Utility of High-Frequency Ultrasound in Preoperative Evaluation of the Thickness of Cutaneous Melanoma

Introduction: The Breslow thickness of cutaneous melanoma (CM) is related to the surgical approach and is usually measured using a preoperative biopsy. However, tumor thickness is often underestimated by partial biopsies. Objectives: To identify whether high-frequency ultrasound (HFUS) can improve the accuracy of preoperative detection of Breslow thickness. Methods: Partial biopsies and HFUS measurements of Breslow thickness were analyzed in 17 patients with CM. Postoperative histopathologic examination is considered the gold standard. In different thicknesses, HFUS and partial biopsy were compared with postoperative pathology and their effects on tumor T staging and surgical margins. Results: The mean (±SD) Breslow thicknesses measured using HFUS, partial biopsy, and postoperative histopathology were 3.5 ± 2.2 mm, 1.8 ± 1.1 mm, and 3.2 ± 2.1 mm, respectively. The correlation coefficients were 0.76 (partial biopsy and postoperative histopathology) and 0.96 (HFUS and postoperative histopathology), respectively (all p < 0.01). Partial biopsy underestimated the Breslow thickness, and with a gradual increase in CM thickness, the underestimation became increasingly obvious. Partial biopsy led to an underestimation of T staging of the tumor in 8 (8/17 [47.1%]) patients, 4 (4/8 [50.0%]) of whom may have had insufficient surgical peripheral margins. Conversely, HFUS exhibited a significant downward trend of underestimation (0/17 [0%], p = 0.003). However, only 2 (2/17 [11.8%]) patients had slight overestimation for T staging (p = 0.485), and none of the overestimations changed the surgical margins. Conclusions: HFUS can provide an accurate preoperative assessment of Breslow thickness, and correlates better with postoperative histopathology.