The impact of factors beyond Breslow depth on predicting sentinel lymph node positivity in melanoma.
BACKGROUND
In addition to Breslow depth, the authors previously described how increasing mitotic rate and decreasing age predicted sentinel lymph node (SLN) metastases in patients with melanoma. The objectives of the current study were to verify those previous results and to create a prediction model for the better selection of which patients with melanoma should undergo SLN biopsy.


METHODS
The authors reviewed 1130 consecutive patients with melanoma in a prospective database who underwent successful SLN biopsy. After eliminating patients aged <16 years and patients who had melanomas that measured <1 mm, 910 remaining patients were reviewed for clinical and pathologic features and positive SLN status. Univariate association of patient and tumor characteristics with positive SLN status was explored by using standard logistic regression techniques, and the best multivariate model that predicted lymph node metastases was constructed by using a backward stepwise-elimination technique.


RESULTS
The characteristics that were associated significantly with lymph node metastasis were angiolymphatic invasion, the absence of regression, increasing mitotic rate, satellitosis, ulceration, increasing Breslow depth, decreasing age, and location (trunk or lower extremity compared with upper extremity or head/neck). Previously reported interactions between mitotic rate and age and between Breslow depth and age were confirmed. The best multivariate model included patient age (linear), angiolymphatic invasion, the number of mitoses (linear), the interaction between patient age and the number of mitoses, Breslow depth (linear), the interaction between patient age and Breslow depth, and primary tumor location.


CONCLUSIONS
Younger age, increasing mitotic rate (especially in younger patients), increasing Breslow depth (especially in older patients), angiolymphatic invasion, and trunk or lower extremity location of the primary tumor were associated with a greater likelihood of positive SLN status. The current results support the use of factors beyond Breslow depth to determine the risk of positive SLN status in patients with cutaneous melanoma.
Paek
Sandra C
SC
Department of Dermatology, University of Michigan Health System, Ann Arbor, Michigan, USA.
Griffith
Kent A
KA
Johnson
Timothy M
TM
Sondak
Vernon K
VK
Wong
Sandra L
SL
Chang
Alfred E
AE
Cimmino
Vincent M
VM
Lowe
Lori
L
Bradford
Carol R
CR
Rees
Riley S
RS
Sabel
Michael S
MS
D000328:Adult; D000367:Age Factors; D000368:Aged; D005260:Female; D006801:Humans; D016015:Logistic Models; D008207:Lymphatic Metastasis / Q000473:pathology; D008297:Male; D008545:Melanoma / Q000473:pathology*; D008875:Middle Aged; D008938:Mitosis; D015999:Multivariate Analysis; D009361:Neoplasm Invasiveness; D011336:Probability; D021701:Sentinel Lymph Node Biopsy; D012878:Skin Neoplasms / Q000473:pathology*