Diagnostic performance of MRI- versus MDCT-categorized T3cd/T4 for identifying high-risk stage II or stage III colon cancers: a pilot study

Diagnostic Performance of MRI and FDG PET/CT for Preoperative Locoregional Staging of Colon Cancer: Systematic Review and Meta-Analysis

BACKGROUND. CT is the standard-of-care test for preoperative locoregional staging of colon cancer (CC) but has limited diagnostic performance. More accurate preoperative staging would guide selection among expanding patient-tailored treatment options. OBJECTIVE. The purpose of this study was to evaluate through systematic review the diagnostic performance of MRI for T and N staging and that of FDG PET/CT for N staging in the locoregional staging of CC. EVIDENCE ACQUISITION. PubMed, Embase, and the Cochrane Library were searched through December 31, 2023, for studies reporting the diagnostic performance of MRI or FDG PET/CT for primary (nonrectal) CC before resection without neoadjuvant therapy, with histopathology used as the reference standard. Study quality was assessed using the QUADAS-2 tool. Publication bias was assessed using the Deeks funnel plot asymmetry test. Primary outcomes were estimated pooled predictive values, which were stratified by T and N categories for MRI and by N categories for PET/CT. Secondary outcomes were pooled sensitivity and specificity. EVIDENCE SYNTHESIS. The systematic review included 11 MRI studies (686 patients) and five PET/CT studies (408 patients). Thirteen studies had at least one risk of bias or concern of applicability. The Deek funnel plot asymmetry test indicated possible publication bias in MRI studies for differentiation of T3cd-T4 disease from T1-T3ab disease and differentiation of node-negative disease from node-positive disease. For MRI, for discriminating T1-T2 from T3-T4 disease, PPV was 64.8% (95% CI, 52.9-75.5%) and NPV was 88.9% (95% CI, 82.7-93.7%); for discriminating T1-T3ab from T3cd-T4 disease, PPV was 83.4% (95% CI, 75.0-90.3%) and NPV was 74.6% (95% CI, 58.2-86.7%); for discriminating T1-T3 from T4 disease, PPV was 94.0% (95% CI, 89.4-97.3%) and NPV was 39.9% (95% CI, 24.9-56.6%); for discriminating node-negative from node-positive disease, PPV was 74.9% (95% CI, 69.3-80.0%) and NPV was 53.9% (95% CI, 45.3-62.0%). For PET/CT, for discriminating node-negative from node-positive disease, PPV was 76.4% (95% CI, 67.9-85.1%) and NPV was 68.2% (95% CI, 56.8-78.6%). Across outcomes, MRI and PET/CT showed pooled sensitivity of 55.1-81.4% and pooled specificity of 70.3-88.1%. CONCLUSION. MRI had the strongest predictive performance for T1-T2 and T4 disease. MRI and PET/CT otherwise had limited predictive values, sensitivity, and specificity for evaluated outcomes related to T and N staging. CLINICAL IMPACT. MRI and FDG PET/CT had overall limited utility for preoperative locoregional staging of colon cancer. TRIAL REGISTRATION. PROSPERO (International Prospective Register of Systematic Reviews) CRD42022326887.

ESR Essentials: Imaging in colorectal cancer-practice recommendations by ESGAR

Colorectal cancer (CRC) is a significant global health concern. Diagnostic imaging, using different modalities, has a pivotal role in CRC, from early detection (i.e., screening) to follow-up. The role of imaging in CRC screening depends on each country's approach: if an organized screening program is in place, the role of CT colonography (CTC) is limited to the study of either individuals with a positive stool test unwilling/unable to undergo colonoscopy (CC) or in patients with incomplete CC. Although CC is the most common modality to diagnose CRC, CRC can be also incidentally detected during a routine abdominal imaging examination or at the emergency room in patients presenting with intestinal occlusion/subocclusion or perforation. Staging is a crucial aspect of CRC management, guiding treatment decisions and providing valuable prognostic information. An accurate local staging is mandatory in both rectal and colon cancer to drive the appropriate therapeutic workflow. Important limitations of US, CT, and MR in N-staging can be partially solved by FDG PET/CT. Distant staging is usually managed by CT, with MR and FDG PET/CT which can be used as problem-solving techniques. Follow-up is performed according to the general recommendations of the oncological societies. CLINICAL RELEVANCE STATEMENT: It is essential to summarize each phase of colorectal cancer workup, differentiating the management for colon and rectal cancer supported by the main international guidelines and literature data, with the aim to inform the community on the best practice imaging in colorectal cancer. KEY POINTS: • Colorectal cancer is a prevalent disease that lends itself to imaging at each stage of detection and management. • Various imaging modalities can be used as adjuncts to, or in place of, direct visualization methods of screening and are necessary for evaluating metastatic disease. • Reevaluation of follow-up strategies should be considered depending on patients' individual risk of recurrence.

Imaging in the era of risk-adapted treatment in colon cancer

The treatment landscape for patients with colon cancer is continuously evolving. Risk-adapted treatment strategies, including neoadjuvant chemotherapy and immunotherapy, are slowly finding their way into clinical practice and guidelines. Radiologists are pivotal in guiding clinicians toward the most optimal treatment for each colon cancer patient. This review provides an overview of recent and upcoming advances in the diagnostic management of colon cancer and the radiologist's role in the multidisciplinary approach to treating colon cancer.

Nationwide practice in CT-based preoperative staging of colon cancer and concordance with definitive pathology

INTRODUCTION

In an era of exploring patient-tailored treatment options for colon cancer, preoperative staging is increasingly important. This study aimed to evaluate completeness and reliability of CT-based preoperative locoregional colon cancer staging in Dutch hospitals.

MATERIALS AND METHODS

Patients who underwent elective oncological resection of colon cancer without neoadjuvant treatment in 77 Dutch hospitals were evaluated between 2011 and 2021. Completeness of T-stage was calculated for individual hospitals and stratified based on a 60% cut-off. Concordance between routine CT-based preoperative locoregional staging (cTN) and definitive pathological staging (pTN) was examined.

RESULTS

A total of 59,558 patients were included with an average completeness of 43.4% and 53.4% for T and N-stage, respectively. Completeness of T-stage improved from 4.9% in 2011-2014 to 74.4% in 2019-2021. Median completeness for individual hospitals was 53.9% (IQR 27.3-80.5%) and were not significantly different between low and high-volume hospitals. Sensitivity and specificity for T3-4 tumours were relatively low: 75.1% and 76.0%, respectively. cT1-2 tumours were frequently understaged based on a low negative predictive value of 56.8%. Distinction of cT4 and cN2 disease had a high specificity (>95%), but a very low sensitivity (<50%). Positive predictive values of <60% indicated that cT4 and cN1-2 were often overstaged. Completeness and time period did not influence reliability of staging.

CONCLUSION

Completeness of locoregional staging of colon cancer improved during recent years and varied between hospitals independently from case volume. Discriminating cT1-2 from cT3-4 tumours resulted in substantial understaging and overstaging, additionally cT4 and cN1-2 were overstaged in >40% of cases.

Impact of the preoperative clinical N stage on the prognosis of patients with colon cancer

AIM

Although preoperative clinical staging (cStage) is performed for most cancer patients, limited information is currently available on the relationship with postoperative prognosis. We herein investigated the relationship between cStage and prognosis of colon cancer (CC) patients, particularly focusing on the presence or absence of clinical lymph node (LN) metastasis.

METHOD

This was a retrospective study on 840 consecutive patients with colon adenocarcinoma who underwent radical resection at our institution between January 2007 and December 2018. A Kaplan-Meier curve was used to analyse the prognosis of two groups: cN(+)pN(-); a group preoperatively diagnosed with clinical LN metastasis positive, but with no pathological LN metastasis postoperatively, and cN(-)pN(-); a group without clinical and pathological LN metastasis. We also investigated whether a clinical diagnosis is a more accurate prognostic factor than other clinical factors.

RESULTS

Among pN(-) cases, the 5-year recurrence-free survival rate was significantly lower in preoperatively diagnosed cN(+) cases than in cN(-) cases (79.4% vs. 95.6%, 3.04 years vs. 3.85 years, p < 0.01). In a multivariate analysis of various preoperative clinical factors in pStage II cases, including high risk factors for pStage II CC, cN(+) was identified as an independent prognostic factor (hazard ratio: 2.06, 95% CI: 1.02-4.27, p = 0.04).

CONCLUSION

Preoperatively over-staged cN cases had a poorer prognosis than cases without over-staging, indicating its potential as a prognostic factor. In addition to already known high risk factors in pStage II cases, the preoperative cStage may be an indication for adjuvant chemotherapy.

CT and 3 Tesla MRI in the TN Staging of Colon Cancer: A Prospective, Blind Study

(1) Background: Computer tomography (CT) scanning is currently the standard method for staging of colon cancer; however, the CT based preoperative local staging is far from optimal. The purpose of this study was to investigate the sensitivity and specificity of magnetic resonance imaging (MRI) compared to CT in the T- and N-staging of colon cancer. (2) Methods: Patients underwent a standard contrast-enhanced CT examination. For the abdominal MRI scan, a 3 Tesla unit was used, including diffusion weighted imaging (DWI). Experienced radiologists reported the CT and MRI scans blinded to each other and the endpoint of the pathological report. (3) Results: From 2018 to 2021, 134 patients received CT and MRI scans. CT identified 118 of the 134 tumors, whereas MRI identified all tumors. For discriminating between stage T3ab and T3cd, the sensitivity of CT was 51.1% and of MRI 80.0% (p = 0.02). CT and MRI showed a sensitivity of 21.4% and 46.4% in detecting pT4 tumors and a specificity of 79.0% and 85.0%, respectively. (4) Conclusion: Compared to CT, the sensitivity of MRI was statistically significantly higher in staging advanced T3cd and T4 tumors. MRI has the potential to be used in the treatment planning of colon cancer.

The Impact of Patient Characteristics and Tumor Biology on the Accuracy of Preoperative Staging of Colon Cancer in Denmark. A Nationwide Cohort Study

Simple Summary

The roles of mismatch repair and other colon tumor characteristics were investigated in a nationwide registry study with data extracted from the Danish Colorectal Cancer Group. Mismatch repair can arise during DNA replication. In this study, 6102 patients were included with a median age of 72 (range 23–97 years). The mismatch repair was deficient in 24% and proficient in 76%. Mismatch repair deficiency impacted the accuracy of the preoperative staging of colon cancer. In the future, mismatch repair status should be taken into consideration in the clinical staging of colon cancer.

Abstract

Background: Colon cancer is a common disease in western populations. The aim of this study was to assess the impact of mismatch repair (MMR) deficiency and other patient and tumor characteristics on the accuracy of preoperative staging by comparing histopathological T- and N-categories of the resected specimen with the preoperative clinical stage in a nationwide cohort of patients treated for colon cancer by elective bowel resection with curative intent. Methods: A register study of a cohort extracted from the Danish Colorectal Cancer Group (DCCG) database, which holds prospective data on all new cases of colon and rectum cancer in Denmark. Patients diagnosed with colon cancer and treated with an elective bowel resection with curative intent in the years 2016–2019 were analyzed. Results: A total of 6102 patients were included (n = 3161 (52%) men and n = 2941 (48%) women) with a median age of 72 years (range 23–97 years). MMR was deficient in 24% of the patients and proficient in 76%. MMR deficiency, tumor sidedness and histopathological type were significant predictors of the accuracy of preoperative staging of colon cancer in univariate and multivariate analysis. MMR status in particular showed a strong impact on the risk of overstaging. Conclusions: MMR deficiency, but also tumor sidedness and to some degree histopathological type, impacted the accuracy of preoperative staging of colon cancer. MMR status should be taken into consideration in everyday clinical staging.

The Role of Neoadjuvant Chemotherapy in Locally Advanced Colon Cancer

Neoadjuvant systemic therapy has many potential advantages over up-front surgery, including tumor downstaging, early treatment of micrometastatic disease, and providing an in vivo test of tumor biology. Due to these advantages, neoadjuvant therapy is becoming the standard of care for an increasing number of tumor types. Currently, colon cancer patients are still routinely treated with up-front surgery, and neoadjuvant systemic therapy is not yet standard. Limitations to widespread use of neoadjuvant therapy have included inaccurate radiological staging, concerns about tumor progression while undergoing preoperative treatment rendering a patient incurable, and a lack of randomized data demonstrating benefit. However, there is great interest in neoadjuvant chemotherapy, and a number of trials are under way. Early follow up of the first phase III trial of neoadjuvant chemotherapy for colon cancer demonstrated tumor downstaging and suggested an improvement in disease-free survival with neoadjuvant chemotherapy, and it is hoped that this will translate into longer-term overall survival benefit. Clinicians should closely watch this developing field, consider the option of neoadjuvant chemotherapy for colon cancer patients, and actively seek out opportunities for their patients to participate in ongoing clinical trials to further inform this field in future.

Potential image-based criteria of neoadjuvant chemotherapy for colon cancer: multireaders' diagnostic performance

PURPOSE

The objective was to assess which image-based criteria can be best accurately determined at MDCT and which results in least overtreatment.

MATERIALS AND METHODS

A total of 110 consecutive patients, who underwent curative surgery for colon cancer, were included in this retrospective study. Five radiologists independently assessed the longitudinal diameter of cancer as well as T- and N-categories. The five image-based criteria (T3cd/T4, T3/T4, T3/T4 or N+, T3cd/T4 or N2, and T3/T4 with ≥ 4 cm) were evaluated in terms of diagnostic accuracy, interreader agreement, and overtreatment risk using pooled receiver-operating curve and Fleiss kappa analyses. Pathologic high-risk stage II or III was used as a reference standard for assessment of overtreatment risk.

RESULTS

The diagnostic accuracy of multireaders was in the acceptable range (pooled area under curve (AUC): 0.751-0.829). T3/T4 showed the highest AUC (0.829) in terms of diagnostic accuracy. T3/T4 with ≥ 4 cm showed the highest kappa value (κ = 0.695) followed by T3/T4 (κ = 0.623), indicating substantial agreement. The other three criteria revealed moderate agreement (κ = 0.558-0.577). In terms of overtreatment ratio, T3cd/T4 and T3cd/T4 or N2 showed relatively lower ratios (T3cd/T4, 2.2%; T3cd/T4 or N2, 2.9%), whereas T3/T4 and T3/T4 or N+ revealed higher ratios (T3/T4, 8.7%; T3/T4 or N+, 9.5%).

CONCLUSIONS

T3/T4 was the best criterion in terms of diagnostic accuracy. However, in terms of interreader agreement and overtreatment risk, T3/T4 with ≥ 4 cm and T3cd/T4 were better as potential image-based criteria of neoadjuvant chemotherapy for colon cancer.

Performance comparison between MRI and CT for local staging of sigmoid and descending colon cancer

PURPOSE

To compare the diagnostic performance of MRI and CT for local staging of sigmoid and descending colon cancer, with pathological results as the reference standard.

METHOD

This retrospective study included 116 patients with sigmoid or descending colon cancer who underwent both MRI and CT before surgery. MRI and CT images were separately reviewed by two independent and blinded radiologists to assess the following features: T-stage, presence of extramural extension (T3-4 disease), lymph node metastases (N+), and extramural vascular invasion (EMVI+). Diagnostic performance with sensitivity and specificity for detecting positive status (T3-4, N+ or EMVI+) were assessed using receiver-operating-characteristic (ROC) curve, and compared between MRI and CT.

RESULTS

MRI achieved correct T-stage in 81 of 116 patients (69.8 %) while CT in 66 (56.9 %). For detecting T3-4 disease, MRI showed better performance than CT with area under the curve (AUC) of 0.888 versus 0.712 (P =  0.002) and specificity of 81.82 % versus 54.6 % (P =  0.011). No significance was found in sensitivity between two modalities (89.2 % versus 83.1 %, P =  0.302). For detecting N+ disease, performance of MRI and CT were similar (AUC, 0.670 versus 0.650, P =  0.412). For detecting EMVI+, MRI showed better performance than CT (AUC, 0.780 versus 0.575, P =  0.012) with significantly higher sensitivity (68.6 % versus 40.0 %, P =  0.031) and similar specificity (both are 84.3 %).

CONCLUSIONS

MRI may offer more superior diagnostic performance than CT for detecting T3-4 disease and EMVI, thereby supporting its alternative application to CT in local staging of colon cancer.