Results of Screening in Familial Non-Medullary Thyroid Cancer

Abstract

Background: Although a family history of thyroid cancer is one of the main risk factors for thyroid cancer, the benefit of screening individuals with a family history of thyroid cancer is not known.

Methods: A prospective cohort study was performed with yearly screening using neck ultrasound and fine-needle aspiration biopsy of thyroid nodule(s) >0.5 cm in at-risk individuals whose relatives were diagnosed with familial non-medullary thyroid cancer (FNMTC). The eligibility criteria were the presence of thyroid cancer in two or more first-degree relatives and being older than seven years of age. Twenty-five kindred were enrolled in the study (12 families with two members affected, and 13 with three or more members affected at enrollment).

Results: Thyroid cancer was detected by screening in 4.6% (2/43) of at-risk individuals from families with two members affected, and in 22.7% (15/66) of at-risk members from families with three or more patients affected (p = 0.01). FNMTC detected by screening was characterized by a smaller tumor size (0.7 ± 0.5 cm vs. 1.5 ± 1.1 cm; p = 0.006), a lower rate of central neck lymph node metastases (17.6% vs. 51.1%; p = 0.02), less extensive surgery (hemithyroidectomy 23.5% vs. 0%; p = 0.002), and a lower rate of radioactive iodine therapy (23.5% vs. 79%; p < 0.001) compared to those affected at enrollment.

Conclusions: Screening of at-risk family members resulted in earlier detection of low-risk FNMTC and was associated with a less aggressive initial treatment. Screening with thyroid ultrasound should be considered in kindred with three or more family members affected by FNMTC. Since active screening might be associated with the risk of overtreatment, it should be implemented with caution, specifically in elderly individuals.

Trial registration: ClinicalTrials.gov NCT01109420.

Keywords: familial; screening; thyroid cancer; thyroidectomy; ultrasound.

Conflict of interest statement

No competing financial interests exist.

Figures

FIG. 1.

The study design and selection of study population. The deaths were due to thyroid cancer.

FIG. 2.

Rate of thyroid nodule detected at screening and patient age.

FIG. 3.

Summary of indications for fine-needle aspiration biopsy (FNAB) in patients with thyroid nodules.

FIG. 4.

Screening strategy in 17 patients for whom the final diagnosis of thyroid cancer was established.

FIG. 5.

Age at diagnosis of familial non-medullary thyroid cancer (FNMTC) in study group versus general population. The age of diagnosis was earlier compared to the general population (p < 0.001), as reported in the Surveillance, Epidemiology, and End Results (SEER) data on thyroid cancer. The data used in the current study were derived from 17 registries at various geographic locations throughout the United States, representing 28% of the U.S. population. Only non-medullary thyroid cancer cases (N = 61,523) were included from the SEER data for the comparison.