Interobserver agreement in endoscopic ultrasonography staging of esophageal and cardia cancer

Management of gastroesophageal junction tumors

Tumors of the gastroesophageal junction have historically been treated as either gastric or esophageal cancer depending on institutional preferences. The Siewert classification system was designed to provide a more precise means of characterizing these tumors. In general, surgical treatment of Siewert 1 tumors is via esophagectomy. Siewert 2 and 3 tumors may be treated with either esophagectomy with proximal gastrectomy or extended total gastrectomy provided negative margins are obtained. All but the earliest stage tumors should be considered for neoadjuvant chemoradiotherapy.

The impact of time elapsed between endoscopic ultrasound and esophagectomy on concordance of ultrasonographic and pathologic staging of esophageal malignancy

BACKGROUND

Endoscopic ultrasound (EUS) is frequently used for staging of esophageal malignancies prior to esophagectomy.

AIMS

The purpose of this study was to evaluate the effect of elapsed time between endoscopic ultrasound (EUS) staging and esophagectomy on the accuracy of EUS T- and N-staging.

METHODS

This was a retrospective case series of 45 patients with esophageal malignancy who underwent staging EUS and subsequent esophagectomy at our center without neoadjuvant therapy between 2000 and 2009. The main outcome measurements were accuracy of EUS T- and N-staging when compared with surgical pathology.

RESULTS

EUS staging was accurate in 55.6% of patients for tumor stage, and in 75.6% of patients for nodal stage. The median time between EUS and esophagectomy was 26 days (range 3-64). Among patients with surgery performed 3-15, 16-30, and 31-64 days after EUS, EUS tumor staging was accurate in 90.9, 47.4, and 40.0%, respectively (P = 0.02). EUS nodal staging among patients with surgery performed 3-15, 16-30, or 31-64 days after EUS was accurate in 63.6, 84.2, and 73.3% of cases, respectively (P = 0.44). Among the 20 patients for whom T-stage was discordant, 45% were understaged and 55% were overstaged by EUS. There were 11 patients in whom N-stage was discordant; 45.5% were understaged and 54.5% were overstaged.

CONCLUSIONS

Pathologic T-staging is concordant with EUS T-staging when esophagectomy is performed within 15 days of endoscopic evaluation. Correlation between EUS and pathologic N-staging is unlikely to be affected by length of time between EUS and esophagectomy.

Endoscopic ultrasound errors in esophageal cancer

BACKGROUND

Previous assessments of endoscopic ultrasound (EUS) classification of esophageal cancer are dominated by symptomatic patients with advanced stage disease. Fewer data exist on EUS errors in a cohort balanced between early and advanced disease.

PURPOSE

Assess EUS errors in classification of esophageal cancer in a more balanced cohort, and identify clinical and tumor characteristics associated with EUS errors.

METHODS

A total of 266 patients underwent EUS and esophagectomy without preoperative chemoradiotherapy. Pathologic classification of disease extent: 108 (41%) tumors were confined to the esophageal wall (pTis-pT2, pN0, pM0); 158 (59%) were advanced beyond (pT3-pT4, pN1, or pM1). Logistic regression analysis was performed to identify correlates of error in T classification and disease extent using 10 clinical and tumor characteristics (gender, age, dysphagia, weight loss, tumor length, location, traversability, morphology, histopathologic type, and histologic grade).

RESULTS

EUS erroneously predicted pathologic T (pT) in 119 patients (45%). When T classification was dichotomized into tumors whose depth of invasion was not beyond the muscularis propria (pTis-pT2) and those beyond (pT3-pT4), errors occurred in 42 patients (16%). EUS erroneously predicted N classification in 67 patients (25%), and was insensitive to the presence of distant metastases. EUS misclassified disease extent in 40 patients (15%). Logistic regression analysis indicated that weight loss and tumor length were the only clinical and tumor characteristics correlated with EUS errors; more weight loss was associated with decreased odds of misclassification, while the odds of misclassification were four to six times greater for intermediate length tumors than for shorter tumors.

CONCLUSIONS

EUS errors, particularly in predicting pT, are more frequent than previously reported. Weight loss and tumor length are the only clinical and tumor characteristics correlated with EUS errors.

Prognostic value and interobserver agreement of endoscopic ultrasonography for superficial squamous cell carcinoma of the esophagus: a prospective study

BACKGROUND AND AIMS

Submucosal invasion of superficial esophageal cancer (SEC) is related to the prognosis. We prospectively analyzed outcomes of SEC in patients staged by endoscopic ultrasonography (EUS).

PATIENTS AND METHODS

We staged 31 endoscopically diagnosed SEC cases using a 20/15-MHz thin probe. The EUS tumor stage was classified as EUSM (limited within mucosa), EUS-SM (with submucosal invasion), or EUS-MP over (invading the muscularis propria or deeper). Lymph node metastasis and 2-yr survival were analyzed according to the EUS tumor stage in 29 squamous cell carcinoma cases. Interobserver agreement of the EUS stage was tested between the examiner and a blind reviewer.

RESULTS

Lymph node metastasis was significantly frequent in the EUS-SM group (8 of 18 cases [44.4%]) compared with the EUS-M group (1 of 10 cases [10%]) (p = 0.03). Patient survival at 2 yr after initial therapy was 72.2% in the EUS-SM group and 90% in the EUS-M group. Death from cancer was noted only in the EUS-SM group (three cases). The accuracy rates of EUS tumor staging were 74.1% by the examiner and 66.7% by the blind reviewer, with moderate interobserver agreement (kappa = 0.46).

CONCLUSIONS

Thin-probe EUS can classify SEC into two groups: the EUS-M group with excellent outcome and the EUS-SM group with a significant risk of lymph node metastasis.

Interobserver agreement in staging gastric malt lymphoma by EUS

BACKGROUND

EUS is highly accurate for staging gastric lymphoma. Because stage correlates to outcome, interobserver agreement is mandatory. However, previous studies suggest that interobserver agreement might vary according to T-stage. A multicenter evaluation of observer agreement with respect to endosonographic staging of gastric mucosa-associated lymphoid tissue (MALT) lymphoma was therefore conducted.

METHODS

Fifty-four patients were studied; 42 were also evaluated after eradication of Helicobacter pylori infection. EUS was performed at different institutions by 10 experienced endosonographers who collected the best photographs for each examination. Interobserver agreement was estimated with kappa statistics.

RESULTS

Overall interobserver agreement for T-stage was fair, both before and after treatment (kappa = 0.38 and kappa = 0.37, respectively). Overall interobserver agreement for N-stage was substantial before treatment, but only fair after treatment (kappa = 0.63 and kappa = 0.34, respectively). The lowest values of agreement occurred with T1sm (submucosa) and T2 stage lesions.

CONCLUSIONS

Interobserver agreement for staging of gastric MALT lymphoma by EUS is suboptimal before as well as after treatment of H pylori infection. This evidence suggests that gastric EUS may be more difficult technically compared with EUS of other organs. Lack of agreement is crucial because it influences the choice of therapy and assessment of response to treatment. Good interobserver agreement would permit better communication concerning the clinical status of patients, comparison of the results of different studies, and stratification of patients within clinical trials.

Interobserver agreement for EUS in the evaluation and diagnosis of submucosal masses

INTRODUCTION

EUS is an accurate means of evaluating and diagnosing submucosal lesions of the GI tract. The aim of this study was to prospectively determine interobserver agreement for the EUS classification of submucosal masses among endosonographers with different levels of training and experience from multiple centers.

METHODS

Twenty patients with submucosal mass lesions diagnosed by upper endoscopy underwent EUS. Surgical findings were available for 16 patients. In 4 patients with obvious cystic/vascular structures (i.e., varices) no surgical specimen was necessary. A blinded observer developed a study videotape of critical endoscopic and EUS real-time imaging for each lesion. The videotape was distributed to 10 endosonographers, each with at least 1 year of experience, who independently reviewed the videotape and recorded their diagnosis based on EUS features. These endosonographers used previously agreed-upon standardized EUS diagnostic criteria for each category of lesion. A kappa (kappa) statistic, used to evaluate agreement, was calculated for each lesion category for the 10 endosonographers as a group and individually. An overall kappa statistic was also calculated. Significance was analyzed with a two-tailed t test.

RESULTS

Agreement was excellent for cystic lesions (kappa = 0.80) and extrinsic compressions (kappa = 0.94), good for lipoma (kappa = 0.65), fair for leiomyoma and vascular lesions (kappa = 0.53 and 0.54, respectively), and poor for other submucosal lesions (kappa = 0.34). Overall agreement among observers was good (kappa = 0.63). Furthermore, a significant association was noted between total years of EUS experience and the number of correct answers (p = 0.01).

CONCLUSIONS

Interobserver agreement is good for characterizing submucosal masses by EUS. However, it appears to be better for some lesions than others. The overall length of experience with EUS appears to play an important role in the accuracy of this modality in the evaluation of submucosal lesions.

Endosonographic differentiation of benign and malignant stromal cell tumors

BACKGROUND

Endosonography (EUS) is a valuable technique for diagnosing gastrointestinal stromal cell tumors. However, EUS features that are predictive of malignancy in these tumors have not been defined.

METHODS

Videotapes and photographs of EUS examinations performed prior to surgical resection of 35 stromal cell tumors (9 malignant) were blindly reviewed by a single examiner. EUS features associated with malignancy were determined. Interobserver agreement in interpreting these features was then measured among a panel of five expert endosonographers who judged EUS videotapes of 35 resected stromal cell tumors (10 malignant).

RESULTS

Stepwise logistic regression analysis demonstrated that tumor size (diameter > 4 cm), irregular extraluminal border, echogenic foci, and cystic spaces were independently associated with malignancy in stromal cell tumors (p < 0.05). Interobserver agreement for irregular extraluminal border, echogenic foci, and cystic spaces, as measured by mean kappa statistic, was 0.43, 0.39, and 0.28, respectively. For the five experts, the sensitivity for detecting malignancy ranged between 80% to 100% when at least two of the three features were judged to be present. The likelihood of finding malignancy ranged between 0% to 11% for the experts when all three features were judged absent.

CONCLUSIONS

Tumor size and certain EUS features are useful for predicting malignancy in stromal cell tumors. Absence of these features indicates benign disease. Agreement among experts in interpreting these EUS features is fair to moderate.