173: Endoscopic Resection Techniques

Endoscopic resection (ER) of early neoplastic lesions in the gastrointestinal tract has become increasingly important in recent years, both as a diagnostic tool and as a method of performing definitive treatment when the cancer meets certain criteria in which the risk of lymph node metastasis is negligible.¹

Adenocarcinoma in Barrett Esophagus

The indications for ER in esophageal adenocarcinoma are high-grade intraepithelial neoplasia (HGIN) and mucosal cancer. Risk stratification should be carried out in accordance with known risk factors such as grade of differentiation, lymphatic or venous infiltration, and the infiltration depth of the carcinoma. The limitations of ER in early Barrett cancers should be submucosal infiltration or infiltration of the lamina muscularis mucosa in combination with another risk factor, such as poor tumor differentiation or lymphatic and venous infiltration. The largest series ever published on endoscopic treatment of early Barrett neoplasia showed a long-term complete response in 94.5% of patients. Long-term survival of patients treated for Barrett neoplasia in this series did not significantly differ from that of the normal German population with the same age and gender distribution.²

Squamous Cell Carcinoma of the Esophagus

In esophageal squamous cell neoplasia (SCN), ER should only be carried out if the carcinoma is limited to the mucosal layer as has been shown in several publications.^3,4

Accurate staging is mandatory before endoscopic treatment of early esophageal cancer. The most important part of the staging procedure entails careful evaluation of the neoplasia and the borders of the lesion using a high-resolution endoscope, and a thorough search for multifocal neoplasia. In addition, the macroscopic type of the lesion should be determined, as it has been shown to have significant correlation with infiltration depth.^5,6 Conventional endoscopic ultrasound (EUS) and EUS with miniprobes (20 or 30 MHz) can be carried out to evaluate the depth of infiltration and the lymph node status of the tumor. However, the accuracy of T staging is limited, particularly for distinguishing between the important stages of T1 m and T1 sm. The diagnostic accuracy of submucosal cancer ranges from 33% to 85%.^7–11 Underdiagnosis by EUS has been shown in 12.5% to 67% of cases.^7,8 In contrast, EUS is highly accurate in differentiating T1 and T2 tumors.⁹

“ER” is the general term for the different resection techniques used to treat neoplastic and uncertain lesions in the gastrointestinal tract. The term “endoscopic mucosal resection” is widely used; however, it is misleading because significant proportions of the submucosal layer are also resected, which is important in the case of submucosal infiltration of the tumor.

Endoscopic Resection with a Ligation Device

A common method is ER with a ligation device, also used for ligation of esophageal varices. With this method, the target lesion (Fig. 173-1A) is sucked into the cylinder of the ligation device (Fig. 173-1B) and a rubber band is then released to create a pseudopolyp that has the rubber band at its base (Fig. 173-1C). After this, the pseudopolyp is resected with a reusable snare underneath the rubber band to achieve larger resection specimens (Fig. 173-1D).

Several ligation devices are available: single-use devices, multiple usable ligators or ligation devices with multiple rubber bands. Another useful development is a ligation cylinder that has six rubber bands and a facility for advancing a snare through the working channel of a regular endoscope. This enables the endoscopist to perform up to six resections without the necessity of withdrawing and reintroducing the endoscope. This device is widely used for piecemeal resection of larger neoplastic lesions.

Endoscopic Resection with a Transparent Cap

The cap technique was introduced by Inoue and Endo¹² almost 20 years ago. When ER is performed with the cap technique, a specially developed transparent plastic cap is attached to the end of the endoscope. After submucosal injection under the target lesion, usually with a saline-epinephrine solution, the lesion is sucked into the cap and resected with a diathermy snare that has previously been loaded onto a specially designed groove on the lower edge of the cap. Marking the borders of the lesion either with electrocautery using the tip of the snare or an APC probe is recommended before performing the resection, because injecting underneath a discrete neoplastic lesion often makes it difficult to identify the borders of the target lesion afterward.

Ulcerated lesions often have fibrosis, which attaches the submucosa to the lamina muscularis propria, resulting in failure of the lesion to lift as is frequently found in tumors with submucosal infiltration. In these cases, ER is not advisable, or should only be performed with caution. Larger lesions can usually be resected completely with the piecemeal technique, but this method seems to be associated with a higher recurrence rate.

Endoscopic Submucosal Dissection

The endoscopic submucosal dissection (ESD) procedure in the treatment of early gastric cancer was first described by Hosokawa and Yoshida¹³ and Ono et al.¹⁴ They used an insulated-tip knife to obtain a large resection specimen with the neoplasm resected en bloc (Fig. 173-2E). Once the borders of the neoplastic lesion have been adequately visualized, the borders are marked with electrocautery at a distance of 5 to 10 mm from the margin of the carcinoma (Fig. 173-2A). Then submucosal injection of fluid is performed to elevate the lesion from the muscular layer, and the mucosa surrounding the lesion is circumferentially cut outside the markings. Finally, the submucosal connective tissue is dissected with a dedicated knife (Fig. 173-2B). Visible vessels can be coagulated with the top of the knife or a coagulation forceps to prevent bleeding (Fig. 173-2C and D). The fluid used for submucosal injection could be isotonic saline solution or a solution of hyaluronic acid with additives including a dye, such as indigocarmine; a composition defined by the individual endoscopist. A wide variety of different knives are used for ESD, including the insulated-tip knife, Hook knife, flex knife, needle knife, triangle-tip knife, flush knife, and hybrid knife. With the flush and hybrid knife, submucosal injection and dissection can be performed at the same time without changing the instruments. The size of the resected specimen obtained with ESD can extend up to more than 10 cm in diameter. Because of the high complication rate in inexperienced endoscopists, practice with ESD models is highly recommended to become familiar with this technique. Afterward, ESD procedures should be carried out in the stomach, then in the rectum, before this method is used for esophageal lesions. ESD is a demanding, time-consuming technique with a flat learning curve.

A prospective randomized trial with 100 consecutive ERs in 70 patients comparing ER performed with a ligation device versus ER with a cap was able to demonstrate that there is no difference in the complication rate.¹⁵ One minor bleeding incident occurred in each group, but no severe complications were seen.

Another randomized study from the Amsterdam group, performing esophageal piecemeal resection in 84 patients, showed a comparable complication rate between ER with a multiband ligator and cap resection, with four perforations.¹⁶ A recently published European multicenter study has shown that ESD is associated with a substantial complication rate, including perforations that require surgery and bleeding.

For many years, surgery was considered to be the treatment of choice for early neoplastic lesions of the esophagus. Surgery, however, is associated with a 30-day mortality of 1% to 5% and significant morbidity in 30% to 50% of cases, even in high-volume centers.

Because of these data, local treatment methods have been introduced and investigated in several studies. ER with a ligation device or using the cap technique has been proved to be safe. However, ESD should be strictly limited to experienced endoscopists who are familiar with this method. In contrast to ablative treatment methods, such as photodynamic therapy, argon plasma coagulation, cryotherapy, and radiofrequency ablation, ER, regardless of the resection technique used, allows histologic assessment of the resected specimen to assess the depth of infiltration of the tumor and determine whether lymphatic infiltration (L-status) or blood vessel involvement (V-status) is present. These significant advantages of ER are the main reason why ER, regardless of type, should be preferred over all ablative treatment methods.

It is clear that the popularity of ER will continue to grow in the future. Therefore, it is important that all esophageal surgeons read this practical discussion of the several approaches to ER, so as to understand both the risks and benefits of this technology.