Diagnostic value of preoperative CT scan to stratify colon cancer for neoadjuvant therapy

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.

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.

Imaging features associated with survival outcomes among colorectal cancer patients with and without KRAS mutation

Background

Mutations in Kirsten rat sarcoma proto-oncogene (KRAS) have been shown to be associated with advanced-stage colorectal cancer (CRC), negative disease outcomes, and poor response to treatment. The purpose of this study was to investigate which CT features are biomarkers for KRAS gene mutation and impact the survival outcomes of colorectal cancer patients.

Results

Of the 113 CRC patients included in the study, 46 had KRAS mutations (40.71%) and 67 had no mutations (59.29%). Regional lymph node necrosis was the only imaging feature significantly associated with KRAS mutation (P = 0.011). Higher T staging and liver, lung, and distant metastasis were prognostic factors for CRC (P = 0.014, P < 0.001, P = 0.022, P < 0.001, respectively). There were no significant differences in overall survival between patients with KRAS mutations and those without (P = 0.159). However, in patients with no KRAS mutation, those with CRC on the left side had a significantly higher rate of survival than those with CRC on the right (P = 0.005).

Conclusion

Regional lymph node necrosis may be an imaging biomarker of CRC with KRAS mutation, possibly indicating poor prognosis.

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.

Surgical oncology in the age of multimodality therapy for cancer of the upper and lower gastrointestinal tract

INTRODUCTION

To date, all efforts to fight gastrointestinal cancer, regardless of its origin and entity, have resulted in complex therapeutic regimens involving a combination of systemic therapy, radiation therapy and surgery. It is generally accepted across all disciplines that not one, but the combination and the proper timing of all modalities result in the best oncologic outcome.

AREAS COVERED

Here, we provide insight into the current and future value of multimodal therapeutic approaches for upper and lower gastrointestinal cancer. Various aspects of treatment as well as open questions regarding indication and timing of multimodal strategies are addressed in this review.

EXPERT OPINION

In order to further improve the survival and quality of life of patients with gastrointestinal tumors in the future, scientifically proven multimodal therapy concepts are needed first and foremost. In addition, markers are pivotal to assign individual patients to a specific concept and to monitor the success of therapy. The main question is in which situation a neoadjuvant, perioperative or adjuvant radio-, chemo- or immunotherapy is superior. In fact, almost every curatively intended concept still contains surgical resection. Thus, improvement in surgical technique is also critical for multimodality concepts.

The impact of mismatch repair status to the preoperative staging of colon cancer: implications for clinical management

Aims: We sought to investigate if mismatch repair (MMR) status influences the preoperative staging of local colon cancer. Methods: Data from 590 patients in the Danish Colorectal Cancer Group national clinical database who were operated on for stage I-III colon cancer in 2010-15 were included. MMR status was determined by immunohistochemistry. Results: 22.9% had deficient(d) MMR tumors. Correlation of the clinical and pathological T-category was significant for both groups. The correlation of pre- and postoperative N-category was inferior (p >0.05) in dMMR cancers compared to a significant (p <0.01) correlation in proficient MMR cancers. 64.8% of dMMR tumors assessed node-positive demonstrated no sign of metastatic involvement at the postoperative assessment. Conclusion: MMR status seems to impact the accuracy of preoperative lymph node staging.

[Selection criteria for neoadjuvant chemoradiotherapy of rectal cancer : Neoadjuvant therapy even for locally advanced colon cancer?]

During the last two decades a neoadjuvant treatment concept has been established for an increasing number of malignant tumors of the gastrointestinal tract; however, these concepts are still subject to a constant change concerning the indications and type of treatment. A prime example for this is rectal cancer. The rate of local recurrence in particular was significantly reduced by neoadjuvant therapy but until now it has not been possible to validly show an improvement in overall or disease-free survival. At the beginning of the millennium it was recommended to treat every rectal carcinoma in UICC stages II and III with neoadjuvant therapy, independent of the height localization. In the meantime this has increasingly been relativized and only locally advanced tumors of the middle and lower thirds of the rectum should be pretreated, whereas tumors of the upper third of the rectum should basically be treated in the same way as colon cancer. It is to be expected that there will be further differentiation concerning the indications in this context in the future mainly based on a preoperative magnetic resonance imaging (MRI) examination. At the same time, initial studies for colon cancer show that neoadjuvant chemotherapy can be beneficial and that an optimized computed tomography (CT) scan can be a worthwhile tool with respect to pretherapeutic stratification of patients.

Tumor and nodal staging of colon cancer: accuracy of preoperative computed tomography at a Swedish high-volume center

Background

When deciding treatment options for patients with colon cancer, accurate staging is required. In Sweden, the main preoperative evaluation modality to determine tumor and nodal stage is computed tomography (CT).

Purpose

The aim of this study was to investigate how well the preoperative (CT-determined) clinical tumor and nodal stage (cTN) correlated with the postoperative histopathological stage (pTN). Another aim was to validate the tumor and nodal stage data in the Swedish Colorectal Cancer Registry (SCRCR).

Material and Methods

The SCRCR was used to identify patients with colon cancer, treated at a Swedish high-volume center during 2013-2016 (n = 974). Data were gathered from medical records regarding cTN and pTN stage, and predefined patient and tumor variables. The agreement between cTN and pTN was analyzed using kappa statistics.

Results

After excluding patients with either pre- or postoperative TN stage missing, 383 patients remained for further analyses. The analyses showed an agreement between cT and pT of κ: 0.27 and between cN and pN of κ: 0.21 (fair agreement). When comparing tumors with low (T1-3; N0) versus high risk (T4; N1-2), the kappa value was 0.19 (slight agreement). When comparing the SCRCR to medical records, 78% of completely staged tumors had been correctly reported.

Conclusion

The agreement between cTN and pTN was low in this study population, indicating a need for enhanced precision of the preoperative staging process. A high frequency of erroneous preoperative staging data in the SCRCR shows the need for further efforts of ensuring correct data transfers into the registry.

Preoperative T staging of colon cancer using CT colonography with multiplanar reconstruction: new diagnostic criteria based on "bordering vessels"

PURPOSE

Preoperative T staging of colon cancer, in particular, for distinguishing T3 from T2 and T4, has been a challenge. The aim of this study was to evaluate newly developed criteria for preoperative T staging of colorectal cancer using computed tomography colonography (CTC) with multiplanar reconstruction (MPR), based on the spatial relationship of tumors and "bordering vessels," that is, marginal vessels that are detectable by multi-detector row CT with MPR.

METHODS

A total of 172 patients with colon and upper rectal cancer who underwent preoperative CTC and surgery between August 2011 and September 2013 were included. Preoperative T staging using the new criteria was performed prospectively and compared with pathologic results.

RESULTS

Sensitivity, specificity, and accuracy of T staging by CTC using the new criteria were 63%, 80%, and 77% for T2 (n = 30); 72%, 94%, and 81% for T3 (n = 95); and 79%, 99%, and 97% for T4a (n = 14), respectively. Positive predictive value for T3 was 93%, indicating that a T3 diagnosis by CTC is precise. In addition, negative predictive value for pathological T4a was 98%, indicating that a "not T4a" diagnosis by CTC is also precise.

CONCLUSIONS

Our newly developed criteria are useful for preoperative T staging, particularly for distinguishing T3 from T2 and T4.

Colorectal Cancer:: Imaging Conundrums

Progressive technological advancements in imaging have significantly improved the preoperative sensitivity for the detection of very small foci of regionally- or hematogenously-metastatic colorectal cancer. Unfortunately, this information has not translated to continued linear gains in patient survival, and might even result in the false-positive upstaging of some cases: these are two conundrums in the imaging of colorectal cancer. Both conundrums might be resolved by the widespread use of real-time imaging guidance during operative procedures. This might open the way for the widespread use of fluorodeoxyglucose PET/CT for the initial staging of patients with colorectal cancer.

Staging with computed tomography of patients with colon cancer

PURPOSE

Accurate staging of colonic cancer is important for patient stratification. We aimed to correlate the diagnostic accuracy of preoperative computed tomography (CT) with final histopathology as reference standard.

METHODS

Data was collected retrospectively on 615 consecutive patients operated for colonic cancer. Evaluation was based upon T-stage. Patients were stratified into high-risk and low-risk groups, based on the extent of tumor invasion beyond the proper muscle layer of more or less than 5 mm. The Kendall tau correlation coefficient was used to calculate concordance between radiological (r)T-stage obtained at CT imaging and pathological (p)T-stage from the final pathology.

RESULTS

In total, 501 patients were included. We found no significant differences in the Kendall tau values for diagnostic measures between the groups at the 95% confidence interval (CI) level: 49% (95% CI, 43-55) for all individuals, 48% (95% CI, 40-56) for screened individuals, and 47% (95% CI, 37-56) for non-screened individuals. The overall sensitivity and specificity for all individuals in identifying high-risk tumors on CT was 65% (95% CI, 56-73) and 89% (95% CI, 85-92). The risk of ending up in the high-risk group due to overstaging among all individuals was calculated as the number needed to harm 11.7 (95% CI, 9-16).

CONCLUSIONS

There is basis for improvement of CT-based preoperative staging of patients with colorectal cancer. Supplementary modalities may be needed for correct staging of patients preoperatively, especially in relation to stratification of patients into neoadjuvant treatments or tailored therapy in patients with early cancers.

High-risk features in potentially resectable colon cancer: a prospective MDCT-pathology agreement study

PURPOSE

Neoadjuvant chemotherapy in potentially resectable high-risk Stage II and Stage III colon cancer has demonstrated promising results in the PRODIGE 22-ECKINOXE Phase II trial. Identification of adverse morphologic features, namely T3 with >5 mm extramural extension/T4 stages and/or N2, is fundamental and requires accurate noninvasive imaging. Our aim was to assess the value of optimized preoperative MDCT to stratify potentially resectable colon cancer patients for neoadjuvant therapy.

METHODS

this is an observational prospective cross-sectional radiologic-pathologic agreement study. All patients with colon cancer referred to our Institution's Radiology department for preoperative MDCT staging between 01-10-2013 and 11-02-2015 underwent independent reading based on axial and multiplanar reconstruction images by 3 radiologists with 3, 6, and 20 years of experience in gastrointestinal radiology. T stage, extramural extension if T3 (≤5 mm or >5 mm), and N stage were recorded. Surgical specimens subsequently obtained underwent micro-pathologic analysis by a gastrointestinal pathologist with 9 years of experience in gastrointestinal pathology. Main outcome measures were sensitivity, specificity, PPV, NPV, AUROC, diagnostic accuracy, and interobserver agreement of optimized MDCT, and pathologic analysis of the surgical specimen considered the reference standard.

RESULTS

74 patients [43 males; median age 73 (45-89)] were eligible. MDCT sensitivity, specificity, PPV, NPV, AUROC, and diagnostic accuracy ranged between 42.9-76.2, 75.5-90.6, 55.2-76.2, 80.0-90.6, 0.67-0.83 and 0.76-0.86%, respectively, for the identification of T3 > 5 mm/T4 disease, with moderate interobserver agreement (0.49); and 8.3-33.3, 93.5-98.4, 20-66.7, 84.1-88.2, 0.51-0.65 and 0.80-0.86%, respectively, for the identification of N2 disease, with absent interobserver agreement (0.10).

CONCLUSIONS

Specificity of MDCT in the stratification of patients for neoadjuvant therapy may be high enough to prevent overtreatment. However, it may lead to undertreatment in a meaningful proportion of patients. Observer performance may benefit from targeted training programs, given the variability and observer dependence of the results. Limitations include 4-slice MDCT equipment, time to surgery and lack of long-term outcome information based on imaging parameters per se.

Proactive Management for Gastric, Colorectal and Appendiceal Malignancies: Preventing Peritoneal Metastases with Hyperthermic Intraperitoneal Chemotherapy (HIPEC)

An integrated treatment strategy using peritonectomy procedures plus hyperthermic intraperitoneal chemotherapy (HIPEC) is now a clinical standard of care in selected patients with peritoneal metastases and primary peritoneal tumors. This comprehensive approach can offer many patients, who hitherto had no hope of cure, a good quality of life and survival despite limited morbidity. The increasingly successful results and chance of interfering in the natural history of disease has prompted research to develop for some clinical conditions a therapeutic strategy designed to prevent malignant peritoneal dissemination before it becomes clinically evident and treat it microscopically (tertiary prevention). The main factor governing successful cytoreductive surgery and predicting outcome is the extent of peritoneal spread assessed with the peritoneal cancer index (PCI). In peritoneal metastases from colorectal and gastric cancer the PCI score acquires a specific role acting as the cut-off between patients who can undergo curative surgery or palliation. Long-term results show that the only group enjoying favorable results are patients with limited disease (a statistical minority). By applying to appropriately selected patients with primary malignancies a proactive management strategy including HIPEC we can treat patients with microscopic peritoneal dissemination and therefore at PCI 0. Among treated conditions pseudomyxoma peritonei enjoys the best results. But a major future advance comes from identifying among lesions at major risk of pseudomyxoma.