Complex-type chromosomal exchanges in blood lymphocytes during radiation therapy correlate with acute toxicity

The new method of chemical-induced premature chromosome condensation combin ed with fluorescence in situ hybridization was used to analyze chromosomal damage in peripheral blood mononuclear lymphocytes of patients undergoing r adiation treatment for esophageal cancer with high-energy X-rays or acceler ated carbon ions at the National Institute of Radiological Sciences (Chiba, Japan). Total number of aberrant cells correlated with radiation held size , but no correlation was found with acute toxicity. A high frequency of com plex-type exchanges were also recorded. This aberration type presented a hi gh individual variability, and correlated well with the acute morbidity. Cy togenetic analysis by interphase chromosome painting is proposed as a usefu l tool for monitoring normal tissue effects during radiotherapy. (C) 2000 E lsevier Science Ireland Ltd, All rights reserved.