According to the results of a study reported at the 14th International Thyroid Congress, patients with thyroid cancer who show lymphocytic infiltration - a benign cluster of lymph cells - are more likely to have a favorable outcome.
The effect of coexistent lymphocyte infiltration (LI) on the prognosis of thyroid cancer remains controversial, as widespread lymphocyte infiltration is frequently seen in Hashimoto's thyroiditis, an inflammatory thyroid disease.
A retrospective study of 157 patients with thyroid cancer - which included papillary and follicular thyroid cancers - was conducted with all patients undergoing total or near-total thyroidectomy followed by radioiodine therapy.
The diagnosis of LI was made based on a review of the pathology reports on each patient. LI was classified according to diffuse, peritumoral - in or around the tumor - or absent. A total of 93 patients had diffuse LI, 25 had peritumoral LI and 39 had no signs. The rate of tumor recurrence overall was 47 percent, which was lower in patients with peritumoral LI.
"Although the role of the inflammatory immune cells is complex and not well understood, our data indicates that peritumoral LI cells influence tumor behavior, as these tumors [have] lower aggressive characteristics and recurrences," wrote Dr Villagelin of the Pontifica Catholic University Campinas in São Paulo, Brazil.