Neoadjuvant Therapy vs Standard Therapy in Locally Advanced Rectal Cancer

Inclusion Criteria: * diagnosed with rectal adenocarcinoma; * radiologically measurable tumor size; * general condition (ECOG 0-2 points); * stage II or III rectal tumor clinically (pelvic MRI and endorectal ultrasound), * in the absence of long-term spread of the disease (confirmed by radiological examinations (computed tomography of the thorax and abdomen)); * during preoperative proctoscopy, the tumor is detected 0 -15 cm from the anus; * Blood tests 28 days before the start of treatment: and general blood count: neutrophils greater than 1.5x10 9 / l, platelets greater than 100 x 10 9 / l, Hemoglobin greater than 80 g / l, liver enzymes (Aspartate aminotransferase (AST/GOT), alanine aminotransferase (ALT/GPT) not more than 3 times upper limit), and renal function (creatinine up to 1.5 times the upper limit of normal) is normal; women of childbearing potential - negative pregnancy test; • A signed informed consent form. Exclusion Criteria: * patients with signs of intestinal obstruction at the start of treatment; * previous lower abdominal radiation therapy; * other tumors over a five-year period; * pregnant or breastfeeding women; * men and women of childbearing potential who do not agree to use adequate contraception; * Patient co-morbidities that would make the patient unsuitable for this study or significantly interfere with the assessment of safety and toxicity.