Ultrasound screening for thyroid nodules and cancer in individuals with family history of thyroid cancer: a micro-costing approach

PURPOSE

Screening programs that target healthy populations are an important tool for identifying unrecognized, asymptomatic disease. However, ultrasound screening for thyroid cancer has no obvious advantage in terms of cost-effectiveness in asymptomatic adults. There is far less consensus (and data) on the indications for screening in high-risk individuals. The aim of the study was to estimate the costs of ultrasound screening for individuals with first-degree family history of thyroid cancer.

METHODS

We conducted a prospective cross-sectional study from January 1, 2009 through December 31, 2018 in the Thyroid Cancer Outpatient Clinic of a large teaching hospital in Rome, Italy. We estimated the costs of an ultrasound screening protocol using the micro-costing bottom-up method.

RESULTS

For individuals without thyroid nodules, the screening examination had an estimated cost of €66.21 per screenee. For those found to have unsuspicious nodules, the estimated cost rose to €119.52 per screenee, owing to the addition of thyroid function tests. The estimated cost of screening for a subject with newly diagnosed nodules that were submitted to cytology was €259.89. The total cost of screening for the entire population of 1176 individuals was € 118,133.85. The total expenditure to confirm a single thyroid cancer diagnosis was €10,598.71.

CONCLUSION

A sonographic screening implies a significant direct expenditure and is likely to detect a very large number of individuals with benign nodules (more than 45 asymptomatic individuals are diagnosed with a thyroid nodule for each newly detected cancer case), whose long-term follow-up will further increase healthcare costs.

Genetic susceptibility to hereditary non-medullary thyroid cancer

Non-medullary thyroid cancer (NMTC) is the most common type of thyroid cancer. With the increasing incidence of NMTC in recent years, the familial form of the disease has also become more common than previously reported, accounting for 5-15% of NMTC cases. Familial NMTC is further classified as non-syndromic and the less common syndromic FNMTC. Although syndromic NMTC has well-known genetic risk factors, the gene(s) responsible for the vast majority of non-syndromic FNMTC cases are yet to be identified. To date, several candidate genes have been identified as susceptibility genes in hereditary NMTC. This review summarizes genetic predisposition to non-medullary thyroid cancer and expands on the role of genetic variants in thyroid cancer tumorigenesis and the level of penetrance of NMTC-susceptibility genes.

Lack of Mutations in POT1 Gene in Selected Families with Familial Non-Medullary Thyroid Cancer

To date, the genes involved in familial non-medullary thyroid cancer (FNMTC) remain poorly understood, with the exception of syndromic cases of FNMTC. It has been proposed that germline mutations in telomere-related genes, such as POT1, described in familial melanoma might also predispose individuals to thyroid cancer, requiring further research. We aimed to identify germline mutations in POT1 in selected FNMTC families (with at least three affected members) without a history of other cancers or other features, and to describe the clinical characteristics of these families. Sequencing of the 5'UTR and coding regions of POT1 was performed in seven affected people (index cases) from seven families with FNMTC. In addition, we performed whole-exome sequencing (WES) of DNA from 10 affected individuals belonging to four of these families. We did not find germline variants of interest in POT1 by Sanger sequencing or WES. We neither found putative causative mutations in genes previously described as candidate genes for FNMTC in the 4 families studied by WES. In our study, no germline potentially pathogenic mutations were detected in POT1, minimizing the possibilities that this gene could be substantially involved in non-syndromic FNMTC.

Penetrance of a rare familial mutation predisposing to papillary thyroid cancer

Familial non-medullary thyroid cancer (FNMTC) is clinically defined as two or more first-degree relatives with NMTC and appears to follow an autosomal dominant inheritance pattern. Approximately 5-7% of NMTC is hereditary and affects multiple generations with a young age of onset. The primary aim of this study was to determine the age-specific penetrance of NMTC in individuals from a large family with FNMTC with a previously identified private mutation at 4q32, with a secondary aim to determine the penetrance for benign thyroid disease in this family. We present a large family with NMTC in which we had previously described a culpable mutation. Participants provided their personal medical history and family history. The germline 4q32 A > C mutation was detected in 34 of 68 tested individuals. Age-specific penetrance of thyroid cancer and benign thyroid disease was determined using the inverted Kaplan-Meier method of segregation analysis. Individuals who tested positive for the 4q32 mutation have a 68.9% (95% CI 46.5-88.7) risk of developing thyroid cancer by age 70 and a 65.3% (95% CI 46.0-83.8) risk of developing benign thyroid disease by age 70. The 4q32 A > C mutation significantly increases the risk to develop thyroid cancer but not benign thyroid disease in members of this family. The female:male sex ratio of 1.33 that we observed in affected mutation carriers differs greatly from the ratio of approximately 3:1 observed in PTC, supporting a central role of the mutation. Early thyroid surveillance with annual ultrasound is recommended to individuals testing positive for this private familial mutation.

HABP2 G534E variation in familial non-medullary thyroid cancer: an Italian series

INTRODUCTION

Thyroid cancer may have a familial predisposition and may occur in the context of hereditary syndromes or as isolated tumor. Recently, the G534E variant in the HABP2 gene has been suggested as causative mutation for familial thyroid cancer, but other studies gave contradictory results.

METHODS

We have analyzed the G534E variant in an Italian series of 63 familial thyroid cancer patients and 41 unaffected family members with end-point PCR, DHPLC and direct sequencing.

RESULTS

All samples analyzed displayed a pattern typical of the homozygous wild type revealing the absence of the G534E variant.

CONCLUSION

In this study, HABP2 G534E variant is not correlated with the familial form of PTC.