High-Frequency Ultrasound in High-Risk Cutaneous Squamous Cell Carcinoma.

Abstract

Introduction: High-frequency ultrasound (HFUS) is a valuable tool for the preoperative tumor assessment of cutaneous squamous cell carcinoma (cSCC). A subgroup of patients with cSCC is at an increased risk of tumor recurrence, metastasis, and disease-specific mortality - high-risk cSCC (HRcSCC). The use of HFUS can provide early knowledge of tumor thickness and depth of invasion, allowing for more appropriate surgical planning and staging in this subset of patients.

Materials and methods: We designed a prospective observational cohort study on patients diagnosed with cSCC and surgically treated on at Instituto Valenciano de Oncología (IVO) from January 1, 2016 to January 31, 2022. Clinical, histological and imaging data necessary for patient management were used. Patients with cSCC in situ, noncutaneous SCC or located in anogenital areas, and those who did not undergo surgical treatment were excluded. HFUS was used preoperatively to assess tumor size, depth, and morphological patterns, which were then compared with histopathological findings.

Results: A total of 186 patients with cSCC were included in the study, mostly men (M:F = 3:1), with a mean age of 78.4 years. The patients were followed for a mean of 35 months after surgery. Seven distinct HFUS patterns were identified among HRcSCC cases during the study. Seventy-five cases (40.3%) met high-risk clinical-pathological criteria. There was a significant association between the type of ultrasound pattern and the presence of HRcSCC: chi-square (6) = 22.84; P < .001. HFUS tumor measurements showed strong correlation with histopathology (Pearson's r > 0.85; intraclass correlation coefficient [ICC] = 0.842, P < .001; 95%CI, 0.79-0.88). While HFUS modestly improved specificity over palpation in detecting deep invasion, the difference was not statistically significant.

Conclusions: HFUS is a reliable, cost-effective technique for preoperative evaluation of cSCC. It accurately estimates tumor dimensions and helps identify high-risk features based on ultrasonographic patterns. Although not superior to palpation in assessing invasion depth, HFUS enhances risk stratification and informs more precise surgical planning in HRcSCC.