Accuracy of preoperative staging with multidetector computed tomography in colon cancer

Neoadjuvant chemotherapy for colon cancer: A systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Neoadjuvant chemotherapy (NAC) treatment has appeared as a promising alternative to upfront surgery to improve efficacy outcomes in non-metastatic colon cancer, but the findings are still controversial. Considering this ongoing debate, we conducted a systematic review and meta-analysis of randomized controlled trials to assess the benefit of NAC in high-risk stage II and stage III colon cancer.

MATERIALS AND METHODS

We searched PubMed, Embase, and Cochrane for clinical trials evaluating NAC in non-metastatic colon cancer. Random and fixed effects models were employed for statistical analyses in Review Manager software version 5.4. Moreover, to evaluate the heterogeneity, I2 statistics were used.

RESULTS

A total of 1248 patients from 4 clinical trials were included. The NAC group demonstrated a 38 % reduction in the risk of death. (HR 0.62; 95 % CI 0.41-0.92; I2 = 0 %), and a 21 % reduction in the risk of disease recurrence (HR 0.79; 95 % CI 0.65-0.96; I2 = 0 %). Additionally, the NAC group had higher R0 resection, with an increase of 80 % in the odds compared to upfront surgery (OR 1.80; 95 % CI 1.24-2.61; I² = 0 %). Pathological complete response and major pathologic response (PCR) were achieved in 5.9.% % and 36.2 %, respectively. Patients with proficient mismatch repair achieved a higher PCR rate and a consistent reduction in the risk of recurrence compared to the overall population, with proportions of 6.3 % and 32 %, respectively. Also, there was no significant addition to the toxicity profile in the NAC arm.

CONCLUSION

Our systematic review and meta-analysis support the feasibility and survival benefits of neoadjuvant chemotherapy for high-risk stage II and III colon cancer.

Preoperative angio-CT colonography improves the quality of lymph node dissection during minimally invasive right hemicolectomy: a propensity score-matched study

BACKGROUND

Minimally invasive right hemicolectomy for cancer with complete mesocolic excision is a difficult procedure to perform. The aim of this single-center prospective study was to evaluate whether preoperative angio-CT colonography (A-CTC) improved the quality of lymph node dissection during this surgery.

METHODS

All patients undergoing elective minimally invasive right hemicolectomy for colon adenocarcinoma with complete mesocolic excision between 01/2020 and 12/2023 have been prospectively included. The primary endpoint was the number of lymph nodes examined in the surgical specimen, including the total number of lymph nodes and the percentage of patients with at least 12 lymph nodes examined. Secondary endpoints included operating time, intraoperative complications, overall postoperative morbidity, and length of hospital stay. A propensity score was constructed with groups matched 3:1 using nearest neighbor matching based on the propensity score.

RESULTS

Of the 161 patients included, 44 had A-CTC (27%) and 117 had conventional CT scans. After propensity score matching, patients in the A-CTC group had significantly more lymph nodes on the surgical specimen (24 vs. 20, p = 0.006) and a better quality of lymph node dissection (≥ 12 examined lymph nodes: 100% vs. 87%, p < 0.001). Median operative times were similar between the two groups (184 vs. 180 min, p = 0.07), but two patients (2%) in the conventional CT group experienced an intraoperative bleeding complication. Postoperative morbidity and length of hospital stay were comparable.

CONCLUSIONS

Preoperative 3D reconstruction of vascular anatomy with A-CTC is useful and improves the quality of lymph node dissection during minimally invasive right hemicolectomy for cancer.

High-performance CT features supporting accurate pre-operative tumor staging in colon cancer

Background and aims

Accurate pre-treatment tumor staging is essential for treatment decision-making. Multi-slice spiral computed tomography (CT) is currently the standard method for pre-operative clinical tumor staging, but accurately applying the CT findings in tumor staging remains a challenge due to the poor pathological understanding of the CT signs. We aimed to pathologically interpret the key CT findings in order to identify reliable markers for pre-treatment staging of colon cancer.

Patients and methods

The following CT features from 136 colon adenocarcinomas were analyzed: colon wall pliability, outline contour, pericolic fat attenuations and vascularity, tumor fusion with adjacent organs, ascites, tumor size, and relevance between tumor and retroperitoneal fascia. These CT features were corroborated with histopathological findings. The diagnostic performance of these was further analyzed.

Results

Based on the postoperative pathological tumor staging (pT), 136 colon adenocarcinomas were classified into four stages: pT1 (n = 5), pT2 (n = 7), pT3 (n = 96), and pT4 (n = 28). Key findings include the following: (1) soft colon wall is a characteristic of the pT1 tumors, whereas stiff colon wall is a characteristic of the pT2~pT4 tumors; pathologically, stiff colon wall reflects the infiltration of tumor cells with desmoplastic reaction (DR) in muscularis propria; (2) small protuberances may help exclude the pT2 tumors. Histopathologically, small protuberances in pT2 cancer represent the pure DR on the surface of lamina propria, whereas the small protuberances in pT3~pT4 cancers represent the sub-serosal or extra-serosal cancer cell foci enwrapped by DR; (3) the presence of large protuberances, extensive reticulonodular fat stranding, and fusion with surrounding organs and ascites are diagnostic of pT4 tumors; and (4) the presence of extra-fascial nodules/streaks on CT scan could accurately diagnose the ascending/descending colon cancer of pT4 stage. Histologically, the presence of the above five CT features (large protuberances, extensive reticulonodular fat stranding, fusion with surrounding organs, ascites, and extra-fascial nodules/streaks) reflect the farther and deeper infiltration of tumor cells in serosa or retroperitoneal fascia involvement.

Conclusion

Our studies have identified multiple CT features that are practically useful in identifying and differentiating different stages of colon cancer prior to surgical procedures. These high-performance markers will provide valuable insights to the clinicians in making appropriate decisions in the management of patients with colon cancer.

Tailored-surgery for locally advanced colon cancer based on 3D mathematical reconstruction surgical planner: Observational comparative non-randomized study

BACKGROUND

This study investigates the effectiveness of a three-dimensional reconstruction mathematical model (3D-IPR) for preoperative planning in locally advanced colon cancer (LACC) with threatened surgical margins. The objective was to evaluate the utility of a 3D-IPR surgical planner tool in cases of LACC with threatened surgical margins. Additionally, the study aims to compare the diagnostic accuracy of the 3D-IPR model against conventional CT scans in determining the infiltration of neighboring structures.

METHODS

This Single-center, prospective, observational, comparative, non-randomized study. INCLUSIóN CRITERIA: Patients over 18 years old undergoing surgery for LACC as indicated by a radiologist's analysis of CT scans. Preoperative confirmation of neoplasm by colonoscopy.

EXCLUSION CRITERIA

patients who had received neoadjuvant chemotherapy, suspected carcinomatosis on preoperative CT and patients with unresectable tumors. All patients were selected consecutively.

PROCEDURES

Intervention involved using a 3D-IPR model as a surgical planning tool for patients with LACC. The 3D-IPR provided detailed metrics about the tumor and surrounding structures to assist in surgical planning. Surgical procedures were guided by the radiological assessments from CT scans and intraoperative findings, with surgeries categorized based on surgical margins as R0, R1, or R2. The primary endpoint was the diagnostic accuracy of the 3D-IPR model in determining tumor infiltration of neighboring structures compared to conventional CT scans. The measure used to assess this outcome was the definitive pathological report of tumor infiltration, which served as the gold standard for comparison. Demographic, intraoperative, morbidity, mortality, and pathological data were analyzed.

RESULTS

21 patients were assessed, 1 excluded with a final sample of 20 patients. 3D-IPR model demonstrated higher diagnostic accuracy for tumor infiltration of neighboring structures compared to conventional CT scans, with sensitivity, specificity, Positive Predictive Value, and Negative Predictive Value of 70 %, 90 %, 87.5 %, and 75 %, respectively. Surgeries were predominantly minimally invasive (70 %), with no major complications or mortality within 30 days, and a 0 % conversion rate to open surgery.

CONCLUSIONS

The 3D-IPR model significantly enhances preoperative planning accuracy, reducing the risk of incomplete resections and improving surgical outcomes. This technology offers a reliable basis for surgical decisions, potentially improving patient prognosis and survival rates.

Effects of Microsatellite Instability on the Clinical and Pathological Characteristics of Colon Cancer and the Diagnostic Accuracy of Preoperative Abdominal CT Scans

Background: Microsatellite-stable (MSS) and microsatellite-instable (MSI) colon cancer (CC) cases have different characteristics. These characteristics may impact the accuracy of abdominal computed tomography (CT) scan examinations in MSI CC. Methods: A retrospective analysis was conducted to examine the effects of MSI CC on patients' clinical and tumor characteristics. We determined the accuracy of radiological T and N staging compared to pathological T and N staging in CC patients and evaluated the influence of tumor- and patient-related factors on this accuracy. Results: A total of 131 CC patients who had undergone surgical resection were analyzed. Mismatch repair-deficient (dMMR) CC was predominantly found in the right hemicolon (p = 0.023); it was more likely to exhibit moderate (80.8%) or low-grade differentiation (p = 0.01) and had higher rates of mucinous differentiation (p = 0.001). The median neutrophil and platelet counts and C-reactive protein (CRP) levels at diagnosis were significantly higher in patients with dMMR CC (p = 0.022, p = 0.022, and p = 0.018). The depth of invasion influenced the CRP levels in dMMR CC cases (p = 0.015). The abdominal CT exam was accurate regarding the depth of colonic wall invasion in 58.1% and 38.5% of patients with mismatch repair-proficient (pMMR) and dMMR CC, respectively. The assessment of lymph node invasion was accurate in 44.8% of those with pMMR and 50.0% of those with dMMR CC. There was no significant difference in the accuracy in predicting the T and N statuses between the two groups. The accuracy in the determination of the T and N statuses was not affected by the parameters examined. Conclusions: dMMR CC has specific characteristic features. MSI does not affect the accuracy of preoperative abdominal CT.

Optimal extent of lymph node dissection in clinical early-stage right colon cancer: a retrospective analysis

Purpose

Determining the extent of radical lymphadenectomy at clinical early stage is challenging. We aimed to investigate the appropriate extent of lymphadenectomy in clinical early-stage right colon cancer.

Methods

Patients with clinical stage 0 or I right colon cancer who underwent curative surgery from January 2007 to December 2021 were included in this retrospective study. The extent of lymph node (LN) metastases based on the distribution of LN metastases (LND: LND1 pericolic nodes, LND2 intermediate nodes, LND3 apical nodes), along with the depth of submucosal (SM) invasion (classed into SM1-3), were analyzed.

Results

Of the 348 patients, distribution across pathologic stages was as follows: 30 patients (8.6%) at stage 0, 207 (59.5%) at stage I, 52 (14.9%) at stage II, and 59 (17.0%) at stage III. In pT1 tumor patients, LN metastases varied by SM invasion depth: 3.6% in SM1 (all LND1), 5.1% in SM2 (all LND1), and 17.5% in SM3 (LND1 10%, LND2 5%, LND3 2.5%). For pT2, pT3, and pT4 stages, LN metastasis rates were 16.2% (LND1 11.3%, LND2 3.8%, LND3 1.3%), 39.7% (LND1 28.9%, LND2 8.4%, LND3 2.4%), and 50% (LND1 25%, LND2 25%), respectively. Tumor invasion depth and lymphovascular invasion were identified as significant risk factors for LN metastasis extending to LND2-3.

Conclusion

Complete mesocolic excision should be considered for right-sided colon cancer because tumor infiltration deeper than SM2 could metastasize to LND2 or further. If preoperative endoscopy confirms SM1 or SM2 invasion, D2 lymphadenectomy could be a limited surgical option.

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.

Effect of Fluorescence Lymph Node Mapping on Improving Diagnostic Values of CT D3 Lymph Node Staging for Right-Sided Colon Cancer

BACKGROUND/OBJECTIVES

This study evaluated the impact of fluorescence lymph node mapping (FLNM) using indocyanine green (ICG) on the diagnostic accuracy of preoperative computed tomography (CT) in right-sided colon cancer.

METHODS

A total of 218 patients who underwent laparoscopic right hemicolectomy with D3 lymph node dissection (LND) were analyzed: 86 patients in the FLNM group and 132 in the conventional surgery group. The FLNM technique allowed for enhanced intraoperative visualization of lymph node (LN) and more precise dissection, improving the identification of metastatic LNs. The diagnostic value of preoperative CT staging was assessed in both the FLNM and control groups by calculating the apparent prevalence, true prevalence, sensitivity, specificity, positive predictive value (PPV), negative predictive value, positive likelihood ratio (PLR), negative likelihood ratio, false positive and false negative proportions, and accuracy.

RESULTS

FLNM increased the accuracy of CT staging for detecting D3 LN metastasis in advanced cancer cases, with a higher PPV, PLR, and accuracy. In the FLNM group, the false-positive rate was significantly reduced, and the specificity was higher compared to the control group. Multivariate analysis identified FLNM as an independent factor associated with improved D3 LN metastasis detection. These findings suggest that incorporating FLNM into surgical procedures enhances the diagnostic value of preoperative CT by improving the precision of LND, particularly in patients with advanced colon cancer.

CONCLUSIONS

The use of FLNM for D3 LND enhances the diagnostic accuracy of cN staging in right-sided colon cancer by improving surgical precision.

Performances of preoperative CT scan to predict the pTN stage for MSI/dMMR localized colon cancers

BACKGROUND

Neoadjuvant immunotherapy emerges as a promising strategy for patients with localized colon cancer (CC) harboring microsatellite instability/mismatch repair deficiency (MSI/dMMR). The aim of this study is to evaluate the concordance between clinical cTN stage assessed by preoperative computed tomography (CT) scan and pTN stage of MSI/dMMR CC.

PATIENTS AND METHODS

Consecutive patients diagnosed for localized MSI/dMMR CC and treated with upfront surgery between 2013 and 2022 in two French centers were eligible. Two independent radiologists, blinded to pathological findings, reviewed all preoperative CT scans and assessed cTN stage, with a third radiologist reviewing discordant cases. Radiological predictive diagnostic accuracy for pT4 and pN+ (N+ = N1 or N2) were calculated.

RESULTS

One hundred and thirteen patients were included (right CCs = 79%). CT scan diagnostic performances for pT4 were sensitivity (Se) = 33.3%; specificity (Sp) = 94.0%; positive predictive value (PPV) = 66.7%; and negative predictive value (NPV) = 79.6% and for pN+ were Se = 70.3%; Sp = 59.2%; PPV = 45.6%; and NPV = 80.4%. When pT-pN were combined, 37.5% of tumors identified as cT4 and/or cN+ were actually pT1-3 and pN0, and 23.1% of the pT4 and pN+ population was not identified as such radiologically.

CONCLUSION

The ability of preoperative CT scan to predict pT and pN stages is limited for localized MSI/dMMR CCs. Reassessing neoadjuvant strategies' benefit-risk balance in this population is needed.

A Concept for Preoperative and Intraoperative Molecular Imaging and Detection for Assessing Extent of Disease of Solid Tumors

The authors propose a concept of "systems engineering," the approach to assessing the extent of diseased tissue (EODT) in solid tumors. We modeled the proof of this concept based on our clinical experience with colorectal carcinoma (CRC) and gastrinoma that included short and long-term survival data of CRC patients. This concept, applicable to various solid tumors, combines resources from surgery, nuclear medicine, radiology, pathology, and oncology needed for preoperative and intraoperative assessments of a patient's EODT. The concept begins with a patient presenting with biopsy-proven cancer. An appropriate preferential locator (PL) is a molecule that preferentially binds to a cancer-related molecular target (i.e., tumor marker) lacking in non-malignant tissue and is the essential element. Detecting the PL after an intravenous injection requires the PL labeling with an appropriate tracer radionuclide, a fluoroprobe, or both. Preoperative imaging of the tracer's signal requires molecular imaging modalities alone or in combination with computerized tomography (CT). These include positron emission tomography (PET), PET/CT, single-photon emission computed tomography (SPECT), SPECT/CT for preoperative imaging, gamma cameras for intraoperative imaging, and gamma-detecting probes for precise localization. Similarly, fluorescent-labeled PLs require appropriate cameras and probes. This approach provides the surgeon with real-time information needed for R0 resection.

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.

The ELECLA trial: A multicentre randomised control trial on outcomes of neoadjuvant treatment on locally advanced colon cancer

BACKGROUND

Colon cancer (CC) is a public health concern with increasing incidence in younger populations. Treatment for locally advanced CC (LACC) involves oncological surgery and adjuvant chemotherapy (AC) to reduce recurrence and improve overall survival (OS). Neoadjuvant chemotherapy (NAC) is a novel approach for the treatment of LACC, and research is underway to explore its potential benefit in terms of survival. This trial will assess the efficacy of NAC in LACC.

METHODS

This is a multicentre randomised, parallel-group, open label controlled clinical trial. Participants will be selected based on homogenous inclusion criteria and randomly assigned to two treatment groups: NAC, surgery, and AC or surgery followed by AC. The primary aim of this study is to evaluate the 2-year progression-free survival (PFS), with secondary outcomes including 5-year PFS, 2- and 5-year OS, toxicity, radiological and pathological response, morbidity, and mortality.

DISCUSSION

The results of this study will determine whether NAC induces a clinical and histological tumour response in patients with CCLA and if this treatment sequence improves survival without increasing morbidity and mortality.

REGISTRATION NUMBER

NCT04188158.

The diagnostic accuracy of local staging in colon cancer based on computed tomography (CT): evaluating the role of extramural venous invasion and tumour deposits

PURPOSE

The shift from adjuvant to neoadjuvant treatment in colon cancer demands the radiological selection of patients for systemic therapy. The aim of this study was to evaluate the accuracy of the CT-based TNM stage and high-risk features, including extramural venous invasion (EMVI) and tumour deposits, in the identification of patients with histopathological advanced disease, currently considered for neoadjuvant treatment (T3-4 disease).

METHODS

All consecutive patients surgically treated for non-metastatic colon cancer between January 2018 and January 2020 in a referral centre for colorectal cancer were identified retrospectively. All tumours were staged on CT according to the TNM classification system. Additionally, the presence of EMVI and tumour deposits on CT was evaluated. The histopathological TNM classification was used as reference standard.

RESULTS

A total of 176 patients were included. Histopathological T3-4 colon cancer was present in 85.0% of the patients with CT-detected T3-4 disease. Histopathological T3-4 colon cancer was present in 96.4% of the patients with CT-detected T3-4 colon cancer in the presence of both CT-detected EMVI and CT-detected tumour deposits. Histopathological T0-2 colon cancer was present in 50.8% of the patients with CT-detected T0-2 disease, and in 32.4% of the patients without CT-detected EMVI and tumour deposits.

CONCLUSION

The diagnostic accuracy of CT-based staging was comparable with previous studies. The presence of high-risk features on CT increased the probability of histopathological T3-4 colon cancer. However, a substantial part of the patients without CT-detected EMVI and tumour deposits was diagnosed with histopathological T3-4 disease. Hence, more accurate selection criteria are required to correctly identify patients with locally advanced disease.

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.

Tumour deposits in colon cancer predict recurrence and reduced survival in a nationwide population-based study

BACKGROUND

Tumour deposits are suggested to impact prognosis in colon cancer negatively. This study assessed the impact of tumour deposits on oncological outcomes.

METHODS

Data from the Swedish Colorectal Cancer Registry for patients who underwent R0 abdominal surgery for TNM stage I-III colon cancer between 2011 and 2014 with 5-year follow-up were analysed with multivariable analysis. Patients were categorized for their tumour deposit status and compared for the local recurrence and distant metastasis rates and 5-year survivals (overall and relative). Subgroup analyses were performed according to the nodal disease status.

RESULTS

Of 8146 stage I-III colon cancer patients who underwent R0 resection, 8014 patients were analysed (808 tumour deposits positive, 7206 tumour deposits negative). Patients with tumour deposits positive tumours had increased local recurrence and distant metastasis rates (7.2 versus 3.0 per cent; P < 0.001 and 33.9 versus 12.0 per cent; P < 0.001 respectively) and reduced 5-year overall and relative survival (56.8 per cent versus 74.9 per cent; P < 0.001 and 68.5 versus 92.6 per cent; P < 0.001 respectively). In multivariable analysis, tumour deposits moderately increased the risks of local recurrence and distant metastasis (hazard ratio 1.50, 95 per cent c.i. 1.09 to 2.07; P = 0.013 and HR 1.91, 95 per cent c.i. 1.64 to 2.23; P < 0.001 respectively) and worse 5-year overall and relative survival (hazard ratio 1.60, 95 per cent c.i. 1.40 to 1.82; P < 0.001 and excess hazard ratio 2.24, 95 per cent c.i. 1.81 to 2.78; P < 0.001 respectively). Subgroup analysis of N stages found that N1c patients had worse outcomes than N0 for distant metastasis and relative survival. For patients with lymph node metastases tumour deposits increased the risks of distant metastasis and worse overall and relative survival, except for N2b patients.

CONCLUSION

Tumour deposits negatively impact the prognosis in colon cancer and must be considered when discussing adjuvant chemotherapy.

Combined endoscopic and laparoscopic surgery (CELS) for early colon cancer in high-risk patients

BACKGROUND

Local excision of early colon cancers could be an option in selected patients with high risk of complications and no sign of lymph node metastasis (LNM). The primary aim was to assess feasibility in high-risk patients with early colon cancer treated with Combined Endoscopic and Laparoscopic Surgery (CELS).

METHODS

A non-randomized prospective feasibility study including 25 patients with Performance Status score ≥ 1 and/or American Society of Anesthesiologists score ≥ 3, and clinical Union of International Cancer Control stage-1 colon cancer suitable for CELS resection. The primary outcome was failure of CELS resection, defined as either: Incomplete resection (R1/R2), local recurrence within 3 months, complication related to CELS within 30 days (Clavien-Dindo grade ≥ 3), death within 30 days or death within 90 days due to complications to surgery.

RESULTS

Fifteen patients with clinical T1 (cT1) and ten with clinical T2 (cT2) colon cancer and without suspicion of metastases were included. Failure occurred in two patients due to incomplete resections. Histopathological examination classified seven patients as having pT1, nine as pT2, six as pT3 adenocarcinomas, and three as non-invasive tumors. In three patients, the surgical strategy was changed intraoperatively to conventional colectomy due to tumor location or size. Median length of stay was 1 day. Seven patients had completion colectomy performed due to histological high-risk factors. None had LNM.

CONCLUSIONS

In selected patients, CELS resection was feasible, and could spare some patients large bowel resection.

Endoscopic and imaging outcomes of PD-1 therapy in localised dMMR colorectal cancer

BACKGROUND

Neoadjuvant immune checkpoint blockade (IO) is emerging as a therapeutic option for patients with deficient mismatch repair (dMMR) colorectal cancer (CRC) given high pathological response rates. The aim of the study was to characterise imaging and endoscopic response to IO.

METHODS

A retrospective analysis of patients with localised dMMR CRC that received at least one cycle of neoadjuvant anti-PD-1 therapy was conducted. Endoscopy, imaging, and pathological outcomes were reviewed to determine response to treatment according to standardised criteria.

RESULTS

Thirty-eight patients had received IO for the treatment of localised CRC (median eight cycles). Among evaluable cases (n = 31 for endoscopy and n = 34 for imaging), the best endoscopic response was complete response (CR) in 45% of cases, and the best radiographic response was CR in 23% of cases. Imaging CR rate after ≤4 cycles of IO (n = 1) was 6% compared to 44% after >4 IO cycles (n = 7). Among 28 patients with imaging and endoscopy available, a discrepancy in best response was noted in 15 (54%) cases. At a median follow-up of 28.2 months from IO start, 18 patients underwent surgical resection of which 11 (61%) had pathological CR (pCR). Despite pCR or no evidence of progression ≥6 months after completion of IO among non-operatively managed patients, 72% and 42% of patients had non-CR on imaging and endoscopy, respectively.

CONCLUSIONS

Discrepancies between imaging and endoscopy are prevalent, and irregularities identified on these modalities can be identified despite pathological remission. Improved clinical response criteria are warranted.

Accuracy of pre-operative 18-fluoride fluorodeoxyglucose positron emission tomography (FDG-PET) in predicting lymph node involvement in colon cancer

BACKGROUND

Accurate staging of colon cancer is imperative in directing treatment and prognostication. Existing literature on pre-operative accuracy of FDG-PET/CT in detecting lymph node disease often combines colon and rectal cancer, examines rectal cancers alone, and rarely assesses colon cancer in isolation. Our aim was to assess pre-operative utility of FDG-PET/CT in detecting lymph node disease in colon cancer.

METHODS

A retrospective cohort analysis was performed at a single Australian institution between 2017 and 2022 to identify treatment naive primary colonic tumours. Primary outcome was sensitivity and specificity using formal surgical histopathology as gold standard. Secondary outcomes were patient and tumour factors predictive of FDG-PET/CT positive disease including pre-operative CEA, mismatch repair status, duration to surgery, and tumour T-stage.

RESULTS

Three hundred and thirty-nine patients were identified. Thirty-four had pre-operative FDG-PET/CT without neoadjuvant therapy. The mean surgical lymph node harvest was 18 nodes. Twenty-five patients had moderately differentiated tumours. The median duration between FDG-PET/CT and operation was 17 days. Pre-operative FDG-PET/CT suggested positive lymph node involvement in 12 patients. Compared to final lymph node histopathology, FDG-PET/CT had a sensitivity of 53%, specificity of 82%, positive predictive value of 75%, negative predictive value of 64% and accuracy of 68%. There was no significant difference between groups for secondary outcomes.

CONCLUSION

FDG-PET/CT has moderate specificity but poor sensitivity in the detection of lymph node involvement in colon cancer. Its utility should likely remain isolated to investigating equivocal lesions or follow up of known PET avid disease.

Diagnostic accuracy of CT for local staging of colon cancer: A nationwide study in the Netherlands

OBJECTIVE

To determine the accuracy of computed tomography (CT)-based staging in selecting high-risk colon cancer patients who would benefit from neoadjuvant chemotherapy while avoiding overtreatment.

METHODS

Data of adult patients diagnosed with non-metastatic primary colon cancer in 2005-2020, who underwent surgical resection without neoadjuvant chemotherapy, were retrospectively collected from the Netherlands Cancer Registry. Agreement between clinical and pathological evaluation for each T and N stage was calculated. Sensitivity and specificity analyses were conducted to predict T3-T4 and N1-N2 stages, with histopathology as the reference standard.

RESULTS

Data from 44,471 patients (median age, 71 years, 50% female) were evaluated. We included 38,915 patients with complete T stage and 39,565 patients with complete N stage for analyses. The overall clinical-pathological agreement for T stage was 59% and for N stage 57%. The sensitivity and specificity of CT to detect T3-T4 tumours were 80% (95% confidence interval (CI): 0.79, 0.80) and 76% (95% CI: 0.75, 0.77), respectively, with a positive predictive value (PPV) of 92% (95% CI: 0.92, 0.92). The sensitivity and specificity of CT to detect N1-N2 category were 62% (95% CI: 0.61, 0.63) and 70% (95% CI: 0.69, 0.71), respectively, with PPV 60% (95% CI: 0.59, 0.60).

CONCLUSION

CT-based staging shows limited accuracy in selecting colon cancer patients who would benefit from neoadjuvant therapy without risking overtreatment. Detection of lymph node metastases with CT remains unreliable.

Complete mesocolic excision for right hemicolectomy: an updated systematic review and meta-analysis

PURPOSE

Complete mesocolic excision improves lymphadenectomy for right hemicolectomy and respects the embryological planes. However, its effect on cancer-free and overall survival is questioned. Therefore, we aimed to determine the potential benefits of the technique by performing a systematic review of the literature and meta-analysis of the available evidence.

METHODS

Web of Science, PubMed/Medline, and Embase were searched on February 22, 2023. Original studies on short- and long-term oncological outcomes of adult patients undergoing right hemicolectomy with complete mesocolic excision as a treatment for primary colon cancer were considered for inclusion. Outcomes were extracted and pooled using a model with random effects.

RESULTS

A total of 586 publications were identified through database searching, and 18 from citation searching. Exclusion of 552 articles left 24 articles for inclusion. Meta-analysis showed that complete mesocolic excision increased the lymph node harvest (5 studies, 1479 patients, MD 9.62, 95% CI 5.83-13.41, p > 0.0001, I2 84%), 5-year overall survival (5 studies, 2381 patients, OR 1.88, 95% CI 1.14-3.09, p = 0.01, I2 66%), 5-year disease-free survival (4 studies, 1376 patients, OR 2.21, 95% CI 1.51-3.23, p < 0.0001, I2 0%) and decreased the incidence of local recurrence (4 studies, 818 patients, OR 0.27, 95% CI 0.09-0.79, p = 0.02, I2 0%) when compared to standard right hemicolectomy. Perioperative morbidity was similar between the techniques (8 studies, 3899 patients, OR 1.04, 95% CI 0.89-1.22, p = 0.97, I2 0%).

CONCLUSION

Meta-analysis of observational and randomised studies showed that right hemicolectomy with complete mesocolic excision for primary right colon cancer improves oncologic results without increasing morbidity/mortality. These results need to be confirmed by high-quality evidence and randomised trials in selected patients to assess who may benefit from the procedure.

Diagnostic Accuracy of Abdominal CT for Locally Advanced Colon Tumors: Can We Really Entrust Certain Decisions to the Reliability of CT?

Many different options of neoadjuvant treatments for advanced colon cancer are emerging. An accurate preoperative staging is crucial to select the most appropriate treatment option. A retrospective study was carried out on a national series of operated patients with T4 tumors. Considering the anatomo-pathological analysis of the surgical specimen as the gold standard, a diagnostic accuracy study was carried out on the variables T and N staging and the presence of peritoneal metastases (M1c). The parameters calculated were sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios, as well as the overall accuracy. A total of 50 centers participated in the study in which 1950 patients were analyzed. The sensitivity of CT for correct staging of T4 colon tumors was 57%. Regarding N staging, the overall accuracy was 63%, with a sensitivity of 64% and a specificity of 62%; however, the positive and negative likelihood ratios were 1.7 and 0.58, respectively. For the diagnosis of peritoneal metastases, the accuracy was 94.8%, with a sensitivity of 40% and specificity of 98%; in the case of peritoneal metastases, the positive and negative likelihood ratios were 24.4 and 0.61, respectively. The diagnostic accuracy of CT in the setting of advanced colon cancer still has some shortcomings for accurate diagnosis of stage T4, correct classification of lymph nodes, and preoperative detection of peritoneal metastases.

Radiologic T staging of colon cancer: renewed interest for clinical practice

Radiologic imaging, especially MRI, has long been the mainstay for rectal cancer staging and patient selection for neoadjuvant therapy prior to surgical resection. In contrast, colonoscopy and CT have been the standard for colon cancer diagnosis and metastasis staging with T and N staging often performed at the time of surgical resection. With recent clinical trials exploring the expansion of the use of neoadjuvant therapy beyond the anorectum to the remainder of the colon, the current and future state of colon cancer treatment is evolving with a renewed interest in evaluating the role radiology may play in the primary T staging of colon cancer. The performance of CT, CT colonography, MRI, and FDG PET-CT for colon cancer staging will be reviewed. N staging will also be briefly discussed. It is expected that accurate radiologic T staging will significantly impact future clinical decisions regarding the neoadjuvant versus surgical management of colon cancer.

CT is unreliable in locoregional staging of early colon cancer: A nationwide registry-based study

BACKGROUND AND OBJECTIVE

The option to treat early colon cancer (CC) with local resection, as well as trials investigating neoadjuvant treatment, has increased the importance of identifying early-stage disease in the workup. Most CC patients are T- and N-staged preoperatively with CT, although its reliability in staging early CC remains elusive. The aim of this study was to investigate CT-staging accuracy in early CC by evaluating pT and pN stages in patients staged as cT1-2, and cT and cN stages in patients with pT1 tumors.

METHODS

Retrospective population-based cohort study on data from the nationwide Swedish colorectal cancer registry on all CC patients staged as cT1-2 and all patients with pT1 undergoing surgical resection 2009-2018. CT-acquired T- and N-stages were compared with final histopathology. Factors potentially influencing accuracy were analyzed with uni- and multivariate logistic regression.

RESULTS

Computed tomography (CT) staged 4849 patients as cT1-2, whereas 2445 (50%) were pT3 and 453 (9%) pT4. Positive predictive value of the cT1-2 stage was 40%. Of 1401 pT1 patients, 624 (45%) were staged as cT1-2, 139 (10%) as cT3, 15 (1%) as cT4 and 623 (44%) as cTx. In all, 1474 (30%) of the cT1-2 patients were pN+, whereas CT staged 1062 (72%) as cN0. A total of 771 patients were staged as cN+, whereas 403 (52%) were pN0. Overall accuracy in determining N+ was 67%, with 26% sensitivity and 88% specificity. Positive and negative predictive values in determining N+ were 48% and 73%, respectively.

CONCLUSIONS

This nationwide population-based study shows that CT-staging carries a substantial risk of understaging locally advanced tumors as cT1-2 and pT1 tumors as cTx, in addition to poor N-staging. Thus, CT obtained T- and N-staging should not be used for deciding treatment strategies in early CC.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Tailoring the clinical management of colorectal cancer by 18F-FDG PET/CT

Colorectal cancer (CRC) is among the most commonly diagnosed gastrointestinal malignancies worldwide. It is inadequate to handle in terms of staging and restaging only based on morphological imaging modalities and serum surrogate markers. And the correct and timely staging of CRC is imperative to prognosis and management. When compared to established sequential, multimodal conventional diagnostic methods, the molecular and functional imaging ¹⁸F-FDG PET/CT shows superiorities for tailoring appropriate treatment maneuvers to each patient. This review aims to summarize the utilities of ¹⁸F-FDG PET/CT in CRC, focusing on primary staging, follow-up assessment of tumor responses and diagnostic of recurrence. In addition, we also summarize the technical considerations of PET/CT and the conventional imaging modalities in those patients who are either newly diagnosed with CRC or has already been treated from this cancer.

Preoperative prediction of lymph node status in patients with colorectal cancer. Developing a predictive model using machine learning

PURPOSE

Develop a prediction model to determine the probability of no lymph node metastasis (pN0) in patients with colorectal cancer.

METHODS

We used data from four Danish health databases on patients with colorectal cancer diagnosed between 2001 and 2019. The registries were harmonized into one common data model (CDM). Patients with clinical T4 tumors, undergoing palliative or acute surgery, and patients undergoing neoadjuvant therapy were excluded. Preoperative data was used to train the model. A postoperative model including tumor-specific variables potentially available after local tumor resection was also developed. Additionally, both models were compared with a model based on age, sex, and clinical N stage to resemble current standards. A Least Absolute Shrinkage and Selection Operator (LASSO) logistic regression analysis for prediction was used.

RESULTS

In total, 35,812 patients with 16,802 variables were identified in the CDM, and 194 variables affected the probability of pN0 preoperative. The area under the receiver operating characteristic curve (AUROC) was 0.64 (95% CI 0.63-0.66), and the area under the precision-recall curve (AUPRC) was 0.75 (95% CI 0.74-0.76). The mean predicted risk was 0.649, observed risk was 0.650, and calibration-in-large was 0.998. Adding histopathological data from the tumor improved the model slightly by increasing AUROC to 0.69. In comparison, the AUROC of the current standard clinical staging model was 0.57.

CONCLUSION

Using Danish National Patient Registry data in a machine learning-based predictive model showed acceptable results and outperforms current tools for clinical staging in predicting pN0 status in patients scheduled for CRC surgery.

Risk of Local Recurrence After Complete Mesocolic Excision for Right-Sided Colon Cancer: Post-Hoc Sensitivity Analysis of a Population-Based Study

BACKGROUND

A causal treatment effect of complete mesocolic excision for right-sided colon cancer on the risk of recurrence has been shown, but it is still unclear whether this is caused solely by a risk reduction of local recurrence.

OBJECTIVE

The goal of this study was to assess to what extent complete mesocolic excision contributes to the risk of local recurrence.

DESIGN

This study was a posthoc analyses of data from a population-based cohort. Inverse probability of treatment weighting and competing risk analyses were used to estimate the possible causal effects of complete mesocolic excision.

SETTING

Data were collected from the 4 public colorectal cancer centers in the Capital Region of Denmark.

PATIENTS

Patients undergoing elective colon resections for right-sided colon cancer without distant metastases during the period 2010-2013 were included. One center performed complete mesocolic excision and the remaining 3 centers performed conventional resections.

MAIN OUTCOME MEASURES

The primary outcome was the cumulative incidence of solely local recurrence 5.2 years after surgery. Secondary outcomes were solely distant recurrence and both local and distant recurrence diagnosed within 180 days.

RESULTS

A total of 807 patients were included with 186 undergoing complete mesocolic excision and 621 conventional resections. The 5.2-year cumulative incidence of a solely local recurrence was 3.7% (95% CI, 0.5-6.1) after complete mesocolic excision compared with 7.0% (5.0-8.9) in the control group, and the absolute risk reduction of complete mesocolic excision was 3.7% (2.5-7.1; p = 0.035). The absolute risk reduction on local and distant recurrence was 3.4% (1.3-5.6; p = 0.002) and on solely distant recurrence was 3.1% (0.0-6.2; p = 0.052).

LIMITATIONS

The recurrence risk after conventional resection might be underestimated by the use of inappropriate modalities to diagnose local recurrence for some patients and the shorter duration in this group.

CONCLUSION

This study shows a causal treatment effect of complete mesocolic excision on the risk of a solely local recurrence and of distant recurrence with or without local recurrence. See Video Abstract at http://links.lww.com/DCR/B832 .RIESGO DE RECURRENCIA LOCAL DESPUÉS DE LA ESCISIÓN MESOCÓLICA COMPLETA PARA EL CÁNCER DE COLON DEL LADO DERECHO: ANÁLISIS DE SENSIBILIDAD POST-HOC DE UN ESTUDIO POBLACIONALANTECEDENTES:Se ha demostrado un efecto del tratamiento causal de la escisión mesocólica completa para el cáncer de colon del lado derecho sobre el riesgo de recurrencia, pero aún no está claro si esto se debe únicamente a una reducción del riesgo de recurrencia local.OBJETIVO:Evaluar en qué medida la escisión mesocólica completa se atribuye al riesgo de recurrencia local.DISEÑO:Análisis posthoc de datos de una cohorte poblacional. Se utilizaron análisis de probabilidad inversa de ponderación del tratamiento y de riesgo competitivo para estimar los posibles efectos causales de la escisión mesocólica completa.AJUSTE:Datos de los cuatro centros públicos de cáncer colorrectal en la Región Capital de Dinamarca.PACIENTES:Pacientes sometidos a resecciones de colon electivas por cáncer de colon derecho sin metástasis a distancia durante el período 2010-2013. Un centro realizó escisión mesocólica completa, el resto resecciones convencionales.PRINCIPALES MEDIDAS DE RESULTADO:El resultado primario fue la incidencia acumulada de la recidiva local únicamente, 5,2 años después de la cirugía. Los resultados secundarios fueron únicamente la recidiva a distancia y ambas,la recidiva local y a distancia diagnosticada dentro de los 180 días.RESULTADOS:Se incluyeron un total de 807 pacientes, 186 sometidos a escisión mesocólica completa y 621 resecciones convencionales. La incidencia acumulada de 5,2 años de una recidiva únicamente local fue del 3,7% (IC del 95%: 0,5 a 6,1) después de la escisión mesocólica completa en comparación con el 7,0% (5,0 a 8,9) en el grupo de control, y la reducción del riesgo absoluto de la escisión mesocólica completa fue del 3,7% (2,5-7,1; p = 0,035). La reducción del riesgo absoluto de recidiva local y distante fue del 3,4% (1,3-5,6; p = 0,0019) y de recidiva únicamente a distancia 3,1% (0,0-6,2; p = 0,052).LIMITANTES:El riesgo de recurrencia después de la resección convencional podría subestimarse por el uso de modalidades inapropiadas para el diagnostico de la recurrencia local en algunos pacientes y la duración más corta en este grupo.CONCLUSIÓN:Este estudio muestra un efecto del tratamiento causal de la escisión mesocólica completa sobre el riesgo de una recidiva únicamente local y de recidiva a distancia con o sin recidiva local. Consulte Video Resumen en http://links.lww.com/DCR/B832 . (Traducción-Dr. Mauricio Santamaria ).

Prediction of Metachronous Peritoneal Metastases After Radical Surgery for Colon Cancer: A Scoring System Obtained from an International Multicenter Cohort

Background

Since novel strategies for prevention and treatment of metachronous peritoneal metastases (mPM) are under study, it appears crucial to identify their risk factors. Our aim is to establish the incidence of mPM after surgery for colon cancer (CC) and to build a statistical model to predict the risk of recurrence.

Patients and Methods

Retrospective analysis of consecutive pT3–4 CC operated at five referral centers (2014–2018). Patients who developed mPM were compared with patients who were PM-free at follow-up. A scoring system was built on the basis of a logistic regression model.

Results

Of the 1423 included patients, 74 (5.2%) developed mPM. Patients in the PM group presented higher preoperative carcinoembryonic antigen (CEA) [median (IQR): 4.5 (2.5–13.0) vs. 2.7 (1.5–5.9), P = 0.001] and CA 19-9 [median (IQR): 17.7 (12.0–37.0) vs. 10.8 (5.0–21.0), P = 0.001], advanced disease (pT4a 42.6% vs. 13.5%; pT4b 16.2% vs. 3.2%; P < 0.001), and negative pathological characteristics. Multivariate logistic regression identified CA 19-9, pT stage, pN stage, extent of lymphadenectomy, and lymphovascular invasion as significant predictors, and individual risk scores were calculated for each patient. The risk of recurrence increased remarkably with score values, and the model demonstrated a high negative predictive value (98.8%) and accuracy (83.9%) for scores below five.

Conclusions

Besides confirming incidence and risk factors for mPM, our study developed a useful clinical tool for prediction of mPM risk. After external validation, this scoring system may guide personalized decision-making for patients with locally advanced CC.

Supplementary Information

The online version contains supplementary material available at 10.1245/s10434-022-12097-9.

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.

Recurrence after complete mesocolic excision for right-sided colon cancer: post hoc sensitivity analyses-early recurrence, surgery by specialist and dissection in the mesocolic plane

AIM

The aim was to investigate whether the previously reported causal treatment effect of complete mesocolic excision on the risk of recurrence was biased by inclusion of patients with potentially undiagnosed disseminated disease at the time of surgery, by non-specialist surgery, or caused by mesocolic plane dissection.

METHOD

A population of 1069 patients, 813 undergoing conventional resection and 256 complete mesocolic excision for colon cancer during the period 2008-2013, was stepwise reduced in the following order by excluding patients with recurrence diagnosed within 6 months of the resection, having surgery performed by a non-specialist without supervision, and specimens assessed as not being mesocolic plane dissection. The primary outcome measure was risk of recurrence after 5.2 years using competing risk analyses.

RESULTS

The absolute risk reduction of complete mesocolic excision was 6.0% (95% CI 1.8-10.2; P = 0.0049) after excluding patients with recurrence within 6 months of resection, 6.1% (95% CI 1.9-10.4; P = 0.0045) after excluding non-specialist surgery, and 7.5% (95% CI 2.9-12.0; P = 0.0013) after the exclusion of patients whose specimens were assessed as dissections not being performed in the mesocolic plane.

CONCLUSION

The absolute risk reduction of recurrence after complete mesocolic excision for right-sided colon cancer in our previous study was not biased by potentially undiagnosed disseminated disease at the time of surgery or non-specialist surgery, and was not solely caused by dissection in the mesocolic plane. Central vascular dissection with central lymphadenectomy seems a major factor for better oncological results.