Presurgical GI Evaluation in Bariatric Surgery

Fig. 4.1

(a) Fundic gland polyps. (b) Fundic gland polyps on narrow band imaging (NBI); they do not appear to have a bluish cap that most adenomas do

Hyperplastic polyps are usually associated with chronic inflammation such as H. pylori infection, and while small ones are smooth, larger ones can be lobulated, present mostly in the antrum or body. Biopsies should be taken, and even though dysplasia is rare—present in less than 2%—it may be present in larger polyps, especially those greater than 2 cm in size [17]. Most regress after removing the inflammatory focus, such as via H. pylori treatment. When a hyperplastic polyp is found, even without dysplasia, some experts recommend gastric mapping with topographically defined biopsy specimens, as there can be dysplasia or intestinal metaplasia present in the surrounding gastric epithelium [17, 18]. If this is found, then the patient is considered at risk for gastric cancer, and resectional gastric bypass, sleeve gastrectomy, or band is preferred.

Adenomatous polyps can be present sporadically or in patients with FAP. They are solitary more than 80% of the time, present mostly in the antrum, and can be lobulated, pedunculated, or sessile [17]. They usually arise in the context of atrophic gastritis and intestinal metaplasia [18]. While they are much more common in some eastern countries with higher rates of gastric cancer, they have only been found in 0.5–3.75% of patients in the western world [17]. As with all polyps, size matters; larger polyps, especially those greater than 2 cm, have a focus of adenocarcinoma in up to 50%. Up to 30% of patients may have a synchronous cancer in another area of the stomach as well [17]. Gastric mapping with multiple biopsies are warranted here as well. Since they portend an increased risk of cancer, not just in the polyp but also in the rest of the stomach, the surgeon must avoid leaving a remnant that is inaccessible in the future. If gastric bypass is considered in a setting of a large adenomatous polyp, the gastric remnant may be best treated with a resection.

Inflammatory polyps are benign and usually do not recur after resection, so they usually do not alter bariatric surgical management. Polyposis syndromes such as FAP, Peutz–Jeghers, and juvenile polyposis are rare and have variable risk of cancer throughout the gastrointestinal (GI) system; thus, any exclusion of the GI tract that precludes surveillance should be avoided.

Other lesions that can appear polypoidal, such as Gastrointestinal stromal tumors (GISTs) and carcinoids, are discussed below. Xanthomas and pancreatic heterotopia can also look polypoidal but do not usually alter management.

Duodenal Polyps

Polypoidal lesions in the duodenum can occur in up to 5% of patients undergoing an upper GI endoscopy [19]. Most polypoidal lesions of the duodenum are not true epithelial polyps but comprised of Brunner gland hyperplasia (BGH), ectopic pancreatic or gastric tissue, inflammatory polyps, and submucosal lesions or tumors.

BGH can form up to 30% of all duodenal polypoidal lesions [19]. They can ulcerate and bleed and if larger, pedunculated or ulcerated, should be endoscopically removed. This may delay surgery but usually does not alter surgical plans. Ectopic tissue and inflammatory polyps are treated similar to those found in the stomach: with biopsy but no change in bariatric plans.

Duodenal adenomas can occur in 0.4% of upper endoscopies—see Fig. 4.2a, b [19]. Sporadic adenomas are usually solitary and are mostly amenable to endoscopic therapy. However, they need follow-up and surveillance, so any bariatric surgeries that exclude the duodenum, such as gastric bypass and duodenal switch, are contraindicated.

Fig. 4.2

(a) Duodenal polyp and adenoma. (b) Duodenal polyp on narrow band imaging (NBI) with a bluish cap indicating adenomatous change

Gastrointestinal Stromal Tumors

GIST are probably more common than previously thought. Most of the patients are asymptomatic until the tumor grows to be large. Sanchez et al. reviewed 517 patients who underwent an RYGB, of which 0.8% were noted to have GISTs [20]. These were all small and resected with 1 cm margins, after which the gastric bypasses were completed. This has been described with sleeve gastrectomies as well [21]. Finding lesions suspicious for GIST on endoscopy such as submucosal masses would delay bariatric surgery until the work-up is completed, after which one can proceed to simultaneous bariatric surgery and resection of the GIST. However, the location may alter choices, as a large GIST on the lesser curvature of the stomach may make a sleeve gastrectomy difficult or not feasible and an alternate option, such as a resectional gastric bypass, may have to be chosen.

Carcinoid

Gastric carcinoids are found in less than 2% of gastric polypoid lesions [17]. The chance of spread and metastasis is usually low in most gastric carcinoids associated with chronic autoimmune atrophic gastritis or ZES/MEN type I, and is higher in sporadic carcinoids, although only around 20% are sporadic. Sporadic carcinoids usually require surgical resection and thus could be incorporated in a resectional bariatric procedure such as a sleeve gastrectomy or a resectional gastric bypass. However, the majority of non-sporadic gastric carcinoids are small and can be multiple, requiring surveillance after resection. They can thus be a relative contraindication for bariatric surgery, especially procedures that lead to exclusion of the GI tract.

Cancer Risk and Gastric Bypass

High BMI has been found to be a risk factor for multiple malignancies, including upper GI tract cancers [22]. Preoperative endoscopy may help detect some premalignant or malignant lesions; however, not all bariatric patients get preoperative endoscopy. Hundreds of thousands of gastric bypasses have been performed across the world, yet the reports of cancer either in the pouch or in the excluded remnant have been exceedingly rare. According to a recent publication, only two cases of cancer in the pouch have been reported so far. After a gastric bypass, the distal stomach is excluded and has constant exposure to pancreaticobiliary reflux [22]. Biopsies from the distal stomach 3–24 months after bypass have shown intestinal dysplasia. Reports of remnant cancer appearing soon after a gastric bypass due to a missed tumor are also very rare. Five cases have been reported, occurring 4–22 years later [22]. The patient who developed cancer 4 years after the bypass had intestinal metaplasia and H. pylori on preoperative endoscopy and was treated for H. pylori, although the remnant was not resected at the time of the bypass.

Group IV: Contraindication to Bariatric Surgery

Barrett’s with High-Grade Dysplasia

This would be considered a relative contraindication to bariatric surgery. The treatment of high-grade dysplasia in Barrett’s is controversial. The majority of surgeons advocate an esophagectomy in good-risk patients. However, increasingly, patients are being treated with local therapies and strict surveillance after ablation, endoscopic mucosal resection (EMR), and endoscopic submucosal dissection (ESD)—outside of the United States. As mentioned above about Barrett’s, RYGB is a very good operation to prevent acid and bile reflux, and small series show its efficacy in Barrett’s [12, 13]. Therefore, as some of these local therapies develop and advance, and as data becomes available about their safety (especially oncological safety), they may become an option after initial local therapy.

Upper GI Cancer

The finding of any malignancy, esophageal, gastric, duodenal, or pancreatic, in the upper gastrointestinal system is considered a contraindication to bariatric surgery. This is rare in patients being considered for bariatric surgery and in the various series published about preoperative endoscopy in bariatric patients, has been reported in less than 0.2% of patients [1, 7]. As most of these cancers cause great weight loss, either from the tumor itself, its associated surgery, or adjuvant therapy, bariatric surgery is not an option. Even if a small intramucosal carcinoma is found in the stomach on a random biopsy, further work-up, surveillance, and possible surgery directed toward the lesion is necessary. If a small intramucosal focus is found in an adenomatous polyp, then surveillance biopsies of the rest of the stomach (see section on gastric polyps) should be performed. If no further foci are found, then one could consider procedures that would either maintain access to the remaining stomach, such as a sleeve gastrectomy, or resect the gastric remnant, such as in a resectional gastric bypass. Alternatively, an adjustable gastric band could be an option. Any bariatric surgery in such patients will require a multidisciplinary approach, with involvement of teams from surgery, oncology, gastroenterology, etc., as well as the involvement of the patient and their family.

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