Comparative study of complete and partial omentectomy in radical subtotal gastrectomy for early gastric cancer

Normal saline remodels the omentum and stimulates its receptivity for transcoelomic metastasis

The omentum contains immune cell structures called milky spots that are niches for transcoelomic metastasis. It is difficult to remove the omentum completely, and there are no effective strategies to minimize the risk of colonization of preserved omental tissues by cancer cells that circulate in the peritoneal fluid. Normal saline is commonly administered into the peritoneal cavity for diagnostic and intraoperative lavage. Here we show that normal saline, when administered into the peritoneal cavity of mice, is prominently absorbed by the omentum, exfoliates its mesothelium, and induces expression of CX3CL1, the ligand for CX3CR1, within and surrounding the omental vasculature. Studies using CX3CR1-competent and CX3CR1-deficient mice showed that the predominant response in the omentum following saline administration is an accumulation of CX3CR1+ monocytes/macrophages that expand milky spots and promote neoangiogenesis within these niches. Moreover, saline administration promoted the implantation of cancer cells of ovarian and colorectal origin onto the omentum. By contrast, these deleterious effects were not observed following i.p. administration of lactated Ringer's solution. Our findings suggest that normal saline stimulates the receptivity of the omentum for cancer cells and that the risk of colonization can be minimized by using a biocompatible crystalloid for lavage procedures.

Current standards of surgical management of gastric cancer: an appraisal

PURPOSE

Gastric cancer (GC) is the fifth most common malignancy worldwide and portends a grim prognosis due to a lack of appreciable improvement in 5-year survival. We aimed to analyze the available literature and summarize the current standards of surgical care for curative and palliative intent treatment of GC.

METHODS

We conducted a systematic search on the PubMed database for studies on the management of GC.

RESULTS

Endoscopic resection is an acceptable treatment option for T1a tumors. The role of optimal resection margin for GC remains unclear. D2 lymph node dissection remains the standard of care with splenectomy needed selectively for splenic hilum involvement. A distal pancreatic resection should be avoided. The advantage of bursectomy and omentectomy in GC surgery is not clear. Multi-visceral resection may be considered for locally advanced GC in carefully selected patients. Minimally invasive approaches are non-inferior to open surgery. Surgery should be abandoned prior even in metastatic GC within the frame of multimodal therapy approach.

CONCLUSION

Various trials have conclusively shown improved patient outcomes when well-established surgical standards are followed.

Is Total Omentectomy Mandatory in T3 and T4a Gastric Cancer for Laparoscopic Distal Gastrectomy?

BACKGROUND

Despite the lack of strong evidence, total omentectomy (TO) remains the recommended procedure for gastric cancer (GC) for T3 or deeper tumors. Partial omentectomy (PO) has recently become a preferred procedure owing to its simplicity during laparoscopic distal gastrectomy (LDG); however, the oncological role of PO needs to be elucidated.

METHODS

Overall, 341 patients with T3 or T4a GC who had undergone LDG between 2009 and 2016 were divided into TO (n = 167) and PO (n = 174) groups. Propensity matching was performed with respect to covariance age, sex, T and N stage, tumor size, and degree of tumor differentiation. Clinicopathological characteristics and long-term follow-up data were analyzed for both groups.

RESULTS

After successful propensity matching, both groups included 107 patients. In a matched cohort, no significant difference in clinicopathologic features and short-term surgical outcomes was observed between the two groups. Furthermore, no significant difference in relapse-free survival (RFS; p = 0.201) and peritoneal seeding-free survival (PSFS; p = 0.094) was observed. However, tumor recurrence as peritoneal metastasis occurred in 5 (4.7%) patients in the PO group and 13 (12.1%) patients in the TO group. In Cox proportional hazards analysis, omentectomy was not identified as a significant factor for RFS, PSFS, and overall survival; however, advanced N and T4a stage were considered significant factors for RFS and PSFS, respectively.

CONCLUSIONS

PO may be adopted during the LDG of T3 or T4a GC without definite gross serosal exposure. More large-scale evidence or prospective study is recommended.

Occult Omental Metastasis in Gastric Adenocarcinoma: An Analysis of Incidence, Predictors, and Outcomes

Negine PaulIntroduction  Traditionally, the concept of complete omentectomy during gastric resection for cancer was based on lymphatic drainage and the occurrence of occult omental metastasis (OM). However, recent emerging evidence has challenged this concept of complete omentectomy. We, therefore, aim to find the incidence and risk factors of occult OM and also evaluate the outcome of patients with and without such metastasis. Methods  This is a single institutional, retrospective study of patients with gastric cancer who underwent curative radical gastrectomy for a period of 3 years (April 1, 2016, to March 31, 2019). A complete omentectomy was performed in all patients and the omentum and nodal stations were dissected in the resected specimen and sent for pathological analysis. Clinical and epidemiological data were collected from the hospital patient database and analysis was done. Results  A total of 185 patients have been included in the study, with a mean age of 53.84 years. Twenty of the 185 patients had OM (10.8%). Age, sex, location of the tumor, and neoadjuvant chemotherapy were not statistically significant in predicting OM. However, tumor size and tumor depth were found to have a significant association with OM. The occurrence of OM was more likely to be associated with disease recurrence, especially in the peritoneum. The mean overall survival was 38.15 months (±3.33 SD), whereas patients with OM had lower survival, 23.31 months (±7.79 SD), with a p -value of 0.012. Conclusion  OM was not encountered in T1 and T2 gastric cancers and the incidence of OM in T3 and T4 tumors was approximately 12.7%. Therefore, complete omentectomy may be omitted in early T1/T2 tumors. OM was associated with poor prognosis, increased peritoneal recurrence, and decreased overall survival, in spite of a complete omentectomy, and may serve as a prognostic indicator for disease recurrence and overall survival.

Partial omentectomy maybe practicable for T3 or shallower gastric cancer patients

BACKGROUND

Total omentectomy is often performed with gastrectomy as radical surgery for gastric cancer (GC) patients. However, it remains controversial whether GC patients can benefit from omentectomy. The aim of this study was to analyze the incidence and clinical significance of tumor deposits (TDs) in different anatomical subregions of perigastric omentum in GC patients undergoing gastrectomy with total omentectomy.

METHODS

From October 2011 to December 2013, 1253 patients who underwent gastrectomy with total omentectomy for GC were retrospective reviewed. The TDs in different anatomical subregions of perigastric omentum were examined.

RESULTS

Of 1253 patients, TDs positivity was 11.2%. Tumor deposits in the omentum of greater curvature and in the omentum of lesser curvature were associated with lymphovascular invasion, perineural invasion, advanced tumor node metastasis stages, and unfavorable survival. Besides, TDs in the proximal omentum of greater curvature and in the omentum of lesser curvature correlated with older patients and larger tumors. Kaplan-Meier curves showed that patients with TDs had worser overall survival (OS) than those without, regardless of TD positions. Patients with TDs in the omentum of greater curvature had the worst prognosis, followed by patients with TDs in the omentum of lesser curvature and patients with no TDs. Tumor deposits in the proximal omentum of greater curvature was an independent prognostic factor for OS. Moreover, only patients classified as pT4 had TDs in the distal omentum of greater curvature.

CONCLUSIONS

Patients with TDs in the omentum of greater curvature had the worst prognosis, followed by patients with TDs in the omentum of lesser curvature and patients with no TDs. In addition, partial omentectomy might be practicable for gastric cancer patients classified as T3 or shallower tumors.

Comparison of Survival and Safety Between Total Omentectomy and Partial Omentectomy for Gastric Cancer: A Meta-Analysis

Background: The greater omentum can limit abdominal inflammation and act as a protective cushion, but it is always involved in dissemination of gastric cancer. The purpose of this meta-analysis was to compare the survival and safety between total omentectomy and partial omentectomy for gastric cancer.

Methods: Two investigators independently conducted a systematic search of PubMed, Embase, CNKI, and Cochrane Library ranging from January 2000 to November 2020. The pooled odds ratio (ORs) and weighted mean difference (WMD) with the 95% confidence interval (95% CI) were used to assess perioperative and survival parameters.

Results: A total of 2,031 patients in 11 studies (574 patients in the partial omentectomy group and 1,457 patients in the total omentectomy group) were included. The results found shorter operation time (WMD = −25.584; P = 0.000) and less intraoperative blood loss (WMD = −47.301; P = 0.050) in the partial omentectomy group, compared to total omentectomy. There were no significant differences in terms of incidence of complications (OR = 0.770; P = 0.164), blood transfusions rates (OR = 0.269; P = 0.161), time to first flatus (WMD = 0.160; P = 0.345), hospital stay (WMD = −1.258; P = 0.087), and number of harvested lymph nodes (WMD = 1.265; P = 0.662). For the disease-free survival (OR = 0.80; P = 0.381) and overall survival, there were no statistical differences between the two procedures.

Conclusions: The partial omentectomy could reduce operation time and trended to decrease intraoperative blood loss. And the survival in patients with partial omentectomy seemed to be comparable to that of patients with total omentectomy.

Gastrectomy with omentum preservation versus gastrectomy with omentectomy for locally advanced gastric cancer: A systematic review and meta-analysis

BACKGROUND

Omentectomy has been traditionally a part of standard radical gastrectomy. Its clinical benefit for locally advanced gastric cancer (LAGC) remains controversial. This study aimed at evaluating the impact of gastrectomy with omentum preservation (GOP) on survival, recurrence, surgical outcomes and postoperative complications by comparing with gastrectomy with omentum resection (GOR).

METHODS

Original studies comparing GOP with GOR in LAGC were searched. Meta-analysis was performed using RevMan 5.4.

RESULTS

Seven studies involving 1879 patients were analyzed. Compared with GOR, GOP achieved significantly better overall survival (HR = 0.75 [0.60, 0.95], P = 0.01), with similar relapse-free survival (HR = 0.84 [0.68, 1.03], P = 0.10). The two groups had similar total recurrence rate (OR = 0.86 [0.68, 1.08], P = 0.19) and no significant differences in rates of peritoneal, hematogenous, locoregional or distant lymph node recurrences. GOP had significantly less blood loss (MD = -83 [-139, -28] ml, P = 0.003) and tended to have shorter operation time (MD = -28 [-58, 2] min, P = 0.06), with similar harvested number of lymph nodes (MD = -0.4 [-2.6, 1.8], P = 0.70). The incidences of total all grade and major complications were similar in GOP and GOR (all grade: 31.8% vs. 30.3%, OR = 1.08 [0.79, 1.46], P = 0.64; major: 9.2% vs. 10.1%, OR = 1.14 [0.55, 2.34], P = 0.73). There were no significant differences in incidences of complication or postoperative mortality.

CONCLUSIONS

Omentum preservation did not affect curability or survival in LAGC. These findings require validation in randomized controlled trials with large sample sizes.

Gastrectomy with or without omentectomy for gastric cancer: A systematic review and meta-analysis

BACKGROUND

Omentectomy is conventionally performed in the procedure of gastrectomy for gastric cancer. However, the clinical value and importance of omentectomy remain unclear. This meta-analysis investigated the benefits and safety of gastrectomy with or without omentectomy for patients with gastric cancer.

METHODS

A literature search was conducted in PubMed, Embase, and the Cochrane Library for studies comparing complete omentectomy with omentum preservation or partial omentectomy. Primary outcomes were overall survival, relapse-free survival, and incidences of recurrence and complications, whereas secondary outcomes were the total length of operation and the amount of blood loss.

RESULTS

Nine studies involving 3,561 patients were included. Our meta-analysis revealed no significant differences between omentectomy and omentum preservation in terms of the 5-year overall survival (risk ratio [RR] = 0.95, 95% confidence interval [CI] = 0.89-1.01), 5-year relapse free survival (RR: 0.96, 95% CI: 0.89-1.03), incidence of recurrence in the peritoneum or other visceral organs (RR: 1.13, 95% CI: 0.80-1.60 and RR: 1.06, 95% CI: 0.78-1.45, respectively), and incidence of complications (RR: 1.15, 95% CI: 0.89-1.50). Moreover, omentum preservation significantly reduced the total length of operation (mean difference [MD] 25.70, 95% CI: 3.23-48.17) and the amount of blood loss (MD: 56.29, 95% CI: 14.02-98.56).

CONCLUSION

Omentectomy may not be necessary and can be omitted during gastrectomy for gastric cancer.

Is omentectomy necessary in the treatment of benign or malignant abdominal pathologies? A systematic review

BACKGROUND

The omentum is an organ that is easily sacrificed during abdominal surgery. The scope of omentectomy and whether a routine omentectomy should be performed are still unknown.

AIM

To review the literature in order to determine the physiological functions of the omentum and the roles it plays in pathological events in order to reveal the necessity for removal and preservation of the omentum.

METHODS

A clinical review of the English language literature based on the MEDLINE (PubMed) database was conducted using the keywords: “abdomen”, “gastrointestinal”, “tumor”, “inflammation”, “omental flap”, “metastasis”, “omentum”, and “omentectomy”. In addition, reports were also identified by systematically reviewing all references in retrieved papers.

RESULTS

The omentum functions as a natural barrier in areas where pathological processes occur in the abdominal cavity. The omentum limits and controls inflammatory and infectious pathologies that occur in the abdomen. It also aids in treatment due to its cellular functions including lymphatic drainage and phagocytosis. It shows similar behavior in tumors, but it cannot cope with increasing tumor burden. The stage of the disease changes due to the tumor mass it tries to control. Therefore, it is considered an indicator of poor prognosis. Due to this feature, the omentum is one of the first organs to be sacrificed during surgical procedures. However, there are many unknowns regarding the role and efficacy of the omentum in cancer.

CONCLUSION

The omentum is a unique organ that limits and controls inflammatory processes, foreign masses, and lesions that develop in the abdominal cavity. Omental flaps can be used in all anatomical areas, including the thorax, abdomen, pelvis, and extremities. The omentum is an organ that deserves the title of the abdominal policeman. It is generally accepted that the omentum should be removed in cases where there is tumor invasion. However, the positive or negative contribution of omental resection in the treatment of abdominal pathologies should be questioned.

Partial Versus Total Omentectomy in Patients with Gastric Cancer: A Systemic Review and Meta-Analysis

Background: Surgical treatment is the key to cure localized gastric cancer. There is no strong evidence that supports the value of omentectomy. Thus, a meta-analysis was conducted to compare the safety and efficiency of partial and total omentectomy in patients with gastric cancer. Methods: PubMed, Embase, and Cochrane Library databases were searched. All studies that compared total and partial omentectomy as treatments for gastric cancer were included. The primary outcomes were patients' overall survival and disease-free survival, while the secondary outcomes were perioperative outcome and postoperative complications. Results: A total of nine studies were examined, wherein 1043 patients were included in the partial omentectomy group, and 1995 in the total omentectomy group. The partial omentectomy group was associated with better overall survival (hazard ratio: 0.80, 95% CI: 0.66 to 0.98, p = 0.04, I² = 0%), shorter operative time, and lesser blood loss than the total omentectomy group. In addition, no statistically significant difference was observed in the number of dissected lymph nodes, length of hospital stays, complication rate, and disease-free survival. Conclusions: Our results show that, compared with total omentectomy in gastric cancer surgery, partial omentectomy had non-inferior oncological outcomes and comparable safety outcomes.

Efficacy of Omentum-Preserving Gastrectomy for Patients With Gastric Cancer: A Systematic Review and Meta-Analysis

Background

Complete omentectomy is considered to be essential in the radical gastrectomy for gastric cancer (GC), but its clinical benefit remains unclear. This study aims to evaluate the efficacy of omentum-preserving gastrectomy (OPG) for patients with GC.

Methods

Studies comparing the surgical and oncological outcomes of OPG and gastrectomy with complete omentectomy (GCO) for GC up to March 2021 were systematically searched from PubMed, Web of Science, Embase, and Cochrane Library. A pooled analysis was performed for the available data regarding the baseline features, surgical and oncological outcomes. The RevMan 5.3 software was used to perform the statistical analysis. Quality evaluation and publication bias were also conducted.

Results

Nine studies with a total of 3335 patients (1372 in the OPG group and 1963 in the GCO group) undergoing gastrectomy were included. In the pooled analysis, the baseline data in two groups were all comparable (p > 0.05). However, the OPG group was associated with shorter operative time (MD = −18.67, 95% CI = −31.42 to −5.91, P = 0.004) and less intraoperative blood loss (MD = −38.09, 95% CI = −53.78 to −22.41, P < 0.00001) than the GCO group. However, the number of dissected lymph nodes (MD = 2.16, 95% CI = −0.61 to 4.93, P = 0.13), postoperative complications (OR = 0.92, 95% CI = 0.74 to 1.15, p = 0.47), overall recurrence rate (OR = 0.83, 95% CI = 0.66 to 1.06, p = 0.14), peritoneal recurrence rate (OR = 0.91, 95% CI = 0.65 to 1.29, p = 0.60), 3-year relapse-free survival (RFS) rate (OR = 1.40, 95% CI = 0.86 to 2.27, p = 0.18), and 5-year RFS rate (OR = 1.21, 95% CI = 0.95 to 1.55, p = 0.12) of the two groups were comparable.

Conclusions

OPG might be an oncologically safe procedure with better surgical outcomes for patients with GC than GCO. However, high-quality randomized controlled trials are needed to confirm this benefit.

Efficiency of complete omentectomy in patients with resectable gastric cancer: a meta‑analysis and systematic review

Background

We performed a meta-analysis to investigate the efficacy of complete omentectomy (CO) in patients undergoing radical gastrectomy for gastric cancer.

Methods

We conducted a literature search in PubMed, Web of Science, and the Cochrane Library databases for clinical research that compared CO with non-complete omentectomy (NCO). These articles were published prior to April 2021. Overall survival (OS) rates, relapse-free survival (RFS) rates, recurrence rates, operation times, estimates of blood loss, numbers of harvested lymph nodes, complications, and lengths of hospital stays were compared using relative risks (RRs) and weighted mean differences (WMDs). RevMan 5.3 software was used for statistical analysis.

Results

Nine studies that included 3329 patients (1960 in the CO group) and 1369 in the NCO group comprised the analysis. The meta-analysis showed that CO was associated with a decreased 3-year OS rate (RR = 0.94, 95% CI 0.90–0.98, P = 0.005) and 5-year OS rate (RR = 0.93, 95% CI 0.88–0.98, P = 0.007). However, it was not associated with the 3-year RFS rate (RR = 0.97, 95% CI 0.90–1.04, P = 0.44), 5-year RFS (RR = 0.98, 95% CI 0.90–1.06, P = 0.60), or recurrence rate (RR = 1.17, 95% CI 0.95–1.45, P = 0.15) compared to the NCO group. For surgical-related outcomes, significant heterogeneity existed between the studies. Compared to the NCO group, CO was found to be associated with significantly more estimated blood loss (WMD = 250.90, 95% CI 105.90–396.28, P = 0.0007) and less harvested lymph nodes (WMD = − 3.59, 95% CI − 6.88, − 0.29, P = 0.03). Although, there was no significant difference in the surgical time (WMD = 15.93, 95% CI − 0.21, 32.07, P = 0.05). No statistically significant differences were observed in the rates of overall (P = 0.79) and major complications (P = 0.90), or the lengths of hospital stays (P = 0.11) between the two groups.

Conclusions

Based on the available evidence, CO is not superior to NCO in terms of survival. CO is not recommended as a routine surgery for gastric cancer. Future well-designed high-quality RCTs are warranted.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01921-3.

A randomized controlled trial to evaluate omentum-preserving gastrectomy for patients with T1-T3 gastric cancer

Although complete omentectomy is traditionally performed in patients with gastric cancer as part of radical gastrectomy to ensure the elimination of micrometastases, the prognostic value of omentectomy during gastrectomy remains unclear. Retrospective studies have shown that the incidence of metastases in the greater omentum is very low in T1-T3 gastric cancer. Thus radical gastrectomy with D2 lymphadenectomy and preservation of the greater omentum may be a proper curative treatment for gastric cancer patients with T1-T3 tumors. The aim of this article is to describe the design and rationale for this prospective, randomized controlled DRAGON-05 trial, conducted to evaluate the prognostic value of omentum-preserving gastrectomy for patients with T1-T3 gastric cancer. Clinical trial registration: ChiCTR2000040045 (ClinicalTrials.gov).

Omentum preservation as an oncologically comparable and surgically superior alternative to total omentectomy during radical gastrectomy for T3-T4 gastric cancer

BACKGROUND

Total omentectomy has conventionally been performed and has been regarded as standard procedure in radical gastrectomy for cancer. However, omentum preservation is the preferred procedure during minimally invasive surgery, without sufficient evidence of oncological safety, especially for T3-T4 gastric cancer.

METHOD

A total of 3,510 patients who underwent radical gastrectomy for T3-T4 gastric cancer between January 2003 and December 2015 were reviewed, retrospectively. After propensity score matching, 225 patients in the omentum preservation group were compared with 225 patients in the total omentectomy group. The primary outcome was 5-year overall survival.

RESULTS

The omentum preservation group showed significantly shorter operation time (P = .001) and less blood loss (P = .004) than the total omentectomy group. Shorter operation time was also observed with both open and minimally invasive approaches (P < .001 and P = .007, respectively). The 5-year overall survival rates were 75.4% for the omentum preservation group and 72.6% for the total omentectomy group (log-rank P = .06; hazard ratio 0.7 [95% confidence interval, 0.48-1.01]). The 5-year relapse-free survival was higher in the omentum preservation group (73.8%) than in the total omentectomy group (66.1%), without statistical significance (log-rank P = .09; hazard ratio 0.74 [95% confidence interval, 0.52-1.06]).

CONCLUSION

Regardless of the surgical approach, omentum preservation provided comparable oncologic outcomes with better surgical outcomes, suggesting that this could be an acceptable alternative to total omentectomy for T3-T4 gastric cancer. These findings warrant further investigation in randomized clinical trials.

Long term oncological outcome of patients with grossly early gastric cancer-mimicking advanced gastric cancer

BACKGROUND

The survival of grossly early gastric cancer-mimicking advanced gastric cancer (EGC-mimicking AGC) patients had not been investigated. We evaluated the prognosis of patients who were diagnosed as early gastric cancer before surgery and advanced gastric cancer after surgery.

METHODS

This retrospective study reviewed 3592 gastric cancer patients who had radical surgery from January 2007 to February 2015. We used a 1:2 propensity score matching method for the analysis. The matching factors were age, sex, body mass index and the depth of cancer invasion. The 5-year overall survival (OS) and disease-free survival (DFS) of the two study groups were analyzed.

RESULTS

The 475 grossly EGC-mimicking AGC patients were matched to 910 Borrmann type advanced gastric cancer (AGC) patients. The 5-year OS and DFS of the EGC-mimicking AGC patients were significantly higher than the Borrmann type AGC patients, (89.2% versus 83.4%, p = 0.025; 93.0% versus 85.6%, p < 0.001, respectively). The proportion of patients with lymph node (LN) metastasis was 45.5% in the EGC-mimicking AGC group and 57.1% in the Borrmann type AGC patients (p < 0.001). The ratio of metastatic LNs of N1 and N2 station was 5.2% and 3.1%, respectively, in EGC-mimicking AGC patients; this was lower than in Borrmann type AGC patients (N1: 8.9%, p < 0.001; N2: 3.7%, p = 0.308).

CONCLUSIONS

Patients with grossly EGC-mimicking AGC had better prognosis than patients with the Borrmann type AGC due to fewer LN metastases. This suggests that limited LN dissection of EGC-mimicking AGC patients may be feasible.

Esophagogastric junction adenocarcinomas: individualization of resection with special considerations for Siewert type II, and Nishi types EG, E=G and GE cancers

For Siewert type II adenocarcinoma of the esophagogastric junction (AEG II), or similar tumors classified as Nishi EG, E=G, GE, the type of surgical resection and reconstruction should be individualized. Criteria for decision making mainly focus on the oral extent of esophageal infiltration, the cT and cN category and the functional status of the patient. For cT1/cT2 adenocarcinomas, which are non-poorly cohesive, intestinal type of Lauren Grading 1 or 2 without clinical signs of lymph node metastasis at the distal stomach, a limited transhiatal proximal gastrectomy with double tract reconstruction is recommended. For advanced adenocarcinomas, subtotal esophageal and proximal gastric resection with gastric pull-up or distal esophageal resection with total gastrectomy and esophagojejunostomy are competing procedures. Criteria for choosing the appropriate type of surgery are discussed.

Significance of Omental Infiltration in Gastric Cancer Patients: a Retrospective Cohort Study

BACKGROUND

Stomach cancer is a curative disease in early stages. The optimal extent and approach for gastric resection are still evolving.

PATIENTS AND METHODS

In this study, we examined the value, as well as, the predictors of omental disease spread, retrospectively, in a group of patients with gastric cancer who attended the Oncology Center, Mansoura University, in the period between January 2006 and April 2017.

RESULTS

Nodal metastasis, especially heavy disease (N₂ and beyond), and advanced stage are predictors of the presence of omental disease. However, neither overall nor disease-free survival is affected by omental infiltration.

CONCLUSION

Omental resection will continue being an integral part of gastric resection, but the level of omental cutting needs further studies.

TOTAL OMENTECTOMY IN GASTRIC CANCER SURGERY: IS IT ALWAYS NECESSARY?

BACKGROUND

Traditionally, total omentectomy is performed along with gastric resection and extended lymphadenectomy in gastric cancer (GC) surgery. However, solid evidences regarding its oncologic benefit is still scarce.

AIM

To evaluate the incidence of metastatic omental lymph nodes (LN) in patients undergoing curative gastrectomy for GC, as well as its risk factors and patients' outcomes.

METHODS

All consecutive patients submitted to D2/modified D2 gastrectomy due to gastric adenocarcinoma from March 2009 to April 2016 were retrospectively reviewed from a prospective collected database.

RESULTS

Of 284 patients included, five (1.8%) patients had metastatic omental LN (one: pT3N3bM0; two: pT4aN3bM0; one: pT4aN2M0 and one pT4bN3bM0). Four of them deceased and one was under palliative chemotherapy due relapse. LN metastases in the greater omentum significantly correlated with tumor's size (p=0.018), N stage (p<0.001), clinical stage (p=0.022), venous invasion growth (p=0.003), recurrence (p=0.006), site of recurrence (peritoneum: p=0.008; liver: p=0.023; ovary: p=0.035) and death (p=0.008).

CONCLUSION

The incidence of metastatic omental LN of patients undergoing radical gastrectomy due to GC is extremely low. Total omentectomy may be avoided in tumors smaller than 5.25 cm and T1/T2 tumors. However, the presence of lymph node metastases in the greater omentum is associated with recurrence in the peritoneum, liver, ovary and death.

Role of Hydro-Dissection Facilitated Monopolar Cauterization Dissection Technique on Separation of the Greater Omentum From the Superior Layer of the Transverse Mesocolon During D2 Radical Gastrectomy

Adequate separation of the omentum from the transverse colon mesentery, during D2 radical gastrectomy, is usually difficult and often time-consuming due to anatomic variations. The aim of this prospective study was to compare the electrocautery dissection technique with hydrodissection-facilitated electrocauterization for the separation of the greater omentum from the superior layer of the transverse mesocolon in gastric cancer patients undergoing D2 radical gastrectomy. The time taken to separate the greater omentum from the superior layer of the transverse mesocolon, and the number and extension of iatrogenically-created mesocolonic defects were assessed. Forty patients were prospectively randomized into 2 groups. Separation of the greater omentum from the superior layer of the transverse mesocolon was achieved in Group I (n = 20) patients by the monopolar cauterization dissection technique whereas in Group II (n = 20) patients by the hydrodissection-facilitated monopolar cauterization. No significant difference was found between the 2 groups in terms of age, gender, body mass index (BMI), type of surgical technique, or the number of resected lymph nodes (P &gt; 0.05). The difference between the 2 dissection techniques was not statistically significant when compared according to the number of iatrogenic mesocolonic defects, extension of the defects, or the time period required for the separation of greater omentum from the superior layer of the transverse mesocolon (P &gt; 0.05). The overall survival was not significantly different between the 2 dissection techniques (P &gt; 0.05). Hydrodissection is a safe technique that can be applied as an adjunct to electrocauterization to facilitate the dissection in the correct plane during resection of the mesogastrium.

Role of omentectomy as part of radical surgery for gastric cancer

Background

A complete omentectomy is recommended as part of radical (sub)total gastrectomy for gastric cancer, but there is little evidence to suggest any survival benefit. The aim of this study was to evaluate the incidence of, and risk factors for, metastases in the greater omentum in patients undergoing gastrectomy for gastric cancer.

Methods

This was a multicentre prospective cohort study (OMEGA trial) of consecutive patients with gastric cancer undergoing (sub)total gastrectomy with complete en bloc omentectomy and modified D2 lymphadenectomy. After resection, the omentum was separated from the gastrectomy specimen distal to the gastroepiploic vessels and sent separately for pathological examination. The primary endpoint was the presence of metastases in the greater omentum.

Results

Of 100 included patients, five (5·0 per cent) had metastases in the greater omentum. Pathology results showed advanced tumours in all five (pT4b N1 M1, pT4b N2 M1, ypT4a N1 M1, ypT3 N2 M0, ypT3 N3 M0). The resection was microscopically non-radical at the proximal (3) or distal (2) resection margin in all of these patients. Metastases in the greater omentum correlated significantly with a microscopically non-radical resection, tumour expansion in the oesophagus or duodenum, linitis plastica or a proximal gastric tumour with diameter of at least 5 cm, stage III–IV disease and (y)pM1 category.

Conclusion

In resectable gastric cancer, the incidence of metastases in the greater omentum is low, and when present associated with advanced disease and non-radical features. Thus, omentectomy as part of a radical gastrectomy may be omitted. Registration number: NCT02050659 (http://www.clinicaltrials.gov).

A comparison of endoscopic submucosal dissection (ESD) and radical surgery for early gastric cancer: a retrospective study

Background

Endoscopic submucosal dissection (ESD) has become one of the mainstays of treatment for early gastric cancer (EGC). Radical surgery is also a classical treatment method for EGC. There have been no systematic clinical studies of the curative effects and adverse events associated with ESD vs. radical surgery for EGC. This study investigated the therapeutic efficacy and safety of ESD and radical surgery for EGC.

Methods

Twenty-nine patients with EGC underwent ESD, and 59 underwent radical surgery at Weihai Municipal Hospital. The pathological characteristics, postoperative outcomes, hospital course, morbidity and mortality were retrospectively compared between the two groups.

Results

The oncological clearance was 93.1 % (27/29) in the ESD group. Postoperative delayed haemorrhage occurred in two patients. The hospital stay ranged from 10 to 23 days, and the average stay was 14.3 ± 3.7 days. The patients were followed-up for 1 to 5 years, with a mean follow-up of 26.9 ± 8.5 months. Regular endoscopic examinations showed that the wound had healed with no cancer recurrence in all of the patients. In the radical surgery group, the oncological clearance was 100 % (59/59). The hospital stay ranged from 11 to 55 days, and the average stay was 21.7 ± 9.3 days. The patients were followed-up for 1 to 3.7 years, with a mean follow-up of 22.3 ± 9.4 months. Nine patients developed complications, including acute postoperative adhesive ileus (1/59) and symptomatic residual gastritis (3/59). These complications were improved by an additional operation, drainage, gastrointestinal decompression and comprehensive therapy.

Conclusions

ESD achieved similar efficacy and had many advantages compared with radical surgery for the treatment of EGC.

Laparoscopic Total Gastrectomy in the Western Patient Population: Tips, Techniques, and Evidence-based Practice

Gastric cancer is the second most common malignancy worldwide, and surgical resection is the only curative treatment. Traditionally, open total gastrectomy has been the procedure of choice for large and proximal carcinomas. Over the past decade, however, laparoscopic gastrectomy has emerged and an oncologically safe and feasible alternative to open surgery, and its use has become particularly widespread in Japan and Korea. Patients in the United States have important biological and anatomic distinctions from East Asian patients, and these become important factors when considering minimally invasive resection techniques. The goal of this paper is to describe the technique we have developed for laparoscopic total gastrectomy in our 10-year experience with a western patient population.

Totally laparoscopic 95% gastrectomy for cancer: technical considerations

INTRODUCTION

Total gastrectomy is the standard treatment for tumours arising in the proximal stomach and for diffuse cancer according to the Lauren classification. Laparoscopic approach is progressively accepted and provides encouraging results. In order to reduce complications associated to the esophago-jejunal anastomosis, the concept of the 95 % open gastrectomy was developed in Japan, in the early 1980s. This procedure provides the spearing of a small remnant gastric stump of 2 cm and allows performing a gastro-jejunal anastomosis. Unlike the 7/8 gastrectomy, the 95 % gastrectomy allows the complete resection of the gastric fundus and an optimized pericardial lymph node dissection (group 1 and 2). We herein describe, step-by-step, our technique of full laparoscopic 95 % gastrectomy (G95 %), with D2 lymphadenectomy, including complete lymphadenectomy of the cardial nodes.

DISCUSSION

When it is possible to respect the oncologic criteria regarding proximal resection margin, 95 % gastrectomy would offer best short-term results, such as lower anastomotic leak rate and a better quality of life, limiting the effect of disruption of the eso-gastric junction.

CONCLUSION

In selected patients, laparoscopic G95 % is feasible and safe; it could be performed without any additional technical difficulties. Controlled clinical trials are necessary to confirm the encouraging results of the cases series, recently reported in literature.

A comparison of total versus partial omentectomy for advanced gastric cancer in laparoscopic gastrectomy

Background

Minimally invasive surgery has been slowly introduced into the field of advanced gastric cancer (AGC) surgery. However, the appropriate extent of omentectomy during laparoscopic gastrectomy for AGC is unknown.

Methods

From July 2004 to December 2011, 146 patients with serosa-negative advanced gastric cancer were divided into the total omentectomy group (TO group, n = 80) and the partial omentectomy group (PO group, n = 66). The clinicopathologic characteristics, surgical outcomes, recurrence pattern and survival were analyzed.

Results

There were no significant differences in the clinicopathologic features between the two groups, except for depth of invasion; more T3 (subserosal invasion) cases (65%) were included in total omentectomy group (P = 0.011). The mean time for PO was significantly shorter (35.1 ± 13.0 min) than TO (50.9 ± 15.3 min) (P %0.001), and there were two omentectomy-related complications in the TO group: spleen and mesocolon injuries. Recurrence occurred in 14 (17.5%) and 5 (7.6%) cases in the TO and PO group, respectively (P = 0.054). Disease-free survival (TO versus PO: 81.5% versus 89.3%, P = 0.420) and disease-specific survival (TO versus PO: 89% versus 94.7%) were not significantly different between the two groups. In the case-matched analysis using propensity score matching, there was no difference in disease-free survival (TO versus PO: 83.3% versus 90.5%, P = 0.442).

Conclusions

Partial omentectomy might be an oncologically safe procedure during laparoscopic gastrectomy for serosa-negative advanced gastric cancer, similar to early gastric cancer.

Barium peritonitis in small animals

Barium peritonitis is extremely rare, but is difficult to treat and may be life-threatening. Barium suspension leakage from the gastrointestinal tract into the abdominal cavity has a time-dependent and synergistically deleterious effect in patients who have generalized bacterial peritonitis. The severity of barium peritonitis is dependent on the quantity of barium in the abdominal cavity. Barium sulfate leakage results in hypovolemia and hypoproteinemia by worsening the exudation of extracellular fluid and albumin. Abdominal fluid analysis is a useful and efficient method to diagnose barium peritonitis. Serial radiographs may not be a reliable or timely diagnostic technique. Initial aggressive fluid resuscitation and empirical broad-spectrum antibiotic treatment should be instituted promptly, followed quickly by celiotomy. During exploratory surgical intervention, copious irrigation and direct wiping with gauze are employed to remove as much barium as possible. Omentectomy should be considered when needed to expedite barium removal. Despite aggressive medical and surgical treatments, postoperative prognosis is guarded to poor due to complications, such as acute vascular shock, sepsis, diffuse peritonitis, hypoproteninemia, electrolyte imbalance, cardiac arrest, small bowel obstruction related to progression of granulomas and adhesions in the abdominal cavity. Therefore, intensive postoperative monitoring and prompt intervention are necessary to maximize chances for a positive outcome. For those that do survive, small bowel obstruction is a potential consequence due to progression of abdominal adhesions.

Generation of a dual-functioning antitumor immune response in the peritoneal cavity

Tumor cell metastasis to the peritoneal cavity is observed in patients with tumors of peritoneal organs, particularly colon and ovarian tumors. Following release into the peritoneal cavity, tumor cells rapidly attach to the omentum, a tissue consisting of immune aggregates embedded in adipose tissue. Despite their proximity to potential immune effector cells, tumor cells grow aggressively on these immune aggregates. We hypothesized that activation of the immune aggregates would generate a productive antitumor immune response in the peritoneal cavity. We immunized mice i.p. with lethally irradiated cells of the colon adenocarcinoma line Colon38. Immunization resulted in temporary enlargement of immune aggregates, and after challenge with viable Colon38 cells, we did not detect tumor growth on the omentum. When Colon38-immunized mice were challenged with cells from the unrelated breast adenocarcinoma line E0771 or the melanoma line B16, these tumors also did not grow. The nonspecific response was long-lived and not present systemically, highlighting the uniqueness of the peritoneal cavity. Cellular depletions of immune subsets revealed that NK1.1(+) cells were essential in preventing growth of unrelated tumors, whereas NK1.1(+) cells and T cells were essential in preventing Colon38 tumor growth. Collectively, these data demonstrate that the peritoneal cavity has a unique environment capable of eliciting potent specific and nonspecific antitumor immune responses.