Lymphocytic infiltration as a prognostic factor in papillary thyroid carcinoma

Introduction/Objective We examine the prognostic significance and association between lymphocytic infiltration and papillary thyroid carcinoma. This manuscript aims to establish whether the presence of lymphocytic infiltration in the classical type of papillary thyroid carcinoma is a favorable prognostic factor for survival. Methods This is a retrospective study of patients treated for papillary thyroid carcinoma at the Clinical Centre of Montenegro over a period of seven years (2010-2017). A total of 105 patients aged 12 to 84 years were included in the study, of which 74% showed concomitant histological evidence of lymphocytic infiltration. The patients were divided into two groups - one with lymphocytic infiltration and the other without it. Anti-CD3 and anti-CD20 antibodies were used to identify T and B lymphocytes. The prognostic outcome was assessed using the Kaplan-Meier survival plots. Results The cohort with lymphocytic infiltration revealed a lower frequency of extrathyroidal invasion (p < 0.0001), nodal metastases (p < 0.0001), and the absence of distant metastases, compared with those without lymphocytic infiltration. Chronic lymphocytic thyroiditis is a favorable prognostic factor for survival in our examined group (p < 0.0001). Conclusion The present study shows that immune reaction involving lymphocytic infiltration plays a role in extrathyroidal tumor growth and development of nodal and distant metastases in patients with papillary thyroid cancer. The presence of lymphocytic infiltration is a favorable factor for survival in the classical form of papillary thyroid carcinoma.