The role of preoperative ultrasound scan in detecting lymph node metastasis before sentinel node biopsy in melanoma patients

Abstract

Background and objectives: To evaluate the efficacy of preoperative ultrasound (US) scanning in identifying lymph node metastasis before sentinel node biopsy (SNB), we conducted a prospective study on 125 patients with primary cutaneous melanoma (CM).

Methods: We prospectively enrolled 125 patients with >1 mm thick CM and candidate for SNB. Preoperatively, patients underwent US scanning of regional lymphatic basins and FNA of suspected lymph nodes (LN). All patients underwent lymphatic mapping and SNB.

Results: Combined with fine-needle aspirate (FNA) of suspect LN, US scan allowed the correct preoperative detection of 12 out of 31 histologically positive lymphatic basins, specificity and sensitivity being 100 and 39%, respectively. The false negative rate (61%) was mainly linked to tumor deposits less than 2 mm in diameter, which can be considered the current spatial resolution limit of this technique.

Conclusions: Preoperative US scan could reduce the number of SNB, thus avoiding the stress of this surgical procedure in approximately 10% of patients and reducing health care costs. As a non-invasive and relatively inexpensive technique, lymph node US scan can be part of the preoperative staging process of patients' candidate for SNB in order to avoid unnecessary surgical procedures.