Tumor budding is an independent risk factor for lymph node metastasis in cutaneous squamous cell carcinoma: a single center retrospective study.

Background: Although tumor budding is acknowledged as a risk factor for lymph node metastasis in certain types of carcinoma, it is not well investigated in cutaneous squamous cell carcinomas (SCCs). In this study, we analyzed the correlation between tumor budding and nodal metastasis in cutaneous SCC.
Methods: Histopathologic specimens of 15 metastasizing and 144 non-metastasizing cutaneous SCC were retrospectively reviewed. Cut-off point for tumor budding was determined at five or more foci of an isolated cancer cell or a cluster comprising <5 cells /1.23 mm(2) in the invasive front of the tumor under hematoxylin and eosin sections.
Results: Tumor budding was positive in 93.3% of metastasizing cutaneous SCC and 25.7% of non-metastasizing cutaneous SCC, respectively (p < 0.0001). In multivariate analysis, tumor budding was an independent risk factor for nodal metastasis among the other risk factors (tumor size, tumor thickness, Clark level and poor differentiation) (p = 0.0021). In combination with tumor thickness >4 mm, tumor budding became a better marker for predicting nodal metastasis (sensitivity 93.3%, specificity 84.7%).
Conclusions: In our cohort, tumor budding was an independent risk factor for nodal metastasis. Our data suggests the promising role of tumor budding in risk evaluation of cutaneous SCC.
(© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)