Accuracy of Magnetic Resonance Imaging in Staging Rectal Cancer with Multidisciplinary Team: A Single-Center Experience

Accuracy of Baseline Magnetic Resonance Imaging for Staging Rectal Cancer Patients Proceeding Directly to Surgery

BACKGROUND AND OBJECTIVES

High-resolution magnetic resonance imaging (MRI) accuracy for staging preoperative rectal cancer varies across studies. We examined MRI accuracy for T- and N-staging of rectal cancer compared with final histopathology of the resected specimen in a large Australian cohort who did not receive neoadjuvant therapy or radiation.

METHODS

Retrospective analysis of prospectively-collected clinical data from 153 rectal adenocarcinomas locally staged by high-resolution MRI between January 2012 and December 2019 that did not undergo chemoradiotherapy or radiation before surgery. T- and N-stage agreement between MRI and final histopathology was assessed using Kappa statistic. Agreement at each T-stage was evaluated using log-linear modeling. N-staging accuracy was examined using positive and negative predictive values.

RESULTS

Overall agreement between MRI and final histopathology for T-stage and N-stage was 55% and 65%, respectively. Kappa statistic found higher agreement between MRI and final histopathology for T-staging (κ = 0.33) versus N-staging (κ = 0.18). MRI correctly assessed 91% of T1 tumors, 43% of T2 tumors, 65% of T3 tumors, and 80% of T4 tumors. MRI accuracy was higher for N-negative tumors (74.1%) than for N-positive tumors (44.4%).

CONCLUSION

MRI is moderately accurate at staging T1, T3, and T4 rectal tumors but caution when staging tumors as T2 is advised. Greater accuracy for staging N-negative versus N-positive tumors is indicated.

The predicting value of post neoadjuvant treatment magnetic resonance imaging: a meta-analysis

INTRODUCTION

Neoadjuvant therapy has become standard of care for locally advanced rectal cancer patients. It is correlated with improved clinical and pathological outcomes, including significant tumor downstaging and organ preservation in certain patients. Magnetic resonance imaging (MRI), which has become the standard for pre-operative staging, is also used for clinical and pre-operative restaging following pre-operative treatment. In this meta-analysis, we aimed to evaluate the concordance between restaging MRI (following the completion of neoadjuvant therapy) and postoperative pathology result.

METHODS

We conducted a meta-analysis following the PRISMA 2020 guidelines. Two independent reviewers searched PubMed and Google Scholar for studies reporting restaging MRI results compared to pathological outcomes. Outcomes included tumor and nodal staging, circumferential resection margin (CRM) and pathological complete response (pCR).

RESULTS

Out of 25,000 studies found on the initial search; 33 studies were included. The studies were published between 2005 and 2023 and included 4100 patients (57.14% males). The median age was 62.45 years. The median interval between the conclusion of neoadjuvant treatment and the subsequent restaging MRI was 6 weeks (range 4.14-8.8 weeks). The pooled concordance rates between the restaging MRI and the pathological outcomes for ypT stage and ypN stage were 63.9% (54.5%-73.3%, I2 = 96.02%) and 60.9% (42.9%-78.9%, I2 = 98.96%), respectively. The pooled concordance for predicting pathological complete response was 70.4% (53.6%-87.1%, I2 = 98.21%). As for the circumferential resection margin (CRM), the pooled concordance was 78.2.% (71.6%-84.8%, I2 = 83.76%).

CONCLUSIONS

Our findings suggest that the concordance rates between restaging MRI and pathological outcomes in rectal cancer patients following neoadjuvant therapy are limited. Caregivers should take these results into consideration when making clinical decisions about these patients. More data should be gathered about the predictive value of MRI after total neoadjuvant therapy as well as immunotherapy in rectal cancer patients.

Prospective and multi-reader evaluation of deep learning reconstruction-based accelerated rectal MRI: image quality, diagnostic performance, and reading time

OBJECTIVES

To evaluate deep learning reconstruction (DLR)-based accelerated rectal magnetic resonance imaging (MRI) compared with standard MRI.

MATERIALS AND METHODS

Patients with biopsy-confirmed rectal adenocarcinoma between November/2022 and May/2023 in a single centre were prospectively enrolled for an intra-individual comparison between standard fast spin-echo (FSEstandard) and DLR-based FSE (FSEDL) sequences. Quantitative and qualitative image quality metrics of the pre-therapeutic MRIs were evaluated in all patients; diagnostic performance and evaluating time for T-staging, N-staging, extramural vascular invasion (EMVI), and mesorectal fascia (MRF) status was further analysed in patients undergoing curative surgery, with histopathologic results as the diagnostic gold standard.

RESULTS

A total of 117 patients were enrolled, with 60 patients undergoing curative surgery. FSEDL reduced the acquisition time by 65% than FSEstandard. FSEDL exhibited higher signal-to-noise ratios, contrast-to-noise ratio, and subjective scores (noise, tumour margin clarity, visualisation of bowel wall layering and MRF, overall image quality, and diagnostic confidence) than FSEstandard (p < 0.001). Reduced artefacts were observed in FSEDL for patients without spasmolytics (p < 0.05). FSEDL provided higher T-staging accuracy by junior readers than FSEstandard (reader 1, 58.33% vs 70.00%, p = 0.016; reader 3, 60.00% vs 76.67%, p = 0.021), with similar N-staging, EMVI, and MRF performance. No significant difference was observed for senior readers. FSEDL exhibited shorter diagnostic time in all readers' T-staging and overall evaluation, and junior readers' EMVI and MRF (p < 0.05).

CONCLUSION

FSEDL provided improved image quality, reading time, and junior radiologists' T-staging accuracy than FSEstandard, while reducing the acquisition time by 65%.

CLINICAL RELEVANCE STATEMENT

DLR is clinically applicable for rectal MRI, providing improved image quality with shorter scanning time, which may ease the examination burden. It is beneficial for diagnostic optimisation in improving junior radiologists' T-staging accuracy and reading time.

KEY POINTS

The rising incidence of rectal cancer has demanded enhanced efficiency and quality in imaging examinations. FSEDL demonstrated superior image quality and had a 65% reduced acquisition time. FSEDL can improve the diagnostic accuracy of T-staging and reduce the reading time for assessing rectal cancer.

Impact on CD4+ CD25 High -CD127 low regulatory T (Treg) cells of neoadjuvant therapy for rectal cancer patients

Background

The efficacy of neoadjuvant therapy for rectal cancer has not been assessed.

Objective

To evaluate proportional changes in peripheral blood immune cells in rectal cancer patients after neoadjuvant therapy and assess the relationship between tumor regression and regulatory T (Treg) cells.

Materials and Methods

Rectal cancer patients who had received neoadjuvant therapy prior to surgery at Shanxi Cancer Hospital between January and September 2018 were enrolled in the study. Treg, CD4+ T, CD8+ T, NK, B cells, and CD4+/CD8+ ratio in peripheral blood before and after neoadjuvant therapy were measured by flow cytometry. Patients were divided into down-staging and control groups, depending on their responses to neoadjuvant therapy.

Results

A total of 108 patients were enrolled. The proportion of Treg cells was significantly lower after neoadjuvant therapy (P < 0.05) but no changes were seen in CD4+ T, CD8+ T, NK, B cells, or CD4+/CD8+ ratio (all P > 0.05). There were 76 patients in the down-staging and 32 in the control groups. There were no significant differences in clinical parameters between down-staging and control groups (all P > 0.05). There were no significant differences in immune cell proportions between the two groups prior to neoadjuvant therapy (all P > 0.05). Treg, CD4+ T, and B cells were all significantly lower in the down-staging group after neoadjuvant therapy than before (P < 0.05). CD4+/CD8+ ratios were lower (P < 0.05) while proportions of Treg and natural killer (NK) cells did not change after neoadjuvant therapy in the control group. Following neoadjuvant therapy, Treg and B cells were lower while CD4+ and CD4+/CD8+ ratios were higher in the down-staging group compared to the control group (P < 0.01).

Conclusion

Treg cells may constitute a reference for judging the effect of neoadjuvant therapy in rectal cancer patients.

Concordance of MRI With Pathology for Primary Staging of Rectal Cancer in Routine Clinical Practice: A Single Institution Experience

PURPOSE

MRI is the preferred imaging modality for primary staging of rectal cancer, used to guide treatment. Patients identified with clinical stage I disease receive upfront surgical resection; those with clinical stage II or greater undergo upfront neoadjuvant therapy. Although clinical under-/over-staging may have consequences for patients and presents opportunities for organ preservation, the correlation between clinical and pathologic staging in routine clinical practice within a single institute has not been fully established.

METHODS

This retrospective, Institutional Review Board-approved study, conducted at a National Cancer Institute-Designated Comprehensive Cancer Center with a multi-disciplinary rectal cancer disease center, included patients undergoing rectal MRI for primary staging January 1, 2018-August 30, 2020. Data collection included patient demographics, initial clinical stage via MRI report, pathologic diagnosis, pathologic stage, and treatment. The primary outcome was concordance of overall clinical and pathologic staging. Secondary outcomes included reasons for mismatched staging.

RESULTS

A total 105 rectal adenocarcinoma patients (64 males, mean age 57 ± 12.7 years) had staging MRI followed by surgical resection. A total of 28 patients (27%) had mismatched under-/over- staging. Ten patients (10%) were understaged with mismatched T stage group (clinical stage I, pathologic stage II), five (5%) were understaged with mismatched N stage group (clinical stage I, pathologic stage III), and 13 (12%) were overstaged (clinical stage II-III, pathologic stage 0-I). Treatment matched concordance between clinical and pathologic stages was 86%.

CONCLUSION

MRI for primary rectal cancer staging has high concordance with pathology. Future studies to assess strategies for reducing clinically relevant understaging would be beneficial.

Value of biplane transrectal ultrasonography plus micro-flow imaging in preoperative T staging and rectal cancer diagnosis in combination with CEA/CA199 and MRI

BACKGROUND

Rectal cancer is one of the most common malignant tumors and has a high incidence rate and fatality rate. Accurate preoperative T staging of rectal cancer is critical for the selection of appropriate rectal cancer treatment. Various pre-operative imaging methods are available, and the identification of the most accurate method for clinical use is essential for patient care. We investigated the value of biplane transrectal ultrasonography (TRUS) combined with MFI in preoperative staging of rectal cancer and explored the value of combining TRUS plus MFI with CEA/CA199 and MRI.

METHODS

A total of 87 patients from Daping Hospital with rectal cancer who underwent TRUS examination plus MFI were included. Grades of MFI were determined by Alder classification. Among the total patients, 64 underwent MRI and serum CEA/CA199 tests additionally within one week of TRUS. Pathological results were used as the gold standard for cancer staging. Concordance rates between TRUS, MRI, and CEA/CA199 for tumors at different stages were compared.

RESULTS

There were no significant differences between the Alder classification and pathological T staging. The concordance rate of TRUS and MFI for rectal cancer T staging was 72.4% (K = 0.615, p < 0.001). Serum CEA and CA199 levels were significantly different in tumors at different stages and increased progressively by pathological stage (p < 0.001); the accuracy rate was 71.88% (K = 0.599, p < 0.001), while that of MRI was 51.56% (K = 0.303, p < 0.001), indicating that TRUS had higher consistency in the preoperative T staging of rectal cancer. The combination of TRUS, MRI, and CEA/CA199 yielded an accuracy rate of 90.6%, which was higher than that of any method alone.

CONCLUSIONS

Preoperative T staging of rectal cancer from biplane TRUS plus MFI was highly consistent with postoperative pathological T staging. TRUS combined with MRI and serum CEA/CA199 had a greater value in the diagnosis of rectal cancer and a higher diagnostic rate than any examination alone.

Progress in the diagnosis of lymph node metastasis in rectal cancer: a review

Historically, the chief focus of lymph node metastasis research has been molecular and clinical studies of a few essential pathways and genes. Recent years have seen a rapid accumulation of massive omics and imaging data catalyzed by the rapid development of advanced technologies. This rapid increase in data has driven improvements in the accuracy of diagnosis of lymph node metastasis, and its analysis further demands new methods and the opportunity to provide novel insights for basic research. In fact, the combination of omics data, imaging data, clinical medicine, and diagnostic methods has led to notable advances in our basic understanding and transformation of lymph node metastases in rectal cancer. Higher levels of integration will require a concerted effort among data scientists and clinicians. Herein, we review the current state and future challenges to advance the diagnosis of lymph node metastases in rectal cancer.

Local resection versus radical resection after neoadjuvant chemoradiotherapy for patients with locally advanced rectal cancer: a propensity-score matched cohort analysis

BACKGROUND

We aimed to address the shortage of evidence regarding the safety of the local resection approach by comparing long-term oncological outcomes between patients managed by local resection and those who underwent radical resection.

METHODS

This was a propensity-score matched cohort analysis study that included patients of all ages diagnosed with locally advanced rectal cancer (LARC) who had received neoadjuvant chemoradiotherapy (nCRT) at the Fujian Medical University Union Hospital and Fujian Medical University Affiliated Zhangzhou Hospital, China, between Jan 10, 2011, to Dec 28, 2021. Partial patients with a significant downstage of the tumor were offered management with the local resection approach, and most of the rest were offered radical resection if eligible.

FINDINGS

One thousand six hundred ninety-three patients underwent radical resection after nCRT, and another 60 patients performed local resection. The median follow-up times were 44.0 months (interquartile range = 4-107 months). After propensity-core matching (PSM), in the Kaplan-Meier curves, local resection (n = 56) or radical resection (n = 211) was not significantly associated with 1-, 3-, and 5-year cumulative incidence of overall survival (OS) (HR = 1.103, 95% CI: 0.372 ~ 3.266), disease-free survival (DFS) ((HR = 0.972, 95% CI: 0.401 ~ 2.359), local recurrence (HR = 1.044, 95% CI: 0.225 ~ 4.847), and distant metastasis (HR = 0.818, 95% CI: 0.280 ~ 2.387) (all log-rank P > 0.05). Similarly, multivariate Cox regression analysis indicates that local excision still was not an independent risk factor for OS (HR = 0.863, 95% CI: 0.267 ~ 2.785, P = 0.805) and DFS (HR = 0.885, 95% CI: 0.353 ~ 2.215, p = 0.794).

CONCLUSION

Local resection can be a management option in selected patients with middle-low rectal cancer after nCRT for LARC and without loss of oncological safety at five years.

A prospective study of diagnostic accuracy of multidisciplinary team and radiology reporting of preoperative colorectal cancer local staging

INTRODUCTION

The aim of this study was to correlate and assess diagnostic accuracy of preoperative staging at multidisciplinary team meeting (MDT) against the original radiology reports and pathological staging in colorectal cancer patients.

METHODS

A prospective observational study was conducted at two institutions. Patients with histologically proven colorectal cancer and available preoperative imaging were included. Preoperative tumor and nodal staging (cT and cN) as determined by the MDT and the radiology report (computed tomography [CT] and/or magnetic resonance imaging [MRI]) were recorded. Kappa statistics were used to assess agreement between MDT and the radiology report for cN staging in colon cancer, cT and cN in rectal cancer, and tumor regression grade (TRG) in patients with rectal cancer who received neoadjuvant therapy. Pathological report after surgery served as the reference standard for local staging, and AUROC curves were constructed to compare diagnostic accuracy of the MDT and radiology report.

RESULTS

A total of 481 patients were included. Agreement between MDT and radiology report for cN stage was good in colon cancer (k = .756, Confidence Interval (CI) 95% .686-.826). Agreement for cT and cN and in rectal cancer was very good (kw = .825, CI 95% .758-.892) and good (kw = .792, CI 95% .709-.875), respectively. In the rectal cancer group that received neoadjuvant therapy, agreement on TRG was very good (kw = .919, CI 95% .846-.993). AUROC curves using pathological staging indicated no difference in diagnostic accuracy between MDT and radiology reports for either colon or rectal cancer.

CONCLUSION

Preoperative colorectal cancer local staging was consistent between specialist MDT review and original radiology reports, with no significant differences in diagnostic accuracy identified.

Evaluation of Neutrophil-Lymphocyte Ratio and Platelet-Lymphocyte Ratio on Predicting Responsiveness to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer Patients

Objective

Neutrophil-lymphocyte ratio (NLR) and Platelet-lymphocyte ratio (PLR) have been proposed as prognostic biomarkers in multiple cancers. However, the implications of NLR and PLR in the responsiveness to neoadjuvant chemoradiotherapy (nCRT) remain to be clarified in locally advanced rectal cancer (LARC) patients. This retrospective study investigated the prognostic value of NLR and PLR in nCRT responsiveness of LARC patients.

Methods

A total number of 86 patients diagnosed with LARC and treated with nCRT and total mesorectal excision were retrospectively followed from 2013 to 2016. Receiver operating characteristic (ROC) curve was used to determine the cutoff values of NLR and PLR, and the patients were divided into NLR elevation and NLR decrease groups, or PLR elevation and PLR decrease groups. The correlation between NLR and PLR changes, and clinicopathological factors were analyzed. The relationship between NLR and PLR changes and the curative responsiveness towards nCRT were further evaluated.

Results

NLR and PLR changes after nCRT were significantly correlated with the distance of tumors to the anus and BMI (body mass index) (P < 0.05). The clinical remission rate of patients with NLR reduction was 72.09% (31/43), which was significantly higher than that in patients with NLR increment (22/43, 51.16%). There was no significant difference in the clinic remission rate between the patients with PLR reduction and those with PLR increment (P > 0.05). However, the pathological responsiveness rate was significantly higher in patients with PLR reduction (21/43, 48.84%) when compared to the ones with PLR increment (9/43, 20.9%) (P = 0.036).

Conclusion

Our data indicate that in LARC patients with nCRT, the reduction of NLR and the reduction of PLR could serves as predictors for the clinic remission rate and pathological responsiveness rate, respectively. The combination of NLR and PLR changes may be employed as a simple and effective prognostic parameter to predict the treatment outcome of nCRT in LARC.

MRI tumour regression grade in locally recurrent rectal cancer

BACKGROUND

This study aimed to investigate the agreement between magnetic resonance tumour regression grade (mrTRG) and pathological regression grade (pTRG) in patients with locally recurrent rectal cancer (LRRC). Also, the reproducibility of mrTRG was investigated.

METHODS

All patients with LRRC who underwent a resection between 2010 and 2018 after treatment with induction chemotherapy and neoadjuvant chemo(re)irradiation in whom a restaging MRI was available were retrospectively selected. All MRI scans were reassessed by two independent radiologists using the mrTRG, and the pTRG was reassessed by an independent pathologist. The interobserver agreement between the radiologists as well as between the radiologists and the pathologist was assessed with the weighted kappa test. A subanalysis was performed to evaluate the influence of the interval between imaging and surgery.

RESULTS

Out of 313 patients with LRRC treated during the study interval, 124 patients were selected. Interobserver agreement between the radiologists was fair (k = 0.28) using a two-tier grading system (mrTRG 1-2 versus mrTRG 3-5). For the lead radiologist, agreement with pTRG was moderate (k = 0.52; 95 per cent c.i. 0.36 to 0.68) when comparing good (mrTRG 1-2 and Mandard 1-2) and intermediate/poor responders (mrTRG 3-5 and Mandard 3-5), and the agreement was fair between the other abdominal radiologist and pTRG (k = 0.39; 95 per cent c.i. 0.22 to 0.56). A shorter interval (less than 7 weeks) between MRI and surgery resulted in an improved agreement (k = 0.69), compared with an interval more than 7 weeks (k = 0.340). For the lead radiologist, the positive predictive value for predicting good responders was 95 per cent (95 per cent c.i. 71 per cent to 99 per cent), whereas this was 56 per cent (95 per cent c.i. 44 per cent to 66 per cent) for the other radiologist.

CONCLUSION

This study showed that, in LRRC, the reproducibility of mrTRG among radiologists is limited and the agreement of mrTRG with pTRG is low. However, a shorter interval between MRI and surgery seems to improve this agreement and, if assessed by a dedicated radiologist, mrTRG could predict good responders.

Improved Overall Survival of Colorectal Cancer under Multidisciplinary Team: A Meta-Analysis

Purpose

The purpose of the current meta-analysis was to evaluate whether multidisciplinary team improved overall survival of colorectal cancer.

Methods

PubMed, EMBASE, and Cochrane Library database were searched from inception to October 25, 2020. The hazard ratio (HR) and 95% confidence (CI) of overall survival (OS) were calculated.

Results

A total of 11 studies with 30814 patients were included in this meta-analysis. After pooling the HRs, the MDT group was associated with better OS compared with the non-MDT group (HR = 0.81, 95% CI 0.69-0.94, p = 0.005). In subgroup analysis of stage IV colorectal cancer, the MDT group was associated with better OS as well (HR = 0.73, 95% CI 0.59-0.90, p = 0.004). However, in terms of postoperative mortality, no significant difference was found between MDT and non-MDT groups (OR = 0.84, 95% CI 0.44-1.61, p = 0.60).

Conclusion

MDT could improve OS of colorectal cancer patients.

Endorectal Ultrasound and Magnetic Resonance Imaging for Rectal Cancer Staging: A Modern Multimodality Approach

Preoperative staging represents a crucial point for the management, type of surgery, and candidacy for neoadjuvant therapy in patient with rectal cancer. The most recent clinical guidelines in oncology recommend an accurate preoperative evaluation in order to address early and advanced tumors to different therapeutic options. In particular, potential pitfalls may occur in the assessment of T3 tumors, which represents the most common stage at diagnosis. The depth of tumor invasion is known to be an important prognostic factor in rectal carcinoma; as a consequence, the T3 imaging classification has a substantial importance for treatment strategy and patient survival. However, the differentiation between tumor invasion of perirectal fat and mesorectal desmoplastic reactions remains a main goal for radiologists. Magnetic resonance imaging (MRI) is actually considered as the best imaging modality for rectal cancer staging. Although the endorectal ultrasound (ERUS) is the preferred staging method for early tumors, it could also be useful in identifying perirectal fat invasion. Moreover, the addiction of diffusion weighted imaging (DWI) improves the diagnostic performance of MRI in rectal cancer staging by adding functional information about rectal tumor and adjacent mesorectal tissues. This study investigated the diagnostic performance of conventional MRI alone, in combination with the DWI technique and ERUS in order to assess the best diagnostic imaging combination for rectal cancer staging.