Endocrine Abstracts

Background: The use of prophylactic central neck dissection, especially for low-risk differentiated thyroid cancer, is still very variable from center to center. Obviously, central dissection does allow more complete staging of cancer, including identification of metastases not detectable on preoperative ultrasound. However, it could lead to higher risk of hypoparathyroidism. Above all, it is not entirely clear whether the identification of metastases of the central compartment and the consequent more aggressive treatment leads to a substantial benefit in terms of risk of recurrence and/or survival.

Methods: Retrospective analysis of patients in follow-up for thyroid cancer (histological diagnosis between 1978 and 2021) at an academic endocrinology unit. Among 693 subjects, only those treated with total thyroidectomy with or without bilateral central neck dissection (BCND) were considered. Subjects treated also with laterocervical lymphadenectomy, or with monolateral central neck dissection or diagnosed with medullary carcinoma were excluded. BCND and non- BCND groups were compared for post-surgical complications, post-surgical thyroglobulin (Tg) serum levels, outcome of post-dose whole body scintigraphy after radioiodine ablation (RAI), response to rh-TSH test. Comparisons between groups were performed with the non-parametric Mann-Whitney U-test or Chi-squared test for categorical data.

Results: 106 subjects were treated with BCND and 322 subjects were not. BCND group had higher but not significant rate of post-surgical complications (8.5% vs 4.4%, P = 0.412), mainly persistent hypoparathyroidism. The 67% of BCND group and the 36% of non-BCND underwent RAI. Among them, BCND had lower Tg serum levels before RAI (8.99±52.96 vs 92.59±748.52 ng/ml) but significance is lost after correction for TgAb positivity. Groups did not differ for positivity at post dose whole body scintigraphy. At the rh-TSH test, performed 12 months after ablation, groups did not differ either in baseline Tg (BCND 0.26±1.06 vs non-BCND 0.48±2.14 ng/ml, P = 0.491) or stimulated Tg (BCND 0.56±2.16 vs non-BCND 1.26±8.40 ng/ml, P = 0.354). Stimulated Tg was <1 ng/ml in 93% of BCND and 87% of non-BCND (P = 0.276).

Conclusions: In subjects treated for differentiated thyroid cancer, performing BCND together with thyroidectomy does not seem to improve the short-term response to surgery and RAI. Our retrospective data provide no indication of long-term response, so further studies are needed.