RESUMO
Objective: A sharp increase in pediatric thyroid cancer incidence is observed during adolescence, driven mainly by girls. Differences in disease presentation across sexual maturity stages raise the question of whether sex steroids have a role in the heterogeneity. The aims of this study were to analyze the influence of puberty and sex on clinical presentation and prognosis and to evaluate the correlation between the expression of sex hormone receptors. Design and methods: Clinical records and immunohistochemical of specimens from 79 patients were analyzed. Puberty was analyzed by two criteria: end of puberty and beginning, in which the age of 10 was the cutoff. Results: Postpubertal were more frequently classified as having low-risk disease and a lower frequency of persistent disease, especially when the completion of puberty was used as the criteria. Male sex was associated with a higher risk of persistent disease at the end of the observation period. Estrogen receptor α positivity was low in the entire sample, while progesterone receptor positivity was positive in 30% of the cases. Female hormone receptor expression was not associated with sex, American Thyroid Association risk score, persistent structural disease, or pubertal status. Conclusion: Our study showed that the completion of puberty correlated best with the clinical behaviour of pediatric thyroid cancer. It was also shown that postpubertal patients have a less aggressive initial presentation and better outcomes. However, this observation could not be explained by the expression of estrogen and progesterone receptors in the primary tumors.
RESUMO
PURPOSE: Medullary thyroid carcinoma (MTC) is a malignant neoplasm of parafollicular cells. Because it is a neuroendocrine tumor, it has known somatostatin receptors (SSTRs). The actual frequencies of the SSTR subtypes and their potential influences (by binding with endogenous somatostatin) on MTC cell proliferation have not been fully elucidated to date. The present study evaluated the occurrence of SSTR subtypes 1, 2, 3 and 5 as well as the possible role that each subtype plays in the clinical evolution of patients with MTC. METHODS: This retrospective, longitudinal study analyzed thyroid surgical material from 42 patients with MTC. Immunohistochemical staining was performed with monoclonal antibodies against subtypes 1, 2, 3 and 5 of SSTR. The histological material was classified as negative, focal positive or diffuse positive, in relation to each of the SSTR subtypes. The initial response to treatment, clinical course and patient mortality rate were assessed and related to the presence of SSTR subtypes. RESULTS: The most prevalent SSTR subtype was SSTR 3, which was found in 81% of the patients, when considering any pattern of positivity. However, subtype 2 had the lowest number of positive patients, with 28.6% demonstrating any positive pattern. Subtypes 1 and 5 had an intermediate prevalence of positivity, with subtype 1 present in 45.2% of the patients and subtype 5 positive in 54.8% of the patients, when considering any pattern of positivity. The presence of STR 1, in the form of diffuse positivity, independently predicted a better response to the initial therapy, with a hazard ratio (HR) of 4.80 (p = 0.03). CONCLUSION: This is the first study to show the correlation of the presence of SSTR1, detected by monoclonal immunohistochemical techniques, and better response to initial treatment and possibly better long-term clinical response in patients with MTC. In addition, these patients had low positivity rates for SSTR2, which might explain the low sensitivity of diagnostic and limited therapeutic response to octrotide based radioisotopes.