6-mm vs 10-mm diameter fully covered self-expandable metal stents in patients with unresectable malignant distal bile duct stricture (COSMIC UNISON): study protocol for a multicenter, randomized controlled trial

Table 2 Observation schedule

	Enrollment	Date of treatment^a	Observation period (months)			End^b
	Enrollment	Date of treatment^a	3	6	12	End^b
Informed consent	●
Eligibility screen	●
Allocation		●
Interventions
6-mm diameter FCSEMS		●
10-mm diameter FCSEMS		●
Assessments
Patient background	●
Type of immediate bile duct drainage	●
Presence and severity of acute cholangitis	●
Peripheral blood count and biochemical tests	●
Details of bile duct stenting procedure, prophylaxis use, and surgeon experience in ERCP		●
Time to RBO						●
Clinical success						●
Blood tests			Every 3 months, until RBO occurs
Imaging studies			As needed
Non-RBO rate			●	●	●
Overall survival						●
Presence of anti-tumor therapy						●
Adverse events other than RBO						●
Information on discontinuation			At any time

ERCP endoscopic retrograde cholangiopancreatography, FCSEMS fully covered self-expandable metal stents, RBO recurrent biliary obstruction
^aWithin 14 days of enrollment
^bDate of RBO or study end (31 March 2029)

ISSN: 1745-6215