Increased Risk for Nonmedullary Thyroid Cancer in the First Degree Relatives of Prevalent Cases of Nonmedullary Thyroid Cancer: A Hospital-Based Study

Abstract

The genetic basis for nonmedullary forms of thyroid cancer (NMTC) is less well established than that of medullary thyroid cancer. However, epidemiological and family studies suggest that a proportion of NMTC may be due to inherited predisposition. To estimate the familial risk of thyroid cancer, we conducted a hospital-based case-control study at the Princess Margaret Hospital in Toronto, Ontario, Canada, and at 2 university hospitals in Montréal, Québec, Canada. We obtained pedigrees from 339 unselected patients diagnosed with NMTC and from 319 unaffected ethnically matched controls. Family histories of cancer were obtained from the cases and controls for 3292 first degree relatives of cases and controls. Seventeen cases (5.0%) and 2 controls (0.6%) reported at least one first degree relative with thyroid cancer. In relatives of patients with thyroid cancer, the incidence of any type of cancer (including NMTC) was 38% higher than in relatives of controls (incidence rate ratio, 1.4; 95% confidence interval, 1.1-1.7). The relative risk for thyroid cancer was 10-fold higher in relatives of cancer patients than in controls (incidence rate ratio, 10.3; 95% confidence interval, 2.2-47.6). Our findings suggest that hereditary or other familial factors are important in a small proportion of NMTC. Molecular studies are needed to determine the genetic basis of cancer susceptibility in these families.

ENDOCRINE TUMOURS: Familial nonmedullary thyroid carcinoma is a more aggressive disease: a systematic review and meta-analysis

“…NMTC represents more than 95% of all thyroid cancer, and four histologic subtypes can be distinguished: papillary (85%), follicular (11%), Hürthle syndromes such as Cowden disease (multiple hamartoma syndrome), familial adenomatous polyposis, or Carney complex (8). The reported prevalence of FNMTC varies from 2.5 to 11.3% of all NMTC patients (5,9,10,11). Given the high prevalence of thyroid cancer in the general population, the occurrence of FNMTC may not be rare.…”

Familial history of non‐medullary thyroid cancer is an independent prognostic factor for tumor recurrence in younger patients with conventional papillary thyroid carcinoma

“…Previous population studies have shown that the risk of thyroid cancer is increased fivefold to ninefold in individuals with a first‐degree relative with thyroid cancer . When there are two affected family members with thyroid cancer, the probability that the affected members have a familial syndrome is reported to be 31–53% .…”

CHEK2mutations and the risk of papillary thyroid cancer

“…The most common type of thyroid cancer is papillary thyroid cancer, which comprises 80% of all thyroid tumors . Approximately 5% of cases of papillary thyroid cancer are familial . Epidemiologic data suggests that inherited factors contribute to papillary thyroid cancer .…”