Clinician-performed ultrasound can identify non-palpable pathologic lateral lymph nodes in a significant percentage of patients with differentiated thyroid cancer who previously underwent radiologist-performed ultrasound, potentially leading to better surgical outcomes.
The use of ultrasound has become standard in the evaluation, diagnosis, and management of differentiated thyroid cancer. The majority of ultrasounds in the US are performed by radiologists. However, as the abstract for the current study notes, “evaluation of the lateral neck of pathologic lymph nodes is not standard. As many pathologic lymph nodes are not palpable, reliance on radiology reports alone can lead to an inadequate operation being performed.”
To determine the impact of clinician-performed ultrasound (C-US) in performing the correct initial operation for patients with differentiated thyroid cancer with lateral lymph node metastases, a team of researchers from the Endocrine Surgery Department at the Cleveland Clinic, in Cleveland, OH, carried out a retrospective review of a prospectively maintained database to determine the number of patients who underwent modified radical neck dissection (MRND) for differentiated thyroid cancer between 2000 and 2013 at their tertiary referral center.
The results of this review were presented at the 83rd Annual Meeting of the American Thyroid Association, in San Juan, Puerto Rico, on October 18, 2013.
“We compared our findings with that of the pre-referral imaging studies to determine how many patients would have undergone the wrong initial operation due to missed pathologic lateral lymph nodes,” the study authors explained in the abstract. During the study period, 137 patients underwent MRND for differentiated thyroid cancer. Of these, 69% had pre-referral imaging of the neck (ultrasound, CT, MRI). The remainder had the C-US performed by the research team as their initial imaging test.
Of those patients with pre-referral imaging, C-US detected non-palpable, cytologically confirmed, pathologic lateral lymph nodes not previously identified in 29% of patients. Fifty-nine percent of these patients had radiologist-performed ultrasounds (R-US) as part of their pre-referral imaging, and 41% had other imaging modalities. Of the 59% of patients with R-US, 35% had non-palpable ultrasound-detected pathologic lateral lymph nodes detected on C-US, significantly altering the surgical plan.
In their study population, even the most successful radiology-performed imaging studies, including ultrasonography, missed 30% to 35% of clinically detectable, non-palpable pathologic lateral neck lymph nodes. In the absence of C-US, one-third of the patients in this study would have undergone or did undergo an inadequate initial operation.
“Absence of C-US would have led to an inadequate initial operation in one third of patients with differentiated thyroid cancer and lateral neck metastases in the study population, despite pre-referral neck imaging,” the study authors concluded. “Awareness of the limitations of other imaging of [other image modalities] is important to clinicians evaluating patients with differentiated thyroid cancer, and C-US is critical in ensuring patients with differentiated thyroid cancer get the correct initial operation.”