More sentinel lymph node biopsies for thin melanomas after transition to AJCC 8th edition do not increase positivity rate: A Danish population‐based study of 7148 patients

Abstract

Background We evaluated the outcome of sentinel lymph node biopsies (SLNB) in patients with thin melanoma before and after the implementation of AJCC 8th edition (AJCC8) and identified predictors of positive sentinel lymph nodes (+SLN). Methods Patients diagnosed with T1 melanomas (Breslow thickness ≤1 mm) during 2016–2017 as per AJCC 7th edition (AJCC7) (n = 3414) and 2018–2019 as per AJCC8 (n = 3734) were identified in the Danish Melanoma Database. Results More SLNBs were performed in the AJCC8 cohort compared to the AJCC7 (22.2% vs. 16.2%, p < 0.001), with no significant difference in +SLN rates (4.7% vs. 6.7%, p = 0.118). In the AJCC7 + SLN subgroup, no melanomas were ulcerated, 94.6% had mitotic rate (MR) ≥ 1, 67.6% were ≥0.8 mm and 32.4% would be T1a according to AJCC8. In the AJCC8 + SLN subgroup, 10.3% were ulcerated, 74.4% had MR≥ 1, 97.4% were ≥0.8 mm and 23.1% would be T1a according to AJCC7. On multivariable analysis younger age and MR ≥ 1 were significant predictors of +SLN. Conclusion More SLNBs were performed in T1 melanomas after transition to AJCC8 without an increase in +SLN rate. None of the AJCC8 T1b criteria were significant predictors of +SLN. We suggest that mitosis and younger age should be considered as indications for SLNB in thin melanoma.

Melanoma surgery—An update

“…The implementation of American Joint Committee on Cancer version 8 (AJCC8) criteria for melanoma increased the number of patients with thin melanomas (Breslow thickness ≤1 mm) undergoing SNLB versus AJCC7. However, this did not result in an increased rate of SNL‐positive results 22,23 . A retrospective study on SNLB in T1b melanomas ( n = 203) from Italy registered positive SNL in 2.3% of melanomas 0.8 < 1.0 mm, and in 0% of melanomas <0.8 mm with ulceration.…”

“…However, this did not result in an increased rate of SNL-positive results. 22,23 A retrospective study on SNLB in T1b melanomas (n = 203) from Italy registered positive SNL in 2.3% of melanomas 0.8 < 1.0 mm, and in 0% of melanomas <0.8 mm with ulceration.…”

Cost evaluation of the Merlin assay for predicting melanoma sentinel lymph node biopsy metastasis

“… 1 The incidence of early‐stage melanoma has been on the rise for several decades 2 and has led to the concomitant increase in sentinel lymph node biopsies (SLNB). The recent transition by the American Joint Committee on Cancer (AJCC) to the 8th edition staging system has further increased the number of SLNB procedures performed but not the number of metastatic SLNB detected according to a population‐based study from Denmark, 3 indicating an increase in unnecessary, non‐therapeutic SLNB procedures.…”

RE: More sentinel lymph node biopsies for thin melanomas after transition to AJCC 8th edition do not increase positivity rate: A Danish population‐based study of 7148 patients

“…To the Editor, With great interest, we read the recent study by Weitemeyer et al describing the changing rate of sentinel lymph node biopsy (SLNB) procedures performed in patients staged according to either the American Joint Committee on Cancer Staging Manual, Seventh (AJCC7) or Eight Edition (AJCC8) criteria. 1 The authors reported an increased rate of SLNB's for patients initially diagnosed with a T1a or T1b tumor staged according to AJCC8 compared with AJCC7 (22.2% vs. 16.2%), but with a lower positivity rate (4.7% vs. 6.7%). Furthermore, the traditional staging factors of Breslow thickness and ulceration did not reach statistical significance for SLNB positivity prediction, while younger age and a mitotic rate (MR) ≥1/mm 2 did, suggesting limitations in using current AJCC guidelines for SLNB decisions.…”