Incidence of leukemia and other cancers in Down syndrome subjects in Israel

Epidemiologic data have confirmed the high susceptibility of persons with D own syndrome (DS) to leukemia. The question of proneness to other kinds of cancer is still open. In this study we reassessed the incidence rates of le ukemia and other malignancies in Israeli DS subjects, based on the total po pulation. The target population consisted of all DS subjects in Israel in t he period of 1948-1995. Due to incompleteness of data, the target populatio n was not fully achieved, thus the study population was divided into 2 subg roups: subjects born in Israel between 1979 and 1995 (registry group) and c urrently or past-institutionalized subjects born before! 1979 (institution group). The cohort was linked with the Cancer Registry, and cancer cases th at had been diagnosed through December 1995 were subsequently identified. O bserved incidence rates were compared with expected rates in the general po pulation. Standardized incidence ratios (SIR) and 95% confidence intervals (CI) were computed for each disease category. Analyses were performed separ ately for each subgroup of the study population. In the registry group, 7 c ancer cases were observed, compared with 1.5 expected (SIR = 4.67, 95% Cl 1 .9-9.6), all leukemia cases. For the institution group a total of 17 cancer cases were observed, compared with 12.8 expected. These included 4 cases o f leukemia (SIR = 6.90, 95% Cl 1.90-17.70). An excess of gastric cancer in male subjects (SIR = 11.9, 95% Cl 1.3-42.9) was also observed. Significant excess of leukemia in DS population in Israel is in accordance with previou sly published data. An excess of gastric cancer in DS male subjects born be fore 1979, which has not been reported before, should be further explored. (C) 2001 Wiley-Liss, Inc.