Effects of Preoperative Radiotherapy on Long-Term Bowel Function in Patients With Rectal Cancer Treated With Anterior Resection: A Systematic Review and Meta-analysis

Predicting bowel function after diverting stoma closure in patients with rectal cancer

Background

Patients with rectal cancer undergoing laparoscopic anterior resection and diverting stomas often suffer from bowel dysfunction after stoma closure, impairing their quality of life. This study aims to develop a machine learning tool to predict bowel function after diverting stoma closure.

Methods

Clinicopathological data and post-operative follow-up information from patients with mid-low rectal cancer after diverting stoma closure were collected and analyzed. Patients were randomly divided into training and test sets in a 7:3 ratio. A machine learning model was developed in the training set to predict major low anterior resection syndrome (LARS) and evaluated in the test set. Decision curve analysis (DCA) was used to assess clinical utility.

Results

The study included 396 eligible patients who underwent laparoscopic anterior resection and diverting stoma in Tongji Hospital affiliated with Huazhong University of Science and Technology from 1 January 2012 to 31 December 2020. The interval between stoma creation and closure, neoadjuvant therapy, and body mass index were identified as the three most crucial characteristics associated with patients experiencing major LARS in our cohort. The machine learning model achieved an area under the receiver operating characteristic curve (AUC) of 0.78 [95% confidence interval (CI): 0.74-0.83] in the training set (n=277) and 0.74 (95% CI: 0.70-0.79) in the test set (n=119), and area under the precision-recall curve (AUPRC) of 0.73 and 0.69, respectively, with sensitivity of 0.67 and specificity of 0.66 for the test set. DCA confirmed clinical applicability.

Conclusions

This study developed a machine learning model to predict major LARS in rectal cancer patients after diverting stoma closure, aiding their decision-making and counseling.

Neoadjuvant treatment of colorectal cancer: comprehensive review

BACKGROUND

Neoadjuvant therapy has an established role in the treatment of patients with colorectal cancer. However, its role continues to evolve due to both advances in the available treatment modalities, and refinements in the indications for neoadjuvant treatment and subsequent surgery.

METHODS

A narrative review of the most recent relevant literature was conducted.

RESULTS

Short-course radiotherapy and long-course chemoradiotherapy have an established role in improving local but not systemic disease control in patients with rectal cancer. Total neoadjuvant therapy offers advantages over short-course radiotherapy and long-course chemoradiotherapy, not only in terms of increased local response but also in reducing the risk of systemic relapses. Non-operative management is increasingly preferred to surgery in patients with rectal cancer and clinical complete responses but is still associated with some negative impacts on functional outcomes. Neoadjuvant chemotherapy may be of some benefit in patients with locally advanced colon cancer with proficient mismatch repair, although patient selection is a major challenge. Neoadjuvant immunotherapy in patients with deficient mismatch repair cancers in the colon or rectum is altering the treatment paradigm for these patients.

CONCLUSION

Neoadjuvant treatments for patients with colon or rectal cancers continue to evolve, increasing the complexity of decision-making for patients and clinicians alike. This review describes the current guidance and most recent developments.

Preventative strategies for low anterior resection syndrome

BACKGROUND

A common and debilitating complication of low anterior resection for rectal cancer is low anterior resection syndrome (LARS). As a multifactorial entity, LARS is poorly understood and challenging to treat. Despite this, prevention strategies are commonly overlooked. Our aim was to review the pathophysiology of LARS and explore current evidence on the efficacy and feasibility of prophylactic techniques.

METHODS

A literature review was performed between [1st January 2000 to 1st October 2023] for studies which investigated preventative interventions for LARS. Mechanisms by which LARS develop are described, followed by a review of prophylactic strategies to prevent LARS. Medline, Cochrane, and PubMed databases were searched, 189 articles screened, 8 duplicates removed and 18 studies reviewed.

RESULTS

Colonic dysmotility, anal sphincter dysfunction and neorectal dysfunction all contribute to the development of LARS, with the complex mechanism of defecation interrupted by surgery. Transanal irrigation (TAI) and pelvic floor rehabilitation (PFR) have shown benefits in preventing LARS, but may be limited by patient compliance. Intraoperative nerve monitoring (IONM) and robotic-assisted surgery have shown some promise in surgically preventing LARS. Nerve stimulation and other novel strategies currently used in treatment of LARS have yet to be investigated in their roles prophylactically.

CONCLUSIONS

To date, there is a limited evidence base for all preventative strategies including IONM, RAS, PFP and TAI. These strategies are limited by either access (IONM, RAS and PFP) or acceptability (PFP and TAI), which are both key to the success of any intervention. The results of ongoing trials will serve to assess acceptability, while technological advancement may improve access to some of the aforementioned strategies.