Cytogenetic damage in peripheral blood lymphocytes of cancer patients prior to radiotherapy.

In a study comprised of 79 cancer patients selected for determining chromosomal damage to peripheral blood lymphocytes before, during, and after radiotherapy, four patients revealed chromosome aberrations prior to radiotherapy in 5% of the cells examined. The most common anomalies were dicentric chromosomes and translocations of unidentified chromosomal material on the long or short arm. We attribute this high incidence of chromosomal aberrations before radiotherapy to a combination of various external factors that are known to cause such cytogenetic injury.