[Prognostic value of rectal cancer regression after preoperative chemoradiation therapy].

Despite the international experience enriched in the number of observations of combination treatment in patients with rectal cancer, many issues remain to be the subject-matter of the discussion. This also applies to the estimation of the value of tumor regression after neoadjuvant chemoradiation therapy in order to develop indications for sphincter-sparing operations depending on the site of a tumor in the organ and their impact on long-term treatment results. The authors have gained experience with combination treatment in 157 patients with rectal cancer (T2-4 N0-2 M0) receiving neoadjuvant chemoradiation therapy in a cumulative radiation dose of 39.5-47 Gy and radical surgery 4-6 weeks after radiation. The direct effect of chemoradiation therapy has been investigated using a set of studies involving ultrasonography, magnetic resonance imaging, endoscopic diagnosis, as well as the data of a postoperative morphological study of primary tumor and lymph nodes. The authors have evaluated the impact of preoperative chemoradiation therapy on the rate and degree of resorption of a primary tumor, including the depth of its invasion through the intestinal wall and exit into the cellular tissue, its localization in the organ and the distance to the anus, a difference in the preoperative estimation of stages and according to the data of pathomorphological studies of intraoperative specimens, etc. The degree of tumor resorption was comparatively analyzed with the long-term results and the rate of sphincter-sparing operations.