title: Risk of second primary cancer following differentiated thyroid cancer.
abstract: Concerns remain over the risk of cancer following differentiated thyroid carcinoma and its causes. Iodine-131 ((131)I) and external irradiation are known to have potential carcinogenic effects. Thyroid carcinoma is a polygenic disease which may be associated with other malignancies. We investigated the incidence of second cancer and its aetiology in a cohort of 875 patients (146 men, 729 women) with differentiated thyroid carcinoma originating from Basse-Normandie, France. Cancer incidence was compared with that of the general population of the Département du Calvados matched for age, gender and period. The cumulative proportion of second cancer was estimated using the life-table method. Factors that correlated with the risk of second cancer were studied using the Cox model. After a median follow-up of 8 years, 58 second cancers had been observed. Compared with general population incidence rates, there was an overall increased risk of second cancer in women [standardised incidence ratio (SIR)=1.52; P<0.01], but not in men (SIR=1.27; P>0.20). Increased risk related to cancers of the genitourinary tract (SIR=3.31; P<0.001), and particularly to cancer of the kidney (SIR=7.02; P<0.01). Multivariate analysis showed that age above 40 years (P<0.01) and a history of previous primary cancer (P<0.001) correlated with risk. In contrast, neither cervical irradiation nor cumulative activity of (131)I was related to the risk. These data confirm that women with differentiated thyroid carcinoma are at risk of developing a second cancer of the genitourinary tract and kidney. Only age and medical history of primary cancer before thyroid carcinoma are risk factors for second cancer. Common environmental or genetic factors as well as long-term carcinogenic effects of primary cancer therapy should be considered.
authors.affiliation: Service de Médecine Nucléaire, CLCC François Baclesse, Avenue Général Harris, 14076, Caen Cedex 05, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Berthe
authors.forename: Michel
authors.initials: M
authors.lastname: Henry-Amar
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Michels
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Rame
authors.forename: Pascaline
authors.initials: P
authors.lastname: Berthet
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Babin
authors.forename: Philippe
authors.initials: P
authors.lastname: Icard
authors.forename: Guy
authors.initials: G
authors.lastname: Samama
authors.forename: Françoise
authors.initials: F
authors.lastname: Galateau-Sallé
authors.forename: Jacques
authors.initials: J
authors.lastname: Mahoudeau
authors.forename: Stéphane
authors.initials: S
authors.lastname: Bardet
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000401:mortality* / Q000532:radiotherapy*; D019275:Radiopharmaceuticals / Q000627:therapeutic use; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D017678:Sex Distribution; D016019:Survival Analysis; D013964:Thyroid Neoplasms / Q000401:mortality* / Q000532:radiotherapy*
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals