From the Journals

AGA Clinical Practice Update on the utility of endoscopic submucosal dissection in T1b esophageal cancer: Expert review



Endoscopic submucosal dissection (ESD) is a viable treatment option for patients with submucosal (T1b) esophageal cancer who have a low risk of lymph node metastasis, according to an expert review.

Among patients with T1b esophageal cancer, ideal candidates for ESD have small (less than 2 cm), well-differentiated tumors that do not invade beyond the superficial submucosa (SM1) and lack lymphovascular invasion, reported lead author Mohamed O. Othman, MD, of Baylor College of Medicine in Houston, and colleagues. The literature review was recently commissioned by the American Gastroenterological Association (AGA), because of high clinical relevance.

“[ESD] has been gaining momentum as an alternative to surgery in treating early gastrointestinal neoplasms,” the investigators wrote in Clinical Gastroenterology and Hepatology.

Most patients who undergo surgical resection develop gastroesophageal reflux, the investigators noted, and many others develop serious complications or do not survive the procedure.

“Even a high-volume center such as Mayo Clinic reported a surgical mortality of 4% for T1a esophageal cancer,” the investigators wrote. “Moreover, 34% of patients developed postoperative complications such as anastomotic leaks, anastomotic strictures, cardiopulmonary complications, and feeding jejunostomy leaks. ... Therefore, a less-invasive alternative to esophagectomy would be extremely valuable in the management of early stage [esophageal cancer] if proven effective.”

The investigators reviewed studies evaluating safety and efficacy of surgical and endoscopic techniques, as well as available data for chemoradiation and radiofrequency ablation combinations, which could potentially optimize outcomes of endoscopic resection.

They concluded that most patients with esophageal cancer that does not extend beyond the mucosa (T1a) can be cured with endoscopic resection, based on 5-year survival rates from several Japanese trials. For patients with T1b disease, however, ESD is best suited for those with a low risk of lymph node metastasis. Unfortunately, identifying these candidates can be challenging, according to the investigators.

“The risk of lymph node metastasis depends on the depth of invasion, histologic type, and molecular characterization of the tumor,” the investigators explained, noting that depth of invasion is the trickiest to discern. Although endoscopic ultrasound (EUS) is still recommended for submucosal imaging, the review showed that EUS may overstage cancer in Barrett’s esophagus. The investigators suggested that volume laser endoscopy with infrared light could be a more accurate alternative, but it is not yet a clinical reality.

The review also showed potential for combining ESD with other modalities. For example, a study by Hamada and colleagues involving 66 patients with submucosal (T1b) esophageal squamous cell carcinoma found that a combination of ESD with chemoradiation led to similar 3- and 5-year survival rates as radical esophagectomy. The investigators highlighted the importance of lymph node metastasis in this study, as none of the 30 patients lacking lymph node involvement had metastatic recurrence, compared with 6 of the 36 patients who exhibited lymph node metastasis. According to the investigators, promising data are also anticipated for this combination among those with adenocarcinoma. And for patients with intestinal metaplasia and/or dysplasia, adding radiofrequency ablation after ESD appears to be an effective option; one recent study by Sharmila Subramaniam, BMBS, and colleagues found that this strategy led to clearance rates of 85% and 96% for metaplasia and dysplasia, respectively.

“Additional treatment should be determined by factors such as tumor grade, status of lymphovascular invasion, and depth of tumor, which have a direct influence on metastatic potential,” the investigators wrote.

The investigators suggested that, in the future, better diagnostics will be needed to characterize T1b disease, as this could streamline patient selection. “Future research should focus on novel biological and immunohistochemistry markers that can aid in the prediction of tumor behavior and [lymph node metastasis] in T1b esophageal cancer,” they concluded.

The study was commissioned by the American Gastroenterological Association. The investigators disclosed additional relationships with Boston Scientific, Olympus, Lumendi, and others.

SOURCE: Othman MO et al. CGH. 2019 Jun 4. doi: 10.1016/j.cgh.2019.05.045.

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