CT and 3-T MRI accurately identify T3c disease in colon cancer, which strongly predicts disease-free survival

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 colon cancer (CC) preoperative locoregional staging, but has limited diagnostic performance. More accurate preoperative staging would guide selection among expanding patient-tailored treatment options. Objective: To evaluate the diagnostic performance of MRI for T and N staging and of FDG PET/CT for N staging in CC locoregional staging through systematic review. Evidence Acquisition: PubMed, Embase, and Cochrane Library were searched through December 31, 2023 for studies reporting diagnostic performance of MRI or FDG PET/CT for primary (nonrectal) CC before resection without neoadjuvant therapy using histopathology as reference. Study quality was assessed using the QUADAS-2 tool. Publication bias was assessed with Deeks' funnel plot. Primary outcomes were estimated pooled predictive values, stratified by T and N categories for MRI and 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. Deeks' funnel plot asymmetry indicated possible publication bias in MRI studies for differentiation of T3cd-4 from T1-3ab disease and N- from N+ disease. For MRI, for discriminating T1-2 from T3-4 disease, PPV was 64.8% (95% CI [52.9-75.5%]), and NPV was 88.9% (95% CI [82.7-93.7%]); for discriminating T1-3ab from T3cd-4 disease, PPV was 83.4% (95% CI [75.0-90.3%]), and NPV was 74.6% (95% CI [58.2-86.7%]); for discriminating T1-3 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 N- from N+ 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 N- from N+ 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 exhibited pooled sensitivity of 55.1-81.4% and pooled specificity of 70.3-88.1%. Conclusion: MRI had strongest predictive performance for T1-2 and T4 disease. MRI and PET/CT had otherwise limited predictive values, sensitivity, and specificity for evaluated outcomes related T and N staging. Clinical Impact: MRI and FDG PET/CT had overall limited utility for preoperative locoregional staging in colon cancer.

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.

Performance of CT in the locoregional staging of colon cancer: detailed radiology-pathology correlation with special emphasis on tumor deposits, extramural venous invasion and T staging

PURPOSE

To investigate the performance of computed tomography (CT) in the local staging of colon cancer in different segments, with emphasis on parameters that have been found to be significant for rectal cancer, namely, extramural venous invasion (EMVI) and tumor deposits (TDs).

METHODS

CT and pathology data from 137 patients were independently reviewed by radiology and pathology teams. The performance of CT in categorizing a given patient into good, versus poor prognostic groups was assessed for each segment, as well as the presence of lymph nodes (LNs), TDs and EMVIs. Discordant cases were re-evaluated to determine potential sources of error. Elastic stain was applied for EMVI discordance.

RESULTS

The T staging accuracy was 80.2%. For T stage stratification, CT performed slightly better in the left colon, and the lowest accuracy was in the transverse colon. Under-staging was more common (in 12.4%), and most of the mis-staged cases were in sigmoid colon. According to the first comprehensive correlative analysis, the sensitivity, specificity, and accuracy of CT for detecting TDs were found to be 57.9%, 92.4%, 87.6%, respectively. These figures were 44.7%, 72.7%, and 63.5% for LN, and 58.5%, 82.1% and 73% for EMVI. The detection rate was better for multifocal EMVI. The detection rate was also comparable (although substantially underestimated) for LNs, with the half of the LNs missed by CT being < 5 mm. Four patients that were classified as TD by CT, disclosed to be LNs by pathology. Correlative analysis led to refinement of the pathology criteria, with subsequent modifications of the initial reports in 13 (9.5%) patients.

CONCLUSION

Overall, CT performed well in the evaluation of colon cancer, as did TD and EMVI. It is advisable to include these parameters in CT-based staging. Radiologists should be aware of the pitfalls that occur more commonly in different segments.

Small arteriole sign: an imaging feature for staging T4a colon cancer

OBJECTIVES

By analyzing the distribution of existing and newly proposed staging imaging features in pT1-3 and pT4a tumors, we searched for a salient feature and validated its diagnostic performance.

METHODS

Preoperative multiphase contrast-enhanced CT images of the training cohort were retrospectively collected at three centers from January 2016 to December 2017. We used the chi-square test to analyze the distribution of several stage-related imaging features in pT1-3 and pT4a tumors, including small arteriole sign (SAS), outer edge of the intestine, tumor invasion range, and peritumoral adipose tissue. Preoperative multiphase contrast-enhanced CT images of the validation cohort were retrospectively collected at Beijing Cancer Hospital from January 2018 to December 2018. The diagnostic performance of the selected imaging feature, including accuracy, sensitivity, and specificity, was validated and compared with the conventional clinical tumor stage (cT) by the McNemar test.

RESULTS

In the training cohort, a total of 268 patients were enrolled, and only SAS was significantly different between pT1-3 and pT4a tumors. The accuracy, sensitivity, and specificity of the SAS and conventional cT in differentiating T1-3 and T4a tumors were 94.4%, 81.6%, and 97.3% and 53.7%, 32.7%, and 58.4%, respectively (all p < 0.001). In the validation cohort, a total of 135 patients were collected. The accuracy, sensitivity, and specificity of the SAS and the conventional cT were 93.3%, 76.2%, and 96.5% and 62.2%, 38.1%, and 66.7%, respectively (p < 0.001, p = 0.021, p < 0.001).

CONCLUSION

Small arteriole sign positivity, an indirect imaging feature of serosa invasion, may improve the accuracy of identifying T4a colon cancer.

CLINICAL RELEVANCE STATEMENT

Small arteriole sign helps to distinguish T1-3 and T4a colon cancer and further improves the accuracy of preoperative CT staging of colon cancer.

KEY POINTS

• The accuracy of preoperative CT staging of colon cancer is not ideal, especially for T4a tumors. • Small arteriole sign (SAS) is a newly defined imaging feature that shows the appearance of tumor-supplying arterioles at the site where they penetrate the intestine wall. • SAS is an indirect imaging marker of tumor invasion into the serosa with a great value in distinguishing between T1-3 and T4a colon cancer.

Preoperative Local Staging of Colon Cancer by CT: Radiological Staging Criteria Based on Membrane Anatomy and Visceral Adipose Tissue

BACKGROUND

Accuracy of preoperative T staging for colon cancer remains disappointing.

OBJECTIVE

This study aimed to propose specially designed radiological staging criteria based on membrane anatomy and visceral adipose tissue and compare the staging performance with the routinely used method.

DESIGN

This is a prospective observational study.

SETTING

This study was conducted at a high-volume colorectal center.

PARTICIPANTS

Consecutive patients with colonoscopy-proven colon carcinoma referred for clinical staging and elective resection were enrolled.

INTERVENTION

The preoperative CT data were separately reviewed by 2 teams of radiologists for assigning T-stage categories (T1-2, T3, or T4) using the routine staging method or the newly proposed radiological criteria.

MEASURES

Diagnostic performance for T staging was compared between the 2 criteria.

RESULTS

Between October 2019 and August 2020, 190 patients were included. Compared with pathological results, T stage was correctly determined in 113 of 190 patients (59.5%) with the conventional CT criteria. With the newly developed criteria, 160 patients (84.2%) were found to be correctly staged. Accuracies between the 2 criteria significantly differed ( p < 0.001). For T1-2 staging, there were no significant differences between the sensitivities of conventional and new criteria (57.1% vs 61.9%; p = 0.990) or between their specificities (95.3% vs 98.2%; p = 0.131). However, for T3 and T4 staging, the newly developed CT criteria exhibited significantly higher sensitivity (T3: 85.2% vs 57.4%; p < 0.001; T4: 90.7% vs 64.8%; p < 0.001) and specificity (T3: 82.7% vs 64%; p = 0.006; T4: 89.7% vs 69.1%; p < 0.001) than the conventional criteria. Moreover, the new criteria (area under the curve = 0.902) performed significantly better than the conventional criteria (area under the curve = 0.670; p < 0.001), for identifying the T4-stage tumor.

LIMITATIONS

The limitations are that it is a single-center study and there was no external validation.

CONCLUSIONS

The specially designed radiological criteria can offer more accurate T staging than the routine method in colon cancer. See Video Abstract at http://links.lww.com/DCR/B992 .

PREDICCIN DE LA MORTALIDAD A DAS POSTERIORES A LA PRIMERA CIRUGA EN PACIENTES CON CNCER DE COLON OBSTRUCTIVO DEL LADO IZQUIERDO

ANTECEDENTES:Se cree que la resección aguda para el carcinoma de colon obstructivo del lado izquierdo está asociada con un mayor riesgo de mortalidad que un enfoque puente a la cirugía que utiliza un estoma de descompresión o un stent metálico autoexpandible, pero faltan modelos de predicción.OBJETIVO:Determinar la influencia de la estrategia de tratamiento sobre la mortalidad dentro de los 90 días desde la primera intervención utilizando un modelo de predicción en pacientes que presentan carcinoma de colon obstructivo del lado izquierdo.DISEÑO:Un estudio de cohorte multicéntrico nacional, utilizando datos de una auditoría nacional prospectiva.ENTORNO CLINICO:El estudio se realizó en 75 hospitales holandeses.PACIENTES:Se incluyeron los pacientes que se sometieron a una resección con intención curativa de un carcinoma de colon obstructivo del lado izquierdo entre 2009 y 2016.INTERVENCIONES:La primera intervención fue resección aguda, puente a cirugía con stent metálico autoexpandible o puente a cirugía con estoma descompresor.PRINCIPALES MEDIDAS DE VALORACIÓN:La principal medida de resultado fue la mortalidad a los 90 días después de la primera intervención. Los factores de riesgo se identificaron mediante análisis logístico multivariable. Posteriormente se desarrolló un modelo de riesgo.RESULTADOS:En total se incluyeron 2395 pacientes, siendo la primera intervención resección aguda en 1848 (77%) pacientes, estoma como puente a la cirugía en 332 (14%) pacientes y stent como puente a la cirugía en 215 (9%) pacientes. En general, 152 pacientes (6,3%) fallecieron dentro de los 90 días posteriores a la primera intervención. Un estoma de descompresión se asoció de forma independiente con un menor riesgo de mortalidad a los 90 días (HR: 0,27, IC: 0,094-0,62). Otros predictores independientes de mortalidad fueron la edad, la clasificación ASA, la ubicación del tumor y los niveles índice de creatinina sérica y proteína C reactiva. El modelo de riesgo construido tuvo un área bajo la curva de 0,84 (IC: 0,81-0,87).LIMITACIONES:Solo se incluyeron pacientes que se sometieron a resección quirúrgica.CONCLUSIONES:La estrategia de tratamiento tuvo un impacto significativo en la mortalidad a los 90 días. Un estoma descompresor reduce considerablemente el riesgo de mortalidad, especialmente en pacientes mayores y frágiles. Se desarrolló un modelo de riesgo, que necesita una mayor validación externa. Consulte Video Resumen en http://links.lww.com/DCR/B992 . (Traducción-Dr. Ingrid Melo ).

Current Controversies in the Management of Locally Advanced Colon Cancer

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The usefulness of preoperative CT in colon cancer staging: impact of radiologists' experience

PURPOSE

To assess the agreement between radiologists in the detection of specific features related to T- and N-stage and evaluate accuracy in colon cancer staging.

METHODS

Patients who underwent contrast-enhanced computed tomography (CECT) before surgery were enrolled and evaluated by three radiologists with different experience. Pathological data were used as the reference standard. Tumor location, presence of tumor bulging, fat stranding, lateroconal fascia invasion, enlarged vessels, axial short diameter of the biggest node, shape, enhancement pattern, intranodal necrosis, and cluster were collected. Reliability analysis was performed with κ statistics and intraclass correlation coefficients (ICCs). Logistic regressions were used to determine independent predictors associated with staging.

RESULTS

Seventy five patients were evaluated. The reliability analysis was moderate to substantial for tumor location (κ = 0.853), T staging (κ = 0.531), tumor bulging (κ = 0.478), fat stranding (κ = 0.490), lateroconal fascia invasion (κ = 0.436), enlarged vessels (κ = 0.401), the axial short diameter of the biggest node (ICC = 0.732), shape (κ = 0.484), enhancement pattern (κ = 0.431), intranodal necrosis (κ = 0.606), and cluster (κ = 0.358). For all readers, sensitivity was higher for T3 lesions (60-69%) and specificity was higher for T2 and T4 lesions (84.5-90.0% and 82.4-85.1%). The diagnostic accuracy was acceptable for all lesions and among all readers (50.7-92.1%). The lateroconal fascia invasion and enlarged vessels resulted as independent predictor factors (OR = 3.292 and OR = 2.651) for T staging, while nodes' cluster and dimension as independent predictor factors of N staging [OR = 3.798 and OR = 1.083].

CONCLUSION

Reader's experience is one of the most important factors associated with the correct classification of colon cancer. Moreover, CECT can help depict radiological features independently associated with the T and N stages.

Extramural venous invasion and depth of extramural invasion on preoperative CT as prognostic imaging biomarkers in patients with locally advanced ascending colon cancer

PURPOSE

This study evaluates the prognostic significance of EMVI and DEMI on preoperative CT in patients with ascending colon cancer.

METHODS

This retrospective study included consecutive patients with T3 ascending colon cancer from January 2012 to December 2016 in a tertiary center. Two radiologists independently reviewed EMVI, DEMI, and nodal status on preoperative CT. We assessed the association of age, sex, mucinous adenocarcinoma, EMVI, and DEMI with metastasis on preoperative CT using univariable and multivariable analysis. We also compared disease-free survival (DFS) with and without variables (age, sex, mucinous adenocarcinoma, EMVI, DEMI and adjuvant chemotherapy) using Cox's proportional hazards models. We assessed interobserver agreements on imaging features using the Cohen's weighted kappa.

RESULTS

Of 237 patients [107 men; mean (standard deviation) age, 66 (13) years], 24 had metastases on preoperative CT. Positive EMVI was associated with metastasis (odds ratio 16.9; P < 0.001) on multivariable analysis. Of 194 patients [83 men; 65 (13) years] included for DFS analysis, recurrence was observed in 31 (16%) with median follow-up of 53 months. Positive EMVI [hazard ratio (HR) 4.8; P < 0.001] and DEMI > 5 mm (HR 5.5; P < 0.001) were associated with worse DFS. Interobserver agreements were good (kappa = 0.64-0.67).

CONCLUSION

Positive EMVI and DEMI > 5 mm on preoperative CT were associated with a worse T3 ascending colon cancer prognosis. Thus, these CT findings could be used as imaging biomarkers for T3 ascending colon cancer risk stratification.

Identifying high-risk colon cancer on CT an a radiomics signature improve radiologist's performance for T staging?

PURPOSE

To assess the role of radiomics in detection of high-risk (pT3-4) colon cancer and develop a combined model that combines both radiomics and CT staging of colon cancer.

METHODS

We included 292 colon cancer patients who underwent pre-operative CT and primary surgical resection within 2 months. Three-dimensional segmentations and CT staging of primary colon tumors were done. From each 3D segmentation of colon tumor, radiomic features were automatically extracted. Logistic regression analysis was performed to identify associations between radiomic features and high-risk (pT3-4) colon tumors. A combined model that integrated both radiomics and CT staging was developed and their diagnostic performance was compared with that of conventional CT staging. Tenfold cross-validation was used to validate the performance of the model and CT staging.

RESULTS

The model that combined radiomic features and CT staging demonstrated a significantly better performance in detection of high-risk colon tumors in training set (AUC = 0.799, 95% CI: 0.720-0.839 for combined model and AUC = 0.697, 95% CI = 0.538-0.756 for CT staging only, p < 0.001 for difference). Cross-validation results also demonstrated significantly better detection performance of combined model (AUC = 0.727, 95% Confidence Interval (CI): 0.621-0.777 for combined model and AUC = 0.628, 95% CI = 0.558-0.689 for CT staging only, Boot CI = 0.099).

CONCLUSION

CT radiomic features of primary colon cancer, combined with CT staging, can improve the detection of high-risk colon cancer patients.

Diagnostic accuracy of ≥ 16-slice spiral computed tomography for local staging of colon cancer: A systematic review and meta-analysis

BACKGROUND

Colorectal cancer is one of the most common cancers worldwide with high mortality and is classified as a single entity, although colon cancer and rectal cancer have largely different diagnoses, treatments, surgical methods, and recurrence rates. ≥ 16-slice spiral computed tomography (SCT) is mostly applied to detect the local stage of colon cancer; however, its diagnostic accuracy and whether it is conducive to distinguishing between high-risk and low-risk colon cancer are unclear.

AIM

To systematically review the diagnostic accuracy of ≥ 16-slice SCT for local staging of colon cancer.

METHODS

Based on the PubMed, EMBASE, Cochrane Library, and Web of Science databases, computers were used to search the literature from the establishment of the database to April 2021, and the results of the diagnostic tests on ≥ 16-slice SCT for local staging of colon cancer were collected according to the inclusion criteria. The data were then extracted and assessed on the basis of the Quality Assessment Checklist of the Institute of Economics of Canada, Reference Citation Analysis (https://www.referencecitationanalysis.com/). Afterward, a meta-analysis was performed using the statistical software Meta-disc 14.0 and Stata 15.0.

RESULTS

Eleven studies that provided data on 1613 subjects with computed tomography diagnostic tests were included in this study. Meta-analysis revealed that the pooled sensitivity, pooled specificity, pooled negative likelihood ratio (LR), pooled diagnostic odds ratio, and area under the fitted receiver operating characteristic (ROC) curve of ≥ 16-slice SCT for colon cancer T staging were 0.67 (95%CI: 0.65-0.70), 0.81 (95%CI: 0.80-0.83), 4.13 (95%CI: 2.66-6.41), 0.39 (95%CI: 0.31-0.49), 10.81 (95%CI: 7.33-15.94), and 0.829, respectively, while the specificity, negative LR, diagnostic odds ratio, and area under the fitted ROC curve of ≥ 16-slice SCT for N staging of colon cancer were 0.54 (95%CI: 0.49-0.59), 0.74 (95%CI: 0.70-0.77), 1.92 (95%CI: 1.36-2.70), 0.67 (95%CI: 0.51-0.87), 3.74 (95%CI: 1.76-7.94), and 0.829 respectively. The sensitivity and specificity of ≥ 16-slice SCT for colon cancer T staging were acceptable, while the sensitivity for colon cancer N staging was relatively low, though its specificity was acceptable.

CONCLUSION

≥ 16-slice SCT for local staging of colon cancer has good diagnostic value; however, the accuracy needs to be confirmed by further clinical practice.

Laparoscopic Complete Mesocolic Excision Without Routine Gastro-Pancreatico-Colic Trunk Dissection: Survival Outcomes and Morbidity for 567 Cases

Purpose: It is unclear whether the principles of open complete mesocolic excision (CME) can be safely applied to laparoscopic surgery. Furthermore, definitions vary over how radical optimal CME surgery should be. We report morbidity and oncological outcomes for laparoscopic CME without routine gastro-pancreatico-colic trunk (GPCT) dissection. Materials and Methods: An observational study with consecutive data for patients with Union for International Cancer Control (UICC) stage I-III colon adenocarcinoma who underwent elective laparoscopic resection between 2006 and 2015. Data were retrieved for demographics, tumor characteristics, treatment, and histology from prospectively maintained databases. Standardized, routinely video recorded, laparoscopic resections were performed in two United Kingdom centers from The National Training Programme for Laparoscopic Colorectal Surgery. Overall survival and disease-free survival (DFS) were reported using Kaplan-Meier curves and Cox regression. Results: Laparoscopic CME was performed in 567 patients, 52.7% (288/546) women, median (interquartile range [IQR]) age 73 (65-80) years. Median (IQR) length of stay was 4 (3-5) days with 4.0 (2.2-5.7)-year follow-up. Significant DFS predictors (hazard ratio [HR]) by multivariable Cox regression were age >80 years (1.9), American Society of Anesthesiologists (ASA) 3 and 4 (HR = 1.1), right colon cancer (1.7), UICC stage III (3.4), and intramesocolic grade (2.2). Overall 4-year DFS (95% confidence interval) was 81.3% (77-85). Four-year DFS by UICC grades I, II, and III was 94.6% (89-99), 83.4% (77-88), and 72.2% (66-78), respectively (log-rank P = .001). Morbidity by Clavien-Dindo grade was III 18 (3.2%), IV 4 (0.7%) and V 7 (1.2%). Conclusion: This large series suggests standardized laparoscopic CME without routine GPCT dissection has a low morbidity and achieves equivalent outcomes to the most radical open CME techniques.

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.

Computed Tomography Colonography Angiography (CTC-A) prior to colectomy for cancer: A new tool for surgeons

The pre-operative work-up for non-metastatic colon cancer includes colonoscopy and thoraco-abdomino-pelvic computed tomography (CT) with intravenous (IV) contrast. Colonoscopic determination of the anatomical location of the tumor may be erroneous, particularly with a long redundant colon (dolichocolon), and the search for synchronous colon neoplasms is limited when the endoscope cannot traverse the tumor-bearing segment. While computed tomography colonography angiography (CTC-A) makes it possible to assess distant tumor metastasis, it remains limited for the assessment of loco-regional extension. CTC-A requires specific colonic preparation, controlled colonic insufflation with CO₂, and an injection of IV contrast. CTC-A provides a 3-D view of the overall morphology of the colon and precisely localizes the site of the colonic tumor. Merging the images of the colon with those of mesenteric and colonic vessels provides a representation of anatomical vascular variations. This information could help the surgeon to better plan the colectomy. The use of two-dimensional images of CTC-A with sections perpendicular to the major axis of the tumor-bearing colonic segment can provide precise information on the degree of parietal extension and be useful in evaluating the value of neo-adjuvant chemotherapy.

Neoadjuvant chemotherapy in locally advanced colon cancer: a systematic review and meta-analysis

BACKGROUND

There is increasing evidence to support the use of neoadjuvant chemotherapy (NAC) in locally advanced colon cancer (LACC). However, its safety, efficacy and side effect profile is yet to be completely elucidated. This review aims to assess NAC regimens, duration, compare completion rates, intra-operative and post-operative complication profiles and oncological outcomes, in order to provide guidance for clinical practice and further research.

METHODS

PubMed, EMBASE and MEDLINE were searched for a systematic review of the literature from 2000 to 2020. Eight eligible studies were included, with a total of 1213 patients, 752 (62%) of whom received NAC. Of the eight studies analysed, two were randomised controlled trials comparing neoadjuvant chemotherapy followed by oncological resection to upfront surgery and adjuvant chemotherapy, three were prospective single-arm phase II trials analysing neoadjuvant chemotherapy followed by surgery only, one was a retrospective study comparing neoadjuvant chemotherapy followed by surgery versus surgery first followed by adjuvant chemotherapy and the remaining two were single-arm retrospective studies of neoadjuvant chemotherapy followed by surgery.

RESULTS

All cases of LACC were determined and staged by computed tomography; majority of the studies defined LACC as T3 with extramural depth of 5 mm or more, T4 and/or nodal positivity. NAC administered was either folinic acid, fluorouracil and oxaliplatin (FOLFOX) or capecitabine and oxaliplatin (XELOX) with the exception of one study which utilised 5-fluorouracil and mitomycin. Most studies had NAC completion rates of above 83% with two notable exceptions being Zhou et al. and The Colorectal Cancer Chemotherapy Study Group of Japan who both recorded a completion rate of 52%. Time to surgery from completion of NAC ranged on average from 16 to 31 days. The anastomotic leak rate in the NAC group ranged from 0 to 4.5%, with no cases of postoperative mortality. The R0 resection rate in the NAC group was 96.1%. Meta-analysis of both RCTs included in this study showed that neoadjuvant chemotherapy increased the likelihood of a negative resection margin T3/4 advanced colon cancer (pooled relative risk of 0.47 with a 95% confidence interval) with no increase in adverse consequence of anastomotic leak, wound infection or return to theatre.

CONCLUSIONS

Our systematic review and meta-analysis show that NAC is safe with an acceptable side effect profile in the management of LACC. The current data supports an oncological benefit for tumour downstaging and increased in R0 resection rate.

CT for lymph node staging of Colon cancer: not only size but also location and number of lymph node count

PURPOSE

To evaluate the diagnostic accuracy of imaging features to predict lymph node status of colon cancer using CT.

METHODS

This was a retrospective study from 2 tertiary hospitals in South Korea and Netherlands. 317 Colon cancer patients who underwent primary surgical treatment were included. Number of lymph nodes according to the anatomical location, size, cluster, degree of attenuation, shape, presence of internal heterogeneity and ill-defined margin of the lymph node were assessed and compared according to histological lymph node status.

RESULTS

The largest short diameter of lymph node and presence of internal heterogeneity of lymph node showed significant association with malignant lymph node status (P < 0.001 and P = 0.041, respectively). The ROC curve analysis revealed AUC of 0.703 for the largest short diameter of lymph node (P < 0.001), and AUC of the presence of internal heterogeneity was 0.630 (P < 0.001). In addition, our study showed that a total number of lymph nodes, regardless of size, (P = 0.022) and number of lymph nodes in peritumoral area (P < 0.001) and along the mesenteric vessels (P < 0.001) on CT demonstrated significant association with malignant status of lymph nodes in colon cancer.

CONCLUSIONS

There were significant associations between lymph node status and imaging features of lymph nodes on CT in colon cancer patients. The largest short diameter of lymph node and presence of internal heterogeneity can be used to predict the malignant status of lymph node in colon cancer patients. Also, the number of lymph nodes near the colonic tumor should be considered in assessment of colon cancer lymph node involvement on CT.

Does neoadjuvant FOLFOX chemotherapy improve the prognosis of high-risk Stage II and III colon cancers? Three years' follow-up results of the PRODIGE 22 phase II randomized multicentre trial

AIM

Neoadjuvant chemotherapy has proven valuable in locally advanced resectable colon cancer (CC) but its effect on oncological outcomes is uncertain. The aim of the present paper was to report 3-year oncological outcomes, representing the secondary endpoints of the PRODIGE 22 trial.

METHOD

PRODIGE 22 was a randomized multicentre phase II trial in high-risk T3, T4 and/or N2 CC patients on CT scan. Patients were randomized between 6 months of adjuvant FOLFOX (upfront surgery) or perioperative FOLFOX (four cycles before surgery and eight cycles after; FOLFOX perioperative). In wild-type RAS patients, a third arm testing perioperative FOLFOX-cetuximab was added. The primary endpoint was the tumour regression grade. Secondary endpoints were 3-year overall survival (OS), disease-free survival (DFS), recurrence-free survival (RFS) and time to recurrence (TTR).

RESULTS

Overall, 120 patients were enrolled. At interim analysis, the FOLFOX-cetuximab arm was stopped for futility. The remaining 104 patients represented our intention-to-treat population. In the perioperative group, 96% received the scheduled four neoadjuvant cycles and all but one had adjuvant FOLFOX for eight cycles. In the control arm, 38 (73%) patients received adjuvant FOLFOX. The median follow-up was 54.3 months. Three-year OS was 90.4% in both arms [hazard ratio (HR) = 0.85], 3-year DFS, RFS and TTR were, respectively, 76.8% and 69.2% (HR=0.94), 73% and 69.2% (HR = 0.86) and 82% and 72% (HR = 0.67) in the perioperative and control arms, respectively. Forest plots did not show any subgroup with significant difference for survival outcomes. No benefit from adding cetuximab was observed.

CONCLUSION

Perioperative FOLFOX has no detrimental effect on long-term oncological outcomes and may be an option for some patients with locally advanced CC.

Local recurrence in sigmoid cancer is a hidden problem, could CT prognostic factors be of value in their prevention? A multi-centre study of 414 patients

INTRODUCTION

The incidence and patterns of local recurrence of colon cancer are not well reported. The aim of this study was to investigate the contemporary rates and patterns of local recurrence after sigmoid cancer resection, comparing pre and post-operative biomarkers in predicting local disease recurrence.

MATERIALS AND METHODS

A multi-centre, retrospective analysis of 414 patients undergoing resectional surgery for sigmoid colon cancer was conducted. Multivariable Cox Proportional Hazard models were created to identify variables associated with local disease recurrence. Patterns of recurrence and prognostic significance of pre and post-operative variables were identified.

RESULTS

In 414 patients, the local recurrence rate was 12.6%. The R1/R2 rate was 2.4%. Local recurrence occurred most commonly within the peri-anastomotic region (50%), followed by the peritoneum (33%). On multivariate analysis, local recurrence was predicted by pathological T stage (HR 1.15) and R1 resection (HR 2.95), but also computerised tomography (CT) identified tumour deposits (HR 2.40) and local peritoneal infiltration (2.70).

CONCLUSIONS

Contemporary local recurrence rates for sigmoid cancer are high at 12.6%. Outcomes may be improved if local recurrence is reduced at the most common sites such as the peri-anastomotic area or peritoneum. Extra-nodal CT-imaging biomarkers of local peritoneal infiltration and tumour deposits were prognostically significant on multivariate analysis in addition to pathology staging variables.

Locoregional CT staging of colon cancer: does a learning curve exist?

PURPOSE

To evaluate the learning curve for locoreginal staging of colon cancer in radiologist trainees.

METHODS

Eighty-eight cases of colon cancer CT were included in this retrospective study. Four senior radiology residents staged the CTs according to TNM classification. Two out of four radiologists received feedback after reading every 20 cases. Radiologic staging was compared with pathologic staging and the learning curve, diagnostic performance, reader confidence and reading time were evaluated and compared between the two groups (feedback vs. no feedback). Generalized estimating equations logistic regression, QICu statistic, ANOVA and t test/Mann-Whitney test were utilized.

RESULTS

Radiologists demonstrated a significant increase in their performance to distinguish between ≤ T2 and ≥ T3 and reached an inflection point at 38 cases, with a significant association with increased number of cases reviewed (P < 0.001). Sensitivity (P < 0.001), specificity (P = 0.030) and NPV (P = 0.002) demonstrated significant associations with increased experience. The overall reader's confidence was significantly higher in the group which received feedback (P < 0.001). There was no significant improvement in performance nor in reader's confidence for N staging (N0 vs. ≥ N1) for all readers. Reading time decreased with experience and showed a significant negative association with experience (P < 0.001).

CONCLUSION

Diagnostic performance of senior radiology trainees in differentiating between T2 and T3 colon cancer on CTs improved with increased experience. In contrast, evaluation of lymph node involvement did not improve with more experience. Feedback had no significant effect on improvement of diagnostic performances.

Impact of visceral adipose tissue on the accuracy of T-staging by CT in colon cancer

OBJECTIVE

Accuracy of preoperative T-staging for colon cancer remains disappointing and may potentially influenced by patients' individual characteristics including visceral adipose tissue (VAT). We sought to clarify the impact of VAT on the accuracy of T-staging by CT.

METHODS

This study of 216 consecutive patients who underwent elective surgery was conducted in a single cancer center, to control other potentially confounding factors. Patients were divided into accurate- and mis-staging groups according to the comparison between preoperative CT-defined (cT) and postoperative pathologic T-stages (pT). Patients' individual characteristics, including CT-based VAT at L2/L3 level, age, sex, body mass index (BMI), tumor location, present of bowel obstruction and pathologic subtype, were compared between the two groups. Association between VAT and mis-staging was assessed using multivariate logistic regression to adjust for confounders.

RESULTS

Of the 216 patients, 84 (39%) were mis-staged by CT. The mean VAT in accurate-staging group was significantly higher than that in mis-staging group (146.8 ± 66.1 cm² vs 98.1 ± 44.7 cm², P < 0.001), with an optimal cutoff point of 122 cm² for predicting mis-staging. After partial adjustment, a lower VAT (< 122 cm², P < 0.001) and proximal location of tumor (P = 0.004) were independent factors associated with higher probability of mis-staging. Compared to VAT ≥ 122 cm² as the reference, VAT < 122 cm² exhibited an odds ratio of 2.701 (95% confidence intervals [CI], 1.618-3.907) for the probability of mis-staging.

CONCLUSION

A lower-VAT is associated with an increased probability of inaccurate clinical T-staging in colon cancer.

Neoadjuvant Chemotherapy without Radiation in Colorectal Cancer

In colon cancer, primary surgery followed by postoperative chemotherapy represents the standard of care. In rectal cancer, the standard of care is preoperative radiotherapy or chemoradiation, which significantly reduces local recurrence but has no impact on subsequent metastatic disease or overall survival. The administration of neoadjuvant chemotherapy (NACT) before surgery can increase the chance of a curative resection and improves long-term outcomes in patients with liver metastases. Hence, NACT is being explored in both primary rectal and colon cancers as an alternative strategy to shrink the tumor, facilitate a curative resection, and simultaneously counter the risk of metastases. Yet, this lack of clarity regarding the precise aims of NACT (downstaging, maximizing response, or improving survival) is hindering progress. The appropriate cytotoxic agents, the optimal regimen, the number of cycles, or duration of NACT prior to surgery or in the postoperative setting remains undefined. Several potential strategies for integrating NACT are discussed with their advantages and disadvantages.

Reporting colon cancer staging using a template

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Template reporting increases key colon tumour descriptors.

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Template reporting was used for less than a third of the patients.

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High risk of underreporting.

Purpose

The purpose of this study was to evaluate the effect of completeness of the radiological reports in primary local staging colon cancer when using a template.

Methods

The study used primary staging reports retrieved from the departments RIS/PACS. Five key tumour descriptors were evaluated within each report: tumour morphology (polypoid or annular), information on tumour breach of the colon wall (≥ T3), tumour out-growth in mm, nodal status and TNM in conclusion. The failure to provide a description of the presence or absence of a feature in a report counted as ‘not reported’. To allow comparisons between reporting styles, the template or free-text style of reporting was also recorded.

Results

During a two year period, a total of 666 patients CT reports were evaluated at the colorectal center multidisciplinary team (MDT) conference. In 200 of these reports a template was used. Information on tumour morphology (polypoid or annular) was present in 81% of the template reports vs 9% in free-text style. The figures in percentage for information on tumour breach of the colon wall (≥ T3) were 93% vs 48 %, tumour out-growth in mm: 51% vs 17%, nodal status: 99% vs 86% and TNM in conclusion: 98% vs 51%. P < 0.0001.

Conclusion

The present study provides additional support for the routine use of template reports to improve imaging reporting standards in colonic cancer.

Assessment of a Staging System for Sigmoid Colon Cancer Based on Tumor Deposits and Extramural Venous Invasion on Computed Tomography

IMPORTANCE

Preoperative TNM stratification of colon cancer on computed tomography (CT) does not identify patients who are at high risk of recurrence that could be selected for preoperative treatment.

OBJECTIVE

To evaluate the utility of CT findings for prognosis of sigmoid colon cancer.

DESIGN, SETTING, AND PARTICIPANTS

This prognostic study used retrospective data from patients who underwent bowel resection for sigmoid colon cancer between January 1, 2006, and January 1, 2015, at a tertiary care center receiving international and national referrals for colorectal cancer. Statistical analysis was performed in April 2019.

MAIN OUTCOMES AND MEASURES

Cox proportional hazards regression analysis was performed to investigate CT findings associated with disease recurrence. Kaplan-Meier survival plots were calculated for disease-free survival using CT staging systems.

RESULTS

Of the 414 patients who had sigmoid colon cancer (248 [60.0%] men; mean [SD] age, 66.1 [12.7] years), with median follow-up of 61 months (interquartile range, 40-87 months), 122 patients (29.5%) developed disease recurrence. On multivariate analysis, nodal disease was not associated with disease recurrence; only tumor deposits (hazard ratio [HR], 1.90; 95% CI, 1.21-2.98; P = .006) and extramural venous invasion (HR, 1.97; 95% CI, 1.26-3.06; P = .003) on CT were associated with disease recurrence. Significant differences in disease-free survival were found using CT-T3 substage classification (HR, 1.88; 95% CI, 1.32-2.68) but not CT-TNM (HR, 1.55; 95% CI, 0.94-2.55). The presence of tumor deposits or extramural venous invasion on CT (HR, 2.45; 95% CI, 1.68-3.56) had the strongest association with poor outcome.

CONCLUSIONS AND RELEVANCE

In this study, T3 substaging and detection of tumor deposits or extramural venous invasion on preoperative CT scans of sigmoid colon cancer were prognostic factors for disease-free survival, whereas TNM and nodal staging on CT had no prognostic value. T3 substaging and detection of tumor deposits or extramural venous invasion of sigmoid colon cancer was superior to TNM on CT and could be used to preoperatively identify patients at high risk of recurrence.

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.

Prediction of efficacy of neoadjuvant chemoradiotherapy for rectal cancer: the value of texture analysis of magnetic resonance images

PURPOSE

To explore the clinical feasibility of predicting the efficacy of neoadjuvant chemoradiotherapy (nCRT) for rectal cancer on the basis of texture analysis (TA) of T2-weighted imaging (T2WI).

METHODS

The cohort for this prospective study comprised 136 patients with rectal cancer to be treated with nCRT, all of whom underwent three MR scans (pre-, early, and post-nCRT). Treatment efficacy was assessed on the basis of the outcomes of pathologic complete response (pCR) and non-pCR as determined by postoperative pathological examination. Extraction and analysis of texture features in T2WI of defined tumor regions were performed by AK software. Pre- and early-nCRT texture features were selected as potential predictors of outcomes by logistic regression analysis, and a prediction model for pCR was developed. A receiver operating characteristic (ROC) curve was used to assess the predictive power of texture features in pre- and early-nCRT images.

RESULTS

Univariate logistic regression analysis demonstrated that the pre-nCRT features of energy, entropy, and skewness, and early-nCRT features of variance, kurtosis, energy, and entropy were independent predictors of pCR. A prediction model incorporating these predictors was constructed by multivariate logistic regression, The AUCs of pre-nCRT, early, and combined models were 0.751, 0.831, and 0.873, respectively; the sensitivities 66, 71, and 75%, respectively; and the specificities 87.22, 86.11, and 91.67%, respectively.

CONCLUSIONS

TA of T2WI images can predict the efficacy of nCRT for rectal cancer, possibly providing a new marker of tumor biological response in clinical practice.

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

PURPOSE

The aim of this study was to determine the diagnostic performance of magnetic resonance imaging (MRI)-categorized T3cd/T4 tumors for identifying high-risk stage II or stage III cancer in patients with curatively resectable colon cancer in comparison to that of multidetector computed tomography (MDCT).

MATERIALS AND METHODS

Thirty-eight patients with histopathologically indicated adenocarcinomas prospectively underwent MRI of the colon. Two radiologists independently and retrospectively assessed for T-category, including T3 substage (≤ T3ab vs. ≥ T3cd). The diagnostic accuracies and interreader agreements between assessments using each modality were compared using a pairwise comparison of receiver-operating characteristic curves and a weighted κ statistic, respectively.

RESULTS

Twenty-nine patients (76.3%) were histopathologically diagnosed with high-risk stage II or stage III colon cancer. The false-positive rate with MRI was lower than that with MDCT (0% vs. 7.9% for reader 1, 2.6% vs. 10.6% for reader 2). The diagnostic performance of MRI was better than that of MDCT across both readers (AUC: 0.707 vs. 0.506 [P = 0.032] for reader 1, 0.651 vs. 0.485 [P = 0.055] for reader 2). Moreover, MRI interreader agreement for the assessment of T3cd/T4 was significantly better than that of MDCT (κ = 0.821 vs. 0.391 [P = 0.017]).

CONCLUSION

The diagnostic performance of MR imaging of the colon may be better than that of MDCT for identifying high-risk stage II or stage III cases. Particularly, colon MRI reduced the false-positive rate and improved the interreader agreement, although further studies with a larger sample size are required.

Morphological predictors for lymph node metastases on computed tomography in colon cancer

INTRODUCTION/BACKGROUND

The aim of the study was to assess morphological predictors for lymph node metastases (Stage III disease) in colon cancer on computed tomography.

METHODS AND MATERIALS

Ninety-four patients with histology-proven colon cancer (adenocarcinoma) who underwent elective primary curative resection between the years 2012 and 2014 were included. Contrast-enhanced CT examinations were independently reviewed by two blinded observers regarding tumor location, depth of tumor invasion, and presence of lymph node metastases. Ocular presence of internal heterogeneity and presence of irregular outer border were used as morphological criteria for lymph node involvement. Protocol-based histopathology after curative surgery served as reference standard. Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values, and accuracy for each morphological criterion for prediction of stage III disease were calculated. Inter-observer agreement was compared using Kappa statistics.

RESULTS

According to histopathology, 59 patients were staged as I-II disease and 35 patients were staged as stage III disease. The presence of internal heterogeneity in a lymph node on CT resulted in moderate sensitivity (66-77%) but high specificity (95-95%) for prediction of Stage III disease by both observers. The presence of irregular outer border also resulted in poor sensitivity (49-54%) but high specificity (97-97%). The combination of either internal heterogeneity and/or irregular outer border per patient resulted in a moderate sensitivity (67-77%) and high specificity (95-95%), PPV (89-96%), and NPV (84-88%). Inter-observer agreement (Cohens Kappa) was 0.72. Consensus reading for the combined criteria resulted in sensitivity and specificity of 69% and 100%, respectively.

CONCLUSION

Using morphological criteria for lymph node metastases on CT examination in patients with colon cancer results in high specificity but moderate sensitivity in predicting stage III disease.

CT Colonography in Preoperative Staging of Colon Cancer: Evaluation of FOxTROT Inclusion Criteria for Neoadjuvant Therapy

OBJECTIVE

The purpose of the present study is to evaluate the diagnostic performance of and interreader agreement for CT colonography (CTC) in the local staging of colon cancer, with emphasis given to the FOxTROT (Fluoropyrimidine, Oxaliplatin, and Targeted-Receptor pre-Operative Therapy [Panitumumab]) trial inclusion criteria, which propose a new tailored treatment paradigm for colon cancer that uses neoadjuvant therapy for patients with a high-risk of locoregional disease as determined by imaging.

MATERIALS AND METHODS

This biinstitutional retrospective study involved 89 patients (with 93 tumors) who had colon cancer and underwent presurgical CTC. Two radiologists reviewed the CTC studies for local staging, including measurement of the tumor beyond the muscularis propria on a true orthogonal plane. Histopathologic findings for surgical colectomy specimens served as the reference standard for local pathologic staging. The sensitivity, specificity, positive predictive value, and negative predictive value for local determination of the T category, N category, and extramural vascular invasion (EMVI) were calculated separately for each reader. High-risk T category tumors were the same as those as used in the FOxTROT trial. Interreader agreement was assessed using the kappa statistic.

RESULTS

Thirty-five of 93 tumors (37.6%) were histologically classified as high-risk tumors (T3c, T3d, or T4 tumors). The interreader agreement was substantial (κ = 0.68) for classifying high-risk tumors with the use of CTC, moderate for differentiating N0 from N1 and N2 (κ = 0.44), and slight for detecting EMVI (κ = 0.15). The diagnostic statistics for CTC for the two readers were as follows: for detection of high-risk tumors, sensitivity was 65.7% and 82.9%, and specificity was 81.0% and 87.9%; for detection of N category-positive disease, sensitivity was 50.9% and 69.8%, and specificity was 50.0% and 72.5%; and for detection of EMVI, sensitivity was 18.2% and 66.7%, and specificity was 60.0% and 91.7%.

CONCLUSION

The present study shows that CTC might be a feasible imaging modality for preoperative local staging of higher-risk colon cancers for which neoadjuvant chemotherapy is more suitable on the basis of the FOxTROT trial criteria. However, further studies are required to allow a better generalization of our results.