ABSTRACT
Two groups of patients were involved in the study. In the first group (22 observations) radiation treatment was applied 4 times every other day with a single focal dose of 6 Gy (the total tumor dose 24-30 Gy, 1400-1600 NSD units, 70-85 TDF units). The period between the beginning of irradiation and surgery was usually 15-20 days. In the second group (12 observations) radiation was applied 4 times with a daily single dose of 5 Gy (total tumor dose 20 Gy, 1140 NSD units, 20 TDF units). Operation was performed 24-48 hours after the completion of radiation treatment. The so-called tumor damage index M +/- m was 36% +/- 4.8% in the first group, and 21% +/- 4.4% in the second group. The mitotic index decreased twice in the first group, and in the second group it dropped to zero. The obtained data demonstrate that in different schemes of radiation dose fractionation morphological changes observed in irradiated rectal adenocarcinomas are far from being similar. For objective evaluation of the changes different quantitative morphological criteria are needed.
