Routine preoperative abdominal computed tomography in colon cancer: a utility study

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.

Right pelvic kidney during intersphincteric resection for locally advanced rectal cancer: a case report

Background

Simultaneous occurrence of colorectal malignancy with pelvic kidney has been considered a rare phenomenon. A review of the related literature revealed three previous reports of rectal cancer and pelvice kidney.

Case presentation

This case report describe the case of 40-year-old Asian man with complaints of bleeding and a feeling of discomfort in his anus. A colonoscopy revealed a raised large multilobulated mass in his rectum. Multiple biopsies of the lesion were done after detecting a tumor in his rectum 4 cm above the dentate line; a diagnosis of rectal adenocarcinoma was made by pathological examinations. Subsequent investigations, carried out by computed tomography (CT) scans, incidentally showed an ectopic pelvic kidney. Because of the progress of the rectal cancer, our patient was a candidate for neoadjuvant radiotherapy. Six weeks after radiotherapy, he underwent total mesorectal excision (TME) surgery maintaining the ectopic kidney after using a coloanal anastomosis for additional curative surgery. A very low anterior resection surgery was performed to maintain the ectopic kidney. Thereafter, adjuvant chemotherapy was performed.

Conclusions

Due to the proximity of the tumor to the pelvic viscera, especially the ectopic kidney, the probability of inadequate abscission of the lesion in surgery and radiotherapy, as well as complications and localized relapse were increased so that the kidney could be maintained. Carrying out careful pre-treatment examinations can result in maintaining an ectopic kidney and its daily conditioned function dependent on the status of the patient, including the proximity of the ectopic kidney to the tumor, anatomical position, and prior damage. The lesson learned from the present case is that radiotherapy and surgery are possible treatments in the presence of pelvic kidney and rectal cancer without incurring renal damage.

Electronic supplementary material

The online version of this article (10.1186/s13256-019-2151-3) contains supplementary material, which is available to authorized users.

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.

Assessment and diagnostic accuracy of lymph node status to predict stage III colon cancer using computed tomography

Background

To study different imaging criteria for prediction of lymph node metastases (Stage III disease) in colon cancer using CT.

Methods

In a retrospective setting, 483 consecutive patients with histology proven colon cancer underwent elective primary resection during 2008–2011, a cohort of 119 patients were included. Contrast enhanced CT examinations, in portal-venous phase, were reviewed with assessment of the number of lymph nodes, their anatomical distribution, size, size ratio, internal heterogeneity, presence of irregular outer border and attenuation values. Sensitivity, specificity, PPV and NPV for each studied criteria for prediction of stage III disease was calculated.

Results

According to histopathology 80 patients were stage I-II and 39 were stage III. Of the studied CT-criteria for lymph node metastases per patient, internal heterogeneity in at least one lymph node resulted in the best performance with sensitivity, specificity, PPV and NPV of 79, 84, 70 and 89%, Odds ratio (OR) 20. Presence of irregular outer border resulted in a sensitivity, specificity, PPV and NPV of 59, 81, 61 and 82%, OR 6.2. If both internal heterogeneity and/or irregular outer border was used as a criterion this resulted in a sensitivity, specificity, PPV and NPV of 85, 75, 62 and 91%, OR 16.5. None of the size criteria used were predictive for stage III disease.

Conclusions

When performing preoperative CT in patients with colon cancer, the imaging criteria that allow best prediction of stage III disease on CT are either presence of at least one lymph node with internal heterogeneity or internal heterogeneity and/or irregular outer border. These criteria have to be validated in a prospective study.

Computed tomography has low sensitivity for the diagnosis of early colon cancer

AIM

The accuracy of computed tomography (CT) in detecting local invasion (T status) and nodal metastasis (N status) of colon cancer was determined.

METHOD

Data on the preoperative CT scan of 153 lesions from 152 patients with colon cancer were reviewed retrospectively. Evaluation included the T stage and N stage of the TNM system. The results were compared with those obtained by histopathological examination of the resected tumour.

RESULTS

Of the 153 tumours, 117 (76.5%) were correctly classified as Stage T1 and T2 (33 tumours) and Stage T3 and T4 (84 tumours) by CT. The sensitivity and specificity were 70.2% and 79.2%, respectively, and the positive and negative predictive values were 85.7% and 60.0%. When analysed according to the individual T stage (Tx/Tis, T1, 2, 3, 4) and N stage (N0, 1, 2), the kappa coefficient with linear weighting was 0.208 (fair agreement) for T stage and 0.154 (slight agreement) for N stage. The estimation of tumour size showed good agreement with histopathology (Spearman correlation coefficient 0.865).

CONCLUSION

CT scanning of colonic cancer showed 75% accuracy in identifying T1 and T2 cancers combined, but gave poor agreement between CT and histopathology for individual T stages.

Diagnostic accuracy of computed tomography for colon cancer staging: a systematic review

BACKGROUND

Computed Tomography (CT) is a frequently used staging modality for colon cancer patients in clinical practice. Our aim was to systemically review the available literature on diagnostic accuracy of CT for TNM staging of colon cancer.

METHODS

A systematic review of literature was performed. PubMed was searched using MeSH terms with the following search terms: "Tomography, X-Ray Computed" or "Tomography, Spiral Computed" and Colonic Neoplasms. Studies on rectal cancer and studies without separate analyses for the colon were excluded. We identified 779 publications, of which 11 were included for review. Overall and sample-size-weight sensitivity, specificity, accuracy, true-positive, true-negative, false-positive, false-negative, positive and negative predictive values were calculated for T, N and M stages.

RESULTS

In the 11 studies, a total of 753 patients with 759 colon cancers underwent CT for staging. Sample-size-weighted sensitivity, specificity and accuracy for T-staging was 77%, 3% and 67%, respectively; for N-staging 76%, 55% and 69%, respectively; and for M-staging 85%, 98% and 95%, respectively. Additional clinical findings were reported in 59/372 (16%) patients, with 12 having a malignant and 47 a benign origin.

CONCLUSIONS

While accuracy of CT for TN-staging of colon cancer is only reasonable, the real value of CT is its high accuracy to detect distant metastases.