Should SLNB Be Routinely Considered for Patients With High-Risk Primary Melanoma?

Thirteen percent of patients with high-risk primary melanoma will experience disease recurrence within 2 years, and routine sentinel lymph node biopsy (SLNB) should be considered in these patients to improve prognostic accuracy, according to authors of a prospective study of 700 Australian patients published in JAMA Dermatology.

Primary tumor occurring in the patient’s head or neck, melanoma-positive SLNB, worse T stage, and rapid tumor growth (mitotic rate greater than 3/mm²) were each associated with elevated recurrence risk, the authors found.

“In this cohort of patients with high-risk primary melanoma treated by wide local excision with or without SLNB, 2-year disease-free survival [DFS] was 95% for T1b tumors and 67% for T4b tumors,” reported lead study author Lena A. von Schuckmann, MBBS, MPH, of the QIMR Berghofer medical Research Institute in Herston, Australia, and colleagues.

“Patients who did not undergo an SLNB had a significantly lower 2-year DFS compared with patients with a melanoma of the same tumor category and a negative SLNB result, suggesting that SLNB should be considered routinely for use in high-risk patients,” they wrote.

Ulceration was associated with decreased survival regardless of tumor thickness, they found. Both ulceration and “many mitoses” are histopathologic features prognostic of recurrence, they reported. The recent removal of mitosis from American Joint Committee on Cancer melanoma staging classification criteria “may have a detrimental effect on assessing some patients’ prognosis,” they noted. “It is likely that future melanoma staging will integrate clinicopathologic, molecular, and other correlates of tumor biologic factors to help streamline treatment and more accurately advise on likely prognosis.”

Most (70.2%) of those patients who suffered recurrence within 2 years had locoregional recurrence and 29.8% had distant metastasis. More than half (57.8%) of patients with locoregional recurrence remained disease free 2 years after surgery, but 31% experienced distant metastasis.

The authors cautioned that they did not have information on the method of recurrence detection and that the study’s 2-year recurrence follow-up time was relatively short.

“As expected, more advanced tumors generally recur more frequently and earlier," commented surgical oncologist Daniel G. Coit, MD, of Memorial Sloan Kettering Cancer Center in New York. “The biggest challenge in interpreting the significance of this study is the heterogeneity of the patient data set, a data set that included 442 patients with clinical T1b to T4b who did not undergo sentinel lymph node biopsy, 213 patients with pathologic T1b to T4b who had a negative SLNB result, and 38 patients with at least stage IIIa after a positive SLNB result.”

In an interview with Cancer Network, Sapna Patel, MD, associate professor at The University of Texas MD Anderson Cancer Center, Houston, noted that “we have long known there are certain sites of the body that lend themselves to higher rates of melanoma recurrence or metastasis. These include the head and neck region and melanoma that originates from mucosal surfaces."

"Some reasons that may explain this higher risk of recurrence specific to the head and neck region include a more complicated lymph node drainage in this area, making sentinel node identification difficult, and inconsistent surgical management of head and neck melanomas between surgical specialties and among different practice types,” Patel said.