Confocal laser endomicroscopy and ultrasound endoscopy during the same endoscopic session for diagnosis and staging of gastric neoplastic lesions

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Confocal laser endomicroscopy and ultrasound endoscopy during the same endoscopic session for diagnosis and staging of gastric neoplastic lesions

C. Gheorghe, R. Iacob, G. Becheanu, M. Ionescu, Mona Dumbrava
Original article, no. 1, 2009
* UMPh Carol Davila, Fundeni Clinical Institute, Bucharest
* UMPh Carol Davila, Fundeni Clinical Institute, Bucharest
* Fundeni Clinical Institute, Bucharest


Introduction
Currently the diagnosis for gastrointestinal lesions is based on histopathological analysis of biopsy specimens taken during endoscopic procedures. There is usually a delay between the biopsy is taken and the pathological results become available allowing the physician to decide on the therapeutic strategy. Sometimes, the Pathology Department is loaded with unnecessary biopsy specimens, which do not contribute to the diagnosis. The term of “targeted biopsy” has become available in the recent years by the availability of new endoscopic techniques, which allow the prelevation of the optimal “optical biopsy”, which means that a histopathological image can be captured during ongoing endoscopy and used for in vivo histopathological analysis by the pathologist or for guiding the endoscopist to take the optimal biopsy specimen in a targeted fashion (2). Ultrasound endoscopy (EUS) is an useful technique for staging of malignant GI lesions (3). In case of neoplastic lesions, one important issue is to provide the pathologist with the best biopsy specimen which will lead to the histopathological diagnosis and also to accuratelly stage the lesion in order to select the best therapeutic approach according to current guideliness.
In the present paper we present the results of a pilot study in which we have performed CLE and EUS during the same endoscopic session for in vivo diagnosis and staging of gastric neoplastic lesions. In the future, the availability of new endoscopic techniques will lead to the optimization of workflow in the Endoscopy Unit, decreasing the time to final diagnosis and therapeutic decision.

Materials and methods
Eleven patients have been investigated, 4 females, 7 males, mean age 59.7±12.3 years.
CLE has been performed with the Pentax® EG-3870CIK confocal endomicroscope. After endoscopic examination, the confocal endomicroscope is placed in gentle contact with the lesion, using the blue LASER guide. After a 5 ml 10% fluorescein intravenous injection, the LASER beam of 488 nm and a maximum power of 1 mW excites the contrast agent and performs a “point-by-point” scanning of a focal plane, parallel with the surface of the mucosa. While exerting constant sucction in order to stabilize the lesion and reduce the movement artifacts, the confocal images have been captured and analysed in vivo by the pathologist in order to suggest the histopathological diagnosis and to guide the targeted biopsies. The confocal endomicroscopy images were captured with a scanning rate of 0.8 frames/sec (1024x512 pixeli) or 1.6 frames/sec (1024x1024 pixeli). The magnification factor is 1000x. The optical slices thickness is 7 µm and the field of view 475x475 µm for each confocal endomicroscopy image. The focal plane can be positioned as needed, using the control unit, from the surface of the mucosa up to a depth of 250 µm, with a step of 4 µm. Subsequently, the staging of the lesion was performed by EUS using a radial echo-endoscope.

Results
The indication of CLE/EUS exploration was gastric polypoid lesion in 4 cases, atypical gastric ulcer in 3 of patients, suspected gastric lymphoma in 2 cases, suspected gastric cancer recurrence after resection in one case and infiltrating type gastric lesion in one case.
The confocal endomicroscopy images are black and white images in which cellular structures, microvasculature architecture and intercellular spaces are easily distinguishable. The use of intravenous fluorescein allows a better visualization of the microvasculature aspect but does not permit the visualization of cells nuclei. In vivo histological assessment in our patients was confirmed by targeted biopsy and established the diagnosis of gastric adenocarcinoma in 5 cases, gastric lymphoma in 3 cases, gastric adenoma, gastric GIST and gastric foveolar hyperplasia in one case, respectively. Normal endomicroscopic appearance of the stomach is different according to the anatomical region analyzed. At the level of the antrum, regular gastric pits can be seen as well as coil-shaped vessels (Fig. 1). At the level of the corpus and fundus the gastric pits have a round apearance and the vascular pattern is regular, honeycoombed (Fig. 2 a,b).
Figure 1
Figure 2A
Figure 2B

The gastric adenocarcinoma presents with a complete derrangement of glandular and vascular architecture that can be easily recognized on confocal endomicroscopy images; there are dark athypical cells and aberant blood vessels (Fig. 3 a,b,c,d,e). Usually the regular glandular pattern is disrupted and marked fluorescein leak can be seen on superficial as well as sub-superficial images. EUS can establish the depth of wall infiltration (Fig. 3f), the present of malignant adenopathies and the present of ascites, which can be an indirect sign of peritoneal carcinomatosis.

Figure 3A
Figure 3B
Figure 3C
Figure 3D
Figure 3E
Figure 3F

Gastric lymphoma can be suggested by the identification of dark athypical lymphocites which infiltrate the mucosa leading to the increased spacing of gastric glands (Fig. 4 a,b). Sometimes the normal appearing superficial mucosa can suggest deeper infiltration with malignant lymphocites which can be confirmed by EUS (Fig. 5).
In case of small polypoid lesions, CLE/EUS could distinguish between early gastric cancer, adenomatous polyps and hyperplastic polyps. The adenomatous polyps have a vilous appearance, with dark but well individualized epithelial structures and regular blood vessels in the chorion (Fig. 6) The hyperplastic polyps have a stelate appearance of the gastric glandular epithelium also presenting normal micro-vasculature (Fig. 7). In our study CLE has allowed targeted biopsies in 81.8% of cases. In 3 patients, one with suspected recurrent gastric cancer after surgery, one case of gastric lymphoma, and one patient with a gastric GIST CLE has indicated normal appearance of gastric mucosa (Fig. 8). The EUS has provided aditional informations concerning the examined lesion which has permitted the final diagnosis.

Figure 4A
Figure 4B
Figure 5
Figure 6

Overall, the EUS evaluation has shown T0 lesion in two cases, T1 in 2 cases, T2 in 3 cases, T3 in one case (Table 1). The EUS evaluation showed in one gastric lymphoma patient a lesion interesting the mucosa and submucosa with regional adenopathy and a submucosal lesion with regional adenopathy in the other gastric lymphoma case. In one patint the endomicroscopic analysis of a gastric 2 cm polipoid lesion showed normal superficial mucosal appearance. Subsequently the EUS identified a hypoechoic lesion sugesting gastric GIST.
The therapeutic decision was surgical indication in 73% of cases, chemotherapy and follow-up in 18% of cases and follow-up in 9% of cases.
No complications were registered during the CLE/EUS explorations. For every patient the slight yellowish coloration of the skin and the yellow coloration of the urine were noted 12-18 hours after the examination due to the systemical use of fluorescein.

Figure 7
Figure 8A
Figure 8B

Discussions
Gastric cancer is one of the most common causes of cancer mortality worldwide. Overall, it has the third highest annual cancer incidence worldwide, behind only lung and breast cancer (4). Endoscopy with multiple biopsies is the diagnostic procedure of choice for gastric neoplastic lesions. The sensitivity and specificity of upper endoscopy for the diagnosis of gastric cancer is greater than 90 percent in most series. The site and number of biopsy specimens is important. Any suspicious-appearing gastric ulcer should be biopsied. A single biopsy has a 70 percent sensitivity for diagnosing gastric cancer, and performing seven biopsies from the ulcer margin and base increases the sensitivity to greater than 98 percent (5). On endoscopy, early gastric cancers may appear as a subtle polypoid protrusion, superficial plaque, mucosal discoloration, depression, or ulceration (6).The newly developed technique of CLE provides a convenient method of differentiating malignant from benign lesions because CLE has the ability to observe the surface and subsurface architecture of the gastrointestinal tract at the cellular level during standard white light endoscopy (7, 8).
The purpose of the preoperative evaluation is to initially stratify patients into two clinical groups: those with locoregional (stage I to III) disease, and those with systemic (stage IV) involvement. The staging system of the AJCC /UICC is based on tumor (T), node (N), and metastasis (M) classifications (9).T stage is dependent on depth of tumor invasion and not size. Nodal stage is based upon the number of positive lymph nodes rather than the proximity of the nodes to the primary tumor (as in the TNM classifications used prior to 1997). Patients who have no obvious visceral metastases but who have 16 or more pathologically involved nodes are classified as having stage IV disease, which accurately reflects the poor prognosis of these patients.
EUS is thought to be the most reliable nonsurgical method available for evaluating the depth of invasion of primary gastric cancers, particularly for early (T1) lesions (10). The accuracy of EUS for differentiation of individual tumor stages (T1 to T4) ranges from 77 to 93 percent (11-13), with the experience of the operator markedly influencing these rates. In comparative studies, EUS generally provides a more accurate prediction of T stage than does CT (14-16), although newer CT techniques (such as three-dimensional multidetector row CT) are challenging this viewpoint (17). In contrast, accuracy for nodal staging (65 to 90 percent) is only slightly greater with EUS as compared to CT (18). EUS-guided fine needle aspiration of suspicious nodes and regional areas adds to the accuracy of nodal staging (19). Most errors in staging with EUS are due to understaging nodal involvement and the depth of primary tumor invasion; however, overstaging can also occur that is attributed to inflammation around the tumor or in lymph nodes (18). Distinguishing T2 from T3 lesions is especially difficult because of this problem.
EUS is a relatively low-risk procedure, although it is more invasive than CT. One review quoted a risk of serious complications of 0.3 percent (20). Whether EUS should be included as a component of the pretreatment staging evaluation for all patients with gastric cancer is unclear. The routine use of staging EUS can sometimes alter the therapeutic plan, most often because of the finding of distant metastases (eg, left lobe hepatic lesions, ascites) (21). However, due to the limited field of vision with the echo-endoscope, the utility of EGD as a screen for metastatic disease is questionable. We conclude that CLE and EUS can be successfully associated during the same endoscopic session, for upper GI neoplastic lesions, allowing targeted biopsies for histological assessment and disease staging for optimal therapeutic decision (22).

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