In Papillary Thyroid Cancer, Preoperative Central Neck Ultrasound Detects Only Macroscopic Surgical Disease, But Negative Findings Predict Excellent Long-Term Regional Control and Survival

Abstract

Background: Ultrasound (US) of the central neck compartment (CNC) is considered of limited sensitivity for nodal spread in papillary thyroid cancer (PTC); elective neck dissection is commonly advocated even in the absence of sonographic abnormalities. We hypothesized that US is an accurate predictor for long-term diseasefree survival, regardless of the use of elective central neck dissection in patients with PTC. Methods: A retrospective chart review of 331 consecutive PTC patients treated with total thyroidectomy at M.D. Anderson Cancer Center between 1996 and 2003 was performed. Information retrieved included preoperative sonographic status of the CNC, surgical treatment of the neck, demographics, cancer staging, histopathological variables and use of adjuvant treatment. The endpoints for the study were nodal recurrence and survival. Results: There were 112 males and 219 females with a median age of 44 years (range 11-87). The median followup time for the series was 71.5 months (range 12.7-148.7). There were 151 (45.6%) patients with a T1, 58 (17.5%) with a T2, 70 (21.1%) with a T3, and 52 (15.7%) with a T4. Preoperative sonographic abnormalities were present in the CNC in 79 (23.9%) patients. During the surveillance period, 11 (3.2%) patients recurred in the central neck, with an average time for recurrence of 22.8 months. Advanced T stage (T3/T4) and abnormal US were independent prognostic factors for recurrence in the central neck ( p = 0.013 and p = 0.005 respectively). There were 119 (35%) patients with a sonographically negative central compartment who underwent elective central neck dissection; 85 of them (71.4%) were found to be histopathologically N( + ) while 34 (28.6%) were pN0. There were no differences in overall survival ( p = 0.32), disease specific survival (DSS; p = 0.49), and recurrence-free survival ( p = 0.32) between these two groups. Preoperative US of the CNC was an age-independent predictor for overall survival ( p < 0.001), DSS ( p = 0.0097), and disease-free survival ( p = 0.0005) on bivariate Cox regression. Conclusions: US of the central compartment is an age-independent predictor for survival and CNC recurrencefree survival in PTC. Prophylactic neck dissection of the central compartment does not improve long-term disease control, regardless of the histopathological status of the lymph nodes retrieved. Our findings emphasize the ability of US to clinically detect relevant nodal disease and support conservative management of the CNC in the absence of abnormal findings.

Nodal Metastases in Thyroid Cancer: Prognostic Implications and Management

“…However, there remains little evidence to suggest that microscopic disease, not visible on preoperative imaging or intraoperative palpation, is associated with poorer outcomes. Furthermore, there is little evidence to suggest that the resection of such microscopic disease in prophylactic central neck dissection improves overall survival [45,46]. Advocates for prophylactic central neck dissection argue that this procedure provides more accurate assessment of nodal status.…”

The prognostic value of the metastatic lymph node ratio and maximal metastatic tumor size in pathological N1a papillary thyroid carcinoma

“…The surgical management of the central neck in patients without documented metastatic disease remains controversial and some suggested that prophylactic central neck dissection leads to an increase in pN1 disease that seems not to affect prognosis (18,19,20). In this study, 184 (63%) patients underwent prophylactic central neck dissection and there was no increase in recurrences in cN1 disease compared with cN0 disease.…”

Persistent and recurrent disease in patients with papillary thyroid carcinoma with clinically apparent (cN1), but not extensive, lymph node involvement and without other factors for poor prognosis

“…There was no case of death due to the disease. (9)(10)(11)(12)(13)(14), the presence of more than 5 positive LN (11,(15)(16)(17)(18), metastases ≥ 3 cm (11,16,19), and extranodal extension (15,16,(18)(19)(20)(21) are also associated with a poor prognosis (4,5,7,22). In these cases, there is little controversy about the need for a more aggressive initial approach.…”

“…Furthermore, the risk of persistent disease [defined as metastases on initial posttherapy whole body scanning (RxWBS) or detected by the imaging methods until one year after ablation] and tumor recurrence (defined as strutural disease diagnosed more than one year after ablation) is significantly increased when LNM are detected by preoperative US (9)(10)(11)(12)(13)(14), in the presence of numerous [> 5 positive LN (11,(15)(16)(17)(18)] and large LNM [≥ 3 cm (11,16,19)], or in the presence of extranodal tumor extension (15,16,18-21).…”