therapies," said lead author Sandra Wong, MD, assistant professor of surgery at the University of Michigan in Ann Arbor.
"But we know this procedure is used inconsistently in the United States," she added. "We hope this guideline will provide the clarity physicians need to make the most of the procedure and further improve care for patients with melanoma."
No SLNB for the Most Common Presentations
Melanoma most commonly presents as thin tumors (less than 1 mm in thickness), which can usually be cured by surgically removing the primary tumor, the panel of experts notes. In patients with such tumors, there is insufficient evidence to recommend routine SLNB, they state.
Although SLNB is not necessary in most cases, in certain patients, such as those who present with an ulcerated tumor or who have rapidly diving cancer cells, it should be considered, the experts add.
About one third of melanoma patients present with tumors of intermediate thickness (from 1 to 4 mm). In such cases, a routine SLNB is recommended, the experts state.
In the studies reviewed, SLNB detected cancer in the sentinel node in 18% to 26% of patients with tumors of intermediate thickness, the panel notes.
A less common presentation is thick melanoma tumors (thicker than 4 mm). SLNB is recommended in thicker melanomas because they are more likely to have already spread.
In all cases where the SLNB comes back positive, complete removal of the remaining lymph nodes is recommended. This has been shown to prevent or limit further cancer spread in these patients, the experts explain, but they add that it is not yet known whether this, in turn, improves survival.
An ongoing trial is addressing this issue. The Multicenter Selective Lymphadenectomy Trial II is an international phase 3 trial that is following patients with positive sentinel lymph nodes to see if survival is better with complete lymph node dissection than with observation with nodal ultrasound.
Similar to NCCN Guidelines
The recommendation in the ASCO/SOS guideline to skip SLNB in patients with melanoma less than 1 mm thick that has no adverse features is the same as that in the recently updated guidelines from the National Comprehensive Cancer Network (NCCN).
The NCCN guidelines, which contain many other new recommendations (e.g., on the use of the newly approved drugs for melanoma), have now been published. The updates were discussed earlier this year at the NCCN annual meeting by lead author Daniel Coit, MD, from the Memorial Sloan-Kettering Cancer Center in New York City, as reported by Medscape Medical News.
At the time, Dr. Coit said that SLNB is generally not recommended in early-stage disease because the yield is too low to justify this work-up. "We live in a culture of overtesting," he explained.
"To date, sentinel lymph node biopsy is a staging procedure without any proven benefit on overall survival," he noted. One of the surprises in melanoma is that even when there is a positive lymph node (and thus stage III disease), the overall survival at 5 years is about 80%, which is much higher than is seen in other types of cancer, he said.
J Clin Oncol. Published online July 9, 2012. Abstract
Medscape Medical News © 2012 WebMD, LLC
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