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Stomach Neoplasms

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Digestive System Neoplasms

Gastrointestinal Diseases

Stomach Diseases

Stomach Cancer

Gastrectomy with preservation of the omentum distal to the gastroepiploic vessels

Open or minimally invasive (sub)total gastrectomy

Gastrectomy

Suzanne S. Gisbertz, MD, PhD

Kammy Keywani, MD

Suzanne S Gisbertz, MD, PhD

Suzanne S. Gisberts, MD, PhD

Wietse J. Eshuis, MD, PhD

Mark I. van Berge Henegouwen, MD, PhD

Curative therapy for gastric cancer usually consists of perioperative chemotherapy and a radical (R0) gastrectomy. A radical resection includes a modified D2 lymphadenectomy, and, generally, a complete omentectomy, to ensure the removal of omental metastatic lymph nodes and tumor deposits.

The omentum has some essential functions within the peritoneal cavity. The omentum functions as regulator of regional immune responses to prevent infections and, additionally, it prevents adhesions that can lead to small bowel obstruction. Omentectomy is associated with increased incidence of early and late postoperative complications such as abdominal abscess, ileus, and wound infections in various types of surgery.

There is little evidence regarding survival benefit of routine complete omentectomy during gastrectomy. The investigators hypothesize that omitting a complete omentectomy (and instead preserve the greater omentum distal of the gastroepiploic arcade) during gastrectomy for cancer does not negatively impact survival.

OMEGA is a randomized controlled, open, parallel, non-inferiority, multicenter trial. Adult patients (\>18 years) with primary resectable gastric cancer, clinical stage T2-4a N0-3 M0 or cT1N+ scheduled for open or minimally invasive (sub)total gastrectomy are included. The primary study objective is to investigate whether omentum preservation in gastrectomy for cancer is non-inferior to complete omentectomy in terms of three-year overall survival.

Primary objective:

The primary study objective is evaluate whether preservation of the omentum distal to the gastroepiploic vessels in gastrectomy for cancer is non-inferior to complete omentectomy in terms of three-year overall survival.

Secondary objectives:

Comparing the two study arms with regard to:

* Operating time
* Intraoperative blood loss
* Intraoperative complications
* Postoperative complications, defined according to the Clavien-Dindo classification25 and comprehensive complication index (CCI)
* Distribution of lymph node metastases
* R0-resection rate
* Rate of malignant cells in cytology
* Molecular sub classification of gastric cancer
* ICG fluorescent enhancement of omentum in omentum preservation group (in centers that have ICG fluorescence available)
* Protocol compliance to allocated treatment
* Hospital stay, defined as time interval between date of surgery and date of hospital discharge
* Readmission rate within 30-days after surgery
* Reintervention rate within 30-days after surgery
* Reoperation rate within three years after surgery
* Quality of life at baseline, 3, 6, 9, 12 and 24 months, the following questionnaires will be used: EQ-5D-5L, QLQ-C30, QLQ-OG25, CIPN, Happiness, HADS and work productivity
* 3- \& 5-year disease-free survival, defined as the period of time from operation to locoregional recurrence, peritoneal recurrence, distant metastases, second gastric cancer or death from any cause. Patients alive and free of all these events will be censored at the last follow-up.
* 5-year overall survival, defined as the period of time from operation to death from any cause. Patients alive and free of all these events will be censored at the last follow-up.
* Cost-effectiveness

Study design:

OMEGA is a randomized controlled, open, parallel, non-inferiority, multicenter trial. Eligible patients have to be operable (ASA \<4) with resectable (≦cT4aN3bM0) gastric cancer. Patients will be randomized in a 1:1 ratio between radical (sub)total gastrectomy with omentum preservation or complete omentectomy. Patients will be stratified according to center, neoadjuvant therapy and type of surgery (total or subtotal gastrectomy). The primary endpoint is overall survival at three-years after the operation. In total, 654 patients will be randomized.

Sample size:

The primary endpoint is three-year overall survival. According to survival numbers from the Dutch Cancer Registry (NKR), three-year overall survival after gastrectomy is approximately 50% in the Netherlands. Under the common assumption of exponential survival times, a hazard ratio of 0.862 under the alternative hypothesis, at least 50% and 45% expected events (i.e., death) in the control arm and experimental arm, respectively, at the minimum follow-up of three years, 298 events are needed in total to achieve 80% power at a one-sided significance level of 5% with a non-inferiority hazard ratio of 1.15 (PASS 15 Power Analysis and Sample Size Software (2017). NCSS, LLC. Kaysville, Utah, USA, ncss.com/software/pass), resulting in 314 patients per study arm. Dropouts will be rare (mostly due to loss to follow-up, which is quite rare in cancer patients), with proportion dropping out expected to be at most 5%. After correction for drop-out we plan to include 327 patients in each of the two arms (654 in total).

Statistical analysis:

Primary endpoint: Descriptive statistics will be calculated to summarize patients' groups included in each of trial arms.

Mean and standard deviation will be presented for normally distributed continuous variables. Median plus interquartile-range (IQR) will be presented continuous variables that are skewed and for ordinal variables. Dichotomous and nominal data will be summarized by means of frequencies and percentages.

Non-inferiority of the experimental treatment in terms of overall survival will be tested using Cox-regression. Non-inferiority will be concluded if the upper limit of the 90% confidence interval falls below the non-inferiority hazard ratio of 1.15, corresponding to a one-sided non-inferiority test at significance level of 5%. Survival will be presented graphically using Kaplan-Meier curves. All analyses will be according to the intention to treat principle. A per protocol analysis will also be performed. The experimental treatment will be declared non-inferior if non-inferiority is shown in both the intention to treat and the per protocol analysis.

Secondary endpoint: as independent samples t-test for normally-distributed continuous outcomes, Mann-Whitney tests for continuous outcomes that are not normally distributed or ordinal outcomes. Categorical outcomes will be compared using chi-square test or Fisher's exact test in case of low (expected) cell counts. Repeatedly measured outcomes will be compared between arms using linear mixed models. Secondary time-to-event outcomes will be compared the using log-rank test. Secondary endpoints will be tested at a two-sided significance level of 5%. Effect sizes suitable for the type of outcome measure will be provided (mean differences, ratio of geometric means, relative risks, hazard ratios) together with their 95% confidence interval.

Subgroup analysis for the effect of experimental treatment on overall survival will be performed for the follow subgroups: patient characteristics (age, male/female), diffuse/intestinal type gastric tumor, subtotal/total gastrectomy, and minimally invasive/open gastrectomy. Effect modification will use Cox regression with the subgroup variable, the arm and their two-way interaction. Additionally, stratified analyses will be performed where HR is calculated separately in each of the subgroups.

Quality of life data will be graphically represented across all time points and analyzed according to the manuals and will presented as domain and summarized scores. Questionnaire outcome comparisons will be analyzed using linear mixed models.

Omentum Preservation Versus Complete Omentectomy in Gastrectomy for Gastric Cancer

Overall survival is defined as the period of time from operation to death from any cause. Patients alive and free of all these events will be censored at the last follow-up

Defined as the period of time from operation to death from any cause. Patients alive and free of all these events will be censored at the last follow-up

The volume of blood loss in milliliters during surgery

Defined according to the Clavien-Dindo classification and comprehensive complication index (CCI)

The distribution of lymph node metastases in gastric cancer

R0-resection rate of the distal and proximal margin, according to the College of American Pathologists

The proportion of patients with malignant cells in peritoneal lavage cytology

DNA methylation arrays will be used to classify the gastric tumor into molecular subtypes

The proportion of patients who change from treatment arm

Defined as time interval between date of surgery and date of hospital discharge

Quality of life is assessed using the EuroQol-5 Dimension (EQ-5D-5L) descriptive system.

Defined as the period of time from operation to locoregional recurrence, peritoneal recurrence, distant metastases, second gastric cancer or death from any cause. Patients alive and free of all these events will be censored at the last follow-up

The surgical procedure duration in minutes, defined as time from first incision to last wound closure.

Cost-effectiveness will be calculated by comparing the direct medical cost related to both strategies. The cost-effectiveness is compared by assessing cost per QALY.

Amsterdam UMC

Principal Investigator

Symptoms and General Pathology

Nutritional and Metabolic Diseases

Syndrome

Metabolic Syndrome

Insulin Resistance

Hyperinsulinism

Metabolic Diseases

Glucose Metabolism Disorders

Omentum preserving: The minimum volume of omentum (within 3cm from gastroepiploic vessel) will be removed.

Total omentectomy: Whole omentum will be removed.

The minimum volume of omentum (within 3cm from gastroepiploic vessel) will be removed during gastrectomy with lymph node dissection.

Omentum preserving

Whole omentum will be removed during gastrectomy with lymph node dissection.

Total omentectomy

Seung Wan Ryu, M.D., Ph.D.

Young Kyu Park, MD, PhD

Seong Yeop Ryu, MD, PhD

Jeong Oh, MD, PhD

Mi Ran Jung, MD, PhD

Min Chan Kim, MD, PhD

Seung Wan Ryu, MD, PhD

In Gyu Kwon, MD

Young Gil Son, MD, PhD

Many features of the metabolic syndrome are associated with insulin resistance. And, metabolic syndrome and insulin resistance are related to visceral obesity. Therefore, the investigators hypothesized that visceral fat removal (omentectomy) can make favorable results for the insulin resistance and metabolic syndrome. As the omentectomy is optional procedure during a surgery for early gastric cancer, the investigators will divide patients randomly into two groups, total omentectomy group and omentum preserving group.

The investigators will compare the change of insulin resistance (HOMA-IR) and improvement of metabolic syndrome between total omentectomy and omentum preserving group.

Omentectomy for Metabolic Syndrome in Gastric Cancer Patients

The Effect of Visceral Fat Removal for Gastric Cancer Patients With Metabolic Syndrome, Randomized Pilot Study: Omentectomy for Metabolic Syndrome (OMS)

short-term any complication related to surgery

comparison between Billoth-II and Roux-en-Y

Chonnam National University Hospital

Dong-A University Hospital

Keimyung University Dongsan Medical Center

Director of Gastrointesinal surgery, associate professor

D2 radical gastrectomy with partial omentectomy

D2 radical gastrectomy with total omentectom

Partial omentectomy with preservation of the greater omentum at \>3 cm from the gastroepiploic arcade.Control group with total omentectomy.

Type of omentectomy

Han Liang, Master

Bin Ke, Doctor

The main purpose of this study is to evaluate the impact of omentectomy for advanced gastric cancer on patient survival.

Surgical resection is the mainstay of treatment for gastric cancer. The extent of surgical resection includes total or subtotal gastrectomy, D2 lymphadenectomy, and prophylactic or therapeutic resection of the surrounding organs or tissues (e.g., omentum, peritoneum, etc). However, the oncologic importance of omentectomy during gastrectomy remains unclear. The European guidelines do not give any advice regarding omentectomy, whereas the most recent American guidelines advise to resect both the greater and lesser omentum. Alternatively, the Japanese gastric cancer treatment guidelines recommends preservation of the greater omentum at \>3 cm from the gastroepiploic arcade for patients with T1-T2 tumors and total omentectomy for patients with T3-T4 tumors. In order to evaluate the impact of omentectomy for advanced gastric cancer on patient survival, we designed this trial. Patients who received curative gastrectomy were divided into two groups based on whether they underwent omentectomy. The primary endpoint is the 3-year relapse-free survival rate and the secondary endpoints are 5-year overall survival, and postoperative morbidity.

A Trial of Total Versus Partial Omentectomy for Advanced Gastric Cancer in Gastrectomy

A Single-center, Randomized, Controlled Trial to Evaluate Total Versus Partial Omentectomy for Advanced Gastric Cancer in Radical Gastrectomy

The volume of intraoperative blood loss (IBL) was defined as the total from suction and the weight of gauze sponges at the conclusion of the operation. The Blood loss volume is recorded in milliliters.

The length of the operation was defined as the time from first skin incision to wound closure. The length of the operation is recorded in minutes.

Postoperative hospital stay was defined as the time from the date of operation to the date of discharge. The postoperative hospital stay is recorded in days.

Postoperative morbidity was defined as the incidence rate of the postoperative complication. The postoperative morbidity were examined within 30 days after surgery. Postoperative morbidity was graded with use of the modified Clavien-Dindo classification of surgical complications.

Relapse-free survival l (RFS) was defined as the length of time from the date of randomization to the date of first documentation of relapse of gastric cancer or any other type of cancer or death.

Overall survival (OS) was defined as the length of time from the date of randomization to the date of death of various reasons.

Tianjin Medical University Cancer Institute and Hospital

Partial omentectomy with preservation of the greater omentum at \>3 cm from the gastroepiploic arcade.

Experimental group D2 radical gastrectomy with partial omentectomy. Partial omentectomy with preservation of the greater omentum at \>3 cm from the gastroepiploic arcade.Control group with total omentectomy.

Bik Ke, Doctor

Liang Han

This is a phase III, multicenter, prospective, randomized, controlled clinical trial to evaluate the impact of omentectomy for advanced gastric cancer on patient survival.

In order to evaluate the impact of omentectomy for advanced gastric cancer on patient survival, we designed this trial. Patients who received curative gastrectomy were divided into two groups based on whether they underwent omentectomy. The purpose of this study is to prove the non-inferiority of omentum preservation compared with omentectomy in patients with T3-T4a gastric cancer.

A Phase III Study Comparing Total and Partial Omentectomy for Patients With Advanced Gastric Cancer

A Phase III, Multicenter, Prospective, Randomized, Controlled Clinical Trial Comparing Total and Partial Omentectomy for Patients With Advanced Gastric Cancer (TOP-GC)

Study title	NCT ID	Conditions	Interventions	Eligibility	Organization
Omentum Preservation Versus Complete Omentectomy in Gastrectomy for Gastric Cancer	NCT05180864	Stomach Neoplas...	Gastrectomy	18 Years -	Academisch Medisch Centrum - Universiteit van Amsterdam (AMC-UvA)
Omentectomy for Metabolic Syndrome in Gastric Cancer Patients	NCT02641925	Metabolic Syndr... Gastric Cancer	Omentum preserv... Total omentecto...	20 Years - 80 Years	Keimyung University Dongsan Medical Center
A Trial of Total Versus Partial Omentectomy for Advanced Gastric Cancer in Gastrectomy	NCT04108494	Gastric Cancer	Type of omentec...	18 Years - 70 Years	Tianjin Medical University Cancer Institute and Hospital
A Phase III Study Comparing Total and Partial Omentectomy for Patients With Advanced Gastric Cancer	NCT04843215	Gastric Cancer	Type of omentec...	18 Years - 70 Years	Tianjin Medical University Cancer Institute and Hospital
Omentectomy for Metabolic Syndrome in Gastric Cancer Patients	NCT02641925	Metabolic Syndr... Gastric Cancer	Omentum preserv... Total omentecto...	20 Years - 80 Years	Keimyung University Dongsan Medical Center
Omentum Preservation Versus Complete Omentectomy in Gastrectomy for Gastric Cancer	NCT05180864	Stomach Neoplas...	Gastrectomy	18 Years -	Academisch Medisch Centrum - Universiteit van Amsterdam (AMC-UvA)

Spots Global Cancer Trial Database for omentectomy

Every month we try and update this database with for omentectomy cancer trials from around the world to help patients and their families find trials that might be right for them.
We offer this 100% free of charge and do not endorse any of the trials listed here, we hope it helps you or a loved one.

Spots Global Cancer Trial Database for omentectomy

Every month we try and update this database with for omentectomy cancer trials from around the world to help patients and their families find trials that might be right for them. We offer this 100% free of charge and do not endorse any of the trials listed here, we hope it helps you or a loved one.

Every month we try and update this database with for omentectomy cancer trials from around the world to help patients and their families find trials that might be right for them.
We offer this 100% free of charge and do not endorse any of the trials listed here, we hope it helps you or a loved one.