The American Society of Clinical Oncology (ASCO) and the Society for Surgical Oncology (SSO) earlier today jointly issued their first evidence-based clinical practice guideline on the use of sentinel lymph node biopsy or SLNB to stage patients with newly diagnosed melanoma. Although SLNB has proven to be an important tool for determining prognosis and selecting treatment for many patients with melanoma, recent studies suggest that the procedure is inconsistently used.

The new guideline recommendations, based on a review of all available evidence, are intended to clarify which patients should receive the procedure.

Minimally invasive surgical technique
Sentinel lymph node biopsy is a minimally invasive surgical technique that enables doctors to determine whether cancer has spread, a key factor in determining the appropriate surgical and drug treatments, and establishing a patient’s eligibility for clinical trials. In the procedure, the “sentinel” lymph node – the node close to the tumor, to which cancer cells are most likely to spread – is removed and examined under a microscope for evidence of cancer. If cancer is found, additional surrounding lymph nodes are removed to accurately assess, or “stage,” the disease and prevent further cancer spread. In most cases, however, no cancer is detected in the sentinel node and no additional lymph nodes need to be removed, allowing patients to avoid further pain, discomfort, expense, and possible side effects from a more extensive operation.

Personalizing melanoma treatment
"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," explained Sandra L. Wong, MD, lead author and Co-chair of the guideline panel and Assistant Professor of Surgery at the University of Michigan. "But we know this procedure is used inconsistently in the United States. 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."

Multidisciplinary review
 The new clinical practice guideline was developed by a multidisciplinary panel of 14 clinical and methodological experts convened by ASCO and SSO. The panel reviewed literature published between January 1990 and August 2011, analyzing 73 studies that included more than 25,000 patients.

The new guideline recommendations include:

• Sentinel lymph node biopsy (SLNB) is recommended for all patients with melanoma tumors of intermediate thickness (between 1 and 4 mm): Studies have shown that the technique is useful for identifying small nearby metastases in these patients, who account for about one-third of all melanoma cases. SLNB detects cancer in the sentinel node in about 18 to 26 percent of these patients, according to the guideline authors.
• Evidence is insufficient to recommend routine SLNB for patients with thin melanoma tumors (less than 1 mm): Thin melanomas are the most common form of melanoma, and can usually be cured through surgical removal of the primary tumor. While SNLB is not necessary in most cases, the guideline recommendations note that it may be considered in select patients with thin melanomas who have certain high-risk factors, such as an ulcerated tumor or rapidly dividing cancer cells.
• SLNB for patients with thick melanoma tumors (greater than 4 mm) may be recommended: Thick melanomas are more uncommon than the above two types, but are considered more likely to spread elsewhere in the body. While there are few studies focusing on the use of SLNB in patients with thick melanomas, use of SLN biopsy in this population may be recommended for staging purposes and to facilitate regional disease control.
• Completion lymph node dissection is recommended for all patients with a positive SLNB: Complete removal of the remaining lymph nodes has been shown to prevent or limit further cancer spread in these patients. While it is not yet known whether this approach improves survival, the authors note that an ongoing study, the Multicenter Selective Lymphadenectomy Trial II, is expected to help resolve that question.

The guideline concludes that doctors should discuss SLNB as part of a comprehensive treatment planning process with their patients with melanoma. This discussion should address the risks and benefits of the procedure, and patients’ individual values and preferences, so patients can make fully informed decisions.

“Our rapidly growing understanding of the biology of melanoma is driving development of more effective treatments with fewer side effects for patients,” said Gary H. Lyman, MD, MPH, guideline Co-chair and Professor of Medicine and Director of Comparative Effectiveness and Outcomes Research at Duke University School of Medicine and the Duke Cancer Institute. “But to take advantage of this progress, we need to know the true extent of the disease from the start. This guideline will help ensure that sentinel lymph node biopsy is used appropriately whenever it can provide that vital information while avoiding unnecessary procedures in patients who are unlikely to benefit.”

Reference:
Wong SL, Balch CM, Hurley P, Agarwala SS, Akhurst TJ, Cochran A, et al.Sentinel lymph node biopsy for melanoma: american society of clinical oncology and society of surgical oncology joint clinical practice guideline. J Clin Oncol. 2012 Aug 10;30(23):2912-8. Epub 2012 Jul 9. [Full Guideline PDF]

For more information (for patients):

• What to Know: ASCO/SSO Guideline on Use of Sentinel Lymph Node Biopsy for Melanoma Staging.
• National Cancer Institute Factsheet: What is Sentinel Lymph Node Biopsy?

Illustration courtesy of the American Society of Clinical Oncology

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