Is it Necessary to Perform Sentinel Lymph Node Biopsy in Thin Melanoma? A Retrospective Single Center Analysis

Abstract

Sentinel lymph node biopsy (SLNB) is a standard procedure for regional lymph node staging and still has the most important prognostic value for the outcome of patients with thin melanoma. In addition to ulceration, SLNB had to be considered even for a single mitotic figure in thin (<1 mm) melanoma according to AJCC7th guideline, therefore, a retrospective review was conducted involving 403 pT1 melanoma patients. Among them, 152 patients suffered from pT1b ulcerated or mitotic rate ≥ 1/ mm 2 melanomas according to the AJCC7th staging system. SLNB was performed in 78 cases, of which nine (11.5%) showed SLN positivity. From them, interestingly, we found a relatively high positive sentinel rate (6/78-8%) in the case of thin primary melanomas ˂0.8 mm. Moreover, the presence of regression increased the probability of sentinel positivity by 5.796 fold. After reassessing pT stage based on the new AJCC8 th , 37 pT1b cases were reordered into pT1a category. There was no significant relation between other characteristics examined (age, gender, Breslow, Clark level, and mitosis index) and sentinel node positivity. Based on our data, we suggest that mitotic rate alone is not a sufficiently powerful predictor of SLN status in thin melanomas. If strict histopathological definition criteria are applied, regression might be an additional adverse feature that aids in identifying T1 patients most likely to be SLN-positive. After reassessing of pT1b cases according to AJCC8 th regression proved to be independent prognostic factor on sentinel lymph node positivity. Our results propose that sentinel lymph node biopsy might also be considered at patients with regressive thin (˂0.8 mm) melanomas.

Predictive Factors for Metastasis of Skin Melanoma of Varying Thickness According to Breslow to Sentinel Lymph Nodes

“…5. The thickness of the primary tumor according to Breslow in the study groups (box boundaries represent the 25th and 75th percentiles, the cross is the mean, the line is the median, the points outside are the outliers, the whiskers are the minimum and maximum without taking into account the outliers) [28]. В соответствии с данными Balch et al, пациенты мужского пола были немного старше, чем пациенты женского пола (49,5 против 47,7 лет) [29].…”

“…Согласно двум последним схемам стадирования и классификации меланомы AJCC, тонкие меланомы продолжают классифицироваться как T 1b по наличию изъязвлений [28,29,33]. Однако в большинстве исследований не показано, что изъязвление является значимым предиктором метастатического поражения [5,28,30,31], то же самое сообщается и в отношении митотической активности [11,14,32,33], поэтому мы не стали включать эти факторы в наше исследование.…”

Integrating 31-Gene Expression Profiling With Clinicopathologic Features to Optimize Cutaneous Melanoma Sentinel Lymph Node Metastasis Prediction

“…3 The probability of a positive SLN rises with increasing tumor depth and other high-risk primary tumor features, such as ulceration, high mitotic rate (MR), lymphovascular invasion (LVI), uncertain microstaging, and younger age. 1,[4][5][6][7][8][9][10] However, the tenuous association of many of these features with melanoma metastasis contributes to interstudy variability of SLN positivity rates, particularly in tumors ≤ 1.0 mm in thickness (T1). [4][5][6][7][8] The subjectivity associated with identifying and measuring melanoma-associated clinicopathologic (CP) features may contribute to controversy among physicians regarding which CP features and thresholds should be used to inform decisions about SLNB, 11,12 evidenced by the wide variability in reported SLN positivity rates.…”

“…1,[4][5][6][7][8][9][10] However, the tenuous association of many of these features with melanoma metastasis contributes to interstudy variability of SLN positivity rates, particularly in tumors ≤ 1.0 mm in thickness (T1). [4][5][6][7][8] The subjectivity associated with identifying and measuring melanoma-associated clinicopathologic (CP) features may contribute to controversy among physicians regarding which CP features and thresholds should be used to inform decisions about SLNB, 11,12 evidenced by the wide variability in reported SLN positivity rates. [5][6][7][8][13][14][15][16][17][18] Because of the high cost and increased complication rate of SLNB (10%-16%), better identification of patients likely to have a positive SLN may be possible by integrating molecular profiling with CP features.…”

“…[4][5][6][7][8] The subjectivity associated with identifying and measuring melanoma-associated clinicopathologic (CP) features may contribute to controversy among physicians regarding which CP features and thresholds should be used to inform decisions about SLNB, 11,12 evidenced by the wide variability in reported SLN positivity rates. [5][6][7][8][13][14][15][16][17][18] Because of the high cost and increased complication rate of SLNB (10%-16%), better identification of patients likely to have a positive SLN may be possible by integrating molecular profiling with CP features. 19,20 Currently, a 31-gene expression profile (31-GEP) test for prognosis of melanoma recurrence risk has been developed that yields a continuous probability score between zero and one that stratifies risk of disease recurrence and is binned into one of four categories: lowest (Class 1A; 0-0.41), low (Class 1B; 0.42-0.49), increased (Class 2A; 0.50-0.58), and highest (Class 2B; 0.59-1).…”