Rectal cancer pathomorphology after preoperative radiation treatment.

Using histological and histochemical investigations and morphometric analysis the tumors and surrounding tissues of 70 rectal cancer patients were studied before and after preoperative radiotherapy with the total dose of 19.5 Gy and 40 Gy. Morphological changes proving the radiation damage of the tumors were determined. The extent of radiation damage depended on histological structure, degree of differentiation and radiation dose. The maximum damage was observed in poorly differentiated adenocarcinomas and the minimum--in colloidal cancer.