Sentinel node tumor burden according to the Rotterdam criteria is the most important prognostic factor for survival in melanoma patients: a multicenter study in 388 patients with positive sentinel nodes.
BACKGROUND
The more intensive sentinel node (SN) pathologic workup, the higher the SN-positivity rate. This is characterized by an increased detection of cases with minimal tumor burden (SUB-micrometastasis <0.1 mm), which represents different biology.


METHODS
The slides of positive SN from 3 major centers within the European Organization of Research and Treatment of Cancer (EORTC) Melanoma Group were reviewed and classified according to the Rotterdam Classification of SN Tumor Burden (<0.1 mm; 0.1-1 mm; >1 mm) maximum diameter of the largest metastasis. The predictive value for additional nodal metastases in the completion lymph node dissection (CLND) and disease outcome as disease-free survival (DFS) and overall survival (OS) was calculated.


RESULTS
In 388 SN positive patients, with primary melanoma, median Breslow thickness was 4.00 mm; ulceration was present in 56%. Forty patients (10%) had metastases <0.1 mm. Additional nodal positivity was found in only 1 of 40 patients (3%). At a mean follow-up of 41 months, estimated OS at 5 years was 91% for metastasis <0.1 mm, 61% for 0.1 to 1.0 mm, and 51% for >1.0 mm (P < 0.001). SN tumor burden increased significantly with tumor thickness. When the cut-off value for SUB-micrometastases was taken at <0.2 mm (such as in breast cancer), the survival was 89%, and 10% had additional non-SN nodal positivity.


CONCLUSIONS
This large multicenter dataset establishes that patients with SUB-micrometastases <0.1 mm have the same prognosis as SN negative patients and can be spared a CLND. A <0.2 mm cut-off for SUB-micrometastases does not seem correct for melanoma, as 10% additional nodal positivity is found.
van Akkooi
Alexander C J
AC
Department of Surgical Oncology, Erasmus University Medical Center, Daniel den Hoed Cancer Center, Rotterdam, The Netherlands. a.vanakkooi@erasmusmc.nl
Nowecki
Zbigniew I
ZI
Voit
Christiane
C
Schäfer-Hesterberg
Gregor
G
Michej
Wanda
W
de Wilt
Johannes H W
JH
Rutkowski
Piotr
P
Verhoef
Cornelis
C
Eggermont
Alexander M M
AM
D005260:Female; D006258:Head and Neck Neoplasms / Q000401:mortality / Q000473:pathology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology; D008297:Male; D008545:Melanoma / Q000401:mortality* / Q000473:pathology*; D008875:Middle Aged; D011379:Prognosis; D021701:Sentinel Lymph Node Biopsy / Q000145:classification; D012878:Skin Neoplasms / Q000401:mortality* / Q000473:pathology*