Results of combined treatment with neoadjuvant chemotherapy without radiation therapy and a short-course of radiation therapy in patients with intermediate-risk rectal cancer [Результаты комбинированного лечения с применением неоадъювантной химиотерапии без лучевой терапии и короткого курса лучевой терапии у больных раком прямой кишки промежуточного риска]

Background. Neoadjuvant chemotherapy (NACT) is a potential alternative to chemoradiation therapy (CRT) in intermediate-risk rectal cancer patients, helping to avoid the side effects of radiation therapy and may allow early prevention of distant metastasis. Aim – to study the safety and effectiveness of NACT in patients with intermediate-risk rectal cancer. Material and methods. Patients with histologically confirmed cancer of the mid-ampullar rectum T2–T3cN1–2M0, T2–4aN1–2M0 and T4aN0M0 of the upper ampullary rectum were included in the retrospective study. All patients of the study group underwent NACT according to the CapOx 4 course scheme. Evaluation of the effect was carried out on the basis of MRI of the small pelvis: in the presence of regression or stabilization, surgical treatment was performed, in the presence of progression, CRT, then surgery. After surgery, all patients were scheduled for adjuvant chemotherapy for a total duration of 6 months. Patients in the control group underwent neoadjuvant radiation therapy (25 Gy in fractions of 5 Gy) and then surgery for 4–8 weeks. The primary endpoints included pathological complete response rate (pCR) and 3-year disease-free survival (DFS). Results. The study included 117 patients in each group. 113 (96.5%) patients in the neoadjuvant chemotherapy group completed all 4 courses of chemotherapy. In 12 (10.3%) patients in the NACT group a complete pathological response (pCR) was noted, among patients who received only NACT followed by surgery (n=111) pCR was noted in 11 (9.9%) cases. The median follow-up was 36.2 months for both groups. The distant failure rate was 9 (7.7%) in the NACT group and 20 (17.1%) in the control group (p=0.046). There were no local recurrence. The 3-year OS was 90.6 and 92.5% (p=0.857), and the 3-year DFS was 86.1 and 80.8%, respectively (p=0.394). Conclusion. Neoadjuvant chemotherapy is a promising treatment option for rectal cancer patients with negative prognostic factors. © 2021 GEOTAR Media. All rights reserved

Predictive Factors and Risk Model for Positive Circumferential Resection Margin Rate after Transanal Total Mesorectal Excision in 2653 Patients with Rectal Cancer

The aim of this study was to determine the incidence of, and preoperative risk factors for, positive circumferential resection margin (CRM) after transanal total mesorectal excision (TaTME). Background: TaTME has the potential to further reduce the rate of positive CRM for patients with low rectal cancer, thereby improving oncological outcome. Methods: A prospective registry-based study including all cases recorded on the international TaTME registry between July 2014 and January 2018 was performed. Endpoints were the incidence of, and predictive factors for, positive CRM. Univariate and multivariate logistic regressions were performed, and factors for positive CRM were then assessed by formulating a predictive model. Results: In total, 2653 patients undergoing TaTME for rectal cancer were included. The incidence of positive CRM was 107 (4.0%). In multivariate logistic regression analysis, a positive CRM after TaTME was significantly associated with tumors located up to 1 cm from the anorectal junction, anterior tumors, cT4 tumors, extra-mural venous invasion (EMVI), and threatened or involved CRM on baseline MRI (odds ratios 2.09, 1.66, 1.93, 1.94, and 1.72, respectively). The predictive model showed adequate discrimination (area under the receiver-operating characteristic curve >0.70), and predicted a 28% risk of positive CRM if all risk factors were present. Conclusion: Five preoperative tumor-related characteristics had an adverse effect on CRM involvement after TaTME. The predicted risk of positive CRM after TaTME for a specific patient can be calculated preoperatively with the proposed model and may help guide patient selection for optimal treatment and enhance a tailored treatment approach to further optimize oncological outcomes