SLNB: Wider application than melanoma

September 1, 2005

New Orleans — The role of the sentinel lymph node biopsy in the management of cutaneous melanoma will be better defined when the results of large clinical trials are released, says Pearon Lang Jr., M.D., professor of dermatology, pathology, otolaryngology and communicative sciences at the Medical University of South Carolina in Charleston.

New Orleans - The role of the sentinel lymph node biopsy in the management of cutaneous melanoma will be better defined when the results of large clinical trials are released, says Pearon Lang Jr., M.D., professor of dermatology, pathology, otolaryngology and communicative sciences at the Medical University of South Carolina in Charleston.

"There is growing data out there that suggests that the sentinel lymph node biopsy has a wider application than just melanoma," Dr. Lang says, "We know that it's a great staging procedure, but its role in terms of prognosis is less clear. We will see how these large, multi-institutional studies play out."

Lymph node dissection

"If it turns out that sentinel lymph node biopsy does not affect prognosis, it may be that fewer will be done, at least until we have more effective adjuvant therapy," Dr. Lang tells Dermatology Times.

The National Comprehensive Cancer Network met in March 2004 to revise clinical practice guidelines on lymph node dissection in malignant melanoma. The expert panel concluded that sentinel node status was the most important predictor of outcome and worked very well as a staging policy.

Other neoplasms in which sentinel lymph node biopsy may have a role include sebaceous gland carcinoma sweat gland carcinoma, and squamous cell carcinoma, according to Dr. Lang.

"There aren't any hard and fast rules about the use of the sentinel lymph node biopsy in any of these neoplasms," Dr. Lang says. "We don't have, as yet, large studies in patients with high-risk squamous cell carcinoma, which examine a number of controlled variables that could affect outcome, and thus guide us in terms of selecting a patient for sentinel lymph node biopsy. Moreover, squamous cell carcinoma does not behave as predictably as does melanoma, which makes the selection of patients more difficult."

The incidence of occult metastases in squamous cell carcinoma of the head and neck in one study was 24 percent, Dr. Lang reports. He added that most metastases occur within two years and usually to regional nodes.

Prognostic factors

The prognostic factors associated with metastatic squamous cell carcinoma include acantholysis, single-cell infiltration, recurrence, previous radiation therapy and the size of the lesion and, most importantly, the depth of penetration.

One study published in Dermatologic Surgery in 2003 found preoperative lymphoscintigraphy and sentinel lymphadenectomy were well tolerated in patients. Five of nine patients had negative sentinel nodes and were well at a median follow-up of eight months. Two of the four who had positive sentinel nodes died of metastatic disease within two years.

"There are limited data on the role of the sentinel lymph node biopsy in managing squamous cell cancer of the skin and lip," Dr. Lang says.

Merkel cell carcinoma

Dr. Lang notes that after melanoma, the next most common experience for the role of the sentinel lymph node biopsy for other cutaneous neoplasms is with Merkel cell carcinoma.

"More and more oncologists who have a patient with a Merkel cell carcinoma are using sentinel lymph node biopsy as a way of managing patients," Dr. Lang says.

Some of the side effects from performing a sentinel lymph node biopsy include transient lymphedema and reactions to the blue dye that is used in the procedure. Other concerns include the possible development of hematomas and numbness following surgery due to nerve injury.

"For the most part, the side effects are transient and minor and pose no risk in terms of permanent sequelae," Dr. Lang concludes.