Application of ultrasonic probes prior to endoscopic resection of early gastric cancer

Controversies in EUS: Do we need miniprobes?

This is the fifth in a series of papers entitled "Controversies in EUS." In the current paper, we deal with high-resolution catheter probes, otherwise known as EUS miniprobes (EUS-MPs). The application of miniprobes for early carcinomas in the entire intestinal tract, for subepithelial lesions, and for findings in the bile duct and pancreatic duct as well as endobronchial use is critically discussed. Submucous lesions, especially in the colon, but also early carcinomas in special cases are considered the most important indications. The argument is illustrated by numerous examples.

Use of endoscopic ultrasound in the preoperative staging of gastric cancer: a multi-institutional study of the US gastric cancer collaborative

BACKGROUND

Endoscopic ultrasound (EUS) can be used to guide the therapeutic plan for patients with gastric adenocarcinoma (GAC), but data on its use and accuracy remain poorly defined. We sought to define the use of EUS, as well as characterize the diagnostic accuracy of EUS among patients with GAC.

STUDY DESIGN

We identified 960 patients who underwent resection of GAC between 2000 and 2012 from 7 major academic institutions participating in the US Gastric Cancer Collaborative. Clinicopathologic and EUS data were collected and analyzed using chi and kappa statistics.

RESULTS

Of 960 patients, 223 (23.2%) underwent evaluation with preoperative EUS. Among patients who underwent EUS, 74 (33.2%) received neoadjuvant chemotherapy; 149 (66.8%) proceeded directly to resection. Among patients who did not receive neoadjuvant therapy and received curative intent gastric resection, the EUS T classifications were T1 (33.3%), T2 (35.6%), T3 (18.9%), T4 (12.1%) and the N classifications were N0 (68.1%) and N ≥ 1 (31.9%). In contrast, when tumor stage was based on the final surgical specimen, there was a higher proportion of cases with more advanced T stage (T1, 36.4%; T2, 14.4%; T3, 23.5%; T4, 25.7%) and N stage (N0, 51.3%; N ≥ 1, 48.7%). The agreement of preoperative EUS compared with surgical staging for T (kappa = 0.28, p < 0.001) and N (kappa = 0.33, p < 0.001) classification was only fair.

CONCLUSIONS

Less than one-quarter of patients with GAC underwent preoperative EUS staging. In patients who did not receive preoperative chemotherapy, tumor stage on EUS often did not correlate with T stage and N stage on final pathologic analysis. Endoscopic ultrasound should be combined with other staging modalities to optimize staging of patients with GAC.

What studies are appropriate and necessary for staging gastric adenocarcinoma? Results of an international RAND/UCLA expert panel

BACKGROUND

The approach for staging gastric adenocarcinoma (GC) has not been well defined, with heterogeneity in the application of staging modalities.

METHODS

Utilizing a RAND/UCLA appropriateness methodology (RAM), a multidisciplinary expert panel of 16 physicians scored 84 GC staging scenarios. Appropriateness was scored from 1 to 9. Median appropriateness scores from 1 to 3 were considered inappropriate, 4-6 uncertain, and 7-9 appropriate. Agreement was reached when 12 or more of 16 panelists scored the scenario similarly. Appropriate scenarios were subsequently scored for necessity.

RESULTS

Pretreatment TNM stage determination is necessary. Necessary staging maneuvers include esophagogastroduodenoscopy (EGD); biopsy of the tumor; documentation of tumor size, description, location, distance from gastroesophageal junction (GEJ), and any GEJ, esophageal, or duodenal involvement; if an EGD report is unclear, surgeons should repeat it to confirm tumor location. Pretreatment radiologic assessment should include computed tomography (CT)-abdomen and CT-pelvis, performed with multidetector CT scanners with 5-mm slices. Laparoscopy should be performed before resection of cT3-cT4 lesions or multivisceral resections. Laparoscopy should include inspection of the stomach, diaphragm, liver, and ovaries.

CONCLUSIONS

Using a RAM, we describe appropriate and necessary staging tests for the pretreatment staging evaluation of GC, as well as how some of these staging maneuvers should be conducted.

A systematic review and meta-analysis of the utility of EUS for preoperative staging for gastric cancer

BACKGROUND

Accurate preoperative staging is important in determining the appropriate treatment of gastric cancer. Recently, endoscopic ultrasound (EUS) has been introduced as a staging modality. However, reported test characteristics for EUS in gastric cancer vary. Our purpose in this study was to identify, synthesize, and evaluate findings from all articles on the performance of EUS in the preoperative staging of gastric cancer.

METHODS

Electronic literature searches were conducted using Medline, Embase, and the Cochrane Central Register of Controlled Trials from 1 January 1998 to 1 December 2009. All search titles and abstracts were independently rated for relevance by a minimum of two reviewers. Meta-analysis for the performance of EUS was analyzed by calculating agreement (Kappa statistic), and pooled estimates of accuracy, sensitivity, and specificity for all EUS examinations, using histopathology as the reference standard. Subgroup analyses were also performed.

RESULTS

Twenty-two articles met our inclusion criteria and were included in the review. EUS pooled accuracy for T staging was 75% with a moderate Kappa (0.52). EUS was most accurate for T3 disease, followed by T4, T1, and T2. EUS pooled accuracy for N staging was 64%, sensitivity was 74%, and specificity was 80%. There was significant heterogeneity between the included studies. Subgroup analyses found that annual EUS volume was not associated with EUS T and N staging accuracy (P = 0.836, 0.99, respectively).

CONCLUSION

EUS is a moderately accurate technique that seems to describe advanced T stage (T3 and T4) better than N or less advanced T stage. Stratifying by EUS annual volume did not affect EUS performance in staging gastric cancer.

Usefulness of endoscopic ultrasonography in determining the depth of invasion and indication for endoscopic treatment of early gastric cancer

INTRODUCTION

Endoscopic ultrasonography (EUS) is a useful method for visualizing features of gastric cancer. However, a previously reported classification system tended to result in overstaging. We investigated the usefulness of EUS for evaluation of the depth of gastric cancer invasion and indications for endoscopic treatment.

METHODS

Accuracy of EUS for determining the depth of invasion and incidences of a positive basal margin were assessed in 235 patients who underwent endoscopic treatment or surgery for gastric cancer. The EUS-determined depth of invasion was classified as follows: EUS-M (lesion confined to sonographic layers 1 and 2); EUS-M/SM border (lesion with changes in sonographic layer 3 but no deeper than 1 mm); EUS-SM (lesion with changes in sonographic layer 3 deeper than 1 mm); or EUS-AD (lesion with changes in sonographic layer 4 or 5).

RESULTS

Accuracy of EUS for determining the depth of invasion was as follows: EUS-M, 99% were M and SM1 lesions; EUS-M/SM border, 87% were M and SM1 lesions; EUS-SM, 91% were SM2 lesions; EUS-AD, 100% were muscularis propria or deeper lesions. There was no EUS-M or EUS-M/SM border lesion for which endoscopic treatment resulted in a positive basal margin.

CONCLUSIONS

EUS is useful for accurately determining the depth of invasion of gastric cancer. When there are no endoscopically determined ulcerous changes, endoscopic treatment should be considered for EUS-M and EUS-M/SM border lesions, and EUS-SM lesions should be treated surgically.

Accuracy of endoscopic ultrasound staging of gastric cancer in routine clinical practice in Singapore

OBJECTIVE

Endoscopic ultrasound has emerged as the leading modality to assess the T and N stage in gastric cancer. This study aimed to assess the accuracy of TN staging by endoscopic ultrasound in routine clinical practice in Singapore.

METHODS

Over a period of 7 years, 77 patients (male: 70%; median age 62.8 years) with gastric cancer underwent preoperative staging with endoscopic ultrasound. Fifty-seven patients eventually underwent surgery with tissues available for histopathological staging and comparison.

RESULTS

The tumor locations were: cardia: 13; corpus: 20; incisura: 19; antrum: 25. The majority was poorly differentiated (57.1%); 26% were moderately differentiated and 16.9% were well differentiated adenocarcinoma. Compared to pathological staging, the overall accuracy of T staging by endoscopic ultrasound was 77.2% (17.5% under-staged: 5.3% over-staged). The staging accuracy of T1 (92.9%) and T3 (81.8%) was higher than T2 (57.1%) and T4. For N staging, the accuracy of endoscopic ultrasound was 59.6% (26.3% under-staged; 14% over-staged); this was significantly superior to computer tomography (43.9%).

CONCLUSION

Endoscopic ultrasound is useful for the T staging of gastric cancer, with an overall accuracy rate of 77%, and up to 93% for T1 lesions. Under-staging may occur due to microscopic tumor infiltration, while over-staging may arise due to inflammatory reactions. The accuracy of N staging is lower at 60%, but could be further improved with the use of fine needle aspiration.

The endoscopic diagnosis and staging of oesophageal adenocarcinoma

The endoscopic evaluation of patients with oesophageal adenocarcinoma does not only serve the purpose of diagnosing the lesion and obtaining biopsies for histological evaluation: a systematic description of advanced lesions is also required to guide further therapeutic decisions. New endoscopic imaging modalities hold the promise of better endoscopic detection of early cancer and its precursor lesions in Barrett's oesophagus. Video-autofluorescence and narrow band imaging are the most promising techniques in this respect. The former may be used as a 'red flag' technique, identifying lesions that remain occult with white light endoscopy; the latter may be used as a targeted imaging technique, allowing for detailed inspection of the mucosal and vascular patterns that may help to distinguish early neoplasia from non-dysplastic tissue. Currently, prototypes are under investigation that combine high-resolution endoscopy, narrow band imaging and video-autofluorescence in one endoscopy system. Endoscopic ultrasonography (EUS) is superior to any other imaging modality in the assessment of local tumour infiltration of oesophageal adenocarcinoma and locoregional lymph nodes status. EUS allows for the identification of patients with advanced disease who are unlikely to benefit from attempts at curative surgery and in whom a conservative palliative treatment is indicated. EUS may also play a role in the selection of patients for local endoscopic treatment of early oesophageal cancer. EUS guided fine needle aspiration (EUS-FNA) of locoregional lymph nodes is safe with a high sensitivity and an impeccable specificity for assessment of malignant involvement. The indications for EUS-FNA of lymph nodes, however, depend on local treatment protocols: caeliac nodes (M1a) and lymph nodes located at or above the subcarinal area are the most widely used indications. In addition, it may be important if the choice for specific treatment protocols (e.g. neoadjuvant chemoradiotherapy) depends on lymph node status.

Wider indications for the local resection of gastric cancer by adjacent lymphadenectomy

BACKGROUND AND OBJECTIVES

A variety of minimal invasive treatment strategies for early gastric cancer without reducing the curability have been introduced, however, the indications for the local resection of early gastric cancer have not been precisely established.

METHODS

Two approaches are adopted in this study to elucidate indications for local resection. One is a retrospective review of surgically resected, postoperatively histologically proven early gastric cancers between 1976 and 1996 (611 patients), and the other is the patient selection from those who underwent modified D(1) lymphadenectomy in a prospective manner between 1987 and 1996, based on the preoperative and intraoperative diagnoses of mucosal, node negative, nonpalpable gastric cancer (125 patients). In these approaches, patterns of nodal involvement in association with clinicopathological characteristics of gastric cancer were investigated.

RESULTS

The depressed with ulceration type and histologically high grade type were predominant characteristics of mucosal, node positive gastric cancer patients. Of these patients, after the exclusion of those who were diagnosed to have submucosal or advanced cancer preoperatively or who had palpable cancer intraoperatively, the gastric cancer < or =4 cm in maximum diameter had positive nodes confined to only one station adjacent to the cancer without simultaneous nodal involvement in the other stations.

CONCLUSIONS

Local resection can be performed for gastric cancers < or = 4 cm in maximum diameter that meet our criteria for modified D(1) lymphadenectomy, in association with the frozen section confirmation of cancer negative in the simultaneously dissected lymph nodes in the stations adjacent to the cancer. The adjacent lymphadenectomy and frozen section examination make the application of local resection possible for a wider segment of patients.

Three-dimensional endoscopic ultrasonography of lesions of the upper gastrointestinal tract using a radial-linear switchable thin ultrasound probe

BACKGROUND

The objective of three-dimensional (3-D) endoscopic ultrasonography (EUS) is to recognize lesions stereoscopically.

METHODS AND RESULTS

We investigated a total of 43 lesions in the upper gastrointestinal (GI) tract by regenerating 3-D images in eight cases of oesophageal cancer, two cases of oesophageal submucosal tumour, two oesophageal varices, two cases of achalasia, 27 gastric cancers, one gastric carcinoid, and one duodenal submucosal tumour. Using a prototype system (Fujinon, Omiya, Japan), we reconstructed 3-D images from conventional EUS images taken by a thin ultrasound probe (Sonoprobe, SP-701, Fujinon) having a radial-linear scanning mode. The basic 3-D images could be obtained in a short period during EUS performed using the conventional thin-ultrasound probe. The acceptable quality level of the reconstructed 3-D images was 37% (57% in the oesophagus, 25% in the stomach and 100% in the duodenum). Deterioration of 3-D images was due to a wobbling of linear scanning mainly caused by peristalsis of the GI tract, cardiac impulses, and respiration.

CONCLUSIONS

Our study has proved that the simple and speedy 3-D display system built using the existing linear-radial switchable probe is easily applicable to clinical cases.

The role of gastrointestinal endosonography in diagnostic and therapeutic interventional procedures

Over the past 15 years endoscopic ultrasonography (EUS) has become an integrated part of gastrointestinal imaging. The more recent development of echoendoscopes and needles for EUS guided fine needle aspiration has stimulated the interest in interventional EUS procedures, both for diagnostic and therapeutic purposes. This paper describes the technique and experience with some of the interventional EUS procedures based on the present literature. Many of the techniques must still be considered experimental and will need substantial clinical testing in larger series before any final conclusions can be made. However, the present level of interventional EUS seems to indicate, that some of these techniques could be cost-effective alternatives in specific clinical situations, and in some cases even the only possible theraputic action. Future research in interventional EUS should be concentrated in experienced endosonography centers under careful monitoring of complications and clinical outcome.

Endoscopic ultrasonography in patients with gastro-esophageal cancer

For patients with gastro-esophageal cancer ultrasonography (EUS) is superior to any other imaging modality in the assessment of local tumor infiltration and local lymph nodes status. EUS is especially important in the preoperative staging of patients with esophageal cancer and patients with proximal gastric cancer. Here it allows for the identification of those patients with advanced disease who are unlikely to benefit from surgery and in whom a conservative palliative treatment is indicated. In advanced gastric cancer the clinical implications of EUS less clear. Still preoperative EUS is indicated in every patient with cancer of the proximal stomach to assess tumor infiltration in the esophagus. Relatively new is the use of EUS in staging early cancers in order to select patients for local endoscopic treatment. High-frequency miniprobes are the instruments of choice for imaging these lesions. Strict criteria should be applied in the selection of patients for local endoscopic treatment of early gastro-esophageal cancers. EUS guided fine needle aspiration (EUS-FNA) is currently only indicated in patients with esophageal cancer and suspicious celiac lymph nodes. It may become more important if new treatment protocols demand more objective and reliable assessment of lymph node status.

Evaluation of the colorectal wall in normal subjects and patients with ulcerative colitis using an ultrasonic catheter probe

BACKGROUND

Ulcerative colitis is usually evaluated by barium enema and colonoscopy, methods of imaging that are limited to the mucosal surface. Endoscopic ultrasonography (EUS) is the best modality for the evaluation of transmural changes in the bowel wall. We therefore evaluated the colorectal wall in normal control subjects and patients with ulcerative colitis using an ultrasonic catheter probe.

METHODS

Endoscopic ultrasound with a catheter probe was performed on 36 normal control subjects (36 examinations) and 72 patients (111 examinations) with documented ulcerative colitis.

RESULTS

In normal control subjects, the total wall, mucosa, submucosa, and muscularis propria were significantly thicker in the rectum than in the colon. There was no significant difference in the thickness of the colon and rectum among different age groups or between men and women. In ulcerative colitis, we classified the boundary of each layer into three patterns (smooth, irregular, and blurred) and then classified the wall into six types. In Matts grade 2 and 3 ulcerative colitis lesions, the total wall and each layer were significantly thicker than lower grade lesions and normal control subjects. For grade 1 and most of the grade 2 lesions, the boundary of each layer was smooth. In some of the grade 3 lesions, the mucosa-submucosa and submucosa-muscularis propria layer borders were abnormal. In all grade 4 cases, the mucosa-submucosa boundary was blurred. There was some correlation between the Matts grade and EUS findings except for Matts grade 3 lesions which had various EUS patterns.

CONCLUSION

Endoscopic ultrasound with a catheter probe is a useful modality for the transmural assessment of the colorectal wall and, when used in conjunction with the many clinical and endoscopic parameters currently available, may contribute to the diagnosis and treatment of ulcerative colitis.

Endoscopic ultrasonography and endoscopy for staging depth of invasion in early gastric cancer: a pilot study

BACKGROUND

We compared the accuracy of endoscopic ultrasonography (EUS) for staging depth of invasion of early gastric cancer with that of conventional endoscopy.

PATIENTS AND METHODS

We assessed the depth of invasion of 108 lesions (104 patients) using EUS with a thin 20 MHz probe and compared the results with those of conventional endoscopy and of histologic examination of endoscopically or surgically resected specimens.

RESULTS

The overall accuracy rates for staging depth of invasion for conventional endoscopy and EUS were 72.2% and 64.8%, respectively. Lesions that were classified as limited to the mucosa on both conventional endoscopy and EUS were very likely (92.2%) to be limited to the mucosa on histologic examination. The rates for understaging and overstaging were 16.7% and 11.1%, respectively, for conventional endoscopy; and 7.4% and 24.1%, respectively, for EUS. The highest rate for understaging based on conventional endoscopy occurred for lesions in the gastric body (including cardia, 23.9%).

CONCLUSIONS

EUS appears to be useful in combination with conventional endoscopy for staging depth of invasion of early gastric cancer. In particular, the two techniques in tandem may accurately predict that a lesion is limited to the mucosa, and EUS may be useful to overcome the potential for understaging by conventional endoscopy, particularly in the gastric body.

Endoscopic and pathologic features of Epstein-Barr virus-associated gastric carcinoma

BACKGROUND

Although the presence of Epstein-Barr virus has been documented in approximately 7% of patients with gastric carcinoma, the clinical features of Epstein-Barr virus-associated carcinoma have not been well documented. We studied the histologic and endoscopic characteristics of Epstein-Barr virus-associated gastric carcinoma.

METHODS

We tested 124 gastric carcinomas from 117 patients using in situ hybridization for Epstein-Barr virus encoded small RNA1. The histologic and endoscopic findings in the Epstein-Barr virus-associated groups and the negative control groups were analyzed and compared.

RESULTS

Twelve tumors (9.7%) were identified as Epstein-Barr virus associated. These lesions were located mainly in the upper part of the stomach (p < .05) and had a diffuse-type histology (p < .05) compared with those in the control group. Six of seven (85.7%) early Epstein-Barr virus-associated lesions were type 0 IIc (superficial depressed) or a combined type, and 42.9% were accompanied by submucosal nodules of carcinoma with lymphoid stroma. Four of five (80%) advanced Epstein-Barr virus-associated tumors were type 3 (ulcerated without definite limits), thought to be the advanced shape of superficial depressed lesions.

CONCLUSIONS

Epstein-Barr virus-associated gastric carcinomas often appear as superficial depressed or ulcerated lesions in the upper part of the stomach and have a diffuse-type histology with lymphoid infiltration.

Staging of ampullary and pancreatic carcinoma: comparison between endosonography and surgery

BACKGROUND

The aim of the study was to update our previously published data on the clinical TNM staging of ampullary and pancreatic carcinoma by endosonography.

METHODS

Endosonography was performed in 70 patients with pancreatic cancer and in 32 patients with ampullary carcinoma. TNM staging was carried out before surgery and compared with findings of histology and/or surgery.

RESULTS

Endosonography was accurate in staging the depth of tumor invasion. Early-stage carcinomas could be distinguished from advanced cancers. Nonresectability was accurately assessed on the basis of vascular involvement using real-time ultrasound. Tumor compression due to peritumoral pancreatitis and direct tumor invasion into the base of the mesocolon could not be diagnosed by endosonography. The overall accuracy in tumor staging for pancreatic and ampullary carcinomas was 83.6% and 84.4%, respectively. Endosonography was accurate in diagnosing regional lymph node metastases but not accurate in defining nonmetastatic lymphadenopathy and distant metastases.

CONCLUSION

Endosonography was accurate in staging tumor stage and lymph node metastases. Minimally invasive methods of resection for superficial ampullary cancers should be based on endosonography staging.

Endoscopic ultrasonography of superficial esophageal cancers using a thin ultrasound probe system equipped with switchable radial and linear scanning modes

BACKGROUND

Detailed information on the depth of invasion of superficial esophageal cancer is required for endoscopic mucosal resection. As a pretherapeutic diagnostic procedure, endoscopic ultrasonography using conventional 7.5 MHz systems has been ineffective at providing sufficient details. A newly developed, thin ultrasound probe system provides both radial and linear scanning for evaluation of superficial esophageal cancer.

METHODS

Endoscopic ultrasonography was performed in 16 patients using a switchable probe driven at 20 MHz. Seventeen lesions of superficial esophageal cancer were evaluated for depth of invasion to discriminate mucosal from submucosal penetration.

RESULTS

The overall accuracy of staging was 64.7%. In all six errors, mucosal cancers were overstaged as submucosal invasion. The diagnostic accuracy was 80% when the muscularis mucosae was visualized.

CONCLUSION

A 20 MHz linear-radial switchable probe is a useful new method in the staging of superficial esophageal cancer.

Diagnostic utility of 20-megahertz linear endoscopic ultrasonography in early gastric cancer

BACKGROUND

Because of the widespread endoscopic treatment of early gastric cancer (EGC), accurate pretherapeutic staging of the invasion depth of EGC differentiating those limited within the mucosa from cancers invading the submucosa has become important.

METHODS

We staged the depth of tumor invasion of 47 lesions of EGC using 20 MHz linear endoscopic ultrasonography (EUS). The EUS probe was introduced via the instrument channel of a standard endoscope.

RESULTS

The accuracy of 20 MHz EUS in staging the mucosa or submucosa was 72.3%. There was 19.1% overstaging, 2.1% understaging, and 6.4% indeterminant. The principal causes of errors were inflammation associated with ulcers, benign cystic glands in the submucosal layer, and attenuation of the high-frequency ultrasound beam.

CONCLUSIONS

20 MHz EUS is useful in the pretherapeutic staging of EGC.

Minute and small early gastric cancers in a Western population: a clinicopathologic study

Early endoscopic diagnosis improves the prognosis of patients with gastric cancer, as shown by the finding that 5-year survival rates exceeding 90% are observed in Japanese patients with early gastric cancer. It has been hypothesized that tumor size may have prognostic significance; therefore, a distinction between minute, small, and large early gastric cancers has been proposed. The aim of this study was to determine the prevalence of minute and small early gastric cancers in Western countries and to compare their clinicopathologic features with those of large early gastric cancers. Of 465 Italian patients with gastric cancer who were studied, 20.5% had an early gastric cancer, and 34.7% of these were minute or small. Tumor size is correlated with intramural spreading and metastasis to perigastric lymph nodes. Nodal involvement occurs more frequently in the diffuse than in the intestinal type of early gastric cancer. Long-term survival rate is not correlated with tumor size, intramural spreading, or nodal metastasis. The minute and small early gastric cancers of Italian patients are indistinguishable from those occurring in Japanese patients. These lesions are more common than previously thought and should be carefully searched for by endoscopists. The correlation of tumor size with intramural invasion and perigastric lymph node metastasis suggests that minute and small early gastric cancers are precursors of large early gastric cancers. Although the distinction between minute, small, and large early gastric cancers is of low prognostic value, the distinction might be useful for selecting different therapeutic approaches.

New trends in surgery for gastric cancer in Japan

Although standard radical gastrectomy for gastric cancer, including lymph node dissection of compartments I and II, has been commonly utilized in Japan, new trends in gastric cancer surgery recently have been developed. In the treatment of early gastric cancer, endoscopic and limited surgeries have become more prevalent, whereas for advanced gastric cancer, super extended radical gastrectomy (SERG) and aggressive adjuvant therapy have been applied. Limited surgery includes wedge resection of the stomach, pylorus-preserving gastrectomy, vagus-preserving gastrectomy, and proximal gastrectomy. The purpose of these more limited techniques is usually to improve quality of life after surgery. Since Takahashi's lymph node staining method using fine activated carbon particles (CH40) made possible systematic para-aortic lymph node dissection, SERG has increased in popularity. The survival rate of patients with para-aortic lymph node metastases who underwent SERG was higher than that of patients who underwent extended radical gastrectomy.