In this cohort, most patients requiring a bile duct stent placement presented with either pancreatic or biliary tract neoplasms. Complications developed frequently, in thirty-eight percent of patients, most of which were infectious. Our data is in agreement with the results reported by Lamarca et al,10 in which 43% of the patients developed a complication, in their study infectious complications were the most frequent as well. Regarding the time from procedure to development of complications, our results differ from those of Lamarca et al, in which complications developed 4 months after the stent placement. 10 A possible explanation could be related to the performance status previous to the procedure in our cohort, in which ECOG PS was ≥ 2 for 70% of patients, whereas only 29% in the study by Lamarca.
Overall, the most frequent complication in our study, as in another reported10 was infection, most commonly caused by gram-negative rods. In agreement with other series10, cholangiocarcinoma had a higher rate of complications related to the stent. The majority of infectious complications were diagnosed based on radiological observation; microbiologic confirmation was obtained in 41% of the patients with diagnosis of infection. Most of the patients who developed an infectious complication were not receiving oncological treatment, therefore we hypothesize that infections could be related to, or as a consequence of a progressive disease, creating a suitable environment for microbiological pathogens growth.
Antibiotic prophylaxis was not associated with the development of infections, a possible explanation to this regard is that many patients were being treated for another concurrent infection, frequently cholangitis, prior to the stent placement. Furthermore, most infectious complications develop within a month after the procedure, at a moment where antibiotic prophylaxis is no longer effective.
In our study, the median overall survival was 20.3 weeks (5.1 months). Above 50% of the patients had a survival beyond six months, however 25% of the patients deceased 6.5 weeks after procedure, approximately 1.5 months. These results suggest a need for guidelines or criteria for biliary stent indications in patients in the palliative setting. The population in our study had a lower median OS, compared to one reported by Lamarca et al, of 8.6 months (approximately 34 weeks). However, the population in the study by Lamarca et al, was different, as they excluded patients who did not receive systemic treatment. Regarding mortality within a month after stent placement, it is noteworthy that 90% of the patients did not receive any oncologic treatment prior to the procedure, denoting the advanced disease patients presented with, before the stent placement, therefore suggesting a reason behind a higher mortality rate in our study.
Biliary malignant stenosis in patients with advanced/inoperable PCa or BTCa is a common complication. An effective treatment for this problem is biliary stent by ERCP or TPC, however both techniques are not absent of complications.
At our institution, a highly qualified endoscopist or radiologist performs these procedures; the most frequent method of choice is ERCP, however in the case of contraindications, such as previous surgery, the TPC approach is preferred. The ESGE recommends SEMS insertion for palliative drainage of extrahepatic malignant biliary obstruction, being a strong recommendation, with a high quality evidence. 11 In agreement with these recommendations, 80% of the stents placed in our cohort were metallic.
To the best of our knowledge, this is one of the largest series reporting complications related to bile duct stents in an oncologic setting. A limitation of our study is the fact that it is a retrospective study, however, there is a lack of representation of this issue in the current literature. The use of stents is a feasible option, allowing a further systemic treatment for patients with impaired liver tests due to bile duct obstruction, leading to a bile drainage and further recovery of liver function. However, not all patients are amenable for a bile duct stents, pointing out the need to further improve the criteria for this procedure. Several factors are to be taken into account when analyzing the mortality within the first month post procedure, including an ECOG PS 2, infectious complications, as well as whether or not the patient receives systemic treatment. More evidence is needed elaborate multidisciplinary guidelines to improve the selection of patients who can benefit from this treatment option, further research will help clarify the aforementioned items associated to a higher mortality rate in our cohort.