Family history of thyroid cancer and the risk of differentiated thyroid cancer in French polynesia.
BACKGROUND
Differentiated thyroid carcinoma is considered to be the nonhereditary cancer for which familial inheritance is the highest. To date, no familial aggregation analysis of this cancer has been performed in Maohi populations, which exhibit a very high incidence rate. Therefore, we evaluate the risk of differentiated thyroid cancer associated with a family history of thyroid cancer in natives of French Polynesia.


METHODS
We investigated thyroid cancer incidence in the first-degree relatives of 225 cases of differentiated thyroid carcinomas diagnosed between 1979 and 2004 in patients born in French Polynesia, and 368 randomly selected population controls matched for sex and age, born and residing in French Polynesia. All but five thyroid cancers declared among relatives were validated.


RESULTS
Twenty-four cases declared a family history of thyroid cancer, when compared with 11 controls. Individuals with an affected first-degree relative had a 4.5-fold (95% confidence interval [CI], 1.9-10.6) increased risk of differentiated thyroid cancer. This odds ratio (OR) was not significantly higher when a male first-degree relative was affected (OR, 10.0; 95% CI, 1.3-74.8) compared with a female (OR, 4.0; 95% CI, 1.5-10.3) and was not different for patients who had a nonaggressive thyroid microcarcinoma (OR, 3.5; 95% CI, 0.6-16.4) than those who had a larger cancer (OR, 6.0; 95% CI, 1.8-20.5). This OR was borderline significantly (p, 0.07) higher in Maohis (OR, 11.0; 95% CI, 2.4-48.8) than in individuals of mixed origin (OR, 2.1; 95% CI, 0.8-5.9).


CONCLUSIONS
Our study shows that the familial inheritance of differentiated thyroid cancer is particularly high in Maohi populations.
Brindel
Pauline
P
Radiation Epidemiology Group U1018, INSERM, Villejuif Cedex, France .
Doyon
Françoise
F
Bourgain
Catherine
C
Rachédi
Frédérique
F
Boissin
Jean-Louis
JL
Sebbag
Joseph
J
Shan
Larrys
L
Bost-Bezeaud
Frédérique
F
Petitdidier
Patrice
P
Paoaafaite
John
J
Teuri
Joseph
J
de Vathaire
Florent
F
D000293:Adolescent; D000328:Adult; D002648:Child; D005192:Family Health; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009689:Nuclear Warfare; D016017:Odds Ratio; D011114:Polynesia / Q000453:epidemiology; D012044:Regression Analysis; D013964:Thyroid Neoplasms / Q000453:epidemiology* / Q000235:genetics / Q000473:pathology