The prognostic value of MRI-detected extramural vascular invasion (mrEMVI) for rectal cancer patients treated with neoadjuvant therapy: a meta-analysis

Prediction of metachronous liver metastasis in mid-low rectal cancer using quantitative perirectal fat content from high-resolution MRI

PURPOSE

To investigate the relationship between perirectal fat content and metachronous liver metastasis (MLM) in patients with Mid-low rectal cancer (MLRC).

MATERIALS AND METHODS

A retrospective analysis was conducted on 254 patients who underwent curative surgery for MLRC between December 2016 and December 2021. Preoperative MRI measurements of the rectal mesenteric fat area (MFA), rectal posterior mesorectal thickness (PMT), and rectal mesenteric fascia envelopment volume (MFEV) were performed, along with collection of relevant clinical, pathological, and imaging data. Patients were categorized into the MLM group (Group A), other recurrence or metastasis group (Group B), and no recurrence and metastasis group (Group C). Analyze the differences between Group A and the other groups, and independent risk factors for MLM were explored. Kaplan-Meier analysis and log-rank test were used to validate independent predictive biomarkers for MLM.

RESULTS

Patients with MLM from MLRC had later pathological and imaging T stages and lower perirectal fat content (all P < 0.05). Compared to patients with other types of recurrent metastasis, male gender, poorly differentiated tumors, and advanced tumor N stage were more likely to develop MLM (all P < 0.05). In Cox univariate and multivariate regression analysis, smaller rectal PMT (hazard ratio (HR) 0.361 [0.154-0.846], P = 0.019) and MFEV (HR 0.983 [0.968-0.998], P = 0.022) were independently associated with MLM in MLRC (HR 0.361;0.983). Kaplan-Meier analysis showed that patients with rectal PMT <1.43 cm and rectal MFEV <137.46 cm3 had a significantly higher risk of MLM compared to patients with rectal PMT ≥1.43 cm and rectal MFEV ≥137.46 cm3 (all P < 0.05).

CONCLUSION

Rectal PMT and rectal MFEV can serve as novel parameters for predicting MLM in patients with MLRC.

The Chinese Society of Clinical Oncology (CSCO): Clinical guidelines for the diagnosis and treatment of colorectal cancer, 2024 update

The 2024 updates of the Chinese Society of Clinical Oncology (CSCO) Clinical Guidelines for the diagnosis and treatment of colorectal cancer emphasize standardizing cancer treatment in China, highlighting the latest advancements in evidence-based medicine, healthcare resource access, and precision medicine in oncology. These updates address disparities in epidemiological trends, clinicopathological characteristics, tumor biology, treatment approaches, and drug selection for colorectal cancer patients across diverse regions and backgrounds. Key revisions include adjustments to evidence levels for intensive treatment strategies, updates to regimens for deficient mismatch repair (dMMR)/ microsatellite instability-high (MSI-H) patients, proficient mismatch repair (pMMR)/ microsatellite stability (MSS) patients who have failed standard therapies, and rectal cancer patients with low recurrence risk. Additionally, recommendations for digital rectal examination and DNA polymerase epsilon (POLE)/ DNA polymerase delta 1 (POLD1) gene mutation testing have been strengthened. The 2024 CSCO Guidelines are based on both Chinese and international clinical research, as well as expert consensus, ensuring their relevance and applicability in clinical practice, while maintaining a commitment to scientific rigor, impartiality, and timely updates.

Pretreatment MRI Parameters and Neutrophil-to-Lymphocyte Ratio Could Predict the Long-Term Prognosis of Locally Advanced Rectal Cancer Patients With Pathological Complete Response after Neoadjuvant Chemoradiotherapy

BackgroundLocal advanced rectal cancer (LARC) patients who achieved pathological complete response (pCR) after neoadjuvant chemoradiotherapy (NCRT) generally have a favorable prognosis. This retrospective study aimed to evaluate the prognostic value of magnetic resonance imaging (MRI) parameters and neutrophil-to-lymphocyte ratio (NLR) in LARC patients with pCR.MethodsBetween 2015 and 2019, 180 LARC patients who achieved pCR after NCRT and surgery were included. MRI parameters and NLR were evaluated as potential predictors for 5-year overall survival (OS) and disease-free survival (DFS) using the Kaplan-Meier and COX regression analysis.ResultsWith a median follow-up time of 68.3 months, the 5-year OS and DFS rates were 94.2% and 91.4%, respectively. Thirteen patients (7.2%) died, 2 (1.1%) experienced local recurrence, and 15 (8.3%) experienced distant metastases. Pretreatment MRI parameters and NLR were correlated with 5-year OS and DFS in pCR patients in the univariate analysis. The multivariate analysis identified baseline EMVI and NLR as independent predictors for 5-year OS and DFS (all P < .05). Patients in the low-risk group (EMVI-negative and/or NLR ≤ 2.8, n = 159, 88.3%) had a more favorable 5-year DFS compared to those in the high-risk group (EMVI-positive and NLR > 2.8, n = 21, 11.7%) (95.6% vs 59.4%, P < .001), with similar findings for 5-year OS (97.4% vs 70.6%, P < .001).ConclusionsThis study showed that MRI parameters and NLR were associated with long-term prognosis in patients with pCR. These findings could aid in stratifying pCR patients and guide subsequent treatment and follow-up strategies.

The potential of an artificial intelligence for diagnosing MRI images in rectal cancer: multicenter collaborative trial

BACKGROUND

An artificial intelligence-based algorithm we developed, mrAI, satisfactorily segmented the rectal tumor, rectum, and mesorectum from MRI data of rectal cancer patients in an initial study. Herein, we aimed to validate mrAI using an independent dataset.

METHODS

We utilized MRI images collected in another nationwide research project, "Open versus Laparoscopic Surgery for Advanced Low Rectal Cancer Patients". MRIs from 467 cases with upfront surgery were utilized; six radiologists centralized the MRI evaluations. The diagnostic accuracies of mrAI and the radiologists for tumor depth were compared using pathologic diagnosis as a reference.

RESULTS

For all cases, centralized diagnosis demonstrated 84.2% sensitivity, 37.7% specificity, and 73.7% accuracy; mrAI exhibited 70.6% sensitivity, 61.3% specificity, and 68.5% accuracy. After limiting MRIs to those acquired by a Philips scanner, with an inter-slice spacing of ≤ 6 mm-both conditions similar to those used in the development of mrAI-the performance of mrAI improved to 76.8% sensitivity, 76.7% specificity, and 76.7% accuracy, while the centralized diagnosis showed 81.8% sensitivity, 36.7% specificity, and 71.3% accuracy. Regarding relapse-free survival, the prognosis for tumors staged ≥ T3 was significantly worse than for tumors staged ≤ T2 (P = 0.0484) in the pathologic diagnosis. While no significant difference was observed between ≥ T3 and ≤ T2 tumors in the centralized diagnosis (P = 0.1510), the prognosis for ≥ T3 was significantly worse in the mrAI diagnosis (P = 0.0318).

CONCLUSION

Proper imaging conditions for MRI can enhance the accuracy of mrAI, which has the potential to provide feedback to radiologists without overestimating tumor stage.

Pretreatment MRI-detected extramural venous invasion as a prognostic and predictive biomarker for neoadjuvant chemoradiotherapy in non-metastatic rectal cancer: a propensity score matched analysis

OBJECTIVES

This study evaluated pretreatment magnetic resonance imaging (MRI)-detected extramural venous invasion (pmrEMVI) as a predictor of survival after neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer (LARC).

MATERIALS AND METHODS

Medical records of 1184 patients with rectal adenocarcinoma who underwent TME between January 2011 and December 2016 were reviewed. MRI data were collected from a computerized radiologic database. Cox proportional hazards analysis was used to assess local, systemic recurrence, and disease-free survival risk based on pretreatment MRI-assessed tumor characteristics. After propensity score matching (PSM) for pretreatment MRI features, nCRT therapeutic outcomes according to pmrEMVI status were evaluated. Cox proportional hazards analysis was used to identify risk factors for early recurrence in patients receiving nCRT.

RESULTS

Median follow-up was 62.8 months. Among all patients, the presence of pmrEMVI was significantly associated with worse disease-free survival (DFS; HR 1.827, 95% CI 1.285-2.597, p = 0.001) and systemic recurrence (HR 2.080, 95% CI 1.400-3.090, p < 0.001) but not local recurrence. Among patients with pmrEMVI, nCRT provided no benefit for oncological outcomes before or after PSM. Furthermore, pmrEMVI( +) was the only factor associated with early recurrence on multivariate analysis in patients receiving nCRT.

CONCLUSIONS

pmrEMVI is a poor prognostic factor for DFS and SR in patients with non-metastatic rectal cancer and also serves as a predictive biomarker of poor DFS and SR following nCRT in LARC. Therefore, for patients who are positive for pmrEMVI, consideration of alternative treatment strategies may be warranted.

CLINICAL RELEVANCE STATEMENT

This study demonstrated the usefulness of pmrEMVI as a predictive biomarker for nCRT, which may assist in initial treatment decision-making in patients with non-metastatic rectal cancer.

KEY POINTS

• Pretreatment MRI-detected extramural venous invasion (pmrEMVI) was significantly associated with worse disease-free survival and systemic recurrence in patients with non-metastatic rectal cancer. • pmrEMVI is a predictive biomarker of poor DFS following nCRT in patients with LARC. • The presence of pmrEMVI was the only factor associated with early recurrence on multivariate analysis in patients receiving nCRT.

Survival outcomes of different neoadjuvant treatment regimens in patients with locally advanced rectal cancer and MRI-detected extramural venous invasion

PURPOSE

MRI-detected extramural venous invasion (mrEMVI) is associated with poor survival outcomes in patients with locally advanced rectal cancer (LARC). An mrEMVI-positive status is considered a strong indication for neoadjuvant treatment, but the optimal regimen is unknown.

PATIENTS AND METHODS

We retrospectively compared pathological and survival outcomes of 584 patients diagnosed with mrEMVI-positive rectal cancer between January 2013 and October 2021, and receiving either neoadjuvant chemotherapy (NCT) alone, neoadjuvant chemoradiotherapy (nCRT) alone, or nCRT plus NCT, prior to total mesorectal excision. Propensity score matching (PSM) was used to balance clinical bias between groups, which were compared using chi-square testing and Kaplan-Meier curves.

RESULTS

Median follow-up was 33.9 (range, 10.2-100.4) months. The 3-year overall survival (OS), disease-free survival (DFS), distant metastasis-free survival (DMFS), and locoregional relapse-free survival (LRFS) rates for all patients were 90.4%, 57.5%, 61.1%, and 85.7%, respectively. Of 584 mrEMVI-positive patients at the time of diagnosis, 457 (78.3%) were EMVI-negative on surgical pathology, and they had significantly better 3-year OS, DMFS, DFS, and LRFS rates (all p < 0.001) than patients who remained EMVI-positive. After PSM was applied, patients receiving nCRT alone had significantly better 3-year OS (96.8% vs. 86.5%, p = 0.005) and DMFS (67.1% vs. 53.5%, p = 0.03) rates than those receiving NCT alone. Patients receiving NCT plus nCRT had higher pathological complete response (PCR) (10.8% vs. 2.7%, p = 0.04) and downstaging (33.8% vs. 5.3%, p < 0.001) rates than those receiving nCRT alone, but survival rates did not differ (all p > 0.05).

CONCLUSION

Most EMVI-positive patients with LARC converted to EMVI-negative after neoadjuvant treatment, resulting in improved OS and DFS. Patients receiving nCRT had more favorable survival outcomes than those receiving NCT, suggesting the importance of including neoadjuvant radiotherapy. Patients receiving NCT in addition to nCRT had higher rates of PCR and downstaging, but their survival rates were not better.

Predictive value of infiltrating tumor border configuration of rectal cancer on MRI

BACKGROUND

Infiltrating tumor border configuration (iTBC) is assessed by postoperative pathological examination, thus, is not helpful for preoperative treatment strategies. The study aimed to detect iTBC by magnetic resonance imaging (MRI) and evaluate its predictive value.

MATERIALS AND METHODS

A total of 153 patients with rectal cancer were retrospectively analyzed. Clinicopathological and MRI data mainly including tumor border configuration (TBC) on MRI, MRI-detected extramural vascular invasion (MEMVI), tumor length, tumor growth pattern, maximal extramural depth, pathology-proven lymph node metastasis (PLN) and pathology-proven extramural vascular invasion (PEMVI) were analyzed. The correlation of MRI factors with PEMVI and PLN was analyzed by univariate and multivariate logistic regression analyses. The nomograms were established based on multivariate logistic regression analysis and were confirmed by Bootstrap self-sampling. The receiver operating characteristic (ROC) curve analysis and area under the curve (AUC) were used to evaluate the diagnostic efficiency.

RESULTS

Fifty cases of PEMVI and 48 cases of PLN were found. Forty cases of PEMVI and 34 cases of PLN in 62 cases of iTBC were also found. iTBC, MEMVI and maximal extramural depth were significantly associated with PEMVI and PLN (P < 0.05). iTBC (odds ratio = 3.84 and 3.02) and MEMVI (odds ratio = 7.27 and 3.22) were independent risk factors for PEMVI and PLN. The C-indices of the two nomograms for predicting PEMVI and PLN were 0.863 and 0.752, respectively. The calibration curves and ROC curves of the two nomograms showed that the correlation between the predicted and the actual incidence of PEMVI and PLN was good. The AUCs of iTBC for predicting PEMVI and PLN were 0.793 (95% CI: 0.714-0.872) and 0.721 (95% CI: 0.632-0.810), respectively. The DeLong test showed that the predictive efficiency of the nomogram in predicting PEMVI was better than that of iTBC (P = 0.0009) and MEMVI (P = 0.0095).

CONCLUSION

iTBC and MEMVI are risk factors for PEMVI and pelvic lymph node metastasis. The nomograms based on iTBC show a good performance in predicting PEMVI and pelvic lymph node metastasis, possessing a certain clinical reference value.

TRIAL REGISTRATION

This study was approved by the Ethics Committee of Beijing Friendship Hospital, and individual consent was waived for this retrospective analysis.

Diagnostic accuracy of state-of-the-art rectal MRI sequences for the diagnosis of extramural vascular invasion in locally advanced rectal cancer after preoperative chemoradiotherapy: dos or maybes?

OBJECTIVES

The aim of this study was to determine the accuracy of three state-of-the-art MRI sequences for the detection of extramural venous invasion (EMVI) in locally advanced rectal cancer (LARC) patients after preoperative chemoradiotherapy (pCRT).

METHODS

This retrospective study included 103 patients (median age 66 years old [43-84]) surgically treated with pCRT for LARC and submitted to preoperative contrast-enhanced pelvic MRI after pCRT. T2-weighted, DWI, and contrast-enhanced sequences were evaluated by two radiologists with expertise in abdominal imaging, blinded to clinical and histopathological data. Patients were scored according to the probability of EMVI presence on each sequence using a grading score ranging from 0 (no evidence of EMVI) to 4 (strong evidence of EMVI). Results from 0 to 2 were ranked as EMVI negative and from 3 to 4 as EMVI positive. ROC curves were drawn for each technique, using histopathological results as reference standard.

RESULTS

T2-weighted, DWI, and contrast-enhanced sequences demonstrated an area under the ROC curve (AUC) respectively of 0.610 (95% CI: 0.509-0.704), 0.729 (95% CI: 0.633-0.812), and 0.624 (95% CI: 0.523-0.718). The AUC of DWI sequence was significantly higher than that of T2-weighted (p = 0.0494) and contrast-enhanced (p = 0.0315) sequences.

CONCLUSIONS

DWI is more accurate than T2-weighted and contrast-enhanced sequences for the identification of EMVI following pCRT in LARC patients.

CLINICAL RELEVANCE STATEMENT

MRI protocol for restaging locally advanced rectal cancer after preoperative chemoradiotherapy should routinely include DWI due to its higher accuracy for the diagnosis of extramural venous invasion compared to high-resolution T2-weighted and contrast-enhanced T1-weighted sequences.

KEY POINTS

• MRI has a moderately high accuracy for the diagnosis of extramural venous invasion in locally advanced rectal cancer after preoperative chemoradiotherapy. • DWI is more accurate than T2-weighted and contrast-enhanced T1-weighted sequences in the detection of extramural venous invasion after preoperative chemoradiotherapy of locally advanced rectal cancer. • DWI should be routinely included in the MRI protocol for restaging locally advanced rectal cancer after preoperative chemoradiotherapy.

Predictive value of lesion morphology in rectal cancer based on MRI before surgery

OBJECTIVE

To explore the relationship of MRI morphology of primary rectal cancer with extramural vascular invasion (EMVI), metastasis and local recurrence.

MATERIALS AND METHODS

This retrospective study included 153 patients with rectal cancer. Imaging factors and histopathological index including nodular projection (NP), cord sign (CS) at primary tumor margin, irregular nodules (IN) of mesorectum, MRI-detected peritoneal reflection invasion (PRI), range of rectal wall invasion (RRWI), patterns and length of tumor growth, maximal extramural depth (EMD), histologically confirmed local node involvement (hLN), MRI T stage, MRI N stage, MRI-detected extramural vascular invasion (mEMVI) and histologically confirmed extramural vascular invasion (hEMVI) were evaluated. Determining the relationship between imaging factors and hEMVI, synchronous metastasis and local recurrence by univariate analysis and multivariable logistic regression, and a nomogram validated internally via Bootstrap self-sampling was constructed based on the latter.

RESULTS

Thirty-eight cases of hEMVI, fourteen cases of synchronous metastasis and ten cases of local recurrence were observed among 52 NP cases. There were 50 cases of mEMVI with moderate consistency with hEMVI (Kappa = 0.614). NP, CS, EMD and mEMVI showed statistically significant differences in the negative and positive groups of hEMVI, synchronous metastasis, and local recurrence. Compared to patients with local mass growth, the rectal tumor with circular infiltration had been found to be at higher risk of synchronous metastasis and local recurrence (P < 0.05). NP and IN remained as significant predictors for hEMVI, and mEMVI was a predictor for synchronous metastasis, while PRI and mEMVI were predictors for local recurrences. The nomogram for predicting hEMVI demonstrated a C-index of 0.868, sensitivity of 86.0%, specificity of 79.6%, and accuracy of 81.7%.

CONCLUSION

NP, CS, IN, large EMD, mEMVI, and circular infiltration are significantly associated with several adverse prognostic indicators. The nomogram based on NP has good predictive performance for preoperative EMVI. mEMVI is a risk factor for synchronous metastasis. PRI and mEMVI are risk factors for local recurrence.

Extramural Venous Invasion and Tumor Deposit at Diffusion-weighted MRI in Patients after Neoadjuvant Treatment for Rectal Cancer

Background Diffusion-weighted (DW) imaging is useful in detecting tumor in the primary tumor bed in locally advanced rectal cancer (LARC) after neoadjuvant therapy, but its value in detecting extramural venous invasion (EMVI) and tumor deposit is not well validated. Purpose To evaluate diagnostic accuracy and association with patient prognosis of viable EMVI and tumor deposit on DW images in patients with LARC after neoadjuvant therapy using whole-mount pathology specimens. Materials and Methods This retrospective study included patients who underwent neoadjuvant therapy and surgery from 2018 to 2021. Innovative five-point Likert scale was used by two radiologists to independently evaluate the likelihood of viable EMVI and tumor deposit on restaging DW MRI scans in four axial quadrants (12 to 3 o'clock, 3 to 6 o'clock, 6 to 9 o'clock, and 9 to 12 o'clock). Diagnostic accuracy was assessed at both the per-quadrant and per-patient level, with whole-mount pathology as the reference standard. Weighted κ values for interreader agreement and Cox regression models for disease-free survival and overall survival analyses were used. Results A total of 117 patients (mean age, 56 years ± 12 [SD]; 70 male, 47 female) were included. Pathologically proven viable EMVI and tumor deposit was detected in 29 of 117 patients (25%) and in 44 of 468 quadrants (9.4%). Per-quadrant analyses showed an area under the receiver operating characteristics curve of 0.75 (95% CI: 0.68, 0.83), with sensitivity and specificity of 55% and 96%, respectively. Good interreader agreement was observed between the radiologists (κ = 0.62). Per-patient analysis showed sensitivity and specificity of 62% and 93%, respectively. The presence of EMVI and tumor deposit on restaging DW MRI scans was associated with worse disease-free survival (hazard ratio [HR], 5.6; 95% CI: 2.4, 13.3) and overall survival (HR, 8.9; 95% CI: 1.6, 48.5). Conclusion DW imaging using the five-point Likert scale showed high specificity and moderate sensitivity in the detection of viable extramural venous invasion and tumor deposits in LARC after neoadjuvant therapy, and its presence on restaging DW MRI scans is associated with worse prognosis. Published under a CC BY 4.0 license. Supplemental material is available for this article. See also the editorial by Méndez and Ayuso in this issue.

Radiomics for the Prediction of Pathological Complete Response to Neoadjuvant Chemoradiation in Locally Advanced Rectal Cancer: A Prospective Observational Trial

(1) Background: An increasing amount of research has supported the role of radiomics for predicting pathological complete response (pCR) to neoadjuvant chemoradiation treatment (nCRT) in order to provide better management of locally advanced rectal cancer (LARC) patients. However, the lack of validation from prospective trials has hindered the clinical adoption of such studies. The purpose of this study is to validate a radiomics model for pCR assessment in a prospective trial to provide informative insight into radiomics validation. (2) Methods: This study involved a retrospective cohort of 147 consecutive patients for the development/validation of a radiomics model, and a prospective cohort of 77 patients from two institutions to test its generalization. The model was constructed using T2-weighted, diffusion-weighted, and dynamic contrast-enhanced MRI to understand the associations with pCR. The consistency of physicians' evaluations and agreement on pathological complete response prediction were also evaluated, with and without the aid of the radiomics model. (3) Results: The radiomics model outperformed both physicians' visual assessments in the prospective test cohort, with an area under the curve (AUC) of 0.84 (95% confidence interval of 0.70-0.94). With the aid of the radiomics model, a junior physician could achieve comparable performance as a senior oncologist. (4) Conclusion: We have built and validated a radiomics model with pretreatment MRI for pCR prediction of LARC patients undergoing nCRT.

[Interpretation of Rectal MRI after Neoadjuvant Treatment in Patients with Rectal Cancer]

MRI is currently the imaging modality of choice to evaluate rectal cancer after neoadjuvant treatment. The purposes of restaging MRI are to assess the resectability of rectal cancer and to decide whether organ preservation strategies can be applied in patients with a complete clinical response. This review article indicates the key MRI features needed to evaluate rectal cancer after neoadjuvant treatment using a systematic approach. Assessment of primary tumor response including MRI findings to predict a complete response is discussed. Additionally, MRI evaluation of the relationship between the primary tumor and adjacent structures, lymph node response, extramural venous invasion, and tumor deposits after neoadjuvant treatment is presented. Knowledge of these imaging features and their clinical relevance may help radiologists provide an accurate and clinically valuable interpretation of restaging rectal MRI.

Extramural vascular invasion nomogram before radical resection of rectal cancer based on magnetic resonance imaging

Purpose

This study verified the value of magnetic resonance imaging (MRI) to construct a nomogram to preoperatively predict extramural vascular invasion (EMVI) in rectal cancer using MRI characteristics.

Materials and methods

There were 55 rectal cancer patients with EMVI and 49 without EMVI in the internal training group. The external validation group consisted of 54 rectal cancer patients with EMVI and 55 without EMVI. High-resolution rectal T2WI, pelvic diffusion-weighted imaging (DWI) sequences, and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) were used. We collected the following data: distance between the lower tumor margin and the anal margin, distance between the lower tumor margin and the anorectal ring, tumor proportion of intestinal wall, mrT stage, maximum tumor diameter, circumferential resection margin, superior rectal vein width, apparent diffusion coefficient (ADC), T2WI EMVI score, DWI and DCE-MRI EMVI scores, demographic information, and preoperative serum tumor marker data. Logistic regression analyses were used to identify independent risk factors of EMVI. A nomogram prediction model was constructed. Receiver operating characteristic curve analysis verified the predictive ability of the nomogram. P &lt; 0.05 was considered significant.

Result

Tumor proportion of intestinal wall, superior rectal vein width, T2WI EMVI score, and carbohydrate antigen 19-9 were significant independent predictors of EMVI in rectal cancer and were used to create the model. The areas under the receiver operating characteristic curve, sensitivities, and specificities of the nomogram were 0.746, 65.45%, and 83.67% for the internal training group, respectively, and 0.780, 77.1%, and 71.3% for the external validation group, respectively.

Data conclusion

A nomogram including MRI characteristics can predict EMVI in rectal cancer preoperatively and provides a valuable reference to formulate individualized treatment plans and predict prognosis.

Quantitative Evaluation of Extramural Vascular Invasion of Rectal Cancer by Dynamic Contrast-Enhanced Magnetic Resonance Imaging

This study was carried out to explore the preoperative predictive value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in extramural vascular invasion (EMVI) in patients with rectal cancer. 124 patients with rectal cancer were randomly divided into two groups, with 62 groups in each group. One group used conventional magnetic resonance imaging (MRI) and was recorded as the control group. The other group used DCE-MRI and was recorded as the experimental group. The diagnostic value was evaluated by comparing the MRI quantitative parameters of EMVI positive and EMVI negative patients, as well as the area under the curve (AUC) of the receiver operating characteristic curve (ROC), diagnostic sensitivity, and specificity of the two groups. The results showed that the Ktrans and Ve values of EMVI positive patients in the experimental group and the control group were 1.08 ± 0.97 and 1.03 ± 0.93, and 0.68 ± 0.29 and 0.65 ± 0.31, respectively, which were significantly higher than those in EMVI negative patients (P < 0.05). The AUC of EMVI diagnosis in the experimental group and the control group were 0.732 and 0.534 (P < 0.05), the sensitivity was 0.913 and 0.765 (P < 0.05), and the specificity was 0.798 and 0.756 (P > 0.05), respectively. In conclusion, DCE-MRI has a higher diagnostic value than conventional MRI in predicting EMVI in patients with rectal cancer, which was worthy of further clinical promotion.

Structured and shared MRI staging lexicon and report of rectal cancer: A consensus proposal by the French Radiology Group (GRERCAR) and Surgical Group (GRECCAR) for rectal cancer

PURPOSE

To develop French guidelines by experts to standardize data acquisition, image interpretation, and reporting in rectal cancer staging with magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Evidence-based data and opinions of experts of GRERCAR (Groupe de REcherche en Radiologie sur le CAncer du Rectum [i.e., Rectal Cancer Imaging Research Group]) and GRECCAR (Groupe de REcherche en Chirurgie sur le CAncer du Rectum [i.e., Rectal Cancer Surgery Research Group]) were combined using the RAND-UCLA Appropriateness Method to attain consensus guidelines. Experts scoring of reporting template and protocol for data acquisition were collected; responses were analyzed and classified as "Recommended" versus "Not recommended" (when ≥ 80% consensus among experts) or uncertain (when < 80% consensus among experts).

RESULTS

Consensus regarding patient preparation, MRI sequences, staging and reporting was attained using the RAND-UCLA Appropriateness Method. A consensus was reached for each reporting template item among the experts. Tailored MRI protocol and standardized report were proposed.

CONCLUSION

These consensus recommendations should be used as a guide for rectal cancer staging with MRI.

Development and Validation of an MRI-Based Nomogram Model for Predicting Disease-Free Survival in Locally Advanced Rectal Cancer Treated With Neoadjuvant Radiotherapy

Objectives

To develop a prognostic prediction MRI-based nomogram model for locally advanced rectal cancer (LARC) treated with neoadjuvant therapy.

Methods

This was a retrospective analysis of 233 LARC (MRI-T stage 3-4 (mrT) and/or MRI-N stage 1-2 (mrN), M0) patients who had undergone neoadjuvant radiotherapy and total mesorectal excision (TME) surgery with baseline MRI and operative pathology assessments at our institution from March 2015 to March 2018. The patients were sequentially allocated to training and validation cohorts at a ratio of 4:3 based on the image examination date. A nomogram model was developed based on the univariate logistic regression analysis and multivariable Cox regression analysis results of the training cohort for disease-free survival (DFS). To evaluate the clinical usefulness of the nomogram, Harrell’s concordance index (C-index), calibration plot, receiver operating characteristic (ROC) curve analysis, and decision curve analysis (DCA) were conducted in both cohorts.

Results

The median follow-up times were 43.2 months (13.3–61.3 months) and 32.0 months (12.3–39.5 months) in the training and validation cohorts. Multivariate Cox regression analysis identified MRI-detected extramural vascular invasion (mrEMVI), pathological T stage (ypT) and perineural invasion (PNI) as independent predictors. Lymphovascular invasion (LVI) (which almost reached statistical significance in multivariate regression analysis) and three other independent predictors were included in the nomogram model. The nomogram showed the best predictive ability for DFS (C-index: 0.769 (training cohort) and 0.776 (validation cohort)). It had a good 3-year DFS predictive capacity [area under the curve, AUC=0.843 (training cohort) and 0.771 (validation cohort)]. DCA revealed that the use of the nomogram model was associated with benefits for the prediction of 3-year DFS in both cohorts.

Conclusion

We developed and validated a novel nomogram model based on MRI factors and pathological factors for predicting DFS in LARC treated with neoadjuvant therapy. This model has good predictive value for prognosis, which could improve the risk stratification and individual treatment of LARC patients.