Background: In the evaluation of patients with papillary thyroid cancer (PTC), high definition ultrasound has the highest sensitivity and specificity to detect non-palpable nodal metastasis in the lateral and central compartments of the neck. The cervical lateral neck metastatic status influences the extent of surgery and may affect postoperative adjuvant radioactive iodine (RAI) scans and postoperative treatment decisions. Missed cervical lateral neck lymph node metastases may result in recurrent disease, need for additional surgery, and inappropriate use of RAI in the setting of radiographically apparent disease. The objective of this study was to assess the added value of a preoperative diagnostic high definition lateral neck ultrasound of patients with papillary thyroid cancer at a tertiary care center.
Methods: Patients who presented to the University of Texas MD Anderson Cancer Center (MDACC) from January 1st 2000 to December 31st 2015 with newly diagnosed PTC were retrospectively reviewed. Patients diagnosed with PTC elsewhere and who had outside diagnostic thyroid/neck ultrasound for PTC who sought further management at MDACC were included. The cervical nodal status of bilateral lateral necks (levels II - V) was ascertained from review of ultrasound reports and confirmed with FNA and surgery pathology reports. Statistical analyses were conducted to estimate the proportion of cases diagnosed with lateral neck disease based on outside ultrasound versus high definition ultrasound at MDACC.
Results: The study included 2015 patients with 4030 respective lateral necks. Median patient age was 47 (range 18-97 years) and 73% female. There were a total of 3817 lateral necks that were non-suspicious by outside ultrasound reports, and of these, 636 (16.7%) necks had ultrasonographically suspicious lymph nodes in the lateral neck identified on high definition ultrasound at MDACC. 517 necks underwent fine needle aspiration (FNA) to assess for metastatic disease, while 110 necks proceeded to surgery without FNA. Among these 627 necks with FNA cytopathology and/or surgical pathology, 292 necks (46%) were positive for metastatic disease. Overall, 292 lateral necks with metastatic disease (7.6%) were identified among 3817 lateral necks originally deemed non-suspicious on recent outside ultrasound.
Conclusion: We found significant differences in detection of lateral cervical nodal involvement on ultrasound between community and tertiary care settings. These results help to define the value of high definition and comprehensive neck ultrasound conducted at a tertiary care setting for early detection and effective management of metastatic lateral neck papillary carcinoma.