[Radiation pathomorphosis in single and intensive-concentrated preoperative irradiation of colon cancer].

Single (7.5 Gy) or intensive-concentrated (20 Gy at 5 daily fractions of 4 Gy each) preoperative irradiation was given to 42 colon cancer patients. Operation was performed not later than 24 h after single irradiation and 1-3 days after intensive-concentrated irradiation. Radiation pathomorphosis was studied on histological and electro-microscopic examination of biopsy specimens. Dystrophic changes of tumor cells were noted following the use of both methods, though more noticeable ones were observed after intensive-concentrated irradiation. Obstruction of the microcirculatory bed of a tumor appeared to be a characteristic sign of a tumor stroma response both in single and fractionated irradiation. It was assumed that the latter together with direct radiation damage of tumor cells could be very important to the prevention of implantation recurrences and metastases.