Familial risks for nonmedullary thyroid cancer.
BACKGROUND
Reliable data on familial risks are important for clinical counseling and cancer genetics.


OBJECTIVE
We wanted to define familial risks for histopathology-specific nonmedullary thyroid cancers through parental and sibling probands.


METHODS
The study examines the nationwide Swedish Family-Cancer Database on 10.5 million individuals, containing families with parents and offspring.


METHODS
Cancer data were retrieved from the Swedish Cancer Registry from years 1958 to 2002, including 3292 patients with thyroid adenocarcinoma. The Systematized Nomenclature of Medicine histology was available from 1993 onward, with 1449 papillary, 288 follicular, 148 anaplastic, and 68 Hurthle cell tumors.


METHODS
Familial risk for offspring was defined through standardized incidence ratio, adjusted for many variables.


RESULTS
The familial risk for papillary carcinoma was 3.21 and 6.24 when a parent and a sibling, respectively, were diagnosed with thyroid cancers. There was an apparent gender preference, particularly among sisters, whose risk was 11.19. The risks were highest for early onset cancers. Thyroid adenocarcinoma was shown to be associated with melanoma and connective tissue tumors, and probably also with neurinomas (schwannomas). Associations found in single comparisons with papillary thyroid cancer and other sites included right-sided colon, breast, ovarian, and kidney cancers. Hurthle cell tumors were associated with Hodgkin's and non-Hodgkin's lymphoma, but the numbers of cases were small.


CONCLUSIONS
The present findings were based on a limited number of cases, but they display a complex and heterogeneous pattern of familial nonmedullary thyroid cancer. The high risk for papillary carcinoma among women requires clinical attention, although the absolute risks for this rare cancer are still low.
Hemminki
Kari
K
Division of Molecular Genetic Epidemiology, German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany. K.Hemminki@dkfz.de
Eng
Charis
C
Chen
Bowang
B
D000230:Adenocarcinoma / Q000453:epidemiology* / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D016208:Databases, Factual; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D012042:Registries; D012306:Risk; D012737:Sex Factors; D013548:Sweden / Q000453:epidemiology; D013964:Thyroid Neoplasms / Q000453:epidemiology* / Q000235:genetics*