The National Cancer Institute seeks a small business contractor to conduct health effects studies on cancer and other diseases in radiation-exposed populations in Ukraine, specifically following the Chernobyl accident. The contractor must manage multiple concurrent studies, update participant vital status, collect biological specimens, calculate radiation doses, and maintain databases while coordinating with Ukrainian institutions. Performance of services will be conducted in Ukraine, with local office staff fluent in English, Ukrainian, and Russian required. The anticipated period of performance is from July 1, 2027, to June 30, 2032, with a fixed-price contract expected to be awarded on or before June 15, 2027. No budget amount is specified.