Partially Covered Metal Stents Efficacy in Biliary Drainage of Malignant Extra-hepatic Biliary Obstruction

Malignant obstructions of the bile duct are not rare. The most common and accepted method for biliary drainage is endoscopic stent placement. There are three types of metal stents: fully covered (FC), partially covered (PC) and uncovered (U). PC-SEMS have been recently introduced and compared to FC-SEMS they seem to have a lower risk of migration, although data in the literature are discordant. Therefore the investigators will randomize the participants with biliary obstruction in 2 groups according to the type of stent used: PC-SEMS or U-SEMS. After metallic biliary stent insertion, enrolled patients will be followed for 12 months.

Malignant obstructions of the bile duct are generally caused by: adenocarcinoma of the Vater ampulla, pancreas head cancer, cholangiocarcinoma and external compression secondary to lymph node (LN) metastasis. The management of jaundice and cholangitis, as a result of bile stenosis, is crucial in this group of patients. The most common and accepted method for biliary drainage is endoscopic stent placement with plastic stents or self-expandable metal stents (SEMS). In recent times, the use of SEMS has become more common as it provides longer times of patency and a reduced risk of adverse events such as cholangitic episodes. There are three types of metal stents: fully covered (FC), partially covered (PC) and uncovered (U). PC-SEMS have been recently introduced and compared to FC-SEMS they seem to have a lower risk of migration, however different randomized and non-randomized studies have compared the outcome of U-SEMS vs FC-SEMS with between uncovered and covered stents have produced different results regarding the cumulative patency of stents and endoscopic re-intervention rates. To date, there are few and discordant prospective data on the outcomes of PC-SEMS use in malignant biliary obstructions.

Therefore, the investigators will randomize the participants with biliary obstruction in 2 groups according to the type of stent used: PC-SEMS or U-SEMS (T0 timing).

Then the participants will be followed for total period of 12 months. 2 different timings of follow-up will be considered:

- T1: it will start after stent insertion. The biliary drainage will be considered effective, according to the European guidelines, when the bilirubin values will be \< or = 2 mg/dl for a period of at least 6 weeks if the initial bilirubin values were higher than 10 mg/dl or 3 weeks if at the beginning were lower than 10 mg/dl; After this first phase, all the enrolled patients will be divided in 2 groups according to their "fitness" for chemiotherapy: FIT and UNFIT Group.

FIT group: blood test (including total bilirubin, gamma-GT) will be done for follow-up study once every three months.

UNFIT Group: blood test (including total bilirubin, gamma-GT) will be done for follow-up study after 3, 9 and 12 months.

Eligibility Criteria:
Inclusion Criteria:

•The patients who had malignant biliary obstruction with a estimated survival \>4 months

Exclusion Criteria:

* The patients who had resectable biliary malignancy
* The patients who had hilar obstruction
* The patients who had duodenal obstruction
* The patients who had International Normalized Ratio (INR)\>1.5
* The patients who did not give informed consent
* The patients who had technically difficult structure for Endoscopic retrograde cholangiopancreatography (ERCP)