THE ROLE OF CERVICAL LYMPH NODE METASTASES AND THEIR DISSECTION IN PAPILLARY THYROID CANCER EMPLOYING DIFFERENT SURGICAL APPROACHES WITH REGARDS TO THEIR LONG-TERM PROGNOSIS AND OUTCOMES

Abstract

Background
Papillary Thyroid Cancer (PTC) is a common endocrine cancer which metastases to the cervical lymph nodes (LN). The frequency of metastasis is poorly defined. The imaging modalities commonly employed to detect these metastases have limitations. The aim of this study was to define the extent of cervical LN metastases, the role of imaging in their detection and to determine long term outcomes.
Design and Methods
The study was designed in two parts.
A. Systematic reviews of incidence of cervical LN metastases in PTC and the use of imaging modalities in detection of these LN.
B. Retrospective Cohort Study of PTC patients: Data from three centres in London over the last 9 years was collected and analysed.
Results
I. Systematic reviews
A. Central LN Dissection (LND): 21 studies provided data for 4188 patients. Among patients who underwent prophylactic central LND (pCLND), 772 had positive central LN (44.8 %).
B. Lateral LND: 19 studies provided data for 5587 patients. Out of 2048 patients who underwent pLLND, 1177 were found to have positive lateral LNs (57.5%).
C. Imaging of metastatic cervical LN
Ultrasound: The sensitivity to detect central and lateral cervical LN was 38.4% and 27.2% respectively.
Computerised Tomography: The sensitivity to detect central LN was 67%. For lateral LN none of the studies calculated the sensitivity accurately.
II. Results from the Cohort Study
44 patients were included in the analyses. 53.8% had positive LN when pLLND dissection was performed. Recurrence free survival between the two cohorts was not statistically significant. Overall survival was 100% for both groups.
Conclusions
Prophylactic LND yielded metastatic central and lateral LN in about half of all patients with PTC. Imaging modalities currently utilised for detection of metastatic central and lateral cervical LN have low sensitivities. In our cohort of patients, prophylactic lateral lymph node dissection did not show any significant difference in terms of long term outcomes.

Date of Award	2017
Original language	English
Awarding Institution	King's College London
Supervisor	Alan McGregor (Supervisor), Ameet Patel (Supervisor) & Klaus-Martin Schulte (Supervisor)