Myeloid leukemia in Prader-Willi syndrome

Objective To evaluate the frequency of cancers recorded by the Surveillance, Epidemiology, and End Results (SEER) Program in persons with Prader-Willi syndrome (PWS) Methods A survey was mailed in 1994 to 1852 registrants of the PWS Association (USA) inquiring about a diagnosis of any type of benign tumor or cancer (malignant tumor or leukemia). The risk of developing cancer was then estimated by comparing the observed number of cancers in the PWS population during 1975 to 1994 to the expected number in the general US population using data from the 1971-1994 SEER Cancer Statistics Review. Results Of the 1852 persons, 1160 (63%) responded, or 75% (1160/1552) of those who received the survey. The total number of observed cancer cases in the PWS study population was 8 versus 4.80 expected in the general US population (P =.1610). Three cases of myeloid leukemia were observed versus 0.075 leukemias expected (P =.0001). Conclusions There appears to be an increased risk of myeloid leukemias, but not other cancers, among persons with PWS.