Importance of Sentinel Lymph Node Biopsy in Patients With Thin Melanoma

Abstract

The status of the sentinel node (SN) confers important prognostic information for patients with thin melanoma.Design, Setting, and Patients: We queried our melanoma database to identify patients undergoing sentinel lymph node biopsy for thin (Յ1.00-mm) cutaneous melanoma at a tertiary care cancer institute. Slides of tumor-positive SNs were reviewed by a melanoma pathologist to confirm nodal status and intranodal tumor burden, defined as isolated tumor cells, micrometastasis, or macrometastasis (Յ0.20, 0.21-2.00, or Ͼ2.00 mm, respectively). Nodal status was correlated with patient age and primary tumor depth (Յ0.25, 0.26-0.50, 0.51-0.75, or 0.76-1.00 mm). Survival was determined by log-rank test.Main Outcome Measures: Disease-free and melanomaspecific survival.Results: Of 1592 patients who underwent sentinel lymph node biopsy from 1991 to 2004, 631 (40%) had thin melanomas; 31 of the 631 patients (5%) had a tumor-positive SN. At a median follow-up of 57 months for the 631 patients, the mean (SD) 10-year rate of disease-free survival was 96% (1%) vs 54% (10%) for patients with tumornegative vs tumor-positive SNs, respectively (PϽ.001); the mean (SD) 10-year rate of melanoma-specific survival was 98% (1%) vs 83% (8%), respectively (PϽ.001). Tumorpositive SNs were more common in patients aged 50 years and younger (P=.04). The SN status maintained importance on multivariate analysis for both disease-free survival (PϽ.001) and melanoma-specific survival (PϽ.001). Conclusions:The status of the SN is significantly linked to survival in patients with thin melanoma. Therefore, sentinel lymph node biopsy should be considered to obtain complete prognostic information.

Chinese Guidelines on the Diagnosis and Treatment of Melanoma (2015 Edition)

“…However, the SN-positive rate increased in melanoma patients with small thickness but with at least one risk factor (ulceration Clark level IV, nodular growth, high MR, recurrence, or aged ≤40 years) (62). In melanoma patients with tumor thickness of ≤1 mm, the relationship between positive SLNs and survival is still disputed (63)(64)(65)(66)(67).…”

“…In addition to tumor thickness, other factors such as Clark level (61,63,64,66), MR (64,68), ulceration (61,69), lymphatic vessel invasion (66), VGP (70,71), and TIL (72)(73)(74) can also be used to predict the positive SLNs in patients with thin melanoma. However, some data remain controversial, and whether they can be used for predicting tumor recurrence requires further verification (75)(76)(77).…”

Current Controversies in the Surgical Management of Melanoma

“…However, a recent study has shown rates of further positive findings to be as low as 14.8% (Kunte et al, 2011). Ideally, patients at high risk of non-sentinel nodal metastases could be identified and treated by regional lymph node dissection, and patients with a low risk of non-sentinel nodal metastases could be spared from further intervention (Wright et al, 2008). Recently, researchers have sought to identify factors, which increase a patient's likelihood of nonsentinel node metastases.…”

Melanoma

“…However, with relatively short follow-up, only 1 center has shown any convincing evidence that the SLN status was predictive of outcome in this low-risk group of patients. 52 Larger series and longer-term follow-up are required to assess the prognostic value of SLN in patients with thin melanoma. [53][54][55] The probability of a positive sentinel node in patients with thick melanoma (≥ 4 mm) is 30% to 40%.…”