Morphological evaluation of damage to esophageal tumors caused by preoperative irradiation

Post-radiation changes were studied in 21 patients suffering from esophageal cancer who had undergone preoperative irradiation. The results of quantitative morphological analysis were compared with the data obtained from examination of 15 patients operated for tumors but unexposed to radiation. Tumor damage index proved to be 35.0%+-4. Mitotic index remained unchanged, while pathological mitoses in tumors increased four times after irradiation (62.0%+-5.8 as compared with 15.4%+-4.4). They are mostly observed in the dispersion of chromosomes in metaphase. It is concluded that in order to adequately visualise radiation-induced damage to tumor, different morphological criteria should be used in its evaluaton, depending on the length of post-irradiation period