Background: Sentinel lymph node biopsy (SLNB) allows early detection of metastases, thereby enabling early treatment in melanoma patients likely to benefit from adjuvant therapies. This prospective study analyzes the possible benefits of additional ultrasound (US) and fine needle aspiration cytology (FNAC) of sentinel nodes (SN) prior to SLNB.
Method: Over a 2-year period 127 melanoma patients with 151 SN were scheduled for SLNB. All SN were initially identified with lymphoscintigraphy, then identified and evaluated by US and the cells aspirated for cytology (FNAC). US findings and FNAC results were compared to surgical findings.
Results: Of 127 patients, 114 had one SN each, 12 had two, and one had three. In vivo US achieved a sensitivity of 79% (95% CI: 62-91%) and a specificity of 72% (95% CI: 62-81%). FNAC showed a sensitivity of 59% (95% CI: 41-76%) and a specificity of 100% (95% CI: 95-100%). The combination of these two in vivo methods achieved an overall sensitivity of 82% (95% CI: 65-93%) and an overall specificity of 72% [95% CI: 62-81%].
Conclusion: Combined US and FNAC provides important information prior to SLNB in that both procedures identify metastases in the lymph nodes (sensitivity > 80%). Patients with positive FNAC may proceed directly to complete lymph node dissection (cLND) instead of having initial SLNB. Thus, combined US and FNAC may prevent unnecessary anesthesia and surgical management as well reduce costs. In our study 16% (19/121) fewer SLNB procedures were carried out, subsequently replaced by cLND. For patients with a negative combination of in vivo US and FNAC, SLNB remains the best diagnostic option.