Role of endoscopy in staging colorectal cancer

DNA methylation biomarkers for predicting lymph node metastasis in colorectal cancer

Colorectal cancer is one of the most common cancers worldwide. Lymph node metastasis is an important marker of colorectal cancer progression and plays a key role in the evaluation of patient prognosis. Accurate preoperative assessment of lymph node metastasis is crucial for devising appropriate treatment plans. However, current clinical imaging methods have limitations in many aspects. Therefore, the discovery of a method for accurately predicting lymph node metastasis is crucial clinical decision-making. DNA methylation is a common epigenetic modification that can regulate gene expression, which also has an important impact on the development of colorectal cancer. It is considered to be a promising biomarker with good specificity and stability and has promising application in predicting lymph node metastasis in patients with colorectal cancer. This article reviews the characteristics and limitations of currently available methods for predicting lymph node metastasis in patients with colorectal cancer and discusses the role of DNA methylation as a biomarker.

Endoscopic ultrasound for staging of colonic cancer proximal to the rectum: A systematic review and meta-analysis

Background and Objectives:

Treatment of colonic cancer patients is highly dependent on the depth of tumor invasion (T-stage) as well as the extension of lymph node involvement (N-stage). We aimed to systematically review the accuracy of endoscopic ultrasound (EUS) for staging of colonic cancer proximal to the rectum.

Patients and Methods:

Men and women with colonic adenocarcinomas were included in the study. EUS staging was compared to histopathology as the gold standard. Outcome measures were T- and N-staging accuracies. Articles were searched in PubMed, Web of Science, The Cochrane Library, and EMBASE.

Results:

Six studies were identified comparing EUS staging of colonic cancer to histopathology. The pooled-staging sensitivity and specificity were 0.90 and 0.98 for T1 tumors, 0.67 and 0.96 for T2 tumors, and 0.97 and 0.83 for T3/T4 tumors, respectively. Sensitivity and specificity for N + disease were 0.59 and 0.78, respectively.

Conclusions:

EUS is a feasible method for T-staging of cancers of the colon proximal to the rectum. The accuracy of lymph node staging needs to be verified by prospective multicenter studies including larger patient populations.

Magnifying chromoendoscopy and endoscopic ultrasonography measure invasion depth of early stage colorectal cancer with equal accuracy on the basis of a prospective trial

BACKGROUND & AIMS

Magnifying chromoendoscopy (MC) and endoscopic ultrasonography (EUS) are used to estimate the depth of colorectal cancer (CRC) invasion, but it is not clear which procedure is more accurate. We performed a prospective study to compare MC and EUS.

METHODS

A total of 70 patients with an early stage flat CRC lesion were enrolled at 6 institutions in Japan and randomly assigned to groups assessed by MC followed by EUS or EUS followed by MC. Results from MC and EUS measurements of 66 lesions were included in the final analysis. The invasion depth of each lesion was measured by each procedure and categorized as mucosal to slight submucosal (depth <1000 μm) or deep submucosal (depth ≥ 1000 μm); measurements were compared with the final diagnosis on the basis of the pathology analysis. All participating examiners achieved a mean κ value ≥ 0.6 for both MC and EUS before this trial.

RESULTS

MC and EUS each measured the depth of lesion invasion with 71.2% accuracy (correctly for 47 of 66 lesions). MC identified lesions with deep submucosal invasion with 74.2% sensitivity and 68.6% specificity, whereas EUS identified them with 67.7% sensitivity and 74.3% specificity. The differences between MC and EUS measurements did not differ significantly. However, MC required significantly shorter observation time than EUS (361.7 ± 164.5 seconds vs 451.2 ± 209.4 seconds, P = .002).

CONCLUSIONS

MC and EUS are equally accurate in estimating the invasion depth of early stage CRC lesions. However, neither procedure has sufficient diagnostic accuracy to be used as the standard. University Hospital Medical Network Clinical Trials Registry, Number: UMIN 000005085.

ENDOSCOPIC ULTRASOUND INSTRUMENTATION, APPLICATIONS IN HUMANS, AND POTENTIAL VETERINARY APPLICATIONS

Endoluminal scanning under endoscopic guidance, or endoscopic ultrasonography (EUS), has become the most significant advance for imaging the gastrointestinal (GI) tract wall and contiguous organs in the past 20 years. It was originally designed to overcome the limitations in humans to imaging the abdominal organs transabdominally, such as large penetration depths and GI air. This imaging modality provides detailed images of pathological processes both within and outside of the GI wall since a high-frequency transducer can be brought into close proximity with the target regions. It has found most success in humans for the staging of lung, gastric, and esophageal cancer, the detection of both lymphatic and hepatic metastases, and diagnosis of pancreatitis and pancreatic cancer, as well as achieving an important role in interventional and therapeutic procedures. The EUS examination can be performed to examine both the thorax and abdomen in animals when both conventional transthoracic or transabdominal ultrasound are inadequate due to intervening air, bone, large penetration depths, or obesity. The echoendoscope is similar to a conventional endoscope but has an ultrasound transducer at its tip. Both radial and linear multifrequency scanners are available. Linear scanners allow fine-needle aspiration (FNA) of the bowel wall or extraluminal structures. Transducer coupling is either by direct mucosal contact or by inflation of a water-filled balloon surrounding the transducer. Current thoracic applications for EUS in veterinary medicine include examination of the mediastinum, bronchial lymph nodes, esophagus, and pulmonary lesions as well as FNA of pulmonary masses. Abdominal applications include examination of both pancreatic limbs and the liver, including portosystemic shunts, detection of lymphadenomegaly, and examination of the gastric wall, duodenum, and jejunum. Other potential applications in dogs and cats include tumor staging and intrapelvic ultrasound.