Water-enema multidetector computed tomography for planning surgery

Assessment of water enema PET/CT: an effective imaging technique for the diagnosis of incidental colorectal 18F-FDG uptake

BACKGROUND

To validate the feasibility of water enema PET/CT (WE-PET/CT) in incidental colorectal 18F-FDG uptake and improve the accuracy of diagnosing colorectal neoplastic lesions.

METHODS

We retrospectively analysed the electronic records of 338 patients undergoing common PET/CT and WE-PET/CT at our hospital. PET/CT results were correlated with colonoscopy pathology and follow-up results. The ROC contrast curve was plotted to evaluate the accuracy of SUVmax on common PET/CT and WE-PET/CT for detecting neoplastic lesions. SUVmax and the median retention indexes (RIs) of cancerous, precancerous, and benign lesions and physiologic uptake were compared.

RESULTS

The sensitivity, specificity and accuracy of diagnosing neoplastic lesions with common PET/CT were 84.0%, 78.3% and 80.2%, respectively. The corresponding results with WE-PET/CT were 95.8%, 96.5% and 96.2%. The AUC of SUVmax on WE-PET/CT was significantly higher than that on common PET/CT (0.935 vs. 0.524, p < 0.001). The median SUVmax on WE-PET/CT was significantly higher than that on common PET/CT in cancerous and precancerous lesions, and significantly decreased in benign lesions and physiologic uptake (p < 0.001). The RI was significantly different between cancerous lesions and physiologic uptake, between precancerous lesions and physiologic uptake, between benign lesions and physiologic uptake, and between cancerous and benign lesions (p < 0.05).

CONCLUSIONS

WE-PET/CT is a noninvasive, well-tolerated and effective technique for diagnosing incidental colorectal 18F-FDG uptake. It is helpful for a timely colonoscopy and can effectively avoid an unnecessary colonoscopy for incidental colorectal 18F-FDG uptake.

Pre-colectomy location and TNM staging of colon cancer by the computed tomography colonography: a diagnostic performance study

BACKGROUND

The Chinese Society of Clinical Oncology guidelines 2018 and the recent update of that (version 2020) recommends accurate examination before major treatment for decision(s) in cases of colon cancer. Also, the difficulty in the identification of the lesion during colectomy may lead to resection of a wrong segment of the colon or a more extensive resection than planned. Accurate pre-colectomy local staging of colon cancer is required to make decisions for treatment of colon cancer. The objective of the study was to evaluate the diagnostic performance of the computed tomography colonography (CTC) for pre-colectomy tumor location and tumor, node, and metastasis (TNM) staging of colon cancer.

METHODS

Data of preoperative colonoscopies, CTC, surgeries, and surgical pathology of a total of 269 patients diagnosed with colon cancer by colonoscopy and biopsy and underwent pre-colectomy location and TNM staging by CTC were collected and analyzed. The consistency between the radiological and the surgery/surgical-pathological for location and TN stages of colon tumor were estimated with the weighted kappa or kappa coefficient (κ) at 95% confidence interval (CI).

RESULTS

CTC detected 261 (93%) and colonoscopy detected 201 (72%) correct locations of tumors. Sensitivity and accuracy of CTC for detection of location of colon tumors were 100% and 92.58% (κ = 0.89; 95% Cl: 0.83-0.95). 72.48% sensitivity, 90.64% specificity, and 83.57% accuracy were reported for CTC in differentiation of tumors confined to the colon wall (T1/T2) from advanced tumors (T3/T4) (κ = 0.69, 95% Cl: 0.51-0.75). 81.01% sensitivity, 89.11% specificity, and 83.93% accuracy of CTC was reported for differentiation of tumors between low-intermediate risk and high risk (κ = 0.68, 95% Cl: 0.53-0.75). 69.31% sensitivity, 66.15% specificity, and 67.14% accuracy of CTC were reported for N staging of tumors (κ = 0.41, 95% Cl: 0.59-0.69).

CONCLUSIONS

CTC has high diagnostic parameters for pre-colectomy location and T staging of colon tumors except patients of colon cancer who received neoadjuvant chemotherapy.

LEVEL OF EVIDENCE

III.

TECHNICAL EFFICACY STAGE

2.

Accuracy of CT colonography in the preoperative staging of colon cancer: a prospective study of 217 patients

AIM

The purpose of the present study was to evaluate the accuracy of computed tomography colonography (CTC) in the preoperative localization and TN staging of colon cancer. CTC can be an effective technique for preoperative evaluation of colon cancer and could facilitate the selection of high-risk patients who may benefit from neoadjuvant chemotherapy.

METHOD

This was a prospective observational study conducted at a single tertiary-care centre. It involved 217 patients (225 tumours) who had colon cancer and underwent preoperative CTC and elective colectomy. The radiologist determined the TNM stage using postprocessing software with multiplanar images and virtual colonoscopy. The following criteria were analysed for every colon tumour: location, size and signs of direct colon wall invasion. The histopathological findings of the surgical colectomy specimens served as the reference standard for local staging.

RESULTS

CTC detected all tumours and achieved an exact location in 208 cases (92.4%). CTC findings changed the surgical plan in 31 patients (14.3%) following colonoscopy. The accuracy in differentiating T3/T4 vs T1/T2 tumours was 87.1%, with a sensitivity and specificity of 88.5% and 84.1%, respectively (kappa = 0.71). For high-risk tumours (T3 ≥ 5 mm and T4), CTC showed an accuracy, sensitivity and specificity of 82.7%, 86% and 80%, respectively (kappa = 0.65). The accuracy of N-stage evaluation was 69.3%, the sensitivity 74% and the specificity 67.1% (kappa = 0.37).

CONCLUSION

CTC provides accurate information for the assessment of tumour localization and T staging, allowing better surgical planning and also allows the selection of locally advanced tumours that may benefit from new treatments such as neoadjuvant chemotherapy.

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.

The role of multidetector CT in local staging and evaluation of retroperitoneal surgical margin involvement in colon cancer

PURPOSE

We aimed to evaluate preoperative T and N staging and retroperitoneal surgical margin (RSM) involvement in colon cancer using multidetector computed tomography (MDCT).

METHODS

In this retrospective study, preoperative MDCTs of 141 patients with colon adenocarcinoma were evaluated in terms of T and N staging and retroperitoneal surgical margin involvement by two observers. Results were compared with histopathology.

RESULTS

In determining extramural invasion, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of MDCT were 81%, 50%, 95%, 26%, and 81% for observer 1 and 87%, 75%, 97%, 27%, and 84% for observer 2, respectively. Moderate interobserver agreement was observed (ĸ=0.425). In determining T stage of the tumor, accuracy of MDCT was 55% for observer 1 and 51% for observer 2. In the detection of lymph node metastasis, sensitivity, specificity, PPV, NPV, and accuracy of MDCT were 84%, 46%, 60%, 74% and 64% for observer 1 and 84%, 56%, 65%, 78%, and 70% for observer 2, respectively. Interobserver agreement was substantial (ĸ=0.650). RSM was involved in six cases (4.7%). When only retroperitoneal colon segments were considered, 1.6% of subjects demonstrated RSM involvement. Four of the six RSM-positive tumors were located on sigmoid colon and one tumor was on transverse colon and caecum. Considering all colon tumors, in the detection of RSM involvement, sensitivity and specificity of MDCT were 33% and 81% for observer 1 and 50% and 80% for observer 2. Interobserver agreement was moderate (ĸ=0.518).

CONCLUSION

MDCT is a promising technique with moderate interobserver agreement in detection of extramural invasion, lymph node metastases, and RSM involvement in colon carcinomas.

Preoperative localization of colorectal cancer: a systematic review and meta-analysis

BACKGROUND

Preoperative colorectal tumor localization is crucial for appropriate resection and treatment planning. As the localization accuracy of conventional colonoscopy is considered to be low, several localization techniques have been developed. We systematically reviewed the tumor localization error rates of several preoperative endoscopic techniques and synthesized information on risk factors for localization errors and procedure-related adverse events.

METHODS

MEDLINE, EMBASE, the Cochrane Library, and the grey literature were searched. Studies were included if they reported tumor localization errors in patients with colorectal cancer undergoing resection with curative intent. Using random-effects models, pooled incidence of tumor localization errors were derived for conventional colonoscopy and colonoscopic tattooing. Due to the lack of comparative studies, a direct comparison of the pooled estimates was performed. Procedure-related adverse events, risk factors for localization errors, and the localization outcomes of other techniques such as colonoscopic clip placement, radioguided occult colonic lesion identification, and the use of magnetic endoscope imaging were also synthesized.

RESULTS

A total of 38 non-randomized controlled and observational studies were included in this review (2578 patients underwent conventional colonoscopy and 643 colonoscopic tattooing). The pooled incidence of localization errors with conventional colonoscopy was 15.4 % (95 % CI 12.0-18.7), whereas that of colonoscopic tattooing was 9.5 % (95 % CI 5.7-13.3), mean difference 5.9 % (95 % CI 0.65-11.14, p = 0.03). Adverse events secondary to tattooing were infrequent, and most were cases of ink spillage. Limited information was available for other localization techniques.

CONCLUSION

Conventional colonoscopy has a higher incidence of localization error compared to colonoscopic tattooing for localization of colorectal cancer. Colonoscopic tattooing is safe and leads to fewer tumor localization errors. Given the widespread adoption of laparoscopic resections for colorectal cancer, routine colonoscopic tattooing should be adopted. However, studies directly comparing different localization techniques are needed.