Influence of autoimmune thyroiditis on the prognosis of papillary thyroid carcinoma.

OBJECTIVES: The association of autoimmune thyroiditis (AIT) with papillary thyroid carcinoma (PTC) has been studied for over 60 years, yet their causal relationship has not been elucidated. Most published papers report a better prognosis of the patients with tumour in the field of thyroiditis. In our work we aimed to find out the differences in the clinical behaviour of PTC depending on the presence of autoimmune inflammation. METHODS: We retrospectively analysed a group of 1,201 patients with PTC dispensed in St. Elisabeth Cancer Institute and Faculty of Medicine from 2000 to 2015. We divided patients with AIT according to the time of diagnosis of inflammation into the AIT1 subgroup, which included patients monitored for AIT before tumour detection. In them, we assumed that the factor of long-term endocrinological monitoring could speed up the diagnosis of the tumour and thus improve the prognosis. The AIT2 subgroup consisted of patients with both tumour and inflammation diagnosed simultaneously, thus eliminating the factor of prior monitoring. RESULTS: PTC in the AIT1 subgroup had better prognostic parameters (TNM stage, persistence, disease remission). Patients in the AIT2 group had all monitored parameters comparable with patients with tumours without autoimmune inflammation. CONCLUSION: AIT alone does not have a protective effect on the course of PTC, the cause of a better prognosis in the AIT1 subgroup is a different pathomechanism of carcinogenesis, as well as previous endocrinological monitoring and earlier detection of malignancy (Tab. 4, Fig. 2, Ref. 27).

Diagnostic ipsilateral central neck dissection may reduce undertreatment of initially low-risk papillary thyroid cancer.

Although small papillary thyroid cancer (PTC) patients are considered as low-risk population, approximately 5-20% of these patients relapse after surgery. The objective of this single-center retrospective study was to identify risk factors, which could help to distinguish patients who would need additional treatment after surgery. A total of 268 patients (39 men, 229 women, median age 49 years) underwent surgery between 2007-2015, and fulfilled inclusion criteria: tumor size ≤20 mm, absence of metastatic lymph nodes (LN) in the lateral neck compartment (LC), and absence of local invasion. Total thyroidectomy was performed in 252 cases, in 221 cases with central neck compartment (CC) dissection. The outcome - a more aggressive disease - was defined as the presence of metastases in the LNLC or in distant organs found during follow-up. A median follow-up was 117 months. Overall, 41 patients experienced the outcome with a median time-to-event of 18 months. Male gender (OR=2.2, p=0.049), extra-thyroidal extension ETE (OR=2.61, p=0.015), and metastases in LNCC (OR=4.21, p<0.001) were associated with worse outcome. Multivariable analysis and stratification according to ETE revealed an effect modification with a higher effect of the positive LNCC on the outcome among patients without ETE than in those with ETE. Our findings advocate placing greater emphasis on the role of LNCC metastases in the absence of ETE. In clinically node-negative tumors intraoperative examination of CC on the side of the tumor followed by CC dissection if metastatic lymphadenopathy is present could play an important role in the stratification of patients with small-size PTC.