Sentinel node mapping for gastric cancer: a prospective multicenter trial in Japan

Potential for local resection with sentinel node basin dissection for early gastric cancer based on the distribution of primary sites

BACKGROUND

Based on the sentinel node (SN) concept, function-preserving surgery with SN basin dissection (SNBD) can be performed for SN-negative early gastric cancers. Particularly, a resection area can be minimized when the SN basin and primary site are closely localized. The aim of this study was to compare probabilities of being candidates for local resection with SNBD based on tumor location among patients with early gastric cancer.

METHODS

We retrospectively analyzed 358 patients who underwent surgery with SN mapping for gastric cancer in our institution from November 1999 to April 2014. The proportion of patients who had a localized single basin and the distributions of the SN basins and primary sites were investigated. Patients with single basin drainage excluding remote sentinel node basin were considered as candidates for local resection with SNBD.

RESULTS

Of the 358 patients, 191 (53%) patients were considered eligible for local resection with SNBD. Patients with tumors located in the upper third of the stomach were more likely candidates for local resection than those with tumors in other locations (upper third, 68%; middle third, 50%; and lower third, 51%), whereas patients with tumors located in the anterior wall were less likely candidates than those with tumors other locations (anterior wall, 31%; posterior wall, 58%; greater curvature, 55%; and lesser curvature, 57%).

CONCLUSION

We found that > 50% of the patients indicated for SN navigation surgery, particularly those with tumors in the upper third of the stomach, potentially could undergo partial resection with SNBD.

Re-emerging role of macroscopic appearance in treatment strategy for gastric cancer

Pathological outcomes are definitely the most important prognostic factors in gastric cancer, but they can be obtained only after surgical resection. Use of preoperative adjuvant chemotherapy is becoming widespread for aggressive human cancer, so clinical factors such as macroscopic features are important as they are highly predictive for patient prognosis. In gastric cancer, the macroscopic type represents a distinct prognosis; Type 0 represents early gastric cancer with excellent prognosis, but, among advanced tumors, giant Type III and Type IV tumors have a dismal prognosis. Japan Clinical Oncology Group (JCOG) Stomach Cancer Study Group adopted macroscopic features as high-risk entities in clinical trials. It makes sense for risk classification to use macroscopic phenotypes because The Cancer Genome Atlas (TCGA) Network has lately subcategorized different histologies associated with specific macroscopic types by the molecular features of the whole genome. Dismal prognosis of Type IV gastric cancer is notorious, but similar prognosis was seen in giant Type III gastric cancer defined as 8 cm or beyond, both of which are unique for their propensity of peritoneal dissemination. In this review, clinical relevance including prognosis of such macroscopic high-risk features will be separately debated in the context of precision medicine and updated prognostic outcomes will be presented under the present standard therapy of curative surgery followed by postoperative S-1 chemotherapy. Moreover, promising emerging novel therapeutic strategies including trimodal potent regimens or intraperitoneal chemotherapy will be described for such aggressive gastric cancer.

Sentinel node biospy using intravital blue dye: An useful technique for identification of skip metastases in gastric cancer

As the lymph node status remains the main prognostic factor of gastric cancer (GC), several lymph node-based staging systems have been recently proposed for an appropriate postoperative therapy. The identification of sentinel lymph nodes (SLNs) might improve the postoperative protocols. The aim of this study was to present our experience in detecting SLNs in GC using methylene blue dye.We have performed an observational study and retrospectively analyzed all of the consecutive cases of GC operated by the same surgical team and managed by the same pathologists during 2013 to 2015. In all of the cases SLN status was determined using the methylene blue that was intraoperatively administered in the peritumoral subserosal tissue. All blue colored nodes were histopathologically examined. In the node negative cases immunohistochemical stains using AE1/AE3 keratin were performed.The blue SLNs were identified in 48 out of the 50 cases included in the study, with a 96% sensitivity and 87.50% specificity. From the 48 cases, 34 (70.83%) presented positive SLNs; in the other 14 cases the SLNs were negative (29.17%). False negativity was observed in 6 of the 14 cases. In 2 of the cases the false negativity of the group 20 was induced by the anthracotic pigment. In other 2 false negative cases, although no regional metastases were founded, sentinel skip metastases in the group 8 and 15, respectively, were identified.Mapping of the SLNs is a simple and cheap method that might improve the accuracy of LN-based staging of patients with GC and favor identification of skip metastases.

Techniques and Current Role of Sentinel Lymph Node (SLN) Concept in Gastric Cancer Surgery

Gastric cancer patients represent a rather divergent patient group and in certain carefully selected cases of early forms of gastric cancer the D2 gastrectomy could be considered a more radical procedure than the biological and oncological characteristics of the primary tumor on the gastric wall would require. As any unnecessary dissection increases morbidity without always respective survival benefits, an approach that could accurately predict and actually dictate the exact extent of lymph node dissection would be ideal. It is more than logical the assumption that the standard D2 lymphadenectomy could represent an overtreatment in distinct patients groups such as patients with early gastric cancer with favorable pathological characteristics and clinically negative nodes not suitable for endoscopic treatment because this early stage disease shows limited lymph node metastasis incidence and excellent overall survival. Considering that the D2 gastrectomy has a negative impact on the quality of life of gastric cancer patients due to the post-gastrectomy functional results, a concept of a more targeted lymph node dissection, when appropriate, is certainly appealing. It is yet to be proven whether sentinel lymph node navigation surgery can fulfill such expectations providing the appropriate balance between morbidity and oncological safety in selected gastric cancer patients.

Risk factors for lymph node metastasis in non-sentinel node basins in early gastric cancer: sentinel node concept

BACKGROUND

Sentinel node (SN) concept is being applied to early gastric cancer. However, when SNs are positive for metastasis, it is unclear how often LNs in other LN basins show metastasis. We aimed to investigate LN metastasis possibility in LN basins without SNs (non-SN basins). We determined risk factors for metastasis in non-SN basins and identified a prediction model for non-SN basin metastasis using classification and regression tree (CART) analysis.

METHODS

We enrolled 550 patients who were diagnosed with cT1N0M0 or cT2N0M0 gastric cancer with a single lesion and underwent SN mapping. We adopted a dual-tracer method using a radioactive colloid and blue dye to detect SNs.

RESULTS

Of all, 45 (8.2%) patients had SN metastasis; we divided them into two groups: LN metastasis positive and LN metastasis negative in non-SN basins. Univariate analysis showed that the groups differed significantly regarding lymphatic invasion (p = 0.007), number of identified SNs (p = 0.032), and macrometastasis in SN basins (p = 0.005). The CART decision tree for predicting LN metastasis in non-SN basins had area under the curve value of 0.86. Moreover, there were significantly differences in cancer-specific survival (CSS) between the two groups (p = 0.028).

CONCLUSIONS

Macrometastasis in SN basins, lymphatic invasion, and number of identified SNs ≥ 5 are risk factors for LN metastasis in non-SN basins among gastric cancer patients. We identified a prediction model with CART analysis; patients with macrometastasis in SN basins and lymphatic invasion were considered to be at the highest risk for LN metastasis.

Sealed endoscopic full-thickness resection for gastric cancer: a pilot study in an ex vivo and in vivo porcine model

Background and study aims  Endoscopic full-thickness resection (EFTR) is a useful procedure that allows minimal resection of the gastric wall because the tumor can be located endoscopically. However, the procedure carries a risk of peritoneal infection or dissemination. Thus, we devised a new EFTR technique in which the serosa is sealed using a silicone sheet to prevent the escape of gastric juice. Materials and methods  Three whole stomachs were harvested from pigs for an ex vivo experiment, and seven pigs were used for an in vivo experiment. In both experiments, silicone sheets and gauze were pasted to the serosa using a fibrinogen-thrombin solution. A seromuscular incision was then made endoscopically using a HookKnife. We then evaluated whether stomach collapse could be prevented using this technique. Furthermore, the method was compared with conventional laparoscopic-assisted EFTR (LA-EFTR) in terms of resection time and quality of endoscopic view. Results  In the ex vivo experiment, stomach collapse was suppressed and the seromuscular layer could be incised layer by layer. In the in vivo experiment, the time required for seromuscular incision with the new EFTR technique was significantly shorter than that with the conventional method. All layers of the stomach were smoothly resected under good endoscopic view. Conclusions  Sealed EFTR is a potentially useful technique for the minimally invasive resection of gastric tumor. All layers of the stomach could be incised while confirming the incision line from the inside of the stomach and avoiding exposure of the tumor to the abdominal cavity.

Laparoscopic and endoscopic cooperative surgery for gastric tumors: Perspective for actual practice and oncological benefits

Laparoscopic and endoscopic cooperative surgery (LECS) is a surgical technique that combines laparoscopic partial gastrectomy and endoscopic submucosal dissection. LECS requires close collaboration between skilled laparoscopic surgeons and experienced endoscopists. For successful LECS, experience alone is not sufficient. Instead, familiarity with the characteristics of both laparoscopic surgery and endoscopic intervention is necessary to overcome various technical problems. LECS was developed mainly as a treatment for gastric submucosal tumors without epithelial lesions, including gastrointestinal stromal tumors (GISTs). Local gastric wall dissection without lymphadenectomy is adequate for the treatment of gastric GISTs. Compared with conventional simple wedge resection with a linear stapler, LECS can provide both optimal surgical margins and oncological benefit that result in functional preservation of the residual stomach. As technical characteristics, however, classic LECS involves intentional opening of the gastric wall, resulting in a risk of tumor dissemination with contamination by gastric juice. Therefore, several modified LECS techniques have been developed to avoid even subtle tumor exposure. Furthermore, LECS for early gastric cancer has been attempted according to the concept of sentinel lymph node dissection. LECS is a prospective treatment for GISTs and might become a future therapeutic option even for early gastric cancer. Interventional endoscopists and laparoscopic surgeons collaboratively explore curative resection. Simultaneous intraluminal approach with endoscopy allows surgeons to optimizes the resection area. LECS, not simple wedge resection, achieves minimally invasive treatment and allows for oncologically precise resection. We herein present detailed tips and pitfalls of LECS and discuss various technical considerations.

Fluorescent-guided surgery for sentinel lymph node detection in gastric cancer and carcinoembryonic antigen targeted fluorescent-guided surgery in colorectal and pancreatic cancer

Sentinel lymph node procedures for gastric cancer resections using indocyanine green (ICG) linked to Nanocoll outperformed normal ICG but did not provide information on possible lymph node metastasis. Carcinoembryonic antigen targeted fluorescent imaging using SGM‐101 was successful in both pancreatic and colorectal cancer. A large phase III multicentre trial will soon be initiated in colorectal cancer patients.

Interaction between Medical Treatment and Minimally Invasive Surgical Treatment for the Malignancies of the Digestive Tract

Recently, endoscopic diagnosis and treatment methods for early cancer in the digestive tract have made rapid progress. As for surgery, laparoscopic and thoracoscopic techniques have achieved rapidly advancing development in the last 2 decades. Early detection of the malignant lesion and the evolution of endoscopic and surgical device enabled in performing the minimally invasive surgery. Collaboration of medical treatment and minimally invasive surgery for advanced cancer is ongoing in the case of some conditions and in a few institutes. In this review, the contents of the core symposia on "Interaction between medical treatment and minimally invasive surgical treatment for the malignancies of the digestive tract", held at the 11, 12 and 13th annual meeting of the Japanese Gastroenterological Association, are summarized. At each annual meeting, the core symposium focused primarily on gastric, colorectal, and esophageal cancer treatment. For gastric cancer, endoscopic resection and laparoscopic surgery were 2 important key words. For colorectal cancer, multidisciplinary therapy was a major key word. And for esophageal cancer, endoscopic resection, chemoradiotherapy, thoracoscopic surgery and salvage surgery were key words. Patients' survival and quality of life are expected to further advance as a result of the collaboration of such therapeutic modalities.

Quantitative assessment of fluorescence intensity of ICG in sentinel nodes in early gastric cancer

BACKGROUND

The sentinel node (SN) detection by dual tracer method using indocyanine green (ICG) and a radioisotope (RI) has been recommended for early gastric cancer. However, institutions are limited due to radioactivity in the RI method. The greatest advantage of the RI method is that it objectively assesses RI uptake as a numerical value. The aim of the present study was to verify the usefulness of ICG fluorescence intensity in SN.

METHODS

Seventeen patients with early gastric cancer were enrolled in this study. RI uptake by each lymph node was measured using Navigator GPS and fluorescence nodes were identified using the hyper eye medical system (HEMS). Fluorescence intensity in fluorescence nodes was evaluated using ICG intensity imaging software (Mizuho, Japan) of the HEMS.

RESULTS

The total number of dissected lymph nodes was 227, with an average of 13.3 per patient. The numbers of HN, FN-S, and FN-B were 64, 77, and 34. RI uptake was significantly greater by FN-S than by non-FN-S (P = 0.0016). The median fluorescence intensity value was higher in HN than in non-HN (P < 0.001). A correlation was observed between RI uptake and fluorescence intensity. Dissecting FNs with fluorescence intensity levels of 1-6 resulted in 92.1% dissection of HNs.

CONCLUSION

It is possible that the evaluation of fluorescence intensity is useful for selected SNs instead of RI tracer. If fluorescence intensity is measurable in surgery, an infrared fluorescence method using ICG may be useful and safe for the detection of SN in early gastric cancer.

Sentinel Node Navigation Surgery for Early Gastric Cancer: Analysis of Factors Which Affect Direction of Lymphatic Drainage

BACKGROUND AND PURPOSE

We started performing sentinel node navigation surgery (SNNS) for patients with early gastric cancer (EGC) using infrared ray electronic endoscopy (IREE) with indocyanine green injection from year 2000. The EGCs usually have complex lymphatic drainage, unidirectional or multidirectional lymphatic flow. In this study, we investigated and clarified factors that affect the direction of gastric lymphatic drainage.

PATIENTS AND METHOD

Consecutive 60 patients with EGC who underwent SNNS by IREE from year 2006 to 2014 were enrolled to this study. Patients' age, gender, location of tumors, operative method, previous treatment by endoscopic submucosal dissection (ESD), presence of pathological ulcerative scar and maximum tumor diameter were enrolled as parameters which may affect direction of lymphatic drainage and analyzed.

RESULT

Bivariate analysis demonstrated that the presence of pathological ulcerative scar (P = 0.01), tumor location (g.c vs. a.w vs. p.w vs. l.c, P = 0.01), and maxim tumor diameter (P = 0.0003) were relevant to direction of gastric lymphatic drainage. Multivariate analysis showed that tumor location (g.c/a.w/p.w vs. l.c, odds ratio 8.227, P = 0.011) and the maximum tumor diameter (odds ratio 1.057, P = 0.037) are independent factors that affect direction of gastric lymphatic flow. Of tumors, 78% located at lesser curvature had unidirectional lymphatic drainage, and 93% of tumors whose diameter was 40 mm and more had multidirectional lymphatic drainage.

CONCLUSION

Our investigation revealed that the tumor location and tumor diameter were the key factors which affect the direction of lymphatic drainage, which is useful fact to understand the complexity of gastric lymphatic drainage.

Sentinel node navigation surgery using near-infrared indocyanine green fluorescence in early gastric cancer

BACKGROUND

The aim of this study was to evaluate the feasibility of indocyanine green (ICG) fluorescent method for sentinel lymph node detection in early gastric cancer.

METHODS

Between December 2012 and December 2014, 28 cases of pilot examination were performed at Seoul National University Bundang Hospital. Advanced version of multispectral fluorescence organoscope was used to identify sentinel node by quantitative estimation of ICG fluorescent signal intensity. Sensitivity, specificity, false positive value were analyzed and compared with dual tracer method.

RESULTS

A total of 443 lymph nodes in 28 cases were examined and 184 sentinel nodes (41.5%) were identified by dual tracer method. The sensitivity using near-infrared ICG method was 98.9%. The specificity was 76.0% and false positive rate was 25.4% compared with dual tracer method. The adequate threshold for sentinel node detection was considered as 10% of maximum signal intensity.

CONCLUSION

New near-infrared ICG fluorescent method could be a promising protocol for sentinel node navigation surgery in early gastric cancer.

Update on the indications and results of sentinel node mapping in upper GI cancer

The clinical utilization of sentinel node (SN) mapping for early esophageal cancer or gastric cancer has been unclear for a long time. However, previous investigations regarding SN mapping of these cancers have shown relatively good results with regard to the detection rate and diagnostic accuracy for determining the lymph node status. SN mapping helps obtain information about individual metastatic status and allows the modification of the operation in early-stage upper gastrointestinal (GI) disease. Radio-guided methods for identifying SNs in early esophageal cancer have been established via endoscopic injection of technetium-99m tin colloid. Previous studies have reported that the SN concept seems valid, and radio-guided SN mapping can be feasible in cT1N0 esophageal cancer. SN navigation surgery are believed to have potential as strategies for minimally invasive modified surgery for early esophageal cancer. A Japanese study group conducted a prospective multicenter trial of SN mapping for early gastric cancer using a dual tracer method with radioactive colloid and blue dyes; they demonstrated a high detection rate and accuracy for determining the metastatic status based on SN mapping. Subsequently, minimized gastrectomy, including partial gastrectomy and segmental gastrectomy with individualized selective and modified lymphadenectomy for early gastric cancer with a negative SN has been performed to evaluate the long-term survival and postoperative quality of life (QOL) in a multicenter prospective trial. This study verified the SN concept in early-stage upper GI disease with cN0 and found that function-preserving esophagectomy or gastrectomy may help maintain patients' post-surgical QOL.

Future Perspectives of Surgery for Esophageal Cancer

Esophageal cancer is one of the leading causes of cancer-related death worldwide. Surgery plays an important role in the treatment strategies for esophageal cancer. Recent advances in surgical techniques and perioperative management have dramatically improved the mortality rate; however, esophagectomy remains a highly invasive procedure that can lead to severe postoperative complications. Future advances in thoracoscopic surgery with the development of surgical endoscopy systems such as three-dimensional (3D) imaging systems with a 4K ultra high-definition camera or two-dimensional (2D) imaging systems with an 8K camera, which is expected to provide 3D-like visual sensation, will enable us to further understand the microscopic anatomy of the thoracic cavity and mediastinum, and to perform delicate surgical procedures that enable minimally invasive esophagectomy with mediastinal lymphadenectomy. A robot-assisted thoracoscopic esophagectomy is attractive for surgeons and may be beneficial to esophageal cancer patients. Preoperative simulation and intraoperative real-time navigation are expected to further help surgeons safely perform esophagectomy with lymphadenectomy. Reduction of the lymphadenectomy field and setting of lymphadenectomy areas with highest priority may be feasible when sentinel node (SN) navigation is appropriately performed in cN0 early-stage esophageal cancer. These technical advances are expected to decrease the morbidity and mortality rate of surgery for esophageal cancer and hopefully improve oncological outcomes.

Diagnostic accuracy of T stage of gastric cancer from the view point of application of laparoscopic proximal gastrectomy

The preoperative diagnosis of T stage is important in selecting limited treatments, such as laparoscopic proximal gastrectomy (LPG), which lacks the ability to palpate the tumor. Therefore, the present study examined the accuracy of preoperative diagnosis of the depth of tumor invasion in early gastric cancer from the view point of the indication for LPG. A total of 193 patients with cT1 gastric cancer underwent LPG with gastrointestinal endoscopic examinations and a series of upper gastrointestinal radiographs. The patients with pT1 were classified into the correctly diagnosed group (163 patients, 84.5%), and those with pT2 or deeper were classified into the underestimated group (30 patients, 15.5%). Factors that were associated with underestimation of tumor depth were analyzed. Tumor size in the underestimated group was significantly larger; the lesions were more frequently located in the upper third of the stomach and were more histologically diffuse, scirrhous, with infiltrative growth, and more frequent lymphatic and venous invasion. For upper third lesions, in univariate analysis, histology (diffuse type) was associated with underestimation of tumor depth. Multivariate analysis found that tumor size (≥20 mm) and histology (diffuse type) were independently associated with underestimation of tumor depth. gastric cancer in the upper third of the stomach with diffuse type histology and >20 mm needs particular attention when considering the application of LPG.

Safety of Laparoscopic Sentinel Basin Dissection in Patients with Gastric Cancer: an Analysis from the SENORITA Prospective Multicenter Quality Control Trial

Purpose

We investigated complications after laparoscopic sentinel basin dissection (SBD) for patients with gastric cancer who were enrolled in a quality control study, prior to the phase III trial of sentinel lymph node navigation surgery (SNNS).

Materials and Methods

We analyzed prospective data from a Korean multicenter prerequisite quality control trial of laparoscopic SBD for gastric cancer and assessed procedure-related and surgical complications. All complications were classified according to the Clavien-Dindo Classification (CDC) system and were compared with the results of the previously published SNNS trial.

Results

Among the 108 eligible patients who were enrolled in the quality control trial, 8 (7.4%) experienced complications during the early postoperative period. One patient with gastric resection-related duodenal stump leakage recovered after percutaneous drainage (grade IIIa in CDC). The other postoperative complications were mild and patients recovered with supportive care. No complications were directly related to the laparoscopic SBD procedure or tracer usage, and there were no mortalities. The laparoscopic SBD complication rates and patterns that were observed in this study were comparable to those of a previously reported trial.

Conclusions

The results of our prospective, multicenter quality control trial demonstrate that laparoscopic SBD is a safe procedure during SNNS for gastric cancer.

Laparoscopic and endoscopic cooperative surgery for intra-mucosal gastric carcinoma adjacent to the ulcer scars

Background

Laparoscopic and endoscopic cooperative surgery (LECS) was performed for the local resection of gastrointestinal stromal tumors (GIST). LECS enables less resection of the lesion area and preserves function. Furthermore, LECS can be safely performed and independent of tumor location. However, LECS is not usually used for cases involving gastric carcinoma because it may seed tumor cells into the peritoneal cavity when the gastric wall is perforated. Here, we report seven cases of LECS for intra-mucosal gastric carcinoma, which were difficult to carry out by endoscopic submucosal dissection (ESD) because of ulcer scars.

Methods

We performed LECS (classical LECS and inverted LECS) in seven cases of intra-mucosal gastric carcinoma. All cases had ulcer scars beside the tumor. LECS was chosen because ESD was thought to be difficult because of the ulcer scars. We only selected cases in which the patients did not prefer gastrectomy and endoscopic examination was indicative of intra-mucosal gastric carcinoma.

Results

In all cases, LECS was performed without severe complications including postoperative stenosis. Histopathology findings proved that the tumors were intra-mucosal carcinoma and had been resected completely. Furthermore, there were ulcer scars (Ul IIIs-IVs) beside the tumor. Currently, dissemination and recurrence have not been apparent.

Conclusions

LECS for intra-mucosal gastric carcinoma is an efficient procedure, but strict observation is necessary because of the possibility of peritoneal dissemination. Results suggest that LECS is likely to be effective for cases involving intra-mucosal gastric carcinoma that are difficult to treat by ESD due to ulcer scars.

Diagnostic evaluation of sentinel lymph node biopsy using indocyanine green and infrared or fluorescent imaging in gastric cancer: a systematic review and meta-analysis

BACKGROUND

Sentinel node navigation surgery (SNNS) for gastric cancer using infrared visualization of indocyanine green (ICG) is intriguing because it may limit operative morbidity. We are the first to systematically review and perform meta-analysis on the diagnostic utility of ICG and infrared electronic endoscopy (IREE) or near infrared fluorescent imaging (NIFI) for SNNS exclusively in gastric cancer.

METHODS

A search of electronic databases MEDLINE, EMBASE, SCOPUS, Web of Science, and the Cochrane Library using search terms "gastric/stomach" AND "tumor/carcinoma/cancer/neoplasm/adenocarcinoma/malignancy" AND "indocyanine green" was completed in May 2017. Articles were selected by two independent reviewers based on the following major inclusion criteria: (1) diagnostic accuracy study design; (2) indocyanine green was injected at tumor site; (3) IREE or NIFI was used for intraoperative visualization. 327 titles or abstracts were screened. The quality of included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2.

RESULTS

Ten full text studies were selected. 643 patients were identified with the majority of patients possessing T1 tumors (79.8%). Pooled identification rate, diagnostic odds ratio, sensitivity, and specificity were 0.99 (0.97-1.0), 380.0 (68.71-2101), 0.87 (0.80-0.93), and 1.00 (0.99-1.00), respectively. The summary receiver operator characteristic for ICG + IREE/NIFI demonstrated a test accuracy of 98.3%. Subgroup analysis found improved test performance for studies with low-risk QUADAS-2 scores, studies published after 2010 and submucosal ICG injection. IREE had improved diagnostic odds ratio, sensitivity, and identification rate compared to NIFI. Heterogeneity among studies ranged from low (I² < 25%) to high (I² > 75%).

CONCLUSIONS

We found encouraging results regarding the accuracy, diagnostic odds ratio, and specificity of the test. The sensitivity was not optimal but may be improved by a strict protocol to augment the technique. Given the number and heterogeneity of studies, our results must be viewed with caution.

Clinical outcomes of minimally invasive treatment for early gastric cancer in patients beyond the indications of endoscopic submucosal dissection

BACKGROUND

Endoscopic submucosal dissection (ESD) with laparoscopic sentinel lymph node dissection (ESN) and endoscopic full-thickness gastric resection with laparoscopic sentinel lymph node dissection (Hybrid-natural orifice transluminal endoscopic surgery, Hybrid-NOTES) are minimally invasive treatment options for early gastric cancer (EGC) beyond the indications of ESD. This study aimed to evaluate the short- and long-term clinical outcomes of ESN and Hybrid-NOTES.

METHODS

We retrospectively analyzed patients who had undergone ESN or Hybrid-NOTES for EGC from January 2009 to March 2013. A total of 48 patients, including 21 undergoing ESN and 27 undergoing Hybrid-NOTES, were enrolled. All patients had cancer stage T1N0M0, EGC less than 5 cm in size, and suspected submucosal invasion according to imaging or biopsy-proven diffuse-type histology.

RESULTS

In ESN and Hybrid-NOTES, the curative resection rates were 76.5% and 90.9% of patients, respectively. In the ESN group, 5 patients underwent an additional gastrectomy (1 for lymph node metastasis (LNM), 3 for surgical complications, and 1 for noncurative resection). In the Hybrid-NOTES group, 6 patients underwent additional gastrectomy, (1 for LNM, 3 for surgical complications, and 2 for noncurative resection). Of the 37 patients who were followed up in the long-term (a median follow-up of 59.8 months), one was found to have liver metastasis after ESN and received palliative chemotherapy.

CONCLUSIONS

ESN and Hybrid-NOTES have shown favorable long-term outcomes despite their technical limitations. These methods may be utilized as a bridge between ESD and gastrectomy in cases of EGC with a high risk of LNM beyond the ESD indications.

Potential for peritoneal cancer cell seeding in endoscopic full-thickness resection for early gastric cancer

BACKGROUND AND AIMS

During endoscopic full-thickness resection (EFTR) for cancers, whether exposure of the lumen to the abdominal cavity during the procedure is acceptable is controversial because of the potential risk of tumor cell seeding. To assess the possibility of transplantation as a result of contact with tumor cells during the procedure, we prospectively investigated the ability of cancer cells to be detached by touching the tumor surface.

METHODS

In 48 patients with a single early gastric cancer resected by endoscopic submucosal dissection, stamp cytology was performed by touching the surface of the specimens to glass slides. Samples were obtained from cancerous and noncancerous areas, constituting the study and control groups, respectively. The detection rate of malignant class IV or V (C-IV/C-V) samples was investigated with Papanicolaou staining. The rate of CD44v9-positive cases, a cancer stem cell marker, was assessed in C-IV/C-V samples with immunohistochemical staining.

RESULTS

Detection rates of C-IV/C-V samples in the cancerous group (53/192 slides, 27.6%) differed significantly from those of the C-IV/C-V samples in the noncancerous group (0/96 slides, 0%). Among the 53 slides of C-IV/C-V samples in the cancerous group, CD44v9 cells were expressed in 18 slides (34.0%).

CONCLUSIONS

These data suggest that cancer cells, including cancer stem cells, in early gastric cancers are easily detached via contact with the tumor surface. In EFTR, a nonexposure approach is recommended to avoid the risk of iatrogenic cancer cell seeding via contact with and transplantation of cancer cells.

Update on the Treatment of Gastric Cancer

Gastric cancer remains a major health concern worldwide, particularly in Asia. Surgery is the only curative treatment, and D2 gastrectomy is the standard therapy for resectable cases. Several clinical trials have been conducted in Japan to achieve higher cure rates via extended surgery; however, despite higher morbidity, none demonstrated prolonged survival. Against this background, minimally invasive surgical approaches that preserve gastric function and improve postoperative quality of life have been developed in recent years. For early gastric cancer, endoscopic resection and laparoscopic gastrectomy have achieved remarkable success even for later-stage cases. Long-term outcomes have been investigated in large-scale, randomized controlled trials. In addition, robot-assisted gastrectomy is now more common in clinical practice. S-1, an anti-tumor drug, is a key agent for treating gastric cancer and has resulted in dramatic improvements in survival. For locally advanced gastric cancer, patients are usually treated with surgery and adjuvant or neoadjuvant chemotherapy, and the efficacies of various regimens have been examined in many clinical trials. For unresectable or recurrent gastric cancer, new agents such as molecular-targeted agents and immune checkpoint inhibitors have emerged as notable treatments and are now being tested in numerous clinical trials. This review provides an update on gastric cancer treatment, highlighting current individualized strategies and future perspectives.

Fluorescence image-guided lymphadenectomy using indocyanine green and near infrared technology in robotic gastrectomy

In recent years, some researchers have tried to find a way to improve the surgical identification of the lymphatic drainage routes and lymph node stations during radical gastrectomy, thus starting a new research frontier in this field called " navigation surgery”. Among the different reported solutions, the introduction of the indocyanine green (ICG) has drawn attention for its characteristics, a fluorescence dye that can be detected in the near infrared spectral band (NIR). A fluorescence imaging technology has been integrated in the latest version of the Da Vinci robotic system and surgeons have extensively reported their experiences in colorectal and hepato-biliary surgery for tumors, vascular and lymphatic structures visualization. However, up to date, the combined use of fluorescence imaging and robotic technology has not been adequately investigated during lymphadenectomy in gastric cancer.

Gastric Cancer in Asia: Unique Features and Management

Gastric cancer (GC) poses a burden to patients across the globe as the third leading cause of cancer deaths worldwide. Incidence of GC is particularly high in Asian countries, which is attributed to the prevalence of Helicobacter pylori (H. pylori) infection and has prompted the establishment of unique treatment strategies. D2 gastrectomy, which was established in the 1950s in Japan, has served as a gold standard for locally advanced GC for over half a century. Since the beginning of the 21st century, endoscopic resection (ER) techniques and minimally invasive laparoscopic surgery have greatly changed the treatment of patients with early GC. S-1, which showed a striking survival benefit in a large randomized trial in Japan, has been used as adjuvant therapy for the last decade. Likewise, S-1-based chemotherapy regimens are currently the standard of care for the treatment of unresectable/metastatic GC in Asia. Along with the development of standardized therapy, novel techniques and new drugs have been rapidly brought into clinical practice. State-of-the-art sentinel node (SN) navigation surgery enables clinicians to perform truly minimally invasive surgery for early GC, and appropriate chemotherapy regimens are now determined by a tumor's molecular expression. New classifications based on gene signatures are proposed and may replace conventional clinical classifications. Such highly individualized treatment has the potential to alter our clinical practice in GC in the near future. The best practice in each geographic region should be shared and integrated, resulting in the best practice without borders.

Non-exposure simple suturing endoscopic full-thickness resection (NESS-EFTR) versus laparoscopic wedge resection: a randomized controlled trial in a porcine model

BACKGROUND

Current endoscopic full-thickness resection (EFTR) methods produce transmural communication and expose the tumor to the peritoneum. An EFTR method with a simple suturing technique that does not expose the gastric mucosa to the peritoneum (non-exposure simple suturing, NESS) was recently developed. To date, there have been no prospective studies that compare EFTR with laparoscopic wedge resection in human or animal. The aim of this study was to compare outcomes between NESS-EFTR and laparoscopic wedge resection (LWR) using the linear staplers in a randomized animal study.

METHODS

NESS-EFTR includes steps of laparoscopic seromuscular suturing, EFTR of the inverted stomach wall, and endoscopic mucosal suturing with endoloops and clips. Sixteen pigs underwent NESS-EFTR (n = 8) or LWR (n = 8). The resected locations were the cardia, fundus, upper body anterior and greater curvature, antrum lesser and greater curvature side. The pigs were killed 3 weeks after surgery. Rates of successful complete resection (en-bloc resection with clear margins), successful closure, and complications were evaluated.

RESULTS

The complete resection rates in the NESS-EFTR and LWR groups were 100 and 75%, respectively (P = 0.467). All wounds were successfully closed in both groups. Resected tissues were significantly larger in the LWR group (mean ± SD: 8.0 ± 0.8 cm vs. 4.4 ± 0.5 cm, P < 0.001). Procedure time was significantly shorter in the LWR group (31.7 ± 10.0 min vs. 118.1 ± 23.4 min, P < 0.001). Early deaths due to complications only occurred in the LWR group (a leakage at cardia and a stenosis at the antrum lesser curvature side).

CONCLUSIONS

Incomplete resection and complications were occurred in only LWR group. NESS-EFTR was feasible and safe in animal.

Novel surgical approach based on the sentinel node concept in patients with early gastric cancer

Recent prospective multicenter trials have demonstrated the clinical safety and efficacy of sentinel node navigation surgery (SNNS) in patients with early gastric cancer. Further, development of an intraoperative imaging system and an indocyanine green fluorescence imaging approach has been attracting attention as a novel tool for detection of the sentinel node (SN). The greatest advantage of an in vivo imaging system is that it visualizes SN and afferent lymphatic vessels from the primary tumor site more clearly than the conventional dye approach. Besides visualization of the SN, it is also essential to accurately assess the presence or absence of lymph node metastasis in the intraoperative management of SNNS. However, the clinical significance of lymph node micrometastasis (LNM) in patients with gastric cancer remains controversial. Reverse transcription‐polymerase chain reaction (RT‐PCR) is one of the representative assays used to identify LNM. A rapid RT‐PCR assay that completes the detection of LNM within approximately 40 minutes has recently been produced and applied in the clinical management of SNNS. From the viewpoint of surgical methods, modified laparoscopic and endoscopic cooperative surgery with non‐exposed approaches has recently been highlighted as a promising technique to prevent tumor dissemination caused by surgical procedures, and is likely to be clinically applied to SNNS in the future. When carrying out SNNS as a minimally invasive surgery, it is important to consider the balance between post‐surgical quality of life and curability. Future prospective studies on SNNS will greatly contribute to furthering its establishment as a beneficial procedure for patients with early gastric cancer.

New method of indocyanine green fluorescence sentinel node mapping for early gastric cancer

BACKGROUND

The present study describes the retrospective feasibility study of ICG fluorescence SN mapping in back-table for early gastric cancer using PINPOINT®.

METHOD

SN mapping were performed as following; the day before surgery, 0.5 ml ICG was injected endoscopically in four quadrants of the submucosa surrounding the gastric cancer using an endoscopic puncture. Intraoperatively, the gastrocolic ligament was divided to visualize all possible directions of lymphatic flow from the stomach. PINPOINT® (NOVADAQ, Canada) was used to illuminate regional lymph nodes from the serosal side. Positive staining was confirmed by at least 3 surgeons and an endoscopist during surgery (Figure 1). Lymph node dissection and gastrectomy were performed according to the criteria of gastric cancer treatment guidelines of JGCA.

RESULT

All 6 patients had gastrectomy with laparoscopic approach. ICG positive lymphatic flow and lymph nodes were able to be observed in all the patients. Final pathological diagnosis was all StageI and curative resection. All the patients had ICG positive lymphatic area in left gastric artery (LGA) area. Two patients with tumor located in L area had ICG positive flow to right gastroepipoloic artery (RGEA) area. The mean of ICG positive lymph nodes was 8.6. One patient had a metastatic lymph node in station No.4, which was positive for ICG.

CONCLUSION

Our method made identification of ICG positive lymph nodes easy in SN mapping in back-table under room light. Although further accumulation and analysis are necessary, we may be able to apply this method for intraoperative SN mapping of laparoscopic gastric cancer surgey.

Management of early gastric cancer that meet the indication for radical lymph node dissection following endoscopic resection: a retrospective cohort analysis

BACKGROUND

Endoscopic resection (ER) has been widely accepted as the standard treatment for early gastric cancer (EGC). However, in patients considered to have undergone non-curative ER due to their potential risk of lymph node metastasis (LNM), additional gastrectomy is recommended. The aim of the present study was to identify EGC patients after non-curative ER at high risk of LNM.

METHODS

A total of 150 patients who had undergone ER for EGC were diagnosed as non-curative ER due to their potential risk of LNM. Clinicopathological data and clinical outcomes were examined retrospectively.

RESULTS

Additional gastrectomy with lymph node dissection was performed in 73 patients, and the remaining 77 patients were followed-up without additional gastrectomy. In patients who underwent additional gastrectomy, 8 patients had local residual tumor, and 8 patients had LNM, which were limited in the peritumoral nodes. Only lymphatic invasion (p = 0.012) was a statistically significant factor for LNM. The 5-year overall survival and recurrence-free survival were not significantly different between patients with and without additional gastrectomy.

CONCLUSION

Additional gastrectomy with lymph node dissection is recommended for patients who were diagnosed as non-curative ER with lymphatic invasion, and minimizing the extent of lymph node dissection may be allowed for these patients.

Utility of the sentinel node concept for detection of lateral pelvic lymph node metastasis in lower rectal cancer

Background

There are two lymphatic flows in lower rectal cancer; one along the inferior mesenteric artery and another towards the internal iliac artery. The benefit of dissection of lateral pelvic (LP) lymph nodes (LPLN) remains controversial. This study aimed to clarify the possibility of detecting the sentinel node (SN) of the LP region (LPSN) and examine metastasis, including micrometastasis, using a radio isotope (RI) method.

Methods

In total, 62 patients with clinical (c)T1-T4 rectal cancer were enrolled in this study (11, 16 and 35 patients had tumor located in the upper, middle and lower rectal third, respectively). LPSNs were detected using a radio-isotope method in which 99 m technetium-tin colloid was endoscopically injected into the submucosa in patients with cT1, and into the muscularis propria in patients with cT2, cT3 and cT4. All patients underwent curative resection with lymphadenectomy. LPSN metastases were diagnosed by HE staining, immunohistochemical staining using AE1/AE3 as a primary antibody and by RT-PCR using CEA as a marker.

Results

Of the lower rectal (c)T2–4 tumors, 38.4% had lateral pelvic lymphatic flow that was significantly greater than that of cT1 tumors in the upper and middle thirds of the rectum (p = 0.0074). HE and immunohistochemical staining did not detect LPSN metastases but RT-PCR detected micrometastasis of three SNs. The remaining half of LPSNs were immunohistochemically re-examined; in all three cases, isolated tumor cells were detected.

Conclusion

The SN concept may be useful for detecting lateral pelvic lymphatic flow and LPSN metastases, including micrometastasis in lower rectal cancer.

Which Factors Are Important for Successful Sentinel Node Navigation Surgery in Gastric Cancer Patients? Analysis from the SENORITA Prospective Multicenter Feasibility Quality Control Trial

Background

We investigated the results of quality control study prior to phase III trial of sentinel lymph node navigation surgery (SNNS).

Methods

Data were reviewed from 108 patients enrolled in the feasibility study of laparoscopic sentinel basin dissection (SBD) in gastric cancer. Seven steps contain tracer injection at submucosa (step 1) and at four sites (step 2) by intraoperative esophagogastroduodenoscopy (EGD), leakage of tracer (step 3), injection within 3 minutes (step 4), identification of at least one sentinel basin (SB) (step 5), evaluation of sentinel basin nodes (SBNs) by frozen biopsy (step 6), and identification of at least five SBNs at back table and frozen sections (step 7).

Results

Failure in step 7 (n = 23) was the most common followed by step 3 (n = 15) and step 6 (n = 13). We did not find any differences of clinicopathological factors between success and failure group in steps 1~6. In step 7, body mass index (BMI) was only the significant factor. The success rate was 97.1% in patients with BMI  <  23 kg/m² and 80.3% in those with BMI ≥ 23 kg/m² (P = 0.028).

Conclusions

Lower BMI group showed higher success rate in step 7. Surgeons doing SNNS should be cautious when evaluating sufficient number of SBN in obese patients.

Sentinel Node Mapping Using a Fluorescent Dye and Visible Light During Laparoscopic Gastrectomy for Early Gastric Cancer: Result of a Prospective Study From a Single Institute

OBJECTIVE

The aim of this study was to investigate the feasibility of sentinel node mapping using a fluorescent dye and visible light in patients with gastric cancer.

BACKGROUND

Recently, fluorescent imaging technology offers improved visibility with the possibility of better sensitivity or accuracy in sentinel node mapping.

METHODS

Twenty patients with early gastric cancer, for whom laparoscopic distal gastrectomy with standard lymphadenectomy had been planned, were enrolled in this study. Before lymphadenectomy, the patients received a gastrofiberoscopic peritumoral injection of fluorescein solution. The sentinel basin was investigated via laparoscopic fluorescent imaging under blue light (wavelength of 440-490 nm) emitted from an LED curing light. The detection rate and lymph node status were analyzed in the enrolled patients. In addition, short-term clinical outcomes were also investigated.

RESULTS

No hypersensitivity to the dye was identified in any enrolled patients. Sentinel nodes were detected in 19 of 20 enrolled patients (95.0%), and metastatic lymph nodes were found in 2 patients. The latter lymph nodes belonged to the sentinel basin of each patient. Meanwhile, 1 patient (5.0%) experienced a postoperative complication that was unrelated to sentinel node mapping. No mortality was recorded among enrolled cases.

CONCLUSIONS

Sentinel node mapping with visible light fluorescence was a feasible method for visualizing sentinel nodes in patients with early gastric cancer. In addition, this method is advantageous in terms of visualizing the concrete relationship between the sentinel nodes and surrounding structures.

The Prevalence of Overall and Initial Lymph Node Metastases in Clinical T1N0 Thoracic Esophageal Cancer: From the Results of JCOG0502, a Prospective Multicenter Study

OBJECTIVE

To evaluate the sites and frequencies of overall and initial lymph node (LN) metastases (LNMs) of clinical T1N0 esophageal cancer.

BACKGROUND

The sites and frequencies of initial LNMs and sentinel LNs (SLNs) of esophageal cancer remain unclear.

METHODS

The Japan Clinical Oncology Group JCOG0502 trial was a 4-arm prospective study that compared esophagectomy with chemoradiotherapy for clinical T1N0 esophageal cancer in both randomized and patient-preference arms. The preoperative diagnostic accuracy was evaluated for patients assigned to the surgery arm. Patients who withdrew consent and who were not treated were excluded. All patients underwent esophagectomy with D2 or greater LN dissection. From the pathologic findings, sites and frequencies of LNMs and SLNs were assessed and the frequency of skip LNMs was calculated.

RESULTS

In total, 211 patients underwent LNM and SLN analysis. Regarding N-factor accuracy, 57 (27.0%) of 211 clinical N0 cases had pathologic LNMs. The upper mediastinal and mediastinal/abdominal regions were frequent sites of LNMs in upper and lower thoracic cases, respectively. However, in middle thoracic cases, LNMs were observed in the neck, mediastinal, and abdominal regions, and pathologic SLN spread to all 3 fields. The frequency of skip LNMs was 36.7%.

CONCLUSIONS

A clinical diagnosis of T1N0 is not sufficiently accurate, and therefore, it is unacceptable to omit LN dissection or minimize the prophylactic radiation field. SLNs, which are not location restricted, should be surveyed in all 3 fields.

Feasibility and diagnostic performance of dual-tracer-guided sentinel lymph node biopsy in cT1-2N0M0 gastric cancer: a systematic review and meta-analysis of diagnostic studies

BACKGROUND

Dual-tracer-guided sentinel lymph node (SLN) biopsy may provide a promising diagnostic tool to assess accurately the status of lymph node metastasis in the surgical operation and assure the oncologic safety of the function or stomach preserving surgery. The diagnostic performance of this technology in recent studies varied. Thus, we conducted this meta-analysis.

METHODS

This systematic review and meta-analysis was registered at the PROSPERO. Eligible studies were searched in the PubMed, EMBASE, Web of Knowledge, and Cochrane Library databases. A random-effect model was used to pool the data. Summary receiver operator characteristic curves, analysis for publication bias, meta-regression, and subgroup analysis were also performed.

RESULTS

The pooled SLN identification rate and sensitivity were 0.97 and 0.89. ^99mTc-human serum albumin with indocyanine green (ICG), ^99mTc-antimony sulfur colloid with ICG, performing SLN biopsy ≥15 min after dye injection, an SLN ≥5, the basin dissection, laparoscopic surgery, in studies conducted in Japan and studies published after 2012, were associated with higher sensitivity. CT1 stage, performing SLN biopsy ≥15 min after dye injection, in studies conducted in Japan and studies published after 2012, were related with a higher identification rate.

CONCLUSIONS

Dual tracer is promising in SLN biopsy in gastric cancer, and the clinical application of SLN biopsy should be limited to the patients of cT1N0M0 gastric cancer. The combination of ^99mTc-human serum albumin and ICG as well as the combination of ^99mTc-antimony sulfur colloid and ICG may be the optimal tracer combination. However, it seems not justified to put this technique into routine clinical application recently. Some factors that might enhance diagnostic value are identified.

Laparoscopic sentinel node navigation surgery for early gastric cancer

Currently, the most accurate method for identifying lymph node metastasis is intraoperative diagnosis by sentinel node (SN) biopsy. Based on the SNNS study-a recent large-scale, nationwide, multicenter prospective study-the SN concept seems to be scientifically valid in patients with early gastric cancer. SN biopsy is a multistep technique consisted of six essential elements: indication, the selection of a tracer, a proper tracer injection method, the objective detection of SNs, a reliable biopsy technique, and the precise detection of nodal metastasis. For SN biopsy of gastric cancer, these elements have been validated as follows: the indication should be limited to clinical T1 less than 4 cm in diameter; combination mapping with radioactive colloid and blue dye is used as the standard; and endoscopic submucosal injection is the standard tracer injection. Detection of SNs and a reliable biopsy technique are enabled by adaptation of lymphatic basin dissection, a proper biopsy technique for gastric cancer. Lymphatic basin dissection is a selective lymphadenectomy procedure for dissecting basins en bloc, collecting lymph nodes and lymphatic vessels stained with dye. Lymphatic basin dissection is superior to the ordinary pick-up method, not only for minimizing the rate of missed SNs, but also in terms of oncological safety as it complements an intraoperative frozen section diagnosis by serving as a backup dissection. Moreover, indocyanine green (ICG) fluorescence mapping has been developed in recent years. ICG fluorescence mapping is superior because of its high sensitivity and signal stability. Moreover, it is feasible for both open and laparoscopic gastrectomy in treating early gastric cancer. SN biopsy has brought dramatic changes to laparoscopic surgery for early gastric cancer. With laparoscopic SN biopsy using ICG fluorescence navigation, laparoscopic surgery for early gastric cancer has changed from the uniform standard gastrectomy with D1+ into a tailor-made function-preserving surgical procedure, such as local resection with lymphatic basin dissection.

Laparoscopic endoscopic cooperative surgery (LECS) for the upper gastrointestinal tract

We developed the laparoscopic and endoscopic cooperative surgery (LECS) technique, which combines endoscopic submucosal dissection (ESD) and laparoscopic gastric resection to resect gastric submucosal tumors (SMTs). Many researchers have reported LECS to be a feasible technique for gastric submucosal tumor resection regardless of tumor location, including the esophagogastric junction (EGJ). Recently, the Japanese National Health Insurance system approved LECS for insurance coverage, and it is now widely applied for gastric submucosal tumor resection. Initially, we applied LECS to gastric SMTs without ulcerative lesions due to concern about the possibility of tumor cells seeding into the peritoneal cavity, in a procedure termed "classical LECS". To expand the indication of LECS for gastric epithelial neoplasms, modified LECS procedures such as inverted LECS, non-exposed endoscopic wall-inversion surgery (NEWS), combination of laparoscopic and endoscopic approaches to neoplasia with non-exposure technique (CLEAN-NET), and closed laparoscopic and endoscopic cooperative surgery (closed-LECS) have been developed and applied to patients with gastric epithelial neoplasms. As a future perspective of LECS, we plan to combine the modified LECS procedure and sentinel node (SN) navigation surgery (SNNS) for clinical (c)Stage IA gastric cancer resection. This strategy could be a minimally invasive surgical technique for cStage IA early gastric cancer.

Clinical application and outcomes of sentinel node navigation surgery in patients with early gastric cancer

Sentinel node navigation surgery (SNNS) has been recognized as a minimally invasive tool for individualized lymphadenectomy in patients with early gastric cancer (EGC). The aim of this study was to compare clinicopathological factors, adverse events, and clinical outcomes between sentinel node mapping (SNM) and SN dissection (SND) groups and assess the clinical utility of SNNS in patients with EGC. The clinical data of 157 patients with EGC, diagnosed as clinical T1N0M0 with tumors ≤ 40 mm, undergoing SNNS between March 2004 and April 2016 were retrospectively reviewed. Twenty-seven patients were excluded from the analysis. In the remaining 130 patients, 59 and 71 patients underwent standard lymphadenectomy for SNM and SND, respectively. The sentinel node detection rate in the SNM and SND groups was 98.3% (58/59) and 100% (71/71), respectively. Two (3.5%), 15 (25.9%), and 41 (70.7%) patients having sentinel nodes underwent total gastrectomy, proximal gastrectomy (PG), and distal gastrectomy (DG), respectively, in the SNM group. One (1.4%), 5 (7.0%), 10 (14.1%), 39 (54.9%), and 16 (22.5%) patients underwent PG, DG, segmental gastrectomy, local resection, and endoscopic submucosal dissection, respectively, in the SND group. There was no significant difference in postoperative complications between the SNM and SND groups (P = 0.781). Survival did not differ between the both groups (P = 0.856). The present results suggest that personalized surgery with SND provides technical safety and curability related with a favorable survival outcome in patients with EGC.

Laparoscopic and endoscopic cooperative surgery for gastrointestinal tumor

With technological progress of endoscopic submucosal dissection (ESD) in the last decade, several laparoscopic and endoscopic cooperative surgeries (LECS) for gastrointestinal tumor have recently been developed. LECS is definitely favorable to the minimization of surgical margin, which leads to functional and anatomical preservation of gastrointestinal tract. LECS for gastrointestinal tumor is mainly sorted by two categories: exposure procedures and non-exposure procedures between endoluminal and extraluminal spaces. Exposure procedures have the potential risk of gastric contents or tumor cells spilling out over the abdominal cavity, because the stomach wall has to be perforated intentionally during the procedure. In order to avoid the potential these risks, non-exposure procedures have been developed. Currently, the LECS concept has rapidly permeated for treatment of gastrointestinal tumor due to its certainty and safety, although there is still room for improvement to lessen its technical difficulty. This review describes the current LECS for gastrointestinal tumor based on the several articles.

Function-preserving gastrectomy based on the sentinel node concept in early gastric cancer

Recent meta-analyses and a prospective multicenter trial of sentinel node (SN) mapping in early gastric cancer have demonstrated acceptable SN detection rates and accuracy of determination of lymph node status. SN mapping may play a key role in obtaining individual metastatic information. It also allows modification of surgical procedures, including function-preserving gastrectomy in patients with early gastric cancer. A dual-tracer method that uses radioactive colloids and blue dye is currently considered the most reliable method for the stable detection of SNs in patients with early gastric cancer. New technologies, such as indocyanine green infrared or fluorescence imaging, are also useful for accurate SN mapping in gastric cancer. Theoretically, laparoscopic function-preserving gastrectomy, including partial resection, proximal gastrectomy, segmental gastrectomy, and pylorus-preserving gastrectomy, is feasible in early gastric cancer when the SN(s) is/are nonmetastatic. Our study group conducted a multicenter prospective trial in Japan to evaluate function-preserving gastrectomy with SN mapping for long-term survival and patient quality of life. Non-exposed endoscopic wall-inversion surgery (NEWS) is a new technique for treating gastric cancer with partial resection involving full-thickness resection with endoscopy and laparoscopic surgery without transluminal access. The combination of NEWS and SN biopsy is expected to be a promising, minimally invasive, function-preserving surgery that is ideal for cases of cN0 early gastric cancer.

Current status and challenges in sentinel node navigation surgery for early gastric cancer

Although a number of feasibility studies for sentinel node (SN) concepts in gastric cancer have been conducted since 2000, there remains a debate regarding detailed detection techniques and oncological safety. Two important multicenter phase II clinical trials were performed in Japan that used different methods and reached different conclusions; one confirmed acceptable results with a false-negative rate of 7%, and the other showed an unacceptably high false-negative rate of 46.4%. The Sentinel Node Oriented Tailored Approach (SENORITA) trial is a multicenter randomized controlled phase III trial being performed in Korea. Patient enrollment is now complete and the long-term results are currently awaited. Recently, an image-guided SN mapping technique using infrared ray/fluorescence was introduced. This method might be a promising technology because it allows the clear visualization of SNs. With regard to the primary tumor, the non-exposed endoscopic wall-inversion surgery technique and non-exposure endolaparoscopic full-thickness resection with simple suturing technique have been reported. These methods prevent abdominal infection and tumor seeding and can be good alternatives to conventional laparoscopic gastric wedge resection. For indications, SN navigation surgery can be extended to patients who underwent non-curative endoscopic resection. Although a few studies have been performed on these patients, sentinel concepts may be beneficial to patients as they omit the need for additional gastrectomy. SN navigation surgery can lead to actual organ-preserving surgery and plays a key role in improving the quality of life of patients with early gastric cancer in the future.

Sentinel node navigation in gastric cancer: new horizons for personalized minimally invasive surgical oncology?

Complete (R0) resection and regional lymph nodes (LNs) dissection represent undoubtedly the basic surgical tools for patients with gastric cancer. It is reported that the LN metastasis rate in patients with early gastric cancer (EGC) is approximately 15-20%. Therefore, the innovative clinical application of sentinel node navigation surgery (SNNS) for EGC might be able to prevent unnecessary LN dissection as well as to reduce significantly the volume of gastric resection. Recent evidence suggests that double tracer methods appear superior compared to single tracer techniques. However, the researchers' interest is now focused on the identification of new LN detection methods utilizing sophisticated technology such as infrared ray endoscopy, fluorescence imaging and near-infrared technology. Despite its notable limitations, hematoxylin-eosin is still considered the mainstay staining for assessing the metastatic status of LNs. In this review, we summarize the current evidences and we provide the latest scientific information assessing safety, efficacy and potential limitations of the innovative sentinel node (SN) navigation technique for gastric cancer. We try also to provide a "view" towards a future potential application of personalized minimally invasive surgery in gastric cancer field.

Laparoscopic sentinel node navigation surgery for early gastric cancer: a prospective multicenter trial

BACKGROUND

Prospective multicenter trials have shown the feasibility of sentinel node (SN) navigation surgery using a dual tracer of dye and radioisotope for early gastric cancer. However, comparable trials using the indocyanine green (ICG) and the infrared ray laparoscopic system (IRLS) have not been reported. On the basis of our cohort studies, we assumed that the ICG imaging with the IRLS is as effective as the dual tracer in detecting SNs. Therefore, we conducted a prospective multicenter trial to assess the effectiveness and generalizability of the infrared ICG technique in patients with early gastric cancer.

PATIENTS AND METHODS

Patients with previously untreated cT1 gastric adenocarcinomas less than 4 cm in gross diameter were eligible for inclusion in this study. SN mapping was performed by using ICG combined with IRLS technique. Following biopsy of the identified SNs, D2 or modified D2 laparoscopic gastrectomy was performed according to the current Japanese Gastric Cancer Association guidelines.

RESULTS

Among the 47 patients who gave written informed consent, 44 were eligible from the surgical findings, for whom SN biopsy was performed. The detection rate of the lymphatic basin by the ICG with IRLS was 100% (44/44). The accuracy was also 100% (7/7) for detecting metastatic lymph node, which was verified on the permanent pathologic examination. Following the median follow-up of 114 months (range, 60 to 120 months), no recurrence (0/40) was observed. Although the number of patients was unequally distributed among the hospitals participating in the trial, the detection rates of SNs in low-volume hospitals were comparable to those in high-volume hospitals. Consequently, there was no learning curve in this trial.

CONCLUSION

The infrared ICG imaging accurately detected the lymphatic basin and SNs with occult metastasis in SN-navigated gastrectomy for gastric cancer. This method was feasible even for low-volume surgeons and hospitals.

Lymph node mapping with carbon nanoparticles and the risk factors of lymph node metastasis in gastric cancer

The study aimed to examine the applicability of carbon nanoparticles as a tracer for lymph node mapping and the related factors of lymph node and No.8p subgroup metastasis in patients with gastric cancer. Clinical data of 50 patients with gastric cancer, who had not received treatment preoperatively and underwent gastrectomy in Department of Gastrointestinal Surgery, Wuhan Union Hospital, between October 2014 and August 2015, were retrospectively analyzed. These patients were found to have no distant metastasis preoperatively. Thirty-five out of 50 patients were subjected to lymphatic mapping technique using carbon nanoparticles as the tracer, and the rest 15 cases did not experience the lymphatic mapping and served as controls. The sensitivity, specificity, false positive rate and false negative rate were calculated according to the number of lymph nodes, and the staining and metastasis condition of lymph nodes. The diagnostic value of carbon nanoparticles on metastatic lymph nodes was evaluated. The relationship between the metastasis of lymph nodes or subgroup No.8p lymph nodes and clinicopathologic features was analyzed by χ²-test or Fisher's exact test. All patients underwent D2 surgery (lymph node dissection including all the group 1 and group 2 nodes) plus the dissection of the subgroup No.8p lymph nodes. It was found that the average number of harvested lymph nodes in lymphatic mapping technique group (45.7±14.5) was greater than that in control group (39.2±11.7), but the difference was not significantly different (P=0.138>0.05). The success rate, the accuracy, sensitivity, specificity and false negative rate was 97%, 57%, 28%, 62% and 72% respectively. The metastasis of lymph nodes was correlated to the depth of cancer invasion (T stage) (P=0.004<0.05), and the metastasis of No.8p lymph nodes was correlated to the extent of lymph node involvement (N stage) (P=0.007<0.05). Six cases had lymph node metastasis in subgroup No.8p, and their TNM stages and clinical stages were as follows: T1N2M0 IIA, T3N3M0 IIIB, T4aN3M0 IIIC, T4aN3M0 IIIC, T4aN3M0 IIIC, and T4bN3M0 IIIC. In conclusion, our study indicated that carbon nanoparticles failed to show good selectivity for metastatic lymph nodes; the result of lymphatic mapping does not achieve a satisfactory performance; the incidence of lymph node metastasis may increase, accompanying with the increase of the depth of cancer invasion; No.8p lymph node metastasis tends to occur for gastric carcinoma patients with the extent of lymph node metastasis over N2 stage.

Sentinel Lymph Node Mapping In Gastric Cancer Surgery: Current Status

Lymphonodular metastases remain an important predictive and prognostic factor in gastric cancer development. The precise determination of the lymphonodular invasion stage can be made only by extended intraoperative lymphadenectomy and histopathological examination. But the main controversy is the usefulness of extended lymph dissection in early gastric cancer. This increases the duration of the surgery and the complications rate, and it is unnecessary without lymphonodular invasion. The identification of the sentinel lymph nodes has been successfully applied for some time in the precise detection of lymph nodes status in breast cancer, malignant melanoma and the use for gastric cancer patients has been a controversial issue. The good prognosis in early gastric cancer had been a surgery challenge, which led to the establishment of minimally invasive individualized treatment and acceptance of sentinel lymph node mapping. The dual-tracer method, submucosally administered endoscopically is also recommended in sentinel lymph node biopsy by laparoscopic approach. There are new sophisticated technologies for detecting sentinel lymph node such as: infrared ray endoscopy, florescence imaging and near-infrared technology, carbon nanoparticles, which will open new perspectives in sentinel lymph nodes mapping.

Clinical significance of the anterosuperior lymph nodes along the common hepatic artery identified by sentinel node mapping in patients with gastric cancer

BACKGROUND

The sentinel node (SN) concept is safely applied and validated in early gastric cancer. Gastric lymph nodes are divided into five basins with the main gastric arteries, and the anterosuperior lymph nodes with the common hepatic artery (No. 8a) are classified in the right gastric artery (r-GA) basin. Although No. 8a are considered to have lymphatic flow from the r-GA basin, there might be additional multiple lymphatic flows into No. 8a. The aim of this study is to analyze the lymphatic flows to No. 8a and to investigate the clinical significance of No. 8a as a sentinel node (SN No. 8a).

METHODS

Four hundred and twenty-nine patients with cT1N0 or cT2N0 gastric cancer underwent SN mapping. We used technetium-99 tin colloid solution and blue dye as a tracer.

RESULTS

We detected SN No. 8a in 35 (8.2 %) patients. In these patients, we detected SN No. 8a with SNs that belonged to the left gastric artery (l-GA) basin (66 %), right gastroepiploic artery (r-GEA) basin (54 %), and right gastric artery (r-GA) basin (46 %). In addition, celiac artery lymph nodes were detected as SNs significantly more frequently. Function-preserving surgery was performed significantly less often in patients with SN No. 8a (p =0.018).

CONCLUSIONS

We found that SN No. 8a seemed to have lymphatic flow not only from the r-GA basin, but also from the l-GA basin or r-GEA basin. When SN No. 8a are detected, we should be careful to perform function-preserving surgery, even in SN-negative cases.