Introduction
Sentinel lymph node (SLN) biopsy is recommended for all patients with intermediate thickness melanomas. We sought to identify such patients at low risk of SLN positivity.
Methods
All patients with intermediate thickness melanomas (1.01–4 mm) undergoing SLN biopsy at a single institution from 1995–2011 were included in this retrospective cohort study. Univariate and multivariate logistic regression determined factors associated with a low risk of SLN positivity. Classification and regression tree (CART) analysis was used to stratify groups based on risk of positivity.
Results
Of the 952 study patients, 157 (16.5%) had a positive SLN. In the multivariate analysis, thickness <1.5 mm (OR= 0.29), age ≥60 (OR=0.69), present tumor infiltrating lymphocytes (TIL) (OR=0.60), absent lymphovascular invasion (LVI) (OR=0.46), and absent satellitosis (OR=0.44) were significantly associated with a low risk of SLN positivity. CART analysis identified thickness of 1.5 mm as being the primary cut point for risk of SLN metastasis. Patients with a thickness of <1.5 mm represented 36% of the total cohort and had a SLN positivity rate of 6.6% (95% CI=3.8–9.4%). In patients with melanomas <1.5 mm in thickness, the presence of additional low risk factors identified 257 patients (75% of patients with <1.5 mm melanomas) in which the rate of SLN positivity was <5%.
Discussion
Despite a SLN positivity rate of 16.5% overall, substantial heterogeneity of risk exists among patients with intermediate thickness melanoma. Most patients with melanoma between 1.01–1.5 mm have a risk of SLN positivity similar to that in patients with thin melanomas.
These data support more standardized approaches to regional lymph node examination for patients with epithelioid and possibly clear cell sarcoma and provide compelling evidence that nodal evaluation can be considered a quality measure in the delivery of cancer care for certain sarcoma subtypes.
The risk of DSM increases with age in patients undergoing cytoreduction and IPC. Risk can be stratified using a limited number of patient and operative characteristics.
We observed that non-tumor infiltrating inflammatory cells are often present in the stroma of melanoma. The role of these stromal inflammatory cells (SIC) in cancer has not been studied. We evaluated the prognostic significance of SIC in 299 patients with vertical growth phase primary melanomas with at least 10 years of clinical follow-up. Lymphatic density and lymphatic invasion in the areas with SIC was quantified. The prognostic significance of these factors was evaluated using univariable and multivariable Cox models for melanoma-specific death and the time to first recurrence. Of the 299 melanomas, 161 exhibited areas with SIC. Percentages of vertical growth phase tumor infiltrating lymphocytes and radial growth phase regression were significantly higher in cases with SIC compared to those without SIC (p=0.005); lymphatic invasion was also detected more frequently in cases with SIC (p=0.001). Lymphatic density in SIC areas was higher than that in other areas of the melanomas. Patients with SIC had poorer clinical outcome. Vascular endothelial growth factor-C (VEGFC) staining in a subset of these melanoma patients showed that VEGFC expression in the stromal macrophages was associated with lymphatic invasion in SIC areas. In conclusion, SIC in melanoma is associated with poorer prognosis and the prognostic
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