Clinical Characteristics and Prognostic Relevance of Desmoplastic Cutaneous Squamous Cell Carcinoma in Local Infiltration and Loco-Regional Recurrence

Abstract

Background: Perusal of the literature of cutaneous squamous cell carcinoma reveals that the role of the desmoplastic type is indistinct. The aim of this prospective study was to analyse local infiltration, recurrence and resulting outcome of the desmoplastic type. Methods: Between 2005 and 2015 2149 unselected primary cutaneous squamous cell carcinomas of 1434 patients were diagnosed and treated at the Department of Dermatology, University of Tuebingen/Germany. Data collection was based on prospectively collected data during follow-up of median 36.5 months for tumor infiltration and loco-regional recurrence rate, as well as tumor-specific death, rate of metastasis and perineural infiltration. From this cohort a sample of 320 tumors (non-desmoplastic type, n= 260; desmoplastic type, n= 60) were randomly selected to investigate surgical and histological details. Findings: Desmoplastic type required more re-excisions after initial resection (70.0% vs. non-desmoplastic type 23.9%, p<0.001), more interventions until clear margins achieved (maximal 6 vs. 2) and showed more widespread tumor cells in the histology of re-excisions with larger excisional margins required for a complete removal (median 9 mm, 2-51 mm vs. median 4 mm, 1-10 mm). Desmoplastic type showed a 5-fold higher local recurrence rate (26.7% vs. 5.0%, p<0.001). Rate of metastasis (16.6% vs. 2.3%, p<0.001) as well as tumor specific death (13.3 % vs. 1.9%) were increased for the desmoplastic type. Perineural infiltration was observed in the desmoplastic types only (13.3%). Interpretation: Desmoplastic squamous cell carcinoma is a highly malignant subtype characterized by a widespread local infiltration associated with perineural infiltration and is a precise prognostic marker for loco-regional recurrences and worse prognosis. Further studies targeting the prognostic value of perineural infiltration within desmoplasia are necessary to improve the resulting clinical standard recommendations for this subtype. Funding Statement: The authors declare: None. Declaration of Interests: The authors state that there are no conflicts of interest. Ethics Approval Statement: The study was approved by the local ethics committee (study protocol number: 16111608) and was planned and analysed with support of the Department of Clinical Epidemiology and Biostatistics, University of Tuebingen.