Since laterocervical lymphadenectomy is never routinely performed, all patients who undergo thyroidectomy for differentiated cancer must have an ultrasound examination (US). The aim of this study is to assess the accuracy of the preoperative US conducted at the time of surgery as a staging US (time 0) compared to the US performed sometime before in a location other than the surgical department as screening/diagnostic US (time - 1), to determine the necessity of always performing a preoperative US before surgery. 4060 patients with cytologic diagnosis (FNAB) of differentiated thyroid neoplasm (Tyr 4 and Tyr 5) were recruited at Surgery 2 of the Department of General and Specialist Surgery of the Tertiary Care Hospital "A. Cardarelli" of Naples. All patients had a screening US prior to admission into our hospital (time - 1) and were rescanned in the operating room before surgery (time 0) by the same team of surgeons experienced in the field of thyroid diseases. The examinations conducted at time 0 revealed a sensitivity of 100% and a specificity of 92.3%, while examinations performed at time - 1 showed a sensitivity of 22.8% and a specificity of 72.7%. The statistical analysis shows how the diagnostic timing and the experience of the examiner can make a difference both in terms of PPV and NPV to not only to assist in identifying all the lymph node lesions that would remain indeterminate if not specifically researched during surgery, but also helps avoid surgical overtreatment. The systematic execution of a staging US (time 0) in addition to a screening/diagnostic US (time - 1) results in forming a more appropriate therapeutic plan.
Keywords: Lymph nodes; Metastases; Thyroid cancer; Ultrasound examination.