Biliary Metal Stent Insertion: Indications and Insertion Techniques

SEMS for Malignant Biliary Stricture

The most common causes of malignant biliary obstruction are pancreatic adenocarcinoma, cholangiocarcinoma, ampullary carcinoma, gallbladder cancer, and extrinsic compression associated with lymphadenopathy caused by lymphoma or metastatic carcinoma. Without therapy, the mean survival for patients presenting with malignant biliary obstruction is <200 days. Because most patients have advanced disease at the time of presentation, operative resection with curative intent is possible in only 10% to 15% of cases. Therefore palliation of mechanical obstruction plays a major role in the management of patients with pancreaticobiliary malignancies ( Box 23.1 ). Options for palliation of malignant biliary obstruction include operative bypass, percutaneous drainage, and endoscopic stent placement. For the vast majority of patients with malignant biliary obstruction, endoscopic stent placement is preferred over operative bypass and percutaneous drainage on the basis of expediency, patient comfort, adverse events, and cost.

SEMS Versus PS

Both PS and uSEMS/pcSEMS can be used for palliation of malignant biliary obstruction. PS, discussed in detail in Chapter 22 , are safe and effective, are less expensive than SEMS, and can be removed and replaced if occlusion occurs—usually presenting with a recurrence of jaundice and/or ascending cholangitis. SEMS were designed with a larger internal diameter to extend the duration of patency, thereby reducing the frequency of reintervention. As such, their increased initial cost appears to be offset by a reduction in episodes of cholangitis and the need for elective and emergency interventions. In a meta-analysis of 2436 patients with distal malignant biliary obstruction, SEMS were comparable to PS in technical and therapeutic success rates, mortality, and overall adverse events and were associated with lower rates of obstruction at 4 months. The multicenter US Wallstent study randomized patients to uSEMS or 10-Fr PS for palliation of malignant distal bile duct obstruction. Early stent occlusion as a result of sludge accumulation occurred in ~3% in the PS group compared with 0% in the uSEMS group. During long-term follow-up, uSEMS were associated with one-third the risk of stent occlusion, a significantly reduced adverse event rate (20% vs 31%), and significantly fewer procedures. Numerous subsequent trials, including a recent multicenter randomized trial from the Netherlands, have similarly confirmed a significantly longer duration of patency, fewer hospital stays, and similar costs after 1 year with SEMS in comparison to PS. In fact, Walter et al. found that even in patients with short survival times (<3 months) the total cost per patient was not significantly different between SEMS and PS.

Covered Versus Uncovered SEMS for Malignant Biliary Obstruction

uSEMS are associated with lower rates of stent migration and can be used anywhere in the bile duct, including the hilum. However, tumor ingrowth and lack of removability are limitations of uSEMS. pc/fcSEMS share the same indications as their uncovered counterparts, though they are not advocated for hilar or intrahepatic obstruction because they may block the contralateral intrahepatic system or ipsilateral intrahepatic branches. Similarly, in patients with an intact gallbladder, uSEMS are often preferred when it is anticipated that the stent will cross the cystic duct takeoff; if an fcSEMS is used, it may result in cholecystitis. The anticipated advantage of pc/fcSEMS is the prevention of tissue ingrowth (malignant or hyperplastic) and subsequent stent occlusion while allowing for potential removability (although all but one SEMS are approved by the FDA for only immediate and not delayed removal). However, pc/fcSEMS are considerably more expensive than their uncovered counterparts. Although there are more published data on the use of uncovered stents, there is a substantial body of literature advocating the use of pcSEMS for palliation of malignant biliary obstruction. Studies of pcSEMS have demonstrated very low rates of stent occlusion because of tumor ingrowth. However, concerns have been raised about higher rates of stent migration and stent-induced cholecystitis and pancreatitis from cystic duct obstruction and pancreatic duct obstruction, respectively. Although an earlier meta-analysis of five randomized controlled trials with 781 patients showed that the use of pcSEMS compared with uSEMS was associated with significantly longer stent patency and time to reocclusion, a more recent meta-analysis demonstrated no differences in the number of recurrent biliary obstructions or stent patency after 6 or 12 months. Similarly, a large, single-center retrospective study of 749 patients (171 pcSEMS and 578 uSEMS) demonstrated no difference in recurrent obstruction at 1 year (35% vs 38%), overall or median survival, median time to recurrent biliary obstruction, or rate of adverse events. Of note, however, covered stents may be particularly well suited for recanalization and preservation of occluded indwelling uSEMS. Because many patients with pancreaticobiliary malignancies are experiencing longer, multiyear survival—owing to advances in oncologic therapies such as immunotherapy—enhancing durable endoscopic palliation of biliary obstruction is a welcome challenge.

Preoperative Use of SEMS in Malignant Biliary Disease

When initially introduced into the marketplace, SEMS placement was limited to patients with confirmed, nonoperable, malignant biliary obstruction. However, there has been an evolution in the use of SEMS preoperatively, especially when used for neoadjuvant therapy. Still, in many centers a PS is placed for initial management of suspected but non–biopsy proven malignant biliary obstruction; placement of a SEMS is deferred until occlusion of the initially placed PS, performance status suggesting a greater than 3-month survival, confirmed tissue diagnosis, and/or completed staging to confirm nonoperability. However, recent data suggest a broader application for the up-front use of SEMS. Indeed there are emerging data examining the use of fcSEMS in the palliation of malignant biliary obstruction that may support their use up front in patients with a high clinical suspicion of malignant biliary obstruction when a tissue diagnosis is uncertain (because covered SEMS are removable). However, further studies are needed before recommending the routine use of covered SEMS in this setting.

Concerns about the use of routine preoperative placement of PS for biliary decompression for distal biliary obstruction before pancreatectomy have been raised, particularly after a multicenter study demonstrated a significant increase in the complication rate in patients who underwent routine preoperative biliary drainage. It should be noted that successful initial cannulation failure rates in this study were high (25%), as were post–endoscopic retrograde cholangiopancreatography (ERCP)-related adverse events (46%). Furthermore, only PS were used in the study and many patients (26%) developed occlusion-related cholangitis; this may be ameliorated with the up-front use of SEMS. Preoperative biliary drainage may alleviate jaundice and cholestasis-associated adverse events and allow time for delivery of neoadjuvant chemoradiation. Indeed, as multiple therapeutic options for neoadjuvant therapy have evolved for pancreaticobiliary malignancy, meta-analyses have shown that more than one-third of borderline resectable patients can be effectively downstaged to achieve surgical resection. Although concerns were raised about SEMS complicating operative resection, this has not been borne out in clinical practice. Several series have detailed the utility of preoperative drainage with SEMS in patients with resectable pancreatic adenocarcinoma. Thus far, these series have consistently reported that preoperative SEMS placement does not impose surgical technical difficulties or influence postoperative course or long-term outcome. Studies have also indicated that for preoperative indications, SEMS require fewer endoscopic interventions than PS. A Monte Carlo decision analysis that compared several preoperative strategies in patients with resectable distal pancreaticobiliary cancer concluded that placement of short-length uncovered biliary SEMS provided equal or superior efficacy and reduced overall cost compared with PS placement. Although these published series are neither prospective in nature nor randomized, there is sufficient evidence to support the selective placement of SEMS before anticipated operative resection when considered on an individual basis. Either short-length (4 to 6 cm) uncovered or fully covered SEMS that do not involve the bifurcation are recommended.