Cervical lymph nodes dissection in recurrence of differentiated thyroid carcinoma: is it always worthy?

Background: This study evaluates the curative effect of additional surgery for recurrent differentiated thyroid carcinoma, in terms of positive retrieved lymph nodes after compartment-oriented lymph node dissection (LND). Secondary outcomes are complications rate and the time between first surgery and additional surgery. Materials and Methods: This is an observational retrospective cohort study on consecutive patients underwent additional lymphadenectomy for suspected lymph nodes metastasis from papillary and follicular thyroid cancer. Patients were recruited between December 2007 and October 2021. The following data were recorded: age, sex, cancer type, first surgery, indication to additional surgery (positive neck ultrasonography and/or axial CT with C5 at fine needle aspiration biopsy (FNAB), positive scintigraphy and/or PET-CT, positive Tyrogen test, plasmatic Thyroglobulin levels, diameter of neck lymph nodes at pre-operative imaging, type of LND (central or lateral neck compartment), number of lymph nodes removed, number of metastatic lymph node, time between first and additional surgery, post-operative complications. Results: Thirty-three patients were enrolled. The mean age was 50±17;22 (66.7%) patients were female and 11(33.3%) males. The first diagnosis was papillary cancer in 31 (93.9%) cases, follicular cancer in 2(6.1%). The first surgery consisted in total thyroidectomy in 19(57.6%) cases, 1(3%) hemithyroidectomy, 12(36.4%) total thyroidectomy and lymphadenectomy, 1(3%) thyroid radicalization plus lymphadenectomy. Indications for LND were recorded for 26 patients: 4 (15.4%) had positive PET-CT,19 (73.1%) C5 at FNAB, 2 (7.7%) positive thyrogen test, and one (3.8%) an increase of thyroglobulin plasma level.Themeanlymphnodes dimensionat the pre-operative imaging was 10.5mm±4.7mm. A central compartment LND was performed in 8(24.2%) cases, lateralcompartment LNDin 16(48.5%), and central and lateral LND in 9(27.3%). Themedian of retrieved lymph nodeswas 9(range 1-45), of which metastasis were found in a median of 2 lymph nodes (range 0-12). Patients underwent surgery after a median of 518 days after the first operation (range 39-3967). Five (15.2%) had no metastatic lymph node disease at histological examination. Post-operative complication rate was 15.2% (5 cases): one (3%) post-operative bleeding, one (3%) transient recurrent nerve palsy, one (3.2%) transient hypocalcemia, one (3%) Bernard-Horner syndrome, one (3%) transient marginal mandibular nerve injury. Conclusions: Recurrence of papillary and follicular thyroid carcinoma is a major concern in clinical practice. It can occur even after years from the first surgery, with a median of 518 days in this study. Nevertheless, 15.2% of patients had no metastatic lymph node disease. Since the complication rate is 15.2%, we recommend a careful preoperative patients’ selection.