Operative trends following the adoption of nonoperative management of rectal cancer.

BACKGROUND: Differentiating clinical near-complete and complete responses (cCR) after neoadjuvant therapy (NT) is challenging in rectal cancer patients. We hypothesized that magnetic resonance imaging staging limitations for low rectal cancers may increase the proportion of abdominoperineal resection (APR) with permanent colostomy for those without a cCR. METHODS: Single institution retrospective analysis of rectal cancer cases before and after adoption of nonoperative "watch and wait" (W&W) pathway. APR as a percentage of rectal resections was the primary outcome. RESULTS: There were 76 total mesorectal excisions (TME) in the pre-W&W group and 98 in the post-W&W group. NT was significantly more common in the post-W&W group. There was no significant difference in the APR primary outcome (pre-W&W APR 33.3% vs. post-W&W APR 26.5%, p = 0.482). APR patients had fewer complete TME grades (69.2% vs. 46.2%) and more pathologic complete responses (0% vs. 26.9%) in the post-W&W period. The cCR rate for patients with nonoperative management was 51.4% (n = 37) and 13.5% (n = 5) had regrowths, all of whom underwent salvage surgery. CONCLUSION: APR for those without a cCR to NT has not increased in the nonoperative management era. Balancing the pathologic complete response rate may require restaging some patients with clinical near-complete responses.

MRI in rectal cancer: An institutional real life analysis of technical parameters.

INTRODUCTION: MRI plays a key role in the preoperative staging of rectal cancers and choice of neoadjuvant radiochemotherapy. Yet, the acquisition and interpretation of rectum magnetic resonance imaging (MRI) turn out to be unequal, impacting patients'care. The present study aims at evaluating the quality of the acquisition of technical parameters of the rectal MRI performed by comparing them according to the various guidelines. METHODS: The medical MRI reports of all consecutive patients with locally advanced rectal cancer treated in a curative intent, by preoperative RCT and completion surgery were retrospectively reviewed over two periods (January 2010-December 2014 and January 2018 and December 2020) according to international 2012 and 2016 ESGAR and 2017 SAR MRI recommendation reports. RESULTS: During the first period (69 MRI performed), 58% of these MRI abided by the recommendations and 75% of essential criteria could be found in 25.5% of MRI reportings. During the second period (73 MRI performed), the protocol used by 6.8% of MR images abided by the 2016 Society of Gastrointestinal and Abdominal Radiology (ESGAR) recommendations and 39.7% abided by the Society of Abdominal Radiology (SAR) recommendations. 75% of essential criteria could be found in 52.3% of MRI reportings and 90% of essential criteria could be found in 6.2% of MRI reportings. DISCUSSION: In an era of increasing individualized patient care and conservative treatment focused on tumour response and prognostic factors, the present study showed that compliance to MRI protocols and reporting guidelines needs improving to upgrade patient care.

ACR Appropriateness Criteria® Staging of Colorectal Cancer: 2021 Update.

Preoperative imaging of rectal carcinoma involves accurate assessment of the primary tumor as well as distant metastatic disease. Preoperative imaging of nonrectal colon cancer is most beneficial in identifying distant metastases, regardless of primary T or N stage. Surgical treatment remains the definitive treatment for colon cancer, while organ-sparing approach may be considered in some rectal cancer patients based on imaging obtained before and after neoadjuvant treatment. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Reducing Acquisition Time of Diffusion Weighted MR Imaging of the Rectum with Simultaneous Multi-Slice Acquisition: A Reader Study.

RATIONALE AND OBJECTIVES: To assess the acquisition time and image quality of simultaneous multislice-accelerated diffusion-weighted imaging (SMS-DWI) versus conventional DWI (C-DWI) of the rectum. MATERIALS AND METHODS: In patients scheduled for a magnetic resonance imaging of the rectum, both SMS-DWI and C-DWI were performed on a 3T whole body magnetic resonance scanner. Image quality of the DWI sequences was reviewed by two independent radiologists who were blinded to the method of imaging using a five-point Likert scale: (score ranging from 1 (non-diagnostic) to 5 (excellent). The mean scores of SMS-DWI versus C-DWI were compared for the individual readers using a nonparametric test (Wilcoxon signed ranks). RESULTS: The SMS-DWI protocol acquisition time was 4:08 min vs. 7:24 min per patient, which led to a reduction of 44.1% for the C-DWI protocol, both excluding time for sequence specific adjustments (shimming). No statistical differences between the conventional-, and SMS- diffusion weighted images were seen for both readers. Mean overall image quality of the SMS-DWI TRACE images was 3.5 (SD: 1.3) and 3.3 (SD: 1.0) for reader 1 and reader 2, respectively. Mean overall image quality of the C-DWI TRACE images was 3.4 (SD: 1.3) and 3.2 (SD: 1.1) for reader 1 and reader 2, respectively. CONCLUSION: Optimized SMS-DWI compared to C-DWI in imaging of the rectum showed similar image quality while a significant acquisition time reduction was achieved.

Improving the completeness of structured MRI reports for rectal cancer staging.

PURPOSE: Assess the impact of a multifaceted intervention to improve the completeness of structured MRI reports for patients undergoing initial staging for rectal cancer. METHODS: This Institutional Review Board-approved retrospective study was performed at a large academic hospital. MRI reports for initial staging of rectal cancer in 2017 and 2019 were analyzed pre- and post-implementation of multiple quality improvement interventions in 2018, including harmonizing MRI protocols across the institution, educational conferences and modules, and requiring second opinion consultation for all MRI rectal cancer examinations. The primary outcome measure was the completeness of rectal cancer staging MRI reports, classified as optimal, satisfactory, or unsatisfactory based on the inclusion of 15 quality measures pre-defined by a consensus of abdominal and cancer imaging subspecialists, colorectal surgeons, and radiation oncologists at our institution, based on published recommendations. Fisher's exact test was used to evaluate changes in report quality and documentation of each quality measure. RESULTS: The study included 138 MRI reports, of which 72 (52%) were completed in 2017 pre-intervention. Post intervention, the proportion of optimal reports increased significantly from 52.8% (38/72) to 71.2% (47/66) (p = 0.035). Documentation of 1 quality measure (N stage) increased post intervention from 91.7% (66/72) to 100% (66/66) (p = 0.029). Documentation of 7 quality measures was 100% post intervention, with a documentation rate of > 95% for all quality measures except radial location of tumor. CONCLUSION: A combination of educational and system-wide interventions was associated with an improvement in the completeness of structured MRI reports for rectal cancer staging.

Accuracy of pelvic magnetic resonance imaging in local staging for rectal cancer: a single local health district, real world experience.

BACKGROUND: Neoadjuvant chemoradiotherapy plays a key role in reducing local recurrence rates for locally advanced rectal cancer. Pelvic magnetic resonance imaging (pMRI) is the gold standard for local clinical staging which allows clinicians to decide the treatment patients receive. A more advanced tumour or the presence of high-risk features on pMRI mean that neoadjuvant therapy will be offered to these patients. Understanding the accuracy of pMRI in local staging for rectal cancer is therefore crucial. METHODS: A retrospective cohort analysis of the accuracy of pMRI staging in a subgroup of patients who had primary rectal cancer surgery without neoadjuvant therapy was performed. Specificity and sensitivity for T-staging, N-staging and presence of high-risk features (threatened circumferential resection margin and extramural venous invasion) were calculated. Patients who had previous pelvic surgery, previous pelvic radiotherapy and previous surgery for continence were excluded. RESULTS: A total of 114 patients were included in the analysis. MRI accurately predicts T-stage in 56.6% and N-stage in 55.8%. Prediction of extramural disease was accurate in 51%. A negative circumferential resection margin was accurately predicted in 98.6% of patients. Overall adherence to reporting proforma was 15.8%. CONCLUSION: Overall, this study provided valuable information about the clinical staging of patients with rectal cancer who are at an early stage within a large regional catchment area in Australia with pMRI. These results allow us to assess the accuracy of our local staging with ramifications to the clinical decisions being made in the context of the more recent trials which questioned the need for neoadjuvant chemo-radiotherapy in all node positive patients.

The MRI assessment of SPECC (significant polyps and early colorectal cancer) lesions.

The development of high-resolution magnetic resonance imaging (MRI) has resulted in the ability to clearly depict the finer details of rectal wall anatomy. Careful specialist assessment of images obtained in patients with significant polyps and early rectal cancer lesions enables the identification of lesions that are confined to the bowel wall and amenable to organ preserving local excision. Currently, one-third of screen detected rectal cancers are limited to the bowel wall without nodal spread yet more than 90% undergo major excision surgery resulting in significant loss of bowel function, quality of life and at high economic cost. The SPECC initiative has highlighted the need for specialist training and accreditation of radiology specialists in precision assessment of significant polyps and early rectal cancer. The detailed assessment will enable provision of detailed roadmaps for surgeons and gastroenterologists to facilitate definitive excision of more lesions using minimally invasive endoscopic technique. Finally, the use of high resolution MRI in surveillance will enable the close monitoring of such patients where the preservation of the rectum has been achieved.

Optimal Imaging Strategies for Rectal Cancer Staging and Ongoing Management.

OPINION STATEMENT: Imaging determines the optimal treatment for rectal cancer patients. High-resolution magnetic resonance imaging (MRI) overcomes many of the known limitations of previous methods. When performed in accordance with the recommended standards, MRI enables accurate staging of both early and advanced rectal cancer, accurate response assessment, the delineation of recurrent disease and planning surgical treatment in a safe and effective manner. Tumour-related high-risk features with known adverse outcomes can be preoperatively identified and treated with neoadjuvant chemoradiotherapy. Further, MRI post-treatment tumour response assessment using TRG grading system also predicts the likely survival outcomes and in the future will be used to modify treatment further by stratification into good and poor responders. There is a paucity of literature with validated outcome data concerning use of diffusion-weighted imaging and positron emission tomography (PET)/computed tomography (CT), and in the absence of any validated methods and outcome data, their use in the initial assessment and restaging after treatment is limited to research protocols. Combination MRI and CT is essential for distant spread assessment and recurrent disease, and currently PET-CT is sometimes used in the workup of patients with recurrent and metastatic disease.

Impact of a Structured Report Template on the Quality of MRI Reports for Rectal Cancer Staging.

OBJECTIVE: The purpose of this study is to assess the impact of implementing a structured report template on the quality of MRI reports for rectal cancer staging. MATERIALS AND METHODS: After excluding examinations performed after surgery or neoadjuvant therapy, we analyzed all rectal cancer staging MRI reports finalized at an academic medical center 12 months before and after an intervention consisting of implementing a structured report template integrated into the institution's speech recognition system. The primary outcome measure was the quality of rectal cancer staging MRI reports classified as optimal, satisfactory, or unsatisfactory, on the basis of the documentation of 14 quality measures predefined by a consensus of the institution's abdominal radiology subspecialists. Chi-square and t tests were used to assess differences in report quality and documentation of each discrete quality measure before and after the intervention. RESULTS: The study cohort included 106 MRI reports from 104 patients (mean age, 60 years; 58.5% male); 52 (49.1%) of the reports were completed before implementation of the structured report template. After implementation, the proportion of total reports classified as optimal or satisfactory increased from 38.5% (20/52) to 70.4% (38/54) (p = 0.0010). No reports generated before the intervention were classified as optimal, whereas 40.7% (22/54) of reports were classified as optimal after the intervention. CONCLUSION: Implementation and voluntary use of a structured report template improved the quality of MRI reports for rectal cancer staging compared with free-text format.

A structured approach to reporting rectal cancer with magnetic resonance imaging.

OBJECTIVE: Rectal cancers are the second most common GI carcinoma. Prognosis and therapeutic decisions hinge on the extent of disease. We present a comprehensive structured approach for staging rectal cancer using MRI to ensure the clear, concise, and standardized communication of disease extent to guide optimal treatment planning. CONCLUSION: MRI is crucial for local staging of rectal cancer. A standardized approach to reporting of rectal MRI focused on communication of essential treatment planning and prognostic indicators ensures maximal added value to referring physicians to guide appropriate management.

Magnetic resonance imaging of rectal cancer: staging and restaging evaluation.

Magnetic resonance imaging is used to non-invasively stage and restage rectal adenocarcinomas. Accurate staging is important as the depth of tumor extension and the presence or absence of lymph node metastases determines if an individual will undergo preoperative neoadjuvant chemoradiation. Accurate description of tumor location is important for presurgical planning. The relationship of the tumor to the anal sphincter in addition to the depth of local invasion determines the surgical approach used for resection. High-resolution T2-weighted imaging is the primary sequence used for initial staging. The addition of diffusion-weighted imaging improves accuracy in the assessment of treatment response on restaging scans. Approximately 10%-30% of individuals will experience a complete pathologic response following chemoradiation with no residual viable tumor found in the resected specimen at histopathologic assessment. In some centers, individuals with no residual tumor visible on restaging MR who are thought to be at high operative risk are monitored with serial imaging and a "watch and wait" approach in lieu of resection. Normal rectal anatomy, MR technique utilized for staging and restaging scans, and TMN staging are reviewed. An overview of surgical techniques used for resection including newer, minimally invasive endoluminal techniques is included.

Rectal cancer staging: Correlation between the evaluation with radial echoendoscope and rigid linear probe.

BACKGROUND AND OBJECTIVES: The National Cancer Institute estimated 40,340 new cases of rectal cancer in the United States in 2013. The correct staging of rectal cancer is fundamental for appropriate treatment of this disease. Transrectal ultrasound is considered one of the best methods for locoregional staging of rectal tumors, both radial echoendoscope and rigid linear probes are used to perform these procedures. The objective of this study is to evaluate the correlation between radial echoendoscopy and rigid linear endosonography for staging rectal cancer. PATIENTS AND METHODS: A prospective analysis of 48 patients who underwent both, radial echoendoscopy and rigid linear endosonography, between April 2009 and May 2011, was done. Patients were staged according to the degree of tumor invasion (T) and lymph node involvement (N), as classified by the American Joint Committee on Cancer. Anatomopathological staging of surgical specimen was the gold standard for discordant evaluations. The analysis of concordance was made using Kappa index. RESULTS: The general Kappa index for T staging was 0.827, with general P < 0.001 (confidence interval [CI]: 95% 0.627-1). The general Kappa index for N staging was 0.423, with general P < 0.001 (CI: 95% 0.214-0.632). CONCLUSION: The agreement between methods for T staging was almost perfect, with a worse outcome for T2, but still with substantial agreement. The findings may indicate equivalence in the diagnostic value of both flexible and rigid devices. For lymph node staging, there was moderate agreement between the methods.

MR imaging for rectal cancer: the role in staging the primary and response to neoadjuvant therapy.

Pre-operative staging is an essential aspect of modern rectal cancer management and radiological assessment is central to this process. An ideal radiological assessment should provide sufficient information to reliably guide pre-operative decision-making. Technical advances allow high-resolution imaging to not only provide prognostic information but to define the anatomy, helping the surgeon to anticipate potential pitfalls during the operation. The main imaging modality for local staging of rectal cancer is Magnetic Resonance Imaging (MRI), as it defines the tumour and relevant anatomy providing the most detail on the important prognostic factors that influence treatment choice. In addition, there is an emerging role for MRI in the assessment of the response to neoadjuvant therapy. This article is an evidence-based review of rectal cancer staging focusing on post-treatment assessment of response using MRI. The discussion extends into the implications for reliably assessing response and how this may influence future rectal cancer management.