Endosonographic staging of lower intestinal malignancy

Rectal Endoscopic Ultrasound in Clinical Practice

PURPOSE OF REVIEW

Endoscopic ultrasound (EUS) is routinely utilized for evaluation of disorders of the lower gastrointestinal tract. In this review, we summarize the current status of rectal EUS in clinical practice and describe recent developments in diagnostic and therapeutic rectal EUS.

RECENT FINDINGS

Recent guidelines recommend rectal EUS for rectal cancer staging as a second line modality in cases where MRI is contraindicated. Forward-viewing echoendoscopes and through the scope EUS miniprobes allow for EUS imaging of lesions through the entire colon and for evaluation beyond stenoses or luminal narrowings. EUS can be used to assess perianal disease and drain pelvic abscess associated with IBD, along with newer applications currently under investigation. For rectal varices, EUS can confirm the diagnosis, assess the optimal site for banding, guide therapy placement with sclerotherapy and/or coils, and assess response to treatment by confirming absence of flow. Therapeutic rectal EUS is emerging as a promising modality for drainage of pelvic fluid collection drainage and fiducial placement for rectal or prostatic cancer. Drug delivery mechanisms and substances that may increase the scope of therapy with rectal EUS are in varying stages of development. Rectal EUS continues to be an important modality for evaluation of benign and malignant disorders of the lower gastrointestinal tract, although its use as a cancer staging modality has declined due to improvements in MRI technology. Various technologies to enhance ultrasound imaging and for therapeutics have been developed that have or may contribute to expanded indications for rectal EUS.

Endoscopic ultrasound in oncology: An update of clinical applications in the gastrointestinal tract

An accurate staging is necessary to select the best treatment and evaluate prognosis in oncology. Staging usually begins with noninvasive imaging such as computed tomography, magnetic resonance imaging or positron emission tomography. In the absence of distant metastases, endoscopic ultrasound plays an important role in the diagnosis and staging of gastrointestinal tumors, being the most accurate modality for local-regional staging. Its use for tumor and nodal involvement in pre-surgical evaluation has proven to reduce unnecessary surgeries. The aim of this article is to review the current role of endoscopic ultrasound in the diagnosis and staging of esophageal, gastric and colorectal cancer.

Colon carcinoma staging by endoscopic ultrasonography miniprobes

Background and Objectives:

Due to the increasing use of endoscopic techniques for colon cancer resection, pretreatment locoregional staging may gain critical interest. The use of endoscopic ultrasonography (EUS) miniprobes in this context has been seldom reported. Our aim was to determine the accuracy of EUS miniprobes for colon cancer staging.

Materials and Methods:

Forty patients with colon cancer (2 in the cecum, 9 in the ascending colon, 5 in the transverse colon, 5 in the descending colon, and 19 in the sigmoid colon) were submitted to staging using 12 MHz EUS miniprobes. EUS and the anatomopathological results were compared with regard to the T and N stages. It was assessed if the location, longitudinal extension, or circumferential extension of the tumor had any influence on the accuracy in EUS staging.

Results:

Tumor staging was feasible in 39 (98%) patients except in one case with a stenosing tumor (out of 6). Globally, T stage was accurately determined in 88% of the cases. In the assessment of the presence or absence of lymph node metastasis, miniprobes presented an accuracy of 82% with a sensitivity of 67%. These results were neither affected by the location nor by the longitudinal or circumferential extension of the tumor.

Conclusions:

EUS miniprobes may play an important role in assessing T and N stages in colon cancer and may represent an incentive to the research of new therapeutic areas for this disease.

Management of colorectal T1 carcinoma treated by endoscopic resection from the Western perspective

Detection of early colorectal cancer is expected to rise in light of national colorectal cancer screening programs. This The present review article delineates current endoscopic risk assessments, differentiating invasive from non-invasive neoplasia, for high likelihood of lymph node metastasis in early colorectal cancer, also termed high-risk early colorectal cancer, and endoscopic and surgical resection methods from a Western hemisphere perspective.

Forward-viewing radial-array echoendoscope for staging of colon cancer beyond the rectum

AIM: To evaluate feasibility of the novel forward-viewing radial-array echoendoscope for staging of colon cancer beyond rectum as the first series.

METHODS: A retrospective study with prospectively entered database. From March 2012 to February 2013, a total of 21 patients (11 men) (mean age 64.2 years) with colon cancer beyond the rectum were recruited. The novel forward-viewing radial-array echoendoscope was used for ultrasonographic staging of colon cancer beyond rectum. Ultrasonographic T and N staging were recorded when surgical pathology was used as a gold standard.

RESULTS: The mean time to reach the lesion and the mean time to complete the procedure were 3.5 and 7.1 min, respectively. The echoendoscope passed through the lesions in 13 patients (61.9%) and reached the cecum in 10 of 13 patients (76.9%). No adverse events were found. The lesions were located in the cecum (n = 2), ascending colon (n = 1), transverse colon (n = 2), descending colon (n = 2), and sigmoid colon (n = 14). The accuracy rate for T1 (n = 3), T2 (n = 4), T3 (n = 13) and T4 (n = 1) were 100%, 60.0%, 84.6% and 100%, respectively. The overall accuracy rates for the T and N staging of colon cancer were 81.0% and 52.4%, respectively. The accuracy rates among traversable lesions (n = 13) and obstructive lesions (n = 8) were 61.5% and 100%, respectively. Endoscopic ultrasound and computed tomography had overall accuracy rates of 81.0% and 68.4%, respectively.

CONCLUSION: The echoendoscope is a feasible staging tool for colon cancer beyond rectum. However, accuracy of the echoendoscope needs to be verified by larger systematic studies.

Mini-probe ultrasonography for the staging of colon cancer: a systematic review and meta-analysis

AIM

With an increasing array of treatment modalities available for colon cancer, it is increasingly important to stage tumours accurately to allocate the appropriate management. This study evaluated the accuracy of mini-probe endoscopic ultrasound (EUS) in assigning clinical stage to colon cancer.

METHOD

An electronic search was performed in January 2013 using the Embase, MEDLINE and Cochrane databases. This was supplemented by a hand search of published abstracts from scientific meetings. Trials evaluating the accuracy of the mini-probe EUS compared with histopathological grade in determining the clinical stage of colon cancer were included in this pooled analysis. The main outcome measures included accuracy, sensitivity and specificity for T and N staging.

RESULTS

Ten studies were identified which compared the mini-probe EUS staging of 642 colon or rectal cancers with the histopathological specimen. The pooled sensitivity and specificity for staging were 0.91 and 0.98 for T1 tumours, 0.78 and 0.94 for T2 tumours, 0.97 and 0.90 for T3/T4 tumours and 0.63 and 0.82 for nodal staging. Eight per cent of T1/T2 tumours were upstaged to T3/T4 tumours and 5% of T3/T4 tumours were downstaged.

CONCLUSION

Mini-probe EUS is highly effective for assigning clinical stage in colon cancer and in identifying patients who may be suitable for nonsurgical treatment including neoadjuvant chemotherapy or endoscopic resection.

Simultaneous follow-up of mouse colon lesions by colonoscopy and endoluminal ultrasound biomicroscopy

AIM: To evaluate the potential use of colonoscopy and endoluminal ultrasonic biomicroscopy (eUBM) to track the progression of mouse colonic lesions.

METHODS: Ten mice were treated with a single azoxymethane intraperitoneal injection (week 1) followed by seven days of a dextran sulfate sodium treatment in their drinking water (week 2) to induce inflammation-associated colon tumors. eUBM was performed simultaneously with colonoscopy at weeks 13, 17-20 and 21. A 3.6-F diameter 40 MHz mini-probe catheter was used for eUBM imaging. The ultrasound mini-probe catheter was inserted into the accessory channel of a pediatric flexible bronchofiberscope, allowing simultaneous acquisition of colonoscopic and eUBM images. During image acquisition, the mice were anesthetized with isoflurane and kept in a supine position over a stainless steel heated surgical waterbed at 37 °C. Both eUBM and colonoscopic images were captured and stored when a lesion was detected by colonoscopy or when the eUBM image revealed a modified colon wall anatomy. During the procedure, the colon was irrigated with water that was injected through a flush port on the mini-probe catheter and that acted as the ultrasound coupling medium between the transducer and the colon wall. Once the acquisition of the last eUBM/colonoscopy section for each animal was completed, the colons were fixed, paraffin-embedded, and stained with hematoxylin and eosin. Colon images acquired at the first time-point for each mouse were compared with subsequent eUBM/colonoscopic images of the same sites obtained in the following acquisitions to evaluate lesion progression.

RESULTS: All 10 mice had eUBM and colonoscopic images acquired at week 13 (the first time-point). Two animals died immediately after the first imaging acquisition and, consequently, only 8 mice were subjected to the second eUBM/colonoscopy imaging acquisition (at the second time-point). Due to the advanced stage of colonic tumorigenesis, 5 animals died after the second time-point image acquisition, and thus, only three were subjected to the third eUBM/colonoscopy imaging acquisition (the third time-point). eUBM was able to detect the four layers in healthy segments of colon: the mucosa (the first hyperechoic layer moving away from the mini-probe axis), followed by the muscularis mucosae (hypoechoic), the submucosa (the second hyperechoic layer) and the muscularis externa (the second hypoechoic layer). Hypoechoic regions between the mucosa and the muscularis externa layers represented lymphoid infiltrates, as confirmed by the corresponding histological images. Pedunculated tumors were represented by hyperechoic masses in the mucosa layer. Among the lesions that decreased in size between the first and third time-points, one of the lesions changed from a mucosal hyperplasia with ulceration at the top to a mucosal hyperplasia with lymphoid infiltrate and, finally, to small signs of mucosal hyperplasia and lymphoid infiltrate. In this case, while lesion regression and modification were observable in the eUBM images, colonoscopy was only able to detect the lesion at the first and second time-points, without the capacity to demonstrate the presence of lymphoid infiltrate. Regarding the lesions that increased in size, one of them started as a small elevation in the mucosa layer and progressed to a pedunculated tumor. In this case, while eUBM imaging revealed the lesion at the first time-point, colonoscopy was only able to detect it at the second time-point. All colonic lesions (tumors, lymphoid infiltrate and mucosal thickening) were identified by eUBM, while colonoscopy identified just 76% of them. Colonoscopy identified all of the colonic tumors but failed to diagnose lymphoid infiltrates and increased mucosal thickness and failed to differentiate lymphoid infiltrates from small adenomas. During the observation period, most of the lesions (approximately 67%) increased in size, approximately 14% remained unchanged, and 19% regressed.

CONCLUSION: Combining eUBM with colonoscopy improves the diagnosis and the follow-up of mouse colonic lesions, adding transmural assessment of the bowel wall.

In vivo endoluminal ultrasound biomicroscopic imaging in a mouse model of colorectal cancer

RATIONALE AND OBJECTIVES

The gold-standard tool for colorectal cancer detection is colonoscopy, but it provides only mucosal surface visualization. Ultrasound biomicroscopy allows a clear delineation of the epithelium and adjacent colonic layers. The aim of this study was to design a system to generate endoluminal ultrasound biomicroscopic images of the mouse colon, in vivo, in an animal model of inflammation-associated colon cancer.

MATERIALS AND METHODS

Thirteen mice (Mus musculus) were used. A 40-MHz miniprobe catheter was inserted into the accessory channel of a pediatric flexible bronchofiberscope. Control mice (n = 3) and mice treated with azoxymethane and dextran sulfate sodium (n = 10) were subjected to simultaneous endoluminal ultrasound biomicroscopy and white-light colonoscopy. The diagnosis obtained with endoluminal ultrasound biomicroscopy and colonoscopy was compared and confirmed by postmortem histopathology.

RESULTS

Endoluminal ultrasound biomicroscopic images showed all layers of the normal colon and revealed lesions such as lymphoid hyperplasias and colon tumors. Additionally, endoluminal ultrasound biomicroscopy was able to detect two cases of mucosa layer thickening, confirmed by histology. Compared to histologic results, the sensitivities of endoluminal ultrasound biomicroscopy and colonoscopy were 0.95 and 0.83, respectively, and both methods achieved specificities of 1.0.

CONCLUSIONS

Endoluminal ultrasound biomicroscopy can be used, in addition to colonoscopy, as a diagnostic method for colonic lesions. Moreover, experimental endoluminal ultrasound biomicroscopy in mouse models is feasible and might be used to further develop research on the differentiation between benign and malignant colonic diseases.

EUS-FNA assessment of extramesenteric lymph node status in primary rectal cancer

BACKGROUND

Preoperative staging is an essential factor in the multidisciplinary management of rectal cancer. The accuracy of imaging alone with CT, magnetic resonance imaging, or rigid endorectal US is poor. The addition of EUS-FNA may enhance extramesenteric lymph node metastases detection (M1 disease) and overall staging accuracy.

OBJECTIVE

To evaluate the frequency of extramesenteric lymph node visualization by EUS and the rate of extramesenteric lymph node metastases by FNA. Secondary goals were to evaluate the clinical, endoscopic, and sonographic features associated with extramesenteric lymph node metastases, disease progression, and overall mortality.

DESIGN

Retrospective cohort study.

SETTINGS

Tertiary referral center.

RESULTS

Forty-one of 316 patients (13%) with primary rectal cancer over a 6-year period had M1 disease by EUS-FNA. Significant clinical, endoscopic, and sonographic features associated with extramesenteric lymph node metastases included the serum carcinoembryonic antigen level, tumor length 4 cm and longer, annularity 50% or more, sessile morphology, and lymph node size. The sensitivity and specificity of CT for extramesenteric lymph node metastases were 44% and 89%, respectively. Twenty-three of 316 rectal cancer endosonographic procedures (7.3%) were up-staged by FNA, which established extramesenteric lymph node metastases. Over a 4-year follow-up, disease progression and overall mortality of patients with extramesenteric lymph node metastases was observed in 6 patients (14.6%) and 14 patients (34%), respectively.

CONCLUSIONS

Preoperative EUS-FNA identification of extramesenteric lymph node metastases outside of standard radiation fields or total mesorectal excision resection margins could affect medical and surgical planning.

Staging of rectal cancer by EUS: depth of infiltration in T3 cancers is important

BACKGROUND

EUS is an established method for staging of rectal cancer. Nevertheless, there are few data about the significance of infiltration depth measured by EUS.

OBJECTIVE

Assessment of accuracy of T and N staging by EUS with attention to infiltration depth as provided by EUS.

DESIGN

Part retrospective, part prospective study.

SETTING

Community and tertiary referral hospital, covering the period before neoadjuvant therapy for advanced rectal cancer was established.

PATIENTS

Eighty-three patients (60% men) with untreated rectal cancer.

INTERVENTION

EUS examination.

MAIN OUTCOME MEASUREMENTS

We examined the correlation between EUS findings and postoperative histology. T3 cancers as diagnosed by EUS were classified into minimally invasive (1-2 mm) or advanced (>2 mm) tumors depending on the depth of infiltration beyond the muscularis propria.

RESULTS

Accuracy of T staging and N status was 76% and 63%, respectively. Overstaging by EUS was more common in minimally invasive T3 by EUS (uT3) (8 of 16 [50%]) compared with advanced uT3 tumors (1 of 24 [4%]) (P=.01). Accuracy of EUS discrimination between T1/2 and T3/4 in rectal cancer for all but minimally invasive uT3 rectal tumors was 88%.

LIMITATIONS

Partly retrospective analysis.

CONCLUSIONS

EUS examination of rectal carcinoma determines T stage with high accuracy. Additionally, it provides information beyond T and N staging. The 50% probability of overstaging patients with minimally invasive uT3N0 by EUS may argue for managing these cancers as stage I disease, ie, to refer the patient for surgery without neoadjuvant therapy.

Photodynamic therapy of early stage oral cavity and oropharynx neoplasms: an outcome analysis of 170 patients

The indications of photodynamic therapy (PDT) of oral cavity and oropharynx neoplasms are not well defined. The main reason is that the success rates are not well established. The current paper analyzes our institutional experience of early stage oral cavity and oropharynx neoplasms (Tis-T2) to identify the success rates for each subgroup according to T stage, primary or non-primary treatment and subsites. In total, 170 patients with 226 lesions are treated with PDT. From these lesions, 95 are primary neoplasms, 131 were non-primaries (recurrences and multiple primaries). The overall response rate is 90.7% with a complete response rate of 70.8%. Subgroup analysis identified oral tongue, floor of mouth sites with more favorable outcome. PDT has more favorable results with certain subsites and with previously untreated lesions. However, PDT can find its place for treating lesions in previously treated areas with acceptable results.