Retrospective comparison of individual risk factors hemithyroidectomy and thyroidectomy in patients with papillary carcinoma of the thyroid gland in combination with autoimmune thyroiditis

Abstract

Introduction. Papillary thyroid carcinoma is the most common subtype of thyroid cancer as it comprises 95 % of cases. Frequently, this pathology develops in the presence of autoimmune thyroiditis (Hashimoto’s thyroiditis) which is the main cause of hypothyroidism in various rich in iodine regions. Papillary thyroid carcinoma is characterized by good prognosis, however some patients experience recurrence which depends on the volume of surgical intervention.Aim. To compare clinical outcomes and complications after hemithyroidectomy (HE) and thyroidectomy (TE) in patients with papillary thyroid carcinoma secondary to autoimmune thyroiditis.Materials and methods. The retrospective study included 2031 patients with papillary thyroid carcinoma. Considering individual risk factors, 67 patients were excluded from the HE group, and 588 patients were excluded from the TE group. Each group included 688 patients for whom data were matched. Such individual factors as age, sex, primary tumor size, extrathyroidal invasion, multifocal tumor and cervical lymph node metastasis were taken into account.Results. During 10‑year follow-up, recurrence was diagnosed in 26 (3.8 %) patients of the HE group and 11 (1.6 %) patients of the TE group. Relative risk of recurrence was significantly lower after TE than after HE (risk ratio (RR) 0.41; 95 % confidence interval (CI) 0.21–0.81; р = 0.01). In the HE group, for the majority of patients recurrence was observed in the contralateral lobe of the thyroid (84.6 %). In the TE group, there were no recurrences in all patients. There were no significant differences between the groups after exclusion of recurrence in the contralateral thyroid lobe (RR 2.75; 95 % CI 0.08–8.79; р = 0.08). In the TE group, the number of patients with transient and permanent hypothyroidism in the TE group was significantly higher than in the HE group (р <0.001).Conclusion. Hemithyroidectomy is appropriate for the majority of patients with papillary thyroid carcinoma in the absence of extrathyroidal invasion in the neighboring tissues per preoperative examination. For patients after HE, preoperative and postoperative diagnostic examinations are important as most recurrences develop in the contralateral thyroid lobe.