UMIN-ICDS Clinical Trial

Public title

A Single-Center Randomized Controlled Trial Evaluating the Efficacy of Simultaneous Splenectomy in Living-Donor Liver Transplantation

Acronym

Benefit of Optimal Outcome with Simultaneous Splenectomy in Living-Donor Liver Transplantation (BOOST Trial)

Scientific Title

Benefit of Optimal Outcome with Simultaneous Splenectomy in Living-Donor Liver Transplantation (BOOST Trial)

Scientific Title:Acronym

Benefit of Optimal Outcome with Simultaneous Splenectomy in Living-Donor Liver Transplantation (BOOST Trial)

Region

Japan

Condition

Liver cirrhosis, liver failure

Classification by specialty

Hepato-biliary-pancreatic surgery

Classification by malignancy

Others

Genomic information

NO

Narrative objectives1

The present study aims to evaluate the clinical significance of simultaneous splenectomy in living donor liver transplantation (LDLT) through a prospective randomized controlled trial (RCT). In this trial, patients undergoing simultaneous splenectomy will be compared with those who do not undergo splenectomy to determine whether the procedure contributes to improved liver graft function, reduced postoperative complications, and enhanced graft survival.
Particular attention will be given to the incidence of Small-for-Size Graft Syndrome (SFSS), with the goal of establishing evidence to optimize the indications for splenectomy.
The results of this study are expected to promote the standardization of splenectomy in LDLT and contribute to improved transplant outcomes and better patient prognosis.

Basic objectives2

Safety,Efficacy

Basic objectives -Others

Trial characteristics_1

Confirmatory

Trial characteristics_2

Pragmatic

Developmental phase

Not applicable

Primary outcomes

The primary outcome of this study is the incidence of Small-for-Size Graft Syndrome (SFSS) following living-donor liver transplantation. The diagnosis and grading of SFSS will be determined according to consensus criteria, including those proposed by the International Liver Transplantation Society (ILTS), based on postoperative clinical findings and laboratory parameters such as total bilirubin levels, INR, and ascites volume.

Key secondary outcomes

Key secondary outcomes include the following:
portal venous pressure at abdominal closure, portal venous flow after reperfusion, total intraoperative blood loss, operative time, blood loss during splenectomy, cold ischemia time, warm ischemia time, anhepatic phase duration, incidence of postoperative complications (postoperative bleeding, pancreatic fistula, portal vein thrombosis, sepsis, and acute rejection), length of postoperative hospital stay, 30-day postoperative mortality, 1-year survival, and postoperative liver function parameters (AST, ALT, ALP, GGTP, LDH, PT [% and INR], total bilirubin, direct bilirubin, and platelet count).

Study type

Interventional

Basic design

Parallel

Randomization

Randomized

Randomization unit

Individual

Blinding

Open -no one is blinded

Control

No treatment

Stratification

YES

Dynamic allocation

YES

Institution consideration

Institution is not considered as adjustment factor.

Blocking

NO

Concealment

Central registration

No. of arms

2

Purpose of intervention

Treatment

Type of intervention

Maneuver

Interventions/Control_1

Simultaneous splenectomy group (Spx group): During living-donor liver transplantation using a right lobe graft, splenectomy is performed simultaneously as part of the surgical procedure.

Interventions/Control_2

Non-splenectomy group (non-Spx group): During living-donor liver transplantation using a right lobe graft, splenectomy is not performed and the spleen is preserved.

Interventions/Control_3

Interventions/Control_4

Interventions/Control_5

Interventions/Control_6

Interventions/Control_7

Interventions/Control_8

Interventions/Control_9

Interventions/Control_10

Age-lower limit

18

years-old

<=

Age-upper limit

Not applicable

Gender

Male and Female

Key inclusion criteria

Patients meeting all of the following criteria will be eligible for inclusion:
1. Patients undergoing living-donor liver transplantation using a right lobe graft at the participating institution after study approval
2. Age >18 years
3. Graft-to-recipient weight ratio (GRWR) <0.8% based on preoperative evaluation
4. Patients who have provided written informed consent after receiving sufficient explanation of the study purpose and procedures

Key exclusion criteria

Patients meeting any of the following criteria will be excluded:
1. History of previous splenectomy
2. Marked anatomical variations of graft vasculature (portal vein, bile duct, hepatic artery, or hepatic vein) detected on preoperative imaging (plain or contrast-enhanced CT) and judged by the investigator to make the patient unsuitable for the study
3. Severe comorbidities (e.g., end-stage renal failure, severe cardiac disease, or active infection) that would increase the risk of simultaneous splenectomy
4. Severe perisplenic adhesions or inflammatory involvement identified by preoperative imaging or clinical findings that may increase the risk of splenectomy
5. Patients who decline participation after receiving adequate explanation of the study
6. Patients found intraoperatively to have a prior splenectomy, which will be treated as post-hoc ineligible cases

Target sample size

80

Name of lead principal investigator

1st name	Tomoharu
Middle name
Last name	Yoshizumi

Organization

Graduate School of Medical Sciences, Kyushu University

Division name

Department of Surgery and Science

Zip code

812-8582

Address

3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan

TEL

+81-92-642-5466

Email

toshima.takeo.962@m.kyushu-u.ac.jp

Name of contact person

1st name	Takeo
Middle name
Last name	Toshima

Organization

Graduate School of Medical Sciences, Kyushu University

Division name

Department of Surgery and Science

Zip code

812-8582

Address

3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan

TEL

+81-92-642-5466

Homepage URL

https://surg2.kyushu-u.ac.jp/

Email

toshima.takeo.962@m.kyushu-u.ac.jp

Institute

Kyushu University

Institute

Department

Personal name

Takeo Toshima

Organization

None

Organization

Division

Category of Funding Organization

Other

Nationality of Funding Organization

Japan

Co-sponsor

None

Name of secondary funder(s)

None

Organization

Graduate School of Medical Sciences, Kyushu University

Address

3-1-1, Maidashi, Higashi-ku, 812-8582, Japan

Tel

+81-92-642-5466

Email

toshima.takeo.962@m.kyushu-u.ac.jp

Secondary IDs

NO

Study ID_1

Org. issuing International ID_1

Study ID_2

Org. issuing International ID_2

IND to MHLW

福岡県

Institutions

九州大学（福岡県）

Date of disclosure of the study information

2026

Year

03

Month

04

Day

URL releasing protocol

https://surg2.kyushu-u.ac.jp/

Publication of results

Unpublished

URL related to results and publications

https://surg2.kyushu-u.ac.jp/

Number of participants that the trial has enrolled

80

Results

To be disclosed after completion of the analysis.

Results date posted

2026

Year

03

Month

04

Day

Results Delayed

Results Delay Reason

Date of the first journal publication of results

Baseline Characteristics

To be disclosed after completion of the analysis

Participant flow

Patients who meet the eligibility criteria and provide written informed consent will be enrolled and randomly assigned in a 1:1 ratio to either the simultaneous splenectomy group (Spx group) or the non-splenectomy group (non-Spx group). After allocation, living-donor liver transplantation using a right lobe graft will be performed, and perioperative and postoperative outcomes will be followed and evaluated.

Adverse events

In this study, an adverse event is defined as any unfavorable or unintended medical occurrence in a participant, regardless of its causal relationship to the study, including abnormal laboratory findings. Particular attention will be given to complications related to splenectomy, such as portal vein thrombosis, pancreatic fistula, bleeding from the splenic stump, postoperative infection including overwhelming post-splenectomy infection (OPSI), and sepsis. Appropriate diagnosis, treatment, and management will be provided when such events occur.

Outcome measures

The outcome measures of this study are as follows.
Primary endpoint: Incidence of Small-for-Size Graft Syndrome (SFSS).
Secondary endpoints: Portal venous pressure at abdominal closure, portal venous flow after reperfusion, total intraoperative blood loss, operative time, blood loss during splenectomy, cold ischemia time, warm ischemia time, anhepatic phase duration, incidence of postoperative complications (postoperative bleeding, pancreatic fistula, portal vein thrombosis, sepsis, and acute rejection), length of postoperative hospital stay, 30-day postoperative mortality, 1-year survival, and postoperative liver function parameters (AST, ALT, ALP, GGTP, LDH, PT [% and INR], total bilirubin, direct bilirubin, and platelet count).

Plan to share IPD

None.

IPD sharing Plan description

None.

Recruitment status

Open public recruiting

Date of protocol fixation

2025

Year

07

Month

10

Day

Date of IRB

2025

Year

07

Month

10

Day

Anticipated trial start date

2025

Year

07

Month

11

Day

Last follow-up date

2030

Year

03

Month

31

Day

Date of closure to data entry

2030

Year

03

Month

31

Day

Date trial data considered complete

2030

Year

03

Month

31

Day

Date analysis concluded

2030

Year

03

Month

31

Day

Other related information

None.

Registered date

2026

Year

03

Month

04

Day

Last modified on

2026

Year

03

Month

04

Day

Link to view the page

Value
https://center6.umin.ac.jp/cgi-open-bin/icdr_e/ctr_view.cgi?recptno=R000069593