Thyroid cancer in French Polynesia between 1985 and 1995

Between 1966 and 1974, France performed 41 atmospheric nuclear weapon tests in the Mururoa and Fangataufa atolls in French Polynesia (FP). We performed a geographical analysis of thyroid cancer incidence, using data of the cancer registry of FP, medical evacuation files, insurance records and hospital and pathology laboratory files. A total of 153 thyroid cancers were diagnosed between 1985 and 1995 in the population born before 1976 and residing in FP. The incidence was 2 to 3 times larger in FP than in Maoris of New Zealand and Hawaiians of Hawaii. Although mass screening for thyroid cancer, which would strongly bias comparison between populations, has never been performed in French Polynesia, nor in Hawaii or in New-Zealand, the difference in thyroid cancer incidence between French Polynesia and the other populations could be due to a difference in the accessibility of medical care. Because the difference between Polynesian and reference populations was not larger for Polynesians who were children during the tests than for Polynesians born earlier, as would be expected in case of radio-iodine contamination, the high thyroid cancer rates in FP could hardly be attributed to radio-iodine fallout. Number of thyroid cancers diagnosed in French Polynesia between 1985 and 1995 and standardized incidence ratio (SIR) relative to incidence among New Zealand Maoris and Hawaiians from Hawaii Sex Population born before 1950, not exposed to fallout during childhood Population born in 1950-1975, potentially exposed to fallout during childhood Thyroid cancers SIR (95%CI), Compared to Hawaiians SIR (95%CI), compared to NZ Maoris Thyroid cancers SIR (95%CI) compared to Hawaiians SIR (95%CI) Compared to NZ Maoris M 69 1.9 (1.4 3.5) 2.7 (2.0 ; 5.0) 49 1.9 (1.1 ; 3.2) 2.5 (1.7 ; 4.8) F 25 2.3 (1.2 6.4) 3.4 (2.0 ; 12.8) 10 1.1 (0.5 ; 5.0) 5.2 (1.7 ; + ) Based on few cases, a non-significant (p=0.1) increase with a decreasing distance between Mururoa and the birth place was observed in women born between 1950 and 1975 for thyroid cancer. Thyroid cancer incidence per 10 personyears (number of cases) during the period 1985-1995, according to the archipelago of bith and the distance between Mururoa and the place of birth, for the populations born before 1950 and between 1950 and 1975.