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

Auxiliary diagnosis of lymph node metastasis in early gastric cancer using quantitative evaluation of sentinel node radioactivity

BACKGROUND

Sentinel node (SN) mapping using dye and radioisotope (RI) tracer has been reported to be feasible in cases of early gastric cancer. Because accurate diagnosis of micrometastasis is sometimes difficult in the limited time available during surgery, a faster and simpler method of improving the intraoperative diagnostic precision of lymph node metastasis is needed. The amount of tracer deposited in an SN can be determined from its radioactivity; however, the significance of the RI count has not been fully discussed. We investigated the clinical impact of the RI count when used as an adjunct to conventional lymph node dissection when diagnosing lymphatic metastasis in cases of early gastric cancer.

METHODS

From 2008 to 2009, patients with clinically diagnosed T1N0M0 gastric cancers who underwent gastrectomy and SN mapping were enrolled. SNs were examined by intraoperative and postoperative pathology. The RI count was measured for each SN with a handheld gamma probe; the correlation between nodal metastasis and the RI count was assessed.

RESULTS

A total of 308 SNs were harvested from 72 patients. Patients with SN metastasis had significantly higher total RI counts than those without SN metastasis (p = 0.007). Among cases with SN metastasis, RI counts were also significantly elevated in metastasis-positive nodes, stations, and basins. In these cases, the most of SNs having the highest RI count in each case had metastasis including isolated tumor cells.

CONCLUSION

In early gastric cancer patients, a high RI count from an SN was correlated with lymph node metastasis. Therefore, RI counting may aid efficient pathological diagnosis and focused lymph node dissection.

Risk factors for lymph node metastasis and long-term outcomes of patients with early gastric cancer after non-curative endoscopic submucosal dissection

BACKGROUND

The long-term outcomes after non-curative gastric endoscopic submucosal dissection (ESD) are still unknown. We aimed to clarify the pathological risk factors for lymph node metastasis (LNM) of early gastric cancer (EGC) and the long-term outcomes among patients who were judged to have had non-curative ESD.

METHODS

From September 2002 to December 2012, 506 patients who were judged to have had non-curative gastric ESD were enrolled and classified into two groups: (1) those who subsequently underwent additional surgical resection (surgical group, n = 323) and (2) those followed up without additional surgical resection (nonsurgical group, n = 183). We analyzed pathological risk factors for LNM of EGC in the surgical group. Additionally, we compared long-term outcomes in the two groups.

RESULTS

LNM was found pathologically in 9.3 % of the surgical group (30/323) at the additional surgical resection after non-curative ESD. In the multivariate logistic regression analysis, lymphovascular invasion (LVI) was an independent risk factor for LNM in the surgical group (odds ratio 8.57, 95 % confidence interval 2.76-38.14, P < 0.0001). The 5-year cause-specific survival rate was similar in the surgical and nonsurgical groups (98.7 and 96.5 %, respectively; log-rank test, P = 0.07). In contrast, the 5-year cause-specific survival rate of patients with LVI in the surgical group was better than that in the nonsurgical group (98.2 and 79.1 %, respectively; log-rank test, P < 0.0001).

CONCLUSIONS

A detailed assessment of LVI is essential to the pathological evaluation of endoscopically resected specimens. An additional surgical resection should be strongly recommended for patients with LVI.

Sentinel node biopsy for oral cancer: A prospective multicenter Phase II trial

OBJECTIVE

A recent study identified a survival benefit with prophylactic neck dissection (ND) at the time of primary surgery as compared with watchful waiting followed by therapeutic neck dissection for nodal relapse, in patients with cN0 oral squamous cell carcinoma (OSCC). Alternative management of cN0 neck cancer is recommended to minimize the adverse effects of ND, indicating the need for sentinel node biopsy (SNB) and limited neck dissection. We conducted a multicenter Phase II study to examine the feasibility of SNB for clinically N0 OSCC.

METHODS

Previously untreated N0 OSCC patients (n=57) with clinical late-T2 or T3 tumors were enrolled across 10 institutions. SNB navigated with multislice frozen section analysis of sentinel nodes (SNs) and SNB supported sentinel node lymphatic basin dissection (SN basin dissection) were performed in a one-stage procedure. The endpoint was to investigate the rate of false-negative metastases after SN basin dissection and SNB alone.

RESULTS

Most tumors were late-T2 lesions (n=50; 87.7%). SNs were identified in all patients. A total of 196 SNs were detected. Among these SNs, 35 (17.8%) were positive for metastasis (9 in level I, 12 in level II, 12 in level III, 1 in level V and 2 in the contralateral region of the neck). The false-negative rate of SNB supported by SN basin dissection and SNB alone was 4.5% and 9.1%, respectively. The concordance of the SN status in intraoperative frozen sections with the permanent histopathology was 97.4% (191/196). The sensitivity and specificity of intraoperative pathological evaluation were 85.7% (30/35) and 100% (30/30), respectively. The 3-year overall survival (OS) and disease-free survival was 89.5% and 82.5%, respectively. The OS of SN-negative patients was significantly longer than that of SN-positive patients (P=0.047).

CONCLUSION

The current study verified that SN basin dissection was a useful back-up procedure for SNB performed as a one-stage procedure, showing a low false-negative rate. SNB alone is an appropriate staging method for patients with clinical N0 staging, and a reliable procedure to determine the appropriate levels for neck dissection.

Evaluation of 64-Channel Contrast-Enhanced Multi-detector Row Computed Tomography for Preoperative N Staging in cT2-4 Gastric Carcinoma

BACKGROUND

Preoperative N staging is essential for the best treatment planning in patients with gastric carcinoma. The aim of this study was to evaluate the accuracy of preoperative N staging using contrast-enhanced multi-detector row computed tomography (CE-MDCT) in patients with resectable cT2-4 gastric carcinoma.

METHODS

A total of 218 patients who underwent a gastrectomy with D2 lymphadenectomy for previously untreated cT2-4 primary gastric carcinoma were studied. Preoperative N staging was performed according to the 7th (UICC) TNM Staging System using pre-specified criteria on a 64-channel CE-MDCT and was compared with postoperative pathologic N staging.

RESULTS

In all 218 patients, a distal or total gastrectomy was performed. The overall accuracy of the preoperative N staging was 46.3% (101/218), with the proportion of over- and under-staging being 26.6% (58/218) and 27.1% (59/218), respectively. The sensitivity, specificity, and accuracy for lymph node metastasis (≥pN1) were 79.1% (106/134), 50.0% (42/84), and 67.9% (148/218), respectively. The sensitivity, specificity, and accuracy for multiple lymph node metastases (≥pN2) were 80.2% (73/91), 68.5% (87/127), and 73.4% (160/218), respectively. Multivariate analyses showed that macroscopic type 2 and ≥6 cm-sized tumors were associated with preoperative over-N staging, while macroscopic type 1/3 tumors were associated with under-N staging.

CONCLUSION

Preoperative N staging with pinpoint accuracy is difficult. However, CE-MDCT offers a reasonably high sensitivity and specificity for ≥pN2 and may be useful for selecting candidates for neoadjuvant therapies. The macroscopic type and size of the primary tumor may affect the accuracy of preoperative N staging.

Feasibility of laparoscopic and endoscopic cooperative surgery for gastric submucosal tumors (with video)

BACKGROUND AND AIMS

Laparoscopic gastric resection is widely used for gastric submucosal tumors (SMTs). However, determining an appropriate resection line using only the laparoscopic approach is difficult. We developed a laparoscopic and endoscopic cooperative surgery (LECS) technique by combining laparoscopic gastric resection with endoscopic submucosal dissection, and we have used this procedure to resect gastric SMTs. In this study, the procedure is presented and its safety and feasibility for resecting gastric SMTs are evaluated.

METHODS

This retrospective study included 100 patients who underwent LECS for SMTs at the Department of Gastroenterological Surgery, Cancer Institute, between June 2006 and November 2014. The demographics, tumor histopathologic characteristics, and operative and follow-up data were reviewed.

RESULTS

Complete resection with negative surgical margins was achieved in all patients, and LECS was performed regardless of tumor location. The mean operation time was 174.3 minutes, with an estimated blood loss of 16.3 mL. In addition, the mean time until the initiation of oral intake was 1.4 days, and the mean postoperative hospital stay was 8.4 days. Moreover, no local or distant tumor recurrence was observed. The only severe adverse event was leakage, which was observed in 1 patient.

CONCLUSIONS

LECS was performed with a reasonable operation time, low blood loss, and minimal adverse events. Therefore LECS is safe and feasible for resecting gastric SMTs.

Pylorus-Preserving Surgery Based on the Sentinel Node Concept in Early Gastric Cancer

BACKGROUND

In patients with early stage gastric cancer in the middle third of the stomach, pylorus-preserving gastrectomy (PPG) can be an option as function-preserving surgery, although its oncologic safety is not definitively defined. This issues may be overcome using the sentinel node (SN) concept. The aim of this study was to investigate the effectiveness of the SN concept in early gastric cancer patients who are candidates for PPG.

METHODS

One hundred fifty-six patients with middle-third location of cT1N0 gastric cancer (single lesion, <4 cm) underwent distal gastrectomy with SN mapping. As a tracer, technetium-99 tin colloid solution and blue dye were endoscopically injected into the submucosal layer surrounding the primary tumor.

RESULTS

SN detection rate was 100 % (156 of 156), and the accuracy of the nodal evaluation of metastasis was 99 % (155 of 156). Suprapyloric lymph node (LN; LN No. 5) and infrapyloric LN (LN No. 6) were detected as SNs in 6 and 14 % of the patients, respectively. We also found two cases with metastasis to LN No. 5 or LN No. 6.

DISCUSSION

When performing PPG, the possibility of LN metastasis, especially to LN No. 5 and LN No. 6, cannot be underestimated. SN mapping can play an important role to predict the possibility of metastasis to LN No. 5 and LN No. 6.

Local resection of the stomach for gastric cancer

The local resection of the stomach is an ideal method for preventing postoperative symptoms. There are various procedures for performing local resection, such as the laparoscopic lesion lifting method, non-touch lesion lifting method, endoscopic full-thickness resection, and laparoscopic endoscopic cooperative surgery. After the invention and widespread use of endoscopic submucosal dissection, local resection has become outdated as a curative surgical technique for gastric cancer. Nevertheless, local resection of the stomach in the treatment of gastric cancer in now expected to make a comeback with the clinical use of sentinel node navigation surgery. However, there are many issues associated with local resection for gastric cancer, other than the normal indications. These include gastric deformation, functional impairment, ensuring a safe surgical margin, the possibility of inducing peritoneal dissemination, and the associated increase in the risk of metachronous gastric cancer. In view of these issues, there is a tendency to regard local resection as an investigative treatment, to be applied only in carefully selected cases. The ideal model for local resection of the stomach for gastric cancer would be a combination of endoscopic full-thickness resection of the stomach using an ESD device and hand sutured closure using a laparoscope or a surgical robot, for achieving both oncological safety and preserved functions.

Sentinel node navigation surgery for gastroduodenal neuroendocrine tumors: Two case reports

The percentage of gastroduodenal neuroendocrine tumors (NETs) among all gastroenteropancreatic (GEP) NETs has gradually increased worldwide. Sentinel node navigation surgery (SNNS) has been developed as a personalized approach in the surgical strategy for early gastrointestinal tract cancers. We herein report 2 cases of gastroduodenal NETs treated with SNNS. Technetium-tin colloid including indocyanine green was endoscopically injected into the submucosa around a tumor the day before surgery. Basin dissection including the sentinel nodes (SNs), which were identified by Navigator GPS and near-infrared fluorescence imaging, was performed during laparoscopic surgery. SNs were intraoperatively examined using hematoxylin-eosin (HE) staining.SNs were detected in 2 patients. Lymph node metastasis was intraoperatively identified in 1 of the 2 patients. Consequently, 1 patient with metastatic SNs underwent laparoscopic gastrectomy with lymphadenectomy. Pathological findings identified submucosal NET measuring 6.0 mm × 5.0 mm.Our results suggest that SNNS is a promising surgical tool for detecting subclinical lymph node metastasis in patients with gastroduodenal NETs.

Assessment of laparoscopic stomach preserving surgery with sentinel basin dissection versus standard gastrectomy with lymphadenectomy in early gastric cancer-A multicenter randomized phase III clinical trial (SENORITA trial) protocol

Background

Along with the marked increase in early gastric cancer (EGC) in the Eastern countries, there has been an effort to adopt the sentinel node concept in EGC to preserve gastric function and reduce the occurrence of postoperative complications. Based on promising results from a previous quality control study, this prospective multicenter randomized controlled phase III clinical trial aims to elucidate the oncologic safety of laparoscopic stomach-preserving surgery with sentinel basin dissection (SBD) compared to a standard laparoscopic gastrectomy.

Methods/Design

This trial is an investigator-initiated, open-label, multicenter randomized controlled phase III trial with a non-inferiority design. Patients diagnosed with a single lesion of clinical stage T1N0M0 gastric adenocarcinoma, with a diameter of 3 cm or less are eligible for the present study. A total of 580 patients (290 per group) will be randomized to either laparoscopic stomach-preserving surgery with SBD or standard surgery. The primary end-point is 3-year disease-free survival (DFS) and the secondary endpoints include postoperative morbidity and mortality, quality of life, 5-year DFS, and overall survival. Qualified investigators who completed the prior quality control study are exclusively allowed to participate in this phase III clinical trial.

Discussion

The proposed trial is expected to verify whether laparoscopic stomach-preserving surgery with SBD achieves similar oncologic outcomes and improved quality of life compared to a standard gastrectomy in EGC patients.

Trial registration

This study was registered at the NIH ClinicalTrial.gov database (NCT01804998) on March 4th, 2013.

Ongoing surgical clinical trials on minimally invasive surgery for gastric cancer: Korea

Since Korean Laparoscopic Gastrointestinal Surgery Study (KLASS) group was activated in 2003, several randomized controlled trials (RCTs) have finished or are ongoing in Korea to evaluate oncologic safety and feasibility of minimally invasive surgery (MIS) for gastric cancer by KLASS group as well as other expert surgeons. MIS in gastric cancer is regarded as one of standard treatment modality for early gastric cancer (EGC) and the indication is going expansion with the accumulation of evidence. This review covers current status of ongoing clinical trials on MIS for gastric cancer in Korea.

Practical intraoperative pathologic evaluation of sentinel lymph nodes during sentinel node navigation surgery in gastric cancer patients - Proposal of the pathologic protocol for the upcoming SENORITA trial

Over the last decade, as the number of patients with early gastric cancer increased and the subsequent survival rate improved, there has been a consistent effort to verify the applicability of the sentinel node concept in gastric cancer in a bid to improve postoperative quality of life in these patients. During sentinel node navigation surgery in gastric cancer patients, intraoperative pathologic examination of the retrieved sentinel nodes plays a critical role in determining the extent of surgery, but the optimal method is still under debate. Currently, a multicenter, phase III clinical trial is underway to compare laparoscopic sentinel basin dissection with stomach preserving surgery and standard laparoscopic gastrectomy in terms of oncologic outcomes in patients with clinical stage T1N0 gastric cancer. Herein, the currently available intraoperative pathologic techniques are reviewed and their clinical significance and applicability are appraised based on the published literature. The proper pathologic examination of the sentinel lymph nodes in an upcoming clinical trial (SENORITA trial) is also proposed here based on this review.

Optimal settings and accuracy of indocyanine green fluorescence imaging for sentinel node biopsy in early gastric cancer

Indocyanine green (ICG) fluorescence imaging represents a promising method for sentinel node (SN) biopsy in laparoscopic gastric surgery due to its signal stability. In the present study, the suitability and optimal settings of ICG fluorescence imaging for SN biopsy in early gastric cancer were determined. Patients with single primary superficial-type adenocarcinoma of the stomach, lesions <5 cm in diameter, and no evident nodal metastasis and out of indication for endoscopic submucosal dissection were enrolled. The day prior to surgery, ICG solution was endoscopically injected into four quadrants of the submucosal layer of the tumor. The Photodynamic Eye was used to detect ICG fluorescence. Bright nodes were defined as clearly fluorescent nodes. A total of 72 patients were enrolled; 11 cases presented with metastasis, and of these, 10 could be diagnosed by bright node biopsy. The adequate concentration and injection volume of ICG was determined to be 50 µg/ml (×100) and 0.5 mlx4 points, respectively. There was 1 false-negative case, and this was attributed to the failure of the frozen section diagnosis. These results suggested that ICG fluorescence imaging for SN biopsy in laparoscopic surgery for early gastric cancer is feasible. However, a weakness of ICG fluorescence imaging is the subjectivity of bright node evaluation.

Ongoing clinical studies of minimally invasive surgery for gastric cancer in Japan

Since the development of laparoscopy-assisted distal gastrectomy (LADG) with lymph node dissection for gastric cancer in Japan, this type of surgery is improving and evolving. To establish high-quality evidence of laparoscopic gastrectomy (LAG) in the field of gastric cancer treatments, two large-scale, prospective randomized controlled trials have been performed in Japan; the Japan Clinical Oncology Study Group (JCOG) 0912 for early disease and the Japanese Laparoscopic Surgery Study Group (JLSSG) 0901 for advanced disease. Analyses using mega-data from the National Clinical Database (NCD) have also been carried out as a clinical study to clarify the safety of LAG. Furthermore, as advanced laparoscopic techniques have been developed, prospective clinical studies are being performed with regard to laparoscopy-assisted total gastrectomy (LATG), robotic gastrectomy, and minimally invasive surgery with sentinel node (SN) navigation. This review summarizes the current status of minimally invasive surgeries for gastric cancer based on the latest ongoing clinical trials in Japan.

Near-infrared fluorescence sentinel lymph node detection in gastric cancer: A pilot study

AIM: To investigate feasibility and accuracy of near-infrared fluorescence imaging using indocyanine green: nanocolloid for sentinel lymph node (SLN) detection in gastric cancer.

METHODS: A prospective, single-institution, phase I feasibility trial was conducted. Patients suffering from gastric cancer and planned for gastrectomy were included. During surgery, a subserosal injection of 1.6 mL ICG:Nanocoll was administered around the tumor. NIR fluorescence imaging of the abdominal cavity was performed using the Mini-FLARE™ NIR fluorescence imaging system. Lymphatic pathways and SLNs were visualized. Of every detected SLN, the corresponding lymph node station, signal-to-background ratio and histopathological diagnosis was determined. Patients underwent standard-of-care gastrectomy. Detected SLNs outside the standard dissection planes were also resected and evaluated.

RESULTS: Twenty-six patients were enrolled. Four patients were excluded because distant metastases were found during surgery or due to technical failure of the injection. In 21 of the remaining 22 patients, at least 1 SLN was detected by NIR Fluorescence imaging (mean 3.1 SLNs; range 1-6). In 8 of the 21 patients, tumor-positive LNs were found. Overall accuracy of the technique was 90% (70%-99%; 95%CI), which decreased by higher pT-stage (100%, 100%, 100%, 90%, 0% for respectively Tx, T1, T2, T3, T4 tumors). All NIR-negative SLNs were completely effaced by tumor. Mean fluorescence signal-to-background ratio of SLNs was 4.4 (range 1.4-19.8). In 8 of the 21 patients, SLNs outside the standard resection plane were identified, that contained malignant cells in 2 patients.

CONCLUSION: This study shows successful use of ICG:Nanocoll as lymphatic tracer for SLN detection in gastric cancer. Moreover, tumor-containing LNs outside the standard dissection planes were identified.

Hybrid surgery for early gastric cancer

Endoscopic submucosal dissection (ESD) is the most suitable treatment option in terms of minimally invasive treatment for potential node-negative early gastric cancers (EGCs). Furthermore, making the resection area of the primary lesion as small as possible is ideal for the patient's quality of life, even for potential node-positive EGC. An endoluminal approach is a reasonable option with which to minimize stomach resection area, because this procedure can be accurately demarcated from the inside. From this point of view, endoscopic full-thickness resection (EFTR) may be optimal, while laparoscopic assistance would be more desirable to create a more secure procedure. However, hybrid EFTR for EGCs has two limitations, which must be solved. First, concerns regarding iatrogenic tumor seeding via transluminal communication between the inside and outside of the tract exist. The second limitation relates to the determination of lymphadenectomy. Conventional lymphadenectomy, which involves the removal of the majority of feeding arteries, can lead to necrosis of the remaining gastric wall. Therefore, the resection area of lymphadenectomy should also be carefully determined. To address these two problems, a non-exposed hybrid EFTR combined with sentinel node navigation surgery (SNNS) would be the most ideal method of minimally invasive surgery for EGCs.

Endoscopic Submucosal Dissection (ESD) and Related Techniques as Precursors of "New Notes" Resection Methods for Gastric Neoplasms

Endoscopic full-thickness resection for subepithelial tumors is one of the more attractive proposed methods for less-invasive transluminal surgery but remains challenging in terms of safety and feasibility. Currently, laparoscopic endoscopic cooperative surgery is thought to be a more clinically acceptable approach. In targeting cancers, however, more advanced nonexposure techniques are required to avoid the risk of iatrogenic tumor seeding. By combining these techniques with possible regional lymphadenectomy using sentinel node navigation surgery, an ideal minimally invasive, function-preserving gastric resection can be achieved even in possible node-positive cancers. Further development for this type of advanced endoscopic surgery is expected.

Sentinel Lymph Node Navigation Surgery for Early Gastric Cancer: Is It a Safe Procedure in Countries with Non-Endemic Gastric Cancer Levels? A Preliminary Experience

Purpose

Early diagnosis of gastric cancer is still the exception in Western countries. In the East, as in Japan and Korea, this disease is an endemic disorder. More conservative surgical procedures are frequently performed in early gastric cancer cases in these countries where sentinel lymph node navigation surgery is becoming a safe option for some patients. This study aims to evaluate preliminary outcomes of patients with early gastric cancer who underwent sentinel node navigation surgeries in Brazil, a country with non-endemic gastric cancer levels.

Materials and Methods

From September 2008 to March 2014, 14 out of 205 gastric cancer patients underwent sentinel lymph node navigation surgeries, which were performed using intraoperative, endoscopic, and peritumoral injection of patent blue dye.

Results

Antrectomies with Billroth I gastroduodenostomies were performed in seven patients with distal tumors. The other seven patients underwent wedge resections. Sentinel basin resections were performed in four patients, and lymphadenectomies were extended to stations 7, 8, and 9 in the other 10. Two patients received false-negative results from sentinel node biopsies, and one of those patients had micrometastasis. There was one postoperative death from liver failure in a cirrhotic patient. Another cirrhotic patient died after two years without recurrence of gastric cancer, also from liver failure. All other patients were followed-up for 13 to 79 months with no evidence of recurrence.

Conclusions

Sentinel lymph node navigation surgery appears to be a safe procedure in a country with non-endemic levels of gastric cancer.

Minimally invasive function-preserving surgery based on sentinel node concept in early gastric cancer

Recent meta-analyses and a prospective multicenter trial of sentinel node (SN) mapping for early gastric cancer have shown acceptable SN detection rates and accuracy of determination of lymph node status. A dual-tracer method that employs radioactive colloids and blue dyes is currently considered the most reliable method for the stable detection of SNs in patients with early gastric cancer. However the new technologies such as indocyanine green (ICG) infrared or fluorescence imaging may revolutionize the SN mapping procedures in gastric cancer. For early stage gastric cancer, the establishment of individualized, minimally invasive treatments based on SN concept can retain the patients' quality of life (QOL). The combination of non-exposed endoscopic wall-inversion surgery (NEWS) with SN biopsy is expected to become a promising, ideal minimally invasive, function-preserving surgery to cure cases of cN0 early gastric cancer.

Clinical study of harvesting lymph nodes with carbon nanoparticles in advanced gastric cancer: a prospective randomized trial

Background

The objective of this study is to evaluate the efficiency and safety of carbon nanoparticles (CNPs) for harvesting lymph nodes (LNs) in cases of advanced gastric cancer (AGC).

Methods

Patients with previously untreated resectable AGC were eligible for inclusion in this study. All patients were randomly allocated to two subgroups. In the experimental group, 1.0 mL of CNP was injected into the subserosa of the stomach around the tumor before gastrectomy with D2 dissection. The same procedure was performed directly without any coloring material in the control arm. Following surgery, LNs were harvested, colored LNs were counted, and the diameters were measured by the investigator and pathologist.

Results

Thirty patients were enrolled in the study. We observed no serious adverse effects related to CNP injection. The rate of stained LNs was 46.6 %. The mean number of harvested LNs was larger in the experimental than in the control group (38.33 vs 28.27, p = 0.041). A smaller diameter of LNs was recorded in the experimental arm (3.32 vs 4.30 mm, p = 0.023). In addition, we developed a model for predicting the total number of LNs based on the data from CNP-stained LNs and metastatic LNs (MLNs).

Conclusions

CNP is a safe material. Surgeons could harvest more LNs in patients with AGC. The harvest of an increased number of smaller diameters of LNs may be beneficial. Further study is warranted to demonstrate the model’s practicality.

Sentinel lymph node navigation surgery for gastric cancer: Does it really benefit the patient?

Sentinel lymph node (SLN) navigation surgery is accepted as a standard treatment procedure for malignant melanoma and breast cancer. However, the benefit of reduced lymphadenectomy based on SLN examination remains unclear in cases of gastric cancer. Here, we review previous studies to determine whether SLN navigation surgery is beneficial for gastric cancer patients. Recently, a large-scale prospective study from the Japanese Society of Sentinel Node Navigation Surgery reported that the endoscopic dual tracer method, using a dye and radioisotope for SLN biopsy, was safe and effective when applied to cases of superficial and relatively small gastric cancers. SLN mapping with SLN basin dissection was preferred for early gastric cancer since it is minimally invasive. However, previous studies reported that limited gastrectomy and lymphadenectomy may not improve the patient’s postoperative quality of life (QOL). As a result, the benefit of SLN navigation surgery for gastric cancer patients, in terms of their QOL, is limited. Thus, endoscopic and laparoscopic limited gastrectomy combined with SLN navigation surgery has the potential to become the standard minimally invasive surgery in early gastric cancer.

Sentinel node navigation surgery with indocyanine green fluorescence-guided method for metachronous early gastric carcinoma arising from reconstructed gastric tube after esophagectomy

A 67-year-old man who had undergone a thoracoscopic esophagectomy and posterior mediastinal gastric tube reconstruction for thoracic esophageal cancer 9 years previously was endoscopically diagnosed as having gastric carcinoma arising from the reconstructed gastric tube. No evidence of metastasis was seen in imaging examinations, and the depth of tumor invasion was suspected to be the submucosal layer. Based on these results, we decided that surgery, rather than endoscopic resection, was indicated. The tumor was located in the upper abdomen. Therefore, we performed a partial resection of the gastric tube. Sentinel nodes (SN) were identified using the Hyper Eye Medical System II. Metastasis was not observed in any of the selected SN. While the treatment strategy for gastric tube cancer after an esophagectomy remains controversial, minimally invasive surgery with sentinel node navigation surgery appears to be clinically useful. However, the method of SN dissection should be investigated with due consideration given to arterial preservation.

Clinical significance of lymphadenectomy in patients with gastric cancer

Approximately thirty percent of patients with gastric cancer undergo an avoidable lymph node dissection with a higher rate of postoperative complication. Comparing the D1 and D2 dissections, it was found that there is a significant difference in morbidity, favoured D1 dissection without any difference in overall survival. Subgroup analysis of patients with T3 tumor shows a survival difference favoring D2 lymphadenectomy, and there is a better gastric cancer-related death and non-statistically significant improvement of survival for node-positive disease in patients with D2 dissection. However, the extended lymphadenectomy could improve stage-specific survival owing to the stage migration phenomenon. The deployment of centralization and application of national guidelines could improve the surgical outcomes. The Japanese and European guidelines enclose the D2 lymphadenectomy as the gold standard in R0 resection. In the individualized, stage-adapted gastric cancer surgery the Maruyama computer program (MCP) can estimate lymph node involvement preoperatively with high accuracy and in addition the Maruyama Index less than 5 has a better impact on survival, than D-level guided surgery. For these reasons, the preoperative application of MCP is recommended routinely, with an aim to perform “low Maruyama Index surgery”. The sentinel lymph node biopsy (SNB) may decrease the number of redundant lymphadenectomy intraoperatively with a high detection rate (93.7%) and an accuracy of 92%. More accurate stage-adapted surgery could be performed using the MCP and SNB in parallel fashion in gastric cancer.

Recent advances in photodynamic diagnosis of gastric cancer using 5-aminolevulinic acid

Photodynamic diagnosis based on 5-aminolevulinic acid-induced protoporphyrin IX has been clinically applied in many fields based upon its evidenced efficacy and adequate safety. In order to establish a personalized medicine approach for treating gastric cancer patients, rapid intraoperative detection of malignant lesions has become important. Feasibility of photodynamic diagnosis using 5-aminolevulinic acid for gastric cancer patients has been investigated, especially for the detection of peritoneal dissemination and lymph node metastasis. This method enables intraoperative real-time fluorescence detection of peritoneal dissemination, exhibiting higher sensitivity than white light observation without histopathological examination. The method also enables detection of metastatic foci within excised lymph nodes, exhibiting a diagnostic accuracy comparable to that of a current molecular diagnostics technique. Although several complicating issues still need to be resolved, such as the effect of tissue autofluorescence and the insufficient depth penetration of excitation light, this simple and rapid method has the potential to become a useful diagnostic tool for gastric cancer, as well as urinary bladder cancer and glioma.

Laparoscopic gastric cancer surgery: Current evidence and future perspectives

Laparoscopic gastrectomy has been widely accepted as a standard alternative for the treatment of early-stage gastric adenocarcinoma because of its favorable short-term outcomes. Although controversies exist, such as establishing clear indications, proper preoperative staging, and oncologic safety, experienced surgeons and institutions have applied this approach, along with various types of function-preserving surgery, for the treatment of advanced gastric cancer. With technical advancement and the advent of state-of-the-art instruments, indications for laparoscopic gastrectomy are expected to expand as far as locally advanced gastric cancer. Laparoscopic gastrectomy appears to be promising; however, scientific evidence necessary to generalize this approach to a standard treatment for all relevant patients and care providers remains to be gathered. Several multicenter, prospective randomized trials in high-incidence countries are ongoing, and results from these trials will highlight the short- and long-term outcomes of the approach. In this review, we describe up-to-date findings and critical issues regarding laparoscopic gastrectomy for gastric cancer.

Evaluation of 18F-FDG uptake for detecting lymph node metastasis of gastric cancer: a prospective pilot study for one-to-one comparison of radiation dose and pathological findings

Background

Gastric cancer exhibits various degrees of fluorine F-18 fluorodeoxyglucose (¹⁸F-FDG) uptake on positron emission tomography/computed tomography (PET/CT). We evaluated the relationship between ¹⁸F-FDG uptake and the presence/absence of metastasis in individual lymph nodes (LN) on a one-to-one basis.

Methods

We analyzed 21 patients with gastric cancer. We injected ¹⁸F-FDG intravenously in the morning, and gastrectomy with LN dissection was performed in the afternoon of the same day. Radiation doses were measured at each LN using a well-type counter, and we then compared ¹⁸F-FDG uptake, the shortest diameter, and pathological examination results for each LN.

Results

In our study, 906 LNs were analyzed, including 115 metastatic LNs. Metastatic LNs showed significantly higher ¹⁸F-FDG uptake (P < 0.0001), and were significantly enlarged (P < 0.0001). The receiver operating characteristics (ROC) curve had a larger area under the curve (0.71) for ¹⁸F-FDG uptake than for the shortest LN diameter (0.60). Considering histology, the ROC curve for intestinal type adenocarcinoma had a larger area under the curve than that for diffuse type (0.75 vs 0.61).

Conclusions

F-FDG uptake is potentially a more useful variable than LN diameter for discriminating between LN with and without metastasis, especially in intestinal type gastric cancer cases.

Cutting edge of endoscopic full-thickness resection for gastric tumor

Recently, several studies have reported local full-thickness resection techniques using flexible endoscopy for gastric tumors, such as gastrointestinal stromal tumors, gastric carcinoid tumors, and early gastric cancer (EGC). These techniques have the advantage of allowing precise resection lines to be determined using intraluminal endoscopy. Thus, it is possible to minimize the resection area and subsequent deformity. Some of these methods include: (1) classical laparoscopic and endoscopic cooperative surgery (LECS); (2) inverted LECS; (3) combination of laparoscopic and endoscopic approaches to neoplasia with non-exposure technique; and (4) non-exposed endoscopic wall-inversion surgery. Furthermore, a recent prospective multicenter trial of the sentinel node navigation surgery (SNNS) for EGC has shown acceptable results in terms of sentinel node detection rate and the accuracy of nodal metastasis. Endoscopic full-thickness resection with SNNS is expected to become a treatment option that bridges the gap between endoscopic submucosal dissection and standard surgery for EGC. In the future, the indications for these procedures for gastric tumors could be expanded.

The clinical usefulness of the intraoperative detection of sentinel lymph node metastases by a rapid RT-PCR system in patients with gastric cancer

BACKGROUND

The incidence of pathological lymph node metastases in patients with gastric cancer is 5% to 10%, which means that approximately 90% of patients with gastric cancer may undergo unnecessary lymphadenectomy. The precise intraoperative diagnosis of sentinel lymph node (SN) metastases is essential. The purpose of the current study was to verify the usefulness of a rapid reverse transcriptase-polymerase chain reaction (RT-PCR) system compared with hematoxylin and eosin staining for such diagnoses.

METHODS

A total of 113 patients with clinical T1-T2 (cT1-T2) gastric cancer, including 73 patients with cT1cN0 disease with a tumor diameter <4 cm, were enrolled in the current study. SNs were identified by a radioisotope method. Carcinoembryonic antigen and cytokeratin 19 were used as markers for RT-PCR and the cutoff values were set using 1701 lymph nodes harvested from 157 patients with gastric cancer.

RESULTS

SNs were detected in all 113 patients. Sensitivity and accuracy for detection by paraffin section were both 100% in patients with cT1 disease and were 60% and 90%, respectively, in patients with cT2 disease. The sensitivity of RT-PCR for the detection of pathological SN metastases was 92.3%. Furthermore, 11 patients had SN metastases detected only by RT-PCR, and these patients had frequent lymphatic invasion. Hematoxylin and eosin staining detected SN metastases in 6 of 73 patients with cT1cN0 gastric cancer; RT-PCR and frozen section detected SN metastases in 6 and 4 of these patients, respectively. Accordingly, the sensitivity of RT-PCR and frozen section for the detection of those pathological SN metastases were 100% and 66.6%, respectively.

CONCLUSIONS

The rapid RT-PCR system appears to have clinical usefulness for the intraoperative detection of SN metastases in patients with gastric cancer.

Sentinel lymph node biopsy in gastric cancer

Clinical application of sentinel lymph node (SLN) mapping in patients with early-stage gastric cancer has been a controversial issue for years. However, a recent meta-analysis and a prospective multicenter trial of SLN mapping for early-stage gastric cancer have shown acceptable SLN detection rates and accuracy of determination of lymph node status. A dual-tracer method that uses radioactive colloids and blue dyes is currently considered the most reliable method for the stable detection of SLNs in patients with early-stage gastric cancer. However, the new technologies such as indocyanine green infrared or fluorescence imaging might revolutionize the SLN mapping procedures in gastric cancer. For early-stage gastric cancer, the establishment of individualized, minimally invasive treatments based on SLN concept may retain the patients' quality of life.

Estimation of subepithelial lateral extent in submucosal early gastric cancer: retrospective histological analysis

BACKGROUND

Endoscopic full-thickness resection (EFTR) is expected to make possible minimally invasive local resection of early gastric cancer (EGC). However, no consensus exists regarding how far an optimal safety margin should be set in determining the resection area by endoscopy. We aimed to investigate the optimal lateral margin of EGC which could be a candidate for EFTR by measuring the subepithelial extent (SE) of tumors.

METHODS

In 60 surgically resected submucosal EGCs 4 cm or smaller, 595 prepared slides which showed lateral tumor borders both on the epithelial surface and on the subepithelial layer were assessed. The distance between the epithelial and the subepithelial tumor edge was measured under microscopic observation, followed by analyses of the relationship between the measured SE and the histological characteristics.

RESULTS

The average and the median SE were 1.1 mm (standard deviation 1.8 mm) and 0.3 mm (range 0-12.3 mm), respectively. The 99th percentile was 8.8 mm. With regard to the histological type, the median SE was significantly greater in diffuse-type tumor than in intestinal-type tumor (0.9 mm vs 0 mm, p < 0.0001). With regard to the location of the subepithelilal tumor edge, the median SE was significantly greater in the submucosal layer than in the mucosal layer (2.6 mm vs 0.3 mm, p < 0.0001).

CONCLUSIONS

In most lesions, the SE was less than 1 cm. A safety margin may be set at 1 cm in EFTR of submucosal EGC.

Prospective Multicenter Feasibility Study of Laparoscopic Sentinel Basin Dissection for Organ Preserving Surgery in Gastric Cancer: Quality Control Study for Surgical Standardization Prior to Phase III Trial

The clinical application of sentinel node biopsies in early gastric cancer is still controversial even though it appears promising. This study was conducted as a prerequisite quality control for surgical standardization of laparoscopic sentinel basin dissection (SBD) prior to the initiation of a phase III trial.Laparoscopic SBD was performed in patients with preoperative stage T1-2N0 and tumor size <4 cm in diameter. Intraoperative endoscopic submucosal injection of a standardized dual tracer was administered. All retrieved sentinel basin nodes (SBN) were investigated with intraoperative frozen hematoxylin and eosin (H&E) staining. A strict checklist consisting of 7 essential steps was followed during laparoscopic SBD as the quality control study for a phase III trial. Completion of all essential steps in the checklist for 10 cases was used to define a qualified institution.Seven institutions participated and 112 patients were enrolled in this study. However, 4 patients were excluded owing to screening failure. The mean number of cases required for institutional qualification was 15 cases (range, 13-20 cases). Sentinel basins (SB) were detected and dissected in 100 of the 108 patients (92.6%); the median number of SB and SBN was 2 and 7, respectively. Lymph node metastases were detected in 10 patients by postoperative permanent H&E staining and they were detected by SBD in all 10 patients. Frozen results of SBN were compatible with permanent staining reports.Laparoscopic SBD is feasible and demonstrated improved sensitivity in detecting metastatic lymph nodes compared to the previous study. A future phase III randomized trial comparing laparoscopic SBD with organ-preserving gastrectomy and laparoscopic standard gastrectomy seems promising for qualified institutions.

Single skip metastasis in sentinel lymph node: In an early gastric cancer

Lymph node status is considered a key prognostic and predictive factor in patients with gastric cancer (GC). Although there is a practical approach to the intraoperative detection of sentinel lymph nodes (SLNs), such a procedure is not included in the European surgical protocol. In this report, we present a practical approach to SLN mapping in a representative case with early gastric cancer (EGC). A 74-year-old female was hospitalized with an endoscopically observed, superficially ulcerated tumor located in the antral region. Subtotal gastrectomy with D2 lymphadenectomy and SLN mapping was performed by injecting methylene blue dye into the peritumoral submucosal layer. An incidentally detected blue-stained lymph node located along the middle colic artery was also removed. This was detected 40 min after injection of the methylene blue. Histopathologic examination showed a pT1b-staged well-differentiated HER-2-negative adenocarcinoma. All of the 41 LNs located at the first, third, and fifth station of the regional LN compartments were found to be free of tumor cells. The only lymph node with metastasis was located along the middle colic artery and was considered a non-regional lymph node. This incidentally identified skip metastasis indicated stage IV GC. A classic chemotherapy regimen was given, and no recurrences were observed six months after surgery. In this representative case, low-cost SLN mapping, with a longer intraoperative waiting time, totally changed the stage of the tumor in a patient with EGC.

Evolution of Gastric Cancer Treatment: From the Golden Age of Surgery to an Era of Precision Medicine

Gastric cancer imposes a global health burden. Although multimodal therapies have proven to benefit patients with advanced diseases after curative surgery, the prognosis of most advanced cancer patients still needs to be improved. Surgical extirpation is the mainstay of gastric cancer treatment. Indeed, without curative surgery, variations and combinations of chemotherapy and/or radiation cannot bring clinically meaningful success. Centered around D2 surgery, adjuvant and peri-operative multimodal therapies have improved survival in a certain group of gastric cancer patients. Moving toward a personalized cancer therapy era, molecular targeted strategies have been tested in clinical trials for gastric cancer. With some success and failures, we have learned valuable lessons regarding the biology of gastric cancer and the clinical relevance of biological therapies in addition to conventional treatments. Future treatment of gastric cancer will be shifted to molecularly tailored and genome information-based personalized therapy. Collaboration across disciplines and actively adopting emerging anti-cancer strategies, along with in-depth understanding of molecular and genetic underpinnings of tumor development and progression, are imperative to realizing personalized therapy for gastric cancer. Although many challenges remain to be overcome, we envision that the era of precision cancer medicine for gastric cancer has already arrived and anticipate that current knowledge and discoveries will be transformed into near-future clinical practice for managing gastric cancer patients.

Sentinel node mapping in adenocarcinoma of the esophagogastric junction

BACKGROUND

The incidence of adenocarcinoma of the esophagogastric junction (AEG) is increasing, but the surgical strategy for AEG remains controversial. We hypothesized that sentinel node (SN) mapping for AEG could be validated to avoid unnecessary lymphadenectomy and permit minimally invasive surgery. We examined the feasibility of SN mapping for AEG.

METHODS

We enrolled 15 patients with preoperatively diagnosed cT1 N0 M0 primary AEG (Siewert type I, N = 3; Siewert type II, N = 12) lesions measuring <4 cm in diameter. The dual tracer method employing radioactive colloid and blue dye was used to detect SNs. The distribution of SNs was compared with that of metastatic lymph nodes in 52 patients who were surgically treated without SN mapping.

RESULTS

SNs were successfully identified in all the patients. Two patients with lymph node metastasis had positive SNs identified via an intraoperative pathological examination, and the diagnostic sensitivity and accuracy based on the SN status were both 100 %. For Siewert type II AEG, the SNs were not detected in the lower mediastinum by intraoperative gamma probing. Thus, all surgical procedures were performed via a transhiatal approach. No patient without SN metastasis experienced cancer recurrence during a 38-month median follow-up. The distribution of SNs was similar to that of lymph node metastasis in the patients who were surgically treated without SN mapping.

CONCLUSIONS

We achieved 100 % SN detection. Our results suggested that SN mapping is feasible for AEG and highly sensitive and accurate in diagnosing lymph node metastasis. SN mapping may clarify the necessity of mediastinal lymph node dissection and individualize minimally invasive surgery.

Critical evaluation of ramucirumab in the treatment of advanced gastric and gastroesophageal cancers

Gastric (GC) and gastroesophageal junction (GEJ) cancers are two global health problems with a relatively high mortality, particularly in the advanced stage. Inhibition of angiogenesis is now contemplated as a classic treatment preference for myriad tumor types encompassing renal cell carcinoma, non-small cell lung cancer, colorectal cancer, glioblastoma, and ovarian cancer, among others. Bevacizumab and ramucirumab have been widely investigated in GC and GEJ cancer, with some controversy about their therapeutic role. Ramucirumab is a monoclonal antibody for vascular endothelial growth factor receptor-2, with demonstrated activity both as a monotherapy and as a part of combination strategy in the management of advanced GC/GEJ cancer. In this review article, we present a critical evaluation of the preclinical and clinical data underlying the use of this drug in this indication. Moreover, we provide a spotlight on the future perspectives in systemic therapy for advanced GC/GEJ cancer.

Novel method for hybrid endo-laparoscopic full-thickness gastric resection using laparoscopic transgastric suture passer device

BACKGROUND

Current surgical methods for partial gastric full-thickness resections (FTRs) are limited by long operative times and risk of gastric content spillage, especially for lesions located at the posterior wall. We propose a simplified hybrid approach to FTR with reduced risk of spillage.

METHODS

Resection margins were marked by endoscopic electrocautery to simulate a gastric lesion in the upper third of the posterior wall in eight pigs. A custom-made laparoscopic "suture passer" was made of a sharpened bendable dissecting forceps. Full-thickness sutures were alternatively passed from the serosa side with the suture passer through the gastric wall and grabbed endoluminally using an endoscopic grasper and vice versa. These transgastric sutures formed either a purse string (PS; n = 4) or a continuous horizontal mattress (HM; n = 4). Sutures were then fastened from the laparoscopic side, resulting in external outpouching of the lesion. The pouch was transected using 45-mm linear staplers. Operative time, resection margins, and number of staplers were evaluated.

RESULTS

The combined approach allowed one to precisely place the sutures around the pseudo lesions, despite the inflated stomach, and it included all target markings. PS and HM methods were similar regarding time for transgastric suture (780 s ± 219.1 s vs. 765 s ± 179.2 s, p = .885), resection margins (1.3 ± 1.0 cm vs. 0.8 ± 0.6 cm, p = .248), and number of staplers (3.8 ± 1.0 vs 3.3 ± 0.5, p = .405). Stapling time (600 s ± 189.7 s vs. 330 s ± 24.5 s, p = .028) was significantly shorter in the HM technique.

CONCLUSION

FTR with laparo-endoscopic transgastric suture application was feasible in the animal model. This technique allows one to achieve accurate resection margins with minimal risk of spillage.

Sentinel lymph node mapping for 385 gastric cancer patients

BACKGROUND

The objectives were to investigate the accuracy of sentinel lymph node (SLN) biopsy, detect the predictors for undetected or false-negative cases, evaluate the indications for SLN-navigated gastrectomy, and characterize the problems of SLN mapping in gastric cancer. The SLN concept may be applicable to early gastric cancer, particularly clinical T1N0M0 or T2N0M0 with tumor diameter ≤4 cm.

METHODS

A total of 385 consecutive patients diagnosed with cT1N0M0 or cT2aN0M0 operable gastric cancer from April 1999 to December 2007 underwent radical gastrectomy with SLN mapping. SLNs were identified using radio-guided and dye-guided methods. Predictors for undetected or false-negative cases on SLN mapping were examined by multivariate regression analysis.

RESULTS

The detection rate of hot and/or blue nodes was 96.6% (372 of 385). The accuracy of metastatic status based on SLNs was 98.9% (368 of 372) for all cases in whom SLNs could be detected. Furthermore, the accuracy of metastatic status based on SLNs was 99.1% (344 of 347) in cT1 gastric cancer and 96.0% (24 of 25) in cT2 gastric cancer. Pathologically, the tumors invaded to the muscularis propria or deeper in three of four false-negative cases. All but one case had metastatic lymph nodes within the sentinel basins. In terms of 5-y recurrence free survival, positive SLN cases (SLN(+)) had a worse prognosis than negative SLN cases (SLN(-); P = 0.008). Moreover, SLN(+) and non-SLN(-) cases (SLN(+)/non-SLN(-)) had a similar prognosis as SLN(+) and non-SLN(+) cases (SLN(+)/non-SLN(+)) (P = 0.511). On multivariate regression analysis, undetected or false-negative cases were significantly associated with the time period.

CONCLUSIONS

The present results appeared to validate the SLN concept for untreated cT1 gastric cancer with tumor diameter ≤4 cm. SLN mapping may provide an effective method of staging the lymph node status of patients undergoing minimized gastrectomy. Sentinel basin dissection guards against the possibility of leaving positive lymph nodes. Stabilization of the procedure and experience with SLN mapping in gastric cancer might decrease undetected or false-negative cases.

Current status of randomized controlled trials for laparoscopic gastric surgery for gastric cancer in Korea

Laparoscopic gastrectomy for gastric cancer has rapidly gained popularity as a result of the increased incidence of early gastric cancer in Korea. Although laparoscopic gastrectomy has been considered as an investigational treatment because of the lack of solid evidence of efficacy and safety, it is increasingly regarded as a standard treatment for early gastric cancer. Moreover, solid evidence is anticipated from two studies in Korea, KLASS 01 and KLASS 02, the latter of which examines the suitability of laparoscopic gastrectomy for advanced gastric cancer. The use of cutting-edge techniques for laparoscopic gastrectomy enables surgeons to deliver various treatment options that offer the best possible quality of life after gastrectomy. In this review, we summarize the current status of clinical trials on laparoscopic gastrectomy in Korea and examine future perspectives regarding laparoscopic gastrectomy for the treatment of gastric cancer.

Preferentially examined sentinel nodes for sentinel node navigation surgery in gastric cancer

The intraoperative examination of the sentinel nodes (SNs) is crucial for correctly performing SN navigation surgery (SNNS). Frozen-section diagnosis is ordinarily used; however, when several SNs are being assessed in gastric cancer, which has numerous regional lymph nodes, it is difficult to examine them all correctly within the short duration of surgery. In the present study, we aimed to determine the SNs that should be preferentially examined during SNNS in gastric cancer. A total of 824 SNs were examined in 113 patients with clinically determined T1-2 gastric cancer and no apparent lymph node metastasis. We focused on the accumulation of tracers expressed by hot nodes (HNs) using the radioisotope (RI) method and green nodes (GNs) using the dye-guided method and measured the radioactivity count of the HNs (RI count). We compared these parameters between 35 metastatic and 789 non-metastatic SNs. The percentage of metastasis-positive SNs that were radioactively 'hot' and dyed green was higher compared with that of the negative SNs (89 vs. 43%, respectively; P<0.01). The RI counts of the metastasis-positive SNs were higher compared with those of the negative SNs [median (range): 361 (0-10,670) vs. 53 (0-9,931), respectively; P<0.01]. The area under the receiver operating characteristic curve of the RI count was 0.69 (95% CI: 0.60-0.78). Therefore, when assessing several SNs, those with higher RI counts (HNs and GNs) should be preferentially examined. Further accumulation of cases is required to establish the cut-off value for the diagnosis of metastasis based on the RI count.

Sentinel lymph node navigation surgery for early stage gastric cancer

We attempted to evaluate the history of sentinel node navigation surgery (SNNS), technical aspects, tracers, and clinical applications of SNNS using Infrared Ray Electronic Endoscopes (IREE) combined with Indocyanine Green (ICG). The sentinel lymph node (SLN) is defined as a first lymph node (LN) which receives cancer cells from a primary tumor. Reports on clinical application of SNNS for gastric cancers started to appear since early 2000s. Two prospective multicenter trials of SNNS for gastric cancer have also been accomplished in Japan. Kitagawa et al reported that the endoscopic dual (dye and radioisotope) tracer method for SN biopsy was confirmed acceptable and effective when applied to the early-stage gastric cancer (EGC). We have previously reported the usefulness of SNNS in gastrointestinal cancer using ICG as a tracer, combined with IREE (Olympus Optical, Tokyo, Japan) to detect SLN. LN metastasis rate of EGC is low. Hence, clinical application of SNNS for EGC might lead us to avoid unnecessary LN dissection, which could preserve the patient's quality of life after operation. The most ideal method of SNNS should allow secure and accurate detection of SLN, and real time observation of lymphatic flow during operation.

Feasibility of non-exposed endoscopic wall-inversion surgery with sentinel node basin dissection as a new surgical method for early gastric cancer: a porcine survival study

Non-exposed endoscopic wall-inversion surgery (NEWS) has been developed as an endoscopic full-thickness resection technique without translumenal communication to avoid intraabdominal infection or tumor seeding. We aimed to investigate the feasibility and safety of NEWS with sentinel node basin dissection (SNBD), which can minimize the area of lymphadenectomy for early gastric cancer (EGC), in 10 porcine survival models. After placing laparoscopic ports and making markings on both the mucosal and serosal sides of a simulated lesion, indocyanine green fluid was endoscopically injected into the submucosa at 4 quadrants around the lesion. An SN basin including the stained SNs was dissected, and a circumferential sero-muscular incision around the lesion and sero-muscular suturing were performed laparoscopically, with the lesion inverted toward the inside of the stomach. Finally, circumferential mucosal incision and transoral retrieval were made endoscopically. In all cases, the lesion was resected in an en bloc fashion, and all pigs survived without adverse events. After 1 week of observation, pigs were sacrificed for macroscopic investigation. The average procedural duration was 170 min (range 130-253 min). Intraoperative perforation occurred in 1 case, which could be safely treated by laparoscopic suturing. The number of dissected SN basins was 1 in 9 cases and 2 in 1 case. Necropsy revealed no signs of severe complication. This animal survival study demonstrated that NEWS with SNBD was safe and feasible. It may provide patients with possibly node-positive EGC a minimally-sized local resection and minimally-ranged lymphadenectomy without the risk of tumor dissemination.

A new stage of sentinel node navigation surgery in early gastric cancer

Sentinel node (SN) navigation surgery is expected to realize organ- and function-preserving surgery with SN mapping, and has been applied in operations for breast cancer and melanoma. But there has been no definite evidence for the SN concept in gastric cancer. A prospective multicenter trial to confirm the SN concept for gastric cancer conducted by the Japan Society of Sentinel Node Navigation Surgery reported that the SN detection rate, sensitivity of positive SNs, and accuracy of nodal status are 97.5% (387/397), 93% (53/57), and 99% (383/387), respectively. A detailed analysis of the trial suggested that strictly the "lymphatic basin concept" rather than the "SN concept" was confirmed in early gastric cancer. The Japan Society of Sentinel Node Navigation Surgery started a new trial of function-preserving gastrectomy with lymphatic basin dissection (LBD) for early gastric cancer without metastasis in SNs on the basis of this promising outcome of the trial. It is supposed that LBD guarantees curability in SN navigation surgery for early gastric cancer. Full-thickness resection or endoscopic submucosal dissection in combination with laparoscopic LBD will soon be a new treatment option for early gastric cancer.

First case of non-exposed endoscopic wall-inversion surgery with sentinel node basin dissection for early gastric cancer

INTRODUCTION

Non-exposed endoscopic wall-inversion surgery (NEWS) is a novel technique of endoscopic full-thickness resection without transluminal access mainly designed to treat gastric cancer. Here, we report a successful case of NEWS with sentinel node basin dissection (SNBD) for early gastric cancer (EGC) with the risk of lymph node metastasis.

PATIENT AND METHODS

A 55-year-old female patient with a 2-cm, diffuse-type intramucosal EGC with ulceration was referred to our hospital for a less invasive gastrectomy based on sentinel node navigation surgery. After obtaining informed consent, NEWS with SNBD was applied. After placing mucosal markings, indocyanine green solution was injected endoscopically into the submucosa around the lesion to examine sentinel nodes (SNs). The SN basin (the area of the left gastric artery), including three stained SNs(#3), was dissected, and an intraoperative pathological diagnosis confirmed that no metastasis had occurred. Subsequently, NEWS was performed for the primary lesion. Serosal markings were placed laparoscopically, submucosal injection was added endoscopically, and circumferential sero-muscular incision and suturing were performed laparoscopically, with the lesion inverted toward the inside of the stomach. Finally, the circumferential mucosal incision was performed, and the lesion was retrieved perorally.

RESULTS

The operation was finished in 270 min without complications. The patient was uneventfully discharged 10 days after the procedure. The final pathological diagnosis was coincident with the pre- and intraoperative assessment.

CONCLUSIONS

We demonstrated the feasibility and safety of NEWS with SNBD with a favorable result. This surgical concept is expected to become a promising, minimally invasive, function-preserving surgery to cure cases of EGC that are possibly node-positive.

Techniques that accurately identify the sentinel lymph node in cancer

Sentinel lymph node (SLN) biopsy has become the gold standard for patients with melanoma and breast cancer but it’s clinical application in other solid tumor types such as cancers of the esophagus, stomach, colon and rectum, head and neck, penis, uterine cervix and endometrium has been somewhat limited. Commonly used mapping techniques utilizing the combination of radiocolloid and blue dye may result in reduced SLN detection and increased false negative rates when applied to cancers with more complex lymphatic drainage patterns. Novel localization techniques including near infrared fluorescence, high resolution imaging and molecular targeted agents have been developed to address the limitations of conventional SLN detection practices in many solid tumor types. This article reviews the indications, techniques and detection rates for SLN biopsy in several different solid tumor types as well as the promising novel techniques created to address the contemporary limitations of this procedure.

A New Statistical Model Identified Two-thirds of Clinical T1 Gastric Cancers as Possible Candidates for Endoscopic Treatment

BACKGROUND

Clinical T1 gastric cancer has low metastatic potential to lymph nodes and is generally curable by local treatment. Endoscopic resection can preserve the whole stomach and does not impair the patient's quality of life; however, its indication is strictly limited to the subset of patients without nodal metastasis. The study was designed to predict reliably the patients without nodal metastasis based only on the clinical information.

METHODS

We examined patients with clinical T1 disease who were treated with surgery. The clinically available information was evaluated for its ability to predict nodal metastasis by logistic regression model. Then, the predictive ability of the logistic regression model using the risk factors for nodal metastasis was evaluated by a receiver operating characteristic curve.

RESULTS

A total of 511 patients were entered into this study. The clinical depth (cT1a or cT1b), maximal tumor diameter, and pathological type were confirmed to be significantly different between patients with and without nodal metastasis. The cutoff value of the tumor diameter differed depending on the histology and clinical depth: 79 mm for differentiated type and 48 mm for undifferentiated type in cT1a tumors, and 43 mm for differentiated type and 11 mm for undifferentiated type in cT1b tumors. According to these criteria, 348 of the 511 patients (68.1 %) were classified to have predictive N0 status. The negative predictive value was 95.7 % (95 % confidence interval 94.0-97.5 %).

CONCLUSIONS

The predictive criteria based on the multivariate logistic model identified that almost two-thirds of the patients with clinical T1 gastric cancer were possible candidates for endoscopic treatment.

The clinical significance and risk factors of solitary lymph node metastasis in gastric cancer

AIMS

To assess the clinical significance and risk factors of solitary lymph node metastasis (SLM) in gastric carcinoma and establish a more accurate method to evaluate the possibility of lymph node metastasis (LM).

METHODS

A total of 385 patients with gastric carcinoma who underwent D2 lymphadenectomy at the Cancer Center of Sun Yat-Sen University were included in this research. Then we used a group of data from Sun Yat-sen University Gastrointestinal Hospital (SYSUGIH) to validate the accuracy of our developed method. The χ2 test, Kaplan-Meier analysis, log-rank test, COX model, and discriminate analysis were used to analyze the data with SPSS13.0.

RESULTS

We found that the LM number and pathological T staging were independent prognostic risk factors. CEA grading, LN status by CT, and T staging by CT were independent risk factors for LM in gastric carcinoma. In addition, we developed the equation Y = -5.0 + X1 + 1.8X3 + 0.7X4 (X1 = CEA grading, X3 = LN status by CT, X4 = T staging by CT) to evaluate the situation of LM. The data from SYSUGIH shows this equation has a better accuracy compared with CT.

CONCLUSIONS

SLM is an independent risk factor in gastric cancer. And there was no survival difference between the skip metastasis group and the other SLM group (P = 0.659). It is inappropriate for the patient with SLM doing a standard D2 lymphadenectomy, due to the fact that LM rarely occurs in the splenic artery, splenic hilum. The risk factors for LM include CEA grading, LN status by CT, and T staging by CT. And we can use Y = -5.0 + X1 + 1.8X3 + 0.7X4 (X1, CEA grading, X3 = LN status by CT, X4 = T staging by CT, the critical value is 0.3) to estimate the possibility of LM, which has a better accuracy compared with CT.

Sentinel node navigation surgery for gastric cancer: Overview and perspective

The sentinel node (SN) technique has been established for the treatment of some types of solid cancers to avoid unnecessary lymphadenectomy. If node disease were diagnosed before surgery, minimal surgery with omission of lymph node dissection would be an option for patients with early gastric cancer. Although SN biopsy has been well ascertained in the treatment of breast cancer and melanoma, SN navigation surgery (SNNS) in gastric cancer has not been yet universal due to the complicated lymphatic flow from the stomach. Satisfactory establishment of SNNS will result in the possible indication of minimally invasive surgery of gastric cancer. However, the results reported in the literature on SN biopsy in gastric cancer are widely divergent and many issues are still to be resolved, such as the collection method of SN, detection of micrometastasis in SN, and clinical benefit. The difference in the procedural technique and learning phase of surgeons is also varied the accuracy of SN mapping. In this review, we outline the current status of application for SNNS in gastric cancer.

Biopathologic features and clinical significance of micrometatasis in the lymph node of early gastric cancer

AIM: To evaluate the biopathologic features and clinical significance of nodal micrometastasis (MI) in early gastric cancer (EGC).

METHODS: Among 1022 EGC patients who underwent gastrectomy with lymphadenectomy of D1 + β or more from March 2001 to December 2005 at the Korean National Cancer Center, available nodal metastasis was found in 90 pT1N1 patients. Nodal metastasis was confirmed by immunohistochemistry (IHC) with cytokeratin and patients were classified into MI and macrometastasis (MA) groups based on the main tumor burden according to the 6^th International Union Against Cancer/American Joint Committee on Cancer staging system; the main tumor burden with a diameter of greater than 0.2 mm but no greater than 2 mm as MI, and greater than 2 mm as MA of the representative metastatic node. Proliferative and apoptotic activities of the primary tumor and the nodal metastasis were measured by IHC with Ki-67 and terminal deoxynucleotidyl transferase dUTP nick end labeling, respectively. Biopathologic and clinical features of the patients were analyzed and compared between MI and MA groups. Patients with recurrence were compared with those without recurrence to identify risk factors for recurrence.

RESULTS: Thirty-seven patients showed MI and the other 53 patients revealed MA in the lymph node; the incidence of patients with MI and MA was 41.1% and 58.9%. The main tumor burden was 0.9 and 4.6 mm in the representative metastatic node, respectively. Japanese N2 stations were more frequently involved in MA group (20.9%) than in MI group (10.3%) but the difference was not statistically different (P = 0.338). Proliferative and apoptotic activities of MI were decreased than those of MA (26.7% vs 40.5%, P = 0.004 and 1.0% vs 3.0%, P < 0.001, respectively). However, nodal MI in the current study showed a relatively high proliferative activity and an equivalent apoptotic activity compared to other cancers in the previously published studies. Recurrence was observed in 6 patients during the mean follow up period of 87.6 ± 26.2 mo. The recurrence was significantly associated with the presence of MA (P = 0.041) and lymphovascular invasion of the primary tumor (P = 0.032).

CONCLUSION: Lymphadenectomy of D1 + β or more might be necessary in patients with MI in sentinel node to prevent recurrence by clearing MI involving Japanese N2 station.