MRI-based radiomics to predict neoadjuvant chemoradiotherapy outcomes in locally advanced rectal cancer: A multicenter study.

Background and purpose: Predicting tumour response would be useful for selecting patients with locally advanced rectal cancer (LARC) for organ preservation strategies. We aimed to develop and validate a prediction model for T downstaging (ypT0-2) in LARC patients after neoadjuvant chemoradiotherapy and to identify those who may benefit from consolidation chemotherapy. Materials and methods: cT3-4 LARC patients at three tertiary medical centers from January 2012 to January 2019 were retrospectively included, while a prospective cohort was recruited from June 2021 to March 2022. Eight filter (principal component analysis, least absolute shrinkage and selection operator, partial least-squares discriminant analysis, random forest)-classifier (support vector machine, logistic regression) models were established to select radiomic features. A nomogram combining radiomics and significant clinical features was developed and validated by calibration curve and decision curve analysis. Interaction test was conducted to investigate the consolidation chemotherapy benefits. Results: A total of 634 patients were included (426 in training cohort, 174 in testing cohort and 34 in prospective cohort). A radiomic prediction model using partial least-squares discriminant analysis and a support vector machine showed the best performance (AUC: 0.832 [training]; 0.763 [testing]). A nomogram combining radiomics and clinical features showed significantly better prognostic performance (AUC: 0.842 [training]; 0.809 [testing]) than the radiomic model. The model was also tested in the prospective cohort with AUC 0.727. High-probability group (score > 81.82) may have potential benefits from ≥ 4 cycles consolidation chemotherapy (OR: 4.173, 95 % CI: 0.953-18.276, p = 0.058, pinteraction = 0.021). Conclusion: We identified and validated a model based on multicenter pre-treatment radiomics to predict ypT0-2 in cT3-4 LARC patients, which may facilitate individualised treatment decision-making for organ-preservation strategies and consolidation chemotherapy.

GEC ESTRO ACROP consensus recommendations for contact brachytherapy for rectal cancer.

PURPOSE: To issue consensus recommendations for contact X-Ray brachytherapy (CXB) for rectal cancer covering pre-treatment evaluation, treatment, dosimetric issues and follow-up. These recommendations cover CXB in the definitive and palliative setting. METHODS: Members of GEC ESTRO with expertise in rectal CXB issued consensus-based recommendations for CXB based on literature review and clinical experience. Levels of evidence according to the Oxford Centre for Evidence based medicine guidance are presented where possible. RESULTS: The GEC ESTRO ACROP consensus recommendations support the use of CXB to increase the chances of clinical complete remission and cure for patients who are elderly with high surgical risk, surgically unfit or refusing surgery. For palliative treatment, the use of CXB is recommended for symptomatic relief and disease control. The use of CXB in an organ-preservation setting in surgically fit patients is recommended within the setting of a clinical trial or registry. CONCLUSIONS: The GEC ESTRO ACROP recommendations for CXB are provided. Recommendations towards standardisation of reporting and prescription are given. Practitioners are encouraged to follow these recommendations and to develop further clinical trials to examine this treatment modality and increase the evidence base for its use. The routine collection of outcomes both clinical and patient-reported is also encouraged.

ACO/ARO/AIO-21 - Capecitabine-based chemoradiotherapy in combination with the IL-1 receptor antagonist anakinra for rectal cancer Patients: A phase I trial of the German rectal cancer study group.

Purpose: Recent advances in the treatment algorithm of locally advanced rectal cancer (LARC) have significantly improved complete response (CR) rates and disease-free survival (DFS), but therapy resistance, with its substantial impact on outcomes and survival, remains a major challenge. Our group has recently unraveled a critical role of interleukin-1α (IL-1α) signaling in activating inflammatory cancer-associated fibroblasts (iCAFs) and mediating radiation-induced senescence, extracellular matrix (ECM) accumulation, and ultimately therapy resistance. We here summarize the recently initiated ACO/ARO/AIO-21 phase I trial, testing the IL-1 receptor antagonist (IL-1 RA) anakinra in combination with fluoropyrimidine-based chemoradiotherapy (CRT) for advanced rectal cancer. Methods/Design: The ACO/ARO/AIO-21 is an investigator-driven, prospective, open-labeled phase I drug-repurposing trial assessing the maximum tolerated dose (MTD) of capecitabine administered concurrently to standard preoperative radiotherapy (45 Gy in 25 fractions followed by 9 Gy boost in 5 fractions) in combination with fixed doses of the IL1-RA anakinra (100 mg, days -10 to 30). Capecitabine will be administered using a 3 + 3 dose-escalation design (500 mg/m2 bid; 650 mg/m2 bid; 825 mg/m2 bid, respectively) from day 1 to day 30. Response assessment including digital rectal examination (DRE), endoscopy and pelvic magnetic resonance imaging (MRI) is scheduled 10 weeks after completion of CRT. For patients achieving clinical complete response (cCR), primary non-operative management is provided. In case of non-cCR immediate total mesorectal excision (TME) will be performed. Primary endpoint of this phase I trial is the MTD of capecitabine. Discussion: Based on extensive preclinical research, the ACO/ARO/AIO-21 phase I trial will assess whether the IL-1RA anakinra can be safely combined with fluoropyrimidine-based CRT in rectal cancer. It will further explore the potential of IL-1 inhibition to overcome therapy resistance and improve response rates. A comprehensive translational research program will expand our understanding from a clinical perspective and may help translate the results into a randomized phase II trial.

A study on the clinical application of greater omental pedicle flap transplantation to correct anterior resection syndrome in patients with low rectal cancer.

INTRODUCTION: Low anterior resection syndrome (LARS) is the most common complication after total mesorectal excision (TME) in patients with low rectal cancer and has been a challenge in colorectal surgery that severely impacts the quality of life of patients. This study aimed to introduce a revised surgical procedure which could effectively maintain rectal compliance and significantly improve LARS after the operation. METHODS: We performed mesorectal reconstruction after routine Dixon TME using greater omental pedicle flap transplantation in 11 patients with low rectal cancer (5 cases of preoperative neoadjuvant chemoradiotherapy, 5 cases of preoperative neoadjuvant chemotherapy, and 1 case of postoperative adjuvant chemotherapy), thereby simulating the initial anatomical structure of the mesorectum and significantly reducing the postoperative anterior resection syndrome. The lars precision syndrome assessment scale (LARSS) was used to access the LARS. RESULTS: At 12 weeks after the 11 patients recovered from the anal defecation function, the average score on the LARS questionnaire was 25.5 ± 1.5 (minor). The average time at which anal function began to recover was 6.2 ± 2.6 weeks after surgery. The recovery was rapid, as the rectal and anal function of all patients generally returned to normal levels within 12 weeks, and the quality of life was close to that before surgery. CONCLUSION: Greater omental flap transplantation can significantly improve LARS after Dixon TME in patients with low rectal cancer.

Is pull-through an acceptable replacement for low anterior resection for rectal cancers in low-income setting? A case-control study.

BACKGROUND: Colorectal cancers are the second most common cancers overall and are the third deadliest cancers. Complete resection is the treatment of choice for rectal cancers and chemoradiotherapy (CRT) is strongly recommended in stage 2 and 3. Low anterior resection (LAR) is the most common procedure used, but it requires the use of stapler which might be very expensive as one study estimated the median cost of LAR inpatients to be over 13.000 USD. However, coloanal pull-through (PT) used to be the common procedure before introducing staplers in the twentieth century and can be less expensive, but with higher complication rates. MATERIALS AND METHODS: This is a retrospective case-control study from patients' records who underwent either LAR or PT for their rectal cancer in Syria. All patients had either stage 2 or 3 cancer and were treated by the same group of surgeons and received the same adjuvant and neoadjuvant CRT protocol. Patients from both groups had the same prognosis and stages. RESULTS: This study included 60 participants, of which, 30 had LAR and 30 had PT. They all had successful removal of the cancer and follow-ups were for 1 year after the surgery. There were no significant differences between the two procedures in post-operative leak, urinary retention, stricture, sexual function and recurrence (p > 0.05). However, post-operative incontinence was more frequent with PT (p = 0.027). CONCLUSION: PT can be an acceptable substitute of LAR in low income settings despite having higher incidence of incontinence.

Metformin with neoadjuvant chemoradiation to improve pathologic response in rectal cancer: A pilot phase I/II trial.

PURPOSE: Neoadjuvant radiotherapy with or without chemotherapy decreases the risk of local recurrence after surgery for rectal cancer. Emerging data suggest that diabetic patients on metformin may have improved cancer outcome after radiotherapy. A single institutional pilot study was performed to determine if metformin given concurrently with long course chemoradiation (CRT) may improve pathologic complete response (pCR) in non-diabetic rectal cancer patients. The study was designed to construct a confidence interval (CI) for the pCR rate to determine the sample size for a phase 2 trial. METHODS: Non-diabetic patients with biopsy confirmed rectal cancer deemed candidates for long course neoadjuvant CRT were invited to participate. Radiation consisted of 50.4 Gy in 28 daily fractions with concurrent daily capecitabine (825 mg/m2 twice daily). Participants self-administered metformin (500 mg of twice daily) 2 weeks prior to, during and for 4 weeks after CRT. RESULTS: A total of 16 patients were accrued. One patient withdrew from the study. Only grade 1 or 2 adverse events were observed. Three patients had a clinical complete response (cCR) and did not undergo surgery. Of the 12 patients who underwent surgery, there were two pCRs. For the combined pCR/cCR rate of 33% (95% CI 19-47%), a total of 85 patients will be required to yield a 95% CI with a 10% margin of error. CONCLUSIONS: Adding metformin to neoadjuvant CRT for rectal cancer does not appear to enhance toxicities. These results will be used to refine the design and conduct of a future phase 2 trial to determine whether adding metformin to CRT improves pCR/cCR rates.