Ultrasonography surveillance in papillary thyroid carcinoma patients after total thyroidectomy according to dynamic risk stratification

Purpose To investigate the role of neck US surveillance in patients with papillary thyroid carcinoma (PTC) after total thyroidectomy according to dynamic risk stratification (DRS) based on response to initial therapy. Methods This retrospective study included 812 patients with PTC who underwent total thyroidectomy with prophylactic central neck dissection from January 2003 through February 2007. The relative risk of recurrence/persistence according to DRS was evaluated with the multivariable Cox regression proportional hazard model. Results There were 132 men and 680 women. The mean age at surgery was 45.2 years. Postoperative US was used for DRS. According to DRS, 676 patients had excellent response, 78 indeterminate response, 40 biochemical incomplete response, and 18 structural incomplete response to initial therapy. Neck US was performed during follow-up and detected locoregional recurrences in 21 patients (2.6%): 12 with excellent response, 2 with biochemical incomplete response, and 7 with structural incomplete response according to DRS. Only 1 patient (0.1%) with excellent response had a locoregional recurrence that exceeded 8 mm in its shortest diameter, which is the size cut-off for diagnostic US fine-needle aspiration in suspicious lymph nodes. This patient did not develop biochemical abnormalities during follow-up. Conclusions Postoperative neck US surveillance after total thyroidectomy with prophylactic central neck dissection is not essential in PTC patients who show excellent response to initial therapy. Future studies are needed to verify the role of US surveillance in patients who receive variable degrees of treatments.