Role of Age at Diagnosis in Defining Potential Familial Nonmedullary Thyroid Cancer in Kindreds With Two Affected Members

Ultrasonography screening in children and adolescents who have one parent with familial non-medullary thyroid carcinoma

AIM

To evaluate ultrasonography (US) screening for thyroid cancer in children and adolescents who have one parent with familial non-medullary thyroid carcinoma (FNMTC) unrelated to known genetic syndromes.

METHODS

In this prospective study, we selected 72 children and adolescents (age ≤18 years) without a palpable thyroid nodule or history of radiation exposure, but who have one parent diagnosed with FNMTC (i.e. at least one other affected first-degree relative). The children and adolescents were evaluated by US during initial assessment and after 5 years.

RESULTS

Initial US revealed pure cysts in five participants and nodules in seven, which were ≥5 mm in five. These patients were submitted to fine needle aspiration, which revealed benign cytology in four and a follicular lesion of undetermined significance in one. Fine needle aspiration was repeated in the last case and in one case with benign cytology but suspicious US. The second cytology was benign in both cases. After 5 years, another two participants with initially normal US had nodules <5 mm in the absence of suspicious findings. The frequency of lesions detected by US was not associated with participant sex or age, number of relatives with thyroid cancer (2 or 3), maternal or paternal origin of tumour, or age of the relatives at diagnosis.

CONCLUSION

The present results suggest that US screening is not necessary in children or adolescents when one parent has a diagnosis of FNMTC (≥2 affected relatives).

Prevalence of Thyroid Nodules and Thyroid Cancer in Individuals with a First-Degree Family History of Non-Medullary Thyroid Cancer: A Cross-Sectional Study Based on Sonographic Screening

Background: The actual rates of suspicious thyroid nodules (TNs) and confirmed thyroid cancer (TC) in putatively "at-risk" selected populations (e.g., individuals with family history of TC) are still uncertain. Methods: Our aim was to explore the prevalence of TC and TN in a cross-sectional study of a consenting population of unaffected individuals (10 years of age or older) with a first-degree relative known to have non-medullary TC (NMTC). Enrolled subjects underwent ultrasonographic studies of the neck between 2009 and 2018. Nodules considered suspicious according to current guidelines were subjected to fine-needle aspiration biopsy (FNAB) for cytology. Results: The screenee population comprised 1176 individuals (median age 42 [26-56] years, 650 females, 55.3%) from 473 kindreds (346 with 1 established NMTC diagnosis at entry, 103 with 2 established NMTC diagnoses, and 24 with 3 or more established NMTC diagnoses at entry). Screening revealed TNs in 500 screenees (42.5%; confidence interval [CI] 39.7-45.4%). Ninety-seven of these (19.4%; CI 16.2-23.1%) underwent FNAB. Only 11 cases of TC were diagnosed in the whole population (0.9%; CI 0.5-1.7%). The prevalence of TC in screenees from kindreds with ≥3 cases (3/24, 12.5%) was higher than that for kindreds with one affected member (6/346, 1.7%; p = 0.01, odds ratio [OR] 7.99; CI 1.21-40.75) and for those with two affected members (2/103, 1.9%; p = 0.05, OR 7.05; CI 0.76-89.44). The prevalence of TNs was 61.8% (CI 56.6-66.8%), 75.7% (CI 66.6-83%), and 66.7% (CI 46.7-82%) in the kindreds with 1, 2, and ≥3 cases, respectively (p = 0.03). Conclusions: On the whole, ultrasound-based screening of unaffected relatives of individuals with established diagnoses of NMTC is likely to reveal a high prevalence of TN and a low prevalence of TC. However, a significantly higher prevalence of TC may be found among screenees from kindreds with at least three established NMTC diagnoses before screening, suggesting that closer surveillance may be warranted in kindreds with this level of familiality.

Risk of Second Malignant Neoplasm in Familial Non-Medullary Thyroid Cancer Patients

INTRODUCTION

Survival rates in patients with non-medullary thyroid carcinoma (NMTC) are high, increasing the possibility to develop a second malignant neoplasm (SMN). Many studies investigated the relationship between increased risk of SMN in NMTC patients treated with radioiodine, but few data are available about the impact of family history (FH) of thyroid cancer on SMN risk.

PURPOSE

To assess the risk of SMN in a large cohort of sporadic and familial NMTC using the standardized incidence ratio (SIR).

PATIENTS AND METHODS

We studied 918 NMTC patients (73.9% female patients) followed for a median follow-up of 9 years. In 798/918 (86.9%) patients, NMTC was sporadic, while the remaining 120 (13.1%) were familial NMTC (FNMTC).

RESULTS

We identified 119/918 (13%) patients with SMN in association with NMTC. NMTCs had an increased risk of SMN when compared to the general population (SIR 2.1, 95% CI 1.7-2.5). The rate of SMN for all sites was significantly higher in familial compared to sporadic NMTC (20% versus 11.9%, p = 0.01), primarily driven by families with more than two affected members. The risk of SMN was remarkably higher for breast cancer, especially in familial cases (SIR 22.03, 95% CI 14.4-41.2) compared to sporadic cases (SIR:17, 95% CI 11.9-24.6).

CONCLUSIONS

NMTC patients have a higher risk of SMN compared to the general population and this risk is much higher in patients with FNMTC. This observation raises the hypothesis that genetic risk factors for a first cancer may predispose to SMN, especially among individuals with familial clustering of the same or other tumors.