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

Integrating No.3 lymph nodes and primary tumor radiomics to predict lymph node metastasis in T1-2 gastric cancer

BACKGROUND

This study aimed to develope and validate a radiomics nomogram by integrating the quantitative radiomics characteristics of No.3 lymph nodes (LNs) and primary tumors to better predict preoperative lymph node metastasis (LNM) in T1-2 gastric cancer (GC) patients.

METHODS

A total of 159 T1-2 GC patients who had undergone surgery with lymphadenectomy between March 2012 and November 2017 were retrospectively collected and divided into a training cohort (n = 80) and a testing cohort (n = 79). Radiomic features were extracted from both tumor region and No. 3 station LNs based on computed tomography (CT) images per patient. Then, key features were selected using minimum redundancy maximum relevance algorithm and fed into two radiomic signatures, respectively. Meanwhile, the predictive performance of clinical risk factors was studied. Finally, a nomogram was built by merging radiomic signatures and clinical risk factors and evaluated by the area under the receiver operator characteristic curve (AUC) as well as decision curve.

RESULTS

Two radiomic signatures, reflecting phenotypes of the tumor and LNs respectively, were significantly associated with LN metastasis. A nomogram incorporating two radiomic signatures and CT-reported LN metastasis status showed good discrimination of LN metastasis in both the training cohort (AUC 0.915; 95% confidence interval [CI] 0.832-0.998) and testing cohort (AUC 0.908; 95% CI 0.814-1.000). The decision curve also indicated its potential clinical usefulness.

CONCLUSIONS

The nomogram received favorable predictive accuracy in predicting No.3 LNM in T1-2 GC, and the nomogram showed positive role in predicting LNM in No.4 LNs. The nomogram may be used to predict LNM in T1-2 GC and could assist the choice of therapy.

How useful is sentinel lymph node biopsy for the status of lymph node metastasis in cT1N0M0 gastric cancer? A systematic review and meta-analysis

Sentinel lymph node biopsy (SLNB) is intriguing because it is expected to further expand the indication of endoscopic resection (ER) for cT1N0M0 gastric cancer and as an additional operation for post-ER gastric cancer. The aim of our study was to perform a systematic review and meta-analysis on the feasibility and diagnostic value of SLNB technique in patients with cT1N0M0 gastric cancer. Eligible studies were systematically searched in PubMed, Embase, and Cochrane Library databases from inception to April 2020. A random-effect model was used to pool the data, and subgroup analysis was used to explain the heterogeneities. A total of 22 clinical studies (1993 patients with cT1N0M0 gastric cancer) were included. The pooled SLN identification rate, sensitivity, specificity, and diagnostic odds ratio with 95% confidence intervals were 0.99 (0.99-1.00), 0.92 (0.88-0.95), 1.00 (1.00-1.00), and 832.8 (395.5-1753.6), respectively. The summary receiver operator characteristic displayed a test accuracy of 99.3%. Subgroup analysis found an improved SLN sensitivity for studies with the mean number of SLNs > 4 and studies stained with a combination of hematoxylin-eosin with immunohistochemistry (HE + IHC). Further, studies using the basin dissection were associated with a higher SLN identification rate. The current meta-analysis provides data that favors the use of SLNB for predicting the status of lymph node metastasis in patients with cT1N0M0 gastric cancer. However, establishing standard procedure and suitable criteria for further application and optimization of SLNB is urgently needed.

Intraoperative laparoscopic detection of sentinel lymph nodes with indocyanine green and superparamagnetic iron oxide in a swine gallbladder cancer model

Mapping of sentinel lymph nodes (SLNs) can enable less invasive surgery. However, mapping is challenging for cancers of difficult-to-access visceral organs, such as the gallbladder, because the standard method using radioisotopes (RIs) requires preoperative tracer injection. Indocyanine green (ICG) and superparamagnetic iron oxide (SPIO) have also been used as alternative tracers. In this study, we modified a previously reported magnetic probe for laparoscopic use and evaluated the feasibility of detecting SLNs of the gallbladder using a laparoscopic dual tracer method by injecting ICG and SPIO into five swine and one cancer-bearing swine. The laparoscopic probe identified SPIO nanoparticles in the nodes of 4/5 swine in situ, the magnetic field counts were 2.5-15.9 μT, and fluorescence was detected in SLNs in all five swine. ICG showed a visual lymph flow map, and SPIO more accurately identified each SLN with a measurable magnetic field quite similar to the RI. We then developed an advanced gallbladder cancer model with lymph node metastasis using recombination activating gene 2-knockout swine. We identified an SLN in the laparoscopic investigation, and the magnetic field count was 3.5 μT. The SLN was histologically determined to be one of the two metastatic lymph nodes. In conclusion, detecting the SLNs of gallbladder cancer in situ using a dual tracer laparoscopic technique with ICG and SPIO was feasible in a swine model.

Essential updates 2019/2020: Perioperative and surgical management of gastric cancer

Perioperative and surgical management of gastric cancer have been changing as pivotal phase II trials and landmark phase III trials offer new insights to the existing knowledge. The results of many landmark trials have been published or presented in the past year, many of which have changed or will change current clinical practice. For example, FLOT4 has completely changed the regimen of perioperative chemotherapy in Europe. Furthermore, evidence for minimally invasive surgery for clinical Stage I was firmly established by KLASS-01 and JCOG0912 for distal gastrectomy and CLASS-02, KLASS-03, and JCOG1401 for total gastrectomy. Moreover, promising results were provided by CLASS-01 and KLASS-02 for locally advanced gastric cancer. For adjuvant chemotherapy, JACCRO GC-07 (START-2) has provided a new doublet regimen for pathological Stage III, which is often refractory to chemotherapy. Conversely, JCOG0501 poses a significant challenge for advanced tumors, such as large type 3 and scirrhous (type 4) tumors. In this review, we briefly review recent updates and discuss future perspectives of gastric cancer treatment.

Assessment of diagnostic value of fluorescent lymphography-guided lymphadenectomy for gastric cancer

BACKGROUND

Indocyanine green fluorescent lymphography helps visualize the lymphatic drainage pattern in gastric cancer; however, it is unknown whether fluorescent lymphography visualizes all metastatic lymph nodes. This study aimed to evaluate the sensitivity of fluorescent lymphography to detect metastatic lymph node stations and lymph nodes and the risk of false-negative findings.

METHODS

Patients with clinical T1-4a gastric cancer were included. Indocyanine green was peritumorally injected the day prior to surgery by endoscopy. Gastrectomy with systematic D1+ or D2 lymphadenectomy was performed. Stations and lymph nodes were retrieved at the back-table using near-infrared imaging and classified as "fluorescent" or "non-fluorescent" and later matched with histopathological findings.

RESULTS

Among 592 patients who underwent minimally invasive gastrectomy from September 2013 until December 2016, lymph node metastases were present in 150. The sensitivity of fluorescent lymphography in detecting all metastatic lymph node stations was 95.3% (143/150 patients), with a false-negative rate of 4.7% (7/150 patients) and the sensitivity in detecting all metastatic lymph nodes was 81.3% (122/150 patients). The negative predictive value was 99.3% for non-fluorescent stations and 99.2% for non-fluorescent LNs. For detecting all metastatic LN stations, subgroup analysis revealed 100% sensitivity for pT1a, 96.8% for pT1b, 100% for pT2, 91.3% for pT3, and 93.6% for pT4a tumors.

CONCLUSIONS

Fluorescent lymphography-guided lymphadenectomy can be a useful method for radical lymphadenectomy by facilitating the complete dissection of all potentially positive LN stations. Fluorescent lymphography-guided lymphadenectomy appears to be a reasonable alternative to conventional systematic lymphadenectomy for gastric cancer.

A multicenter non-randomized phase III study of sentinel node navigation surgery for early gastric cancer

This prospective multicenter non-randomized phase III study aims to evaluate the long-term outcome of sentinel node navigation surgery for early gastric cancer compared with conventional distal or total gastrectomy. Clinically diagnosed primary T1N0M0 gastric cancer patients with a single lesion (≤40 mm) and without previous endoscopic treatment will be enrolled in this study. Sentinel nodes are identified by dye and radioisotope tracers and are subjected to intraoperative rapid pathology. For patients with negative sentinel node metastasis, individualized surgery consisting of limited stomach resection and sentinel node basin dissection is performed, while standard gastrectomy with D2 lymph node dissection is employed for the positive sentinel node patients. A total of 225 patients will be accrued from 13 hospitals that have experience in sentinel node mapping. The primary endpoint is 5-year relapse-free survival. The secondary endpoints are overall survival, sentinel node detection rate, diagnostic accuracy for sentinel node, distribution of sentinel nodes and metastatic sentinel node/non-sentinel node, and postoperative quality of life.

Sentinel-Lymph-Node Multicenter Trials

Well executed multicenter clinical trials often provide significant evidence and support for, or against, foundational aspects of clinical procedures perceived to improve clinical management of a medical condition. In this review, discussed are reports of multicenter clinical trials designed to investigate sentinel lymph node biopsy procedures in seven types of cancer: breast, melanoma, head and neck, gastric, colon, uterine, and vulvar-with focus on the most recent reports of the hypotheses, objectives, parameters, data, results, implications, and impacts of the included trials. Such trials generally enroll more subjects, in shorter time periods, than do single-center studies. Such studies generally also have greater diversities among investigator practitioners and investigative environments than do single-center studies. The greater number of subjects provides more power to statistical analyses performed in such studies. The more rapid accrual usually results in data being more consistently acquired. The diversities of practitioners and environments may produce results that are more conservative than might be obtained from more "focused" studies; however, diversities in a study often identify implicitly results that are more robust-that is results applicable by more practitioners and applicable in more environments.

A Systematic Review and Meta-Analysis of Sentinel Lymph Node Biopsy in Gastric Cancer, an Optimization of Imaging Protocol for Tracer Mapping

BACKGROUND

Sentinel lymph node biopsy (SLNB) plays an essential role in the evaluation of lymph node (LN) metastasis status and the extent of LN dissection in gastric cancer. The aim of our study was to perform a systematic review and meta-analysis for corresponding identification rate and sensitivity of different SLNB techniques.

METHODS

Systematic search using PubMed, Embase, and Cochrane library databases was conducted for studies on SLNB in patients with gastric cancer. Studies were stratified according to the sentinel lymph node (SLN) biopsy technique: blue dye (BD), radiocolloid tracer (RI), indocyanine green (ICG), a combination of radiocolloid with blue dye (RI + BD), and a combination of radiocolloid with ICG (RI + ICG). A random-effect model was used to pool the identification rate, sensitivity, and accuracy.

RESULTS

A total of 54 eligible studies (3767 patients) was included. The pooled identification rates of SLNB using BD, RI, ICG, RI + BD, RI + ICG were 95% (95%CI: 92-97%), 95% (95%CI: 93-97%), 99% (95%CI: 97-99%), 97% (95%CI: 96-98%), and 95% (95%CI: 87-99%), respectively. The pooled sensitivities were 82% (95%CI: 77-86%), 87% (95%CI: 81-92%), 90% (95%CI: 82-95%), 89% (95%CI: 84-93%), and 88% (95%CI: 79-94%), respectively. The pooled accuracies were 94% (95%CI: 91-96%), 95% (95%CI: 92-97%), 98% (95%CI: 95-99%), 97% (95%CI: 95-99%), and 98% (95%CI: 95-99%), respectively.

CONCLUSIONS

The current meta-analysis provides reliable evidence that favors the use of ICG and dual tracer method (RI + BD/ICG) for the identification of the SLN. Considering the high costs and potential biohazard of using radioactive substances in dual tracer method, performing SLNB with ICG is the technique of choice for experienced surgeons.

Recent updates and current issues of sentinel node navigation surgery for early gastric cancer

With the increase in the incidence of early gastric cancer (EGC), several endoscopic and laparoscopic approaches, such as endoscopic submucosal dissection and function-preserving gastrectomy, have been accepted as standard treatments. Sentinel node navigation surgery (SNNS) is an ideal surgical option for preservation of most parts of the stomach and consequent maintenance of normal gastric function to improve quality of life in patients with EGC. Although many previous studies and clinical trials have demonstrated the safety and feasibility of the sentinel node concept in gastric cancer, the clinical application of SNNS is debatable. Several issues regarding technical standardization and oncological safety need to be resolved. Recently several studies to resolve these problems are being actively performed, and SNNS might be an important surgical option in the treatment of gastric cancer in the future.

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

As an optimal surgical procedure to accurately evaluate lymph node (LN) metastasis during surgery with minimal surgical resection, we have been developing sentinel node (SN) biopsy for early gastric cancer since the 1990s. Twelve institutions from the Japanese Society of Sentinel Node Navigation Surgery (SNNS), including Keio University Hospital, conducted a multicenter prospective trial to validate the SN concept using the dual-tracer method with blue dye and a radioisotope. According to the results, 397 patients were included in the final analysis, and the overall accuracy in detecting LN metastasis using SN biopsy was 99% (383 of 387). Based on the validation study, we are targeting cT1N0 with a primary tumor of ≤4 cm in diameter as an indication for SN biopsy for gastric cancer. We are currently running a multicenter nonrandomized phase III trial to assess the safety and efficacy of SN navigation surgery. The Korean group has reported the result of a multicenter randomized phase III trial. Since meticulous gastric cancer in the remnant stomach was rescued by subsequent gastrectomy, the disease-specific survival was comparable between the two techniques, implying that SN navigation surgery can be an alternative to standard gastrectomy. With the development of SN biopsy procedure and treatment modalities, the application of SN biopsy will be expanded to achieve an individualized minimally invasive surgery.

Surgical treatment of gastric cancer: Current status and future directions

Surgery is the most important and effective method for the treatment of gastric cancer. Since the first gastrectomy in the early 19th century, surgical treatment of gastric cancer has undergone more than 100 years of development. With the increasing understanding of gastric cancer and the promotion of a series of clinical trials, the concept of gastric cancer surgery has evolved from the initial "bigger is better" to today's "standardized surgery" and is developing towards individualized surgery focusing on accurate resection and quality of life. This trend has had a tremendous impact on the development of surgical treatments, such as minimally invasive surgeries, function-preserving surgeries, and the optimal extent of lymph node dissection. Understanding the development and current status of gastric cancer surgery and exploring the remaining academic controversies are goals that every gastric surgeon should constantly pursue. However, how should gastric cancer surgery develop in the future? What opportunities and challenges will we encounter? In this review, we elaborate on the development and current status of gastric cancer surgery based on a series of clinical studies and discuss the controversy in the development of gastric cancer surgery.

Laparoscopic surgery for gastric cancer: Current status and future direction

Gastric cancer is still a major cause of death worldwide. While laparoscopic gastrectomy (LG) has gained evidence as a standard treatment for early gastric cancer in the distal stomach, there are still concerns regarding its application for gastric cancer in the upper stomach and advanced gastric cancer. Nevertheless, LG has shown to have faster recovery, shorter hospital stay, less pain, and less blood loss in many retrospective and prospective studies. The application of LG has now extended from conventional radical gastrectomy to novel approaches such as function-preserving gastrectomy and sentinel-node navigated surgery. Studies on the use of laparoscopy in treatment for stage IV gastric cancer are rare, but show that there may be some roles of LG in selected cases. With the development of new laparoscopic tools that augment human ability, the future of LG should move on from proving non-inferiority to demonstrating superiority compared to the traditional open gastrectomy.

Lymph Node Mapping in Gastric Cancer Surgery: Current Status and New Horizons

Gastric cancer (GC) remains one of the most important malignant diseases with significant geographical, ethnic, and socioeconomic differences in distribution. Sentinel lymph node (SLN) mapping is an accepted way to assess lymphatic spread in several solid tumors; however, the complexity of gastric lymphatic drainage may discourage use of this procedure, and the estimated accuracy rate is, in general, reasonably good. This study aimed at reviewing the current status of SLN mapping and navigation surgery in GC. SLN mapping should be limited to tumors clinically T1 and less than 4 cm in diameter. Combination SLN mapping with radioactive colloid and blue dye is used as the standard. Despite its notable limitations, SLN mapping and SLN navigation surgery present a novelty individualizing the extent of lymphadenectomy.

Application of Near-Infrared Fluorescence Imaging with Indocyanine Green in Totally Laparoscopic Distal Gastrectomy

Purpose

Recently, totally laparoscopic gastrectomy has been gradually accepted by surgeons worldwide for gastric cancer treatment. Complete dissection of the lymph nodes and the establishment of the surgical margin are the most important considerations for curative gastric cancer surgery. Previous studies have demonstrated that indocyanine green (ICG)-traced laparoscopic gastrectomy significantly improves the completeness of lymph node dissection. However, it remains difficult to identify the tumor location intraoperatively for gastric cancers that are staged ≤T3. Here, we investigated the feasibility of ICG fluorescence for lymph node mapping and tumor localization during totally laparoscopic distal gastrectomy.

Materials and Methods

Preoperative and perioperative data from consecutive patients with gastric cancer who underwent a totally laparoscopic distal gastrectomy were collected and analyzed. The patients were categorized into the ICG (n=61) or the non-ICG (n=75) group based on whether preoperative endoscopic mucosal ICG injection was performed.

Results

The ICG group had a shorter operation time and less intraoperative blood loss. Moreover, significantly more lymph nodes were harvested in the ICG group than the non-ICG group. No pathologically positive margin was found and there was no significant difference in either the proximal or distal surgical margins between the 2 groups.

Conclusions

Near-infrared fluorescence imaging with ICG can be successfully used in totally laparoscopic distal gastrectomy, and it contributes to both the completeness of D2 lymph node dissection and confirmation of the gastric transection line. Well-designed prospective randomized studies are needed in the future to fully validate our findings.

Combination of endoscopic submucosal dissection and laparoscopic sentinel lymph node dissection in early mucinous gastric cancer: Role of lymph node metastasis

BACKGROUND

Recent evidence showed that combining endoscopic submucosal dissection (ESD) and laparoscopic sentinel lymph node dissection may avoid unnecessary gastrectomy in treating early mucinous gastric cancer (EMGC) patients with risks of positive lymph node metastasis (pLNM).

AIM

To explore the predictive factors for pLNM in EMGC, and to optimize the clinical application of combing ESD and sentinel lymph node dissection in a proper subgroup of patients with EMGC.

METHODS

Thirty-one patients with EMGC who had undergone gastrectomy with lymph node dissection were consecutively enrolled from January 1988 to December 2016. Univariate and multivariate logistic regression analyses were used to estimate the association between the rates of pLNM and clinicopathological factors, providing odds ratio (OR) with 95% confidence interval. And the association between the number of predictors and the pLNM rate was also investigated.

RESULTS

Depth of invasion (OR = 7.342, 1.127-33.256, P = 0.039), tumor diameter (OR = 9.158, 1.348-29.133, P = 0.044), and lymphatic vessel involvement (OR = 27.749, 1.821-33.143, P = 0.019) turned out to be significant and might be the independent risk factors for predicating pLNM in the multivariate analysis. For patients with 1, 2, and 3 risk factors, the pLNM rates were 9.1%, 33.3%, and 75.0%, respectively. pLNM was not detected in seven patients without any of these risk factors.

CONCLUSION

ESD might serve as a safe and sufficient treatment for intramucosal EMGC if tumor size ≤ 2 cm, and when lymphatic vessel involvement is absent by postoperative histological examination. Combining ESD and sentinel lymph node dissection could be recommended as a safe and effective treatment for EMGC patients with a potential risk of pLNM.

A new method of sentinel node mapping for early gastric cancer using a fluorescent laparoscope that can adjust the intensity of excitation light and quantify the intensity of indocyanine green fluorescence: Report of a case

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VISION SENSE® is a new near-infrared fluorescence laparoscope, and allows adjustment of the intensity of excitation light and quantification of the intensity of ICG fluorescence during observation.

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Using VISION SENSE®, when many ICG-positive lymph nodes are observed, we can select lymph nodes by quantifying ICG fluorescence during surgery.

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This procedure might improve SN mapping for early gastric cancer.

Introduction

One of the drawbacks of indocyanine green (ICG) fluorescence sentinel node (SN) mapping is the impossibility of quantifying lymph node fluorescence during surgery. VISION SENSE® is a new near-infrared fluorescence laparoscope for bright-field full-color observation, and provides the ability to adjust the intensity of excitation light and quantify the intensity of ICG fluorescence during observation.

We report the case of a patient who underwent ICG SN mapping for early gastric cancer using VISION SENSE®.

Presentation of case

A woman in her 60 s was diagnosed with cType0-IIc early gastric cancer located in the anterior wall of the middle gastric body (25 mm in diameter, cT1b, cN0, cM0, cStage IA). Contrast-enhanced computed tomography showed no metastases. Laparoscopy assisted distal gastrectomy with D1+ lymph node dissection and SN mapping with ICG fluorescence using the VISION SENSE® were successfully performed. Using VISION SENSE®, we could select those lymph nodes objectively showing high intensity by quantifying ICG fluorescence during surgery.

The pathological diagnosis was well-differentiated adenocarcinoma, pT1a, N0, M0, pStage IA. No ICG-positive lymph nodes (8 nodes) contained metastases.

Postoperative course was good, with no complications.

Discussion

The use of VISION SENSE® allowing adjustment of excitation light and quantification of ICG fluorescence intensity might decreased the false-negative rate for SNs and increased the sensitivity of the ICG for detecting SNs.

Conclusion

We successfully performed ICG SN mapping for early gastric cancer using VISION SENSE®.

Should the left gastric artery lymph node be considered as the predictive lymph node for extra-gastric lymph node metastases?

Background

To validate the prognostic impacts of the left gastric artery lymph node (No. 7 LN) metastasis and investigate whether the No. 7 LN metastasis should be considered as the predictive LN for extra-gastric LN metastases.

Methods

Between January 2003 and December 2011, a total of 1,586 patients who underwent R0 gastrectomy were retrospected. Patients with LN metastases were divided into three groups: (I) patients with only peri-gastric LN metastases (peri-gastric group); (II) patients with peri-gastric and only No. 7 LN metastases (No. 7 group); and (III) patients with other extra-gastric LN metastases (extra-gastric group). Propensity score matching (PSM) was adopted to accurately evaluate prognoses of all patients after surgery.

Results

Of 1,586 patients, 235 (14.82%) were pathologically identified to present with the No. 7 LN metastases. Patients with the No. 7 LN metastases presented the significantly lower survival rate both before and after adjustment by pTNM stage, compared to those without the No. 7 LN metastases. Patients in the No. 7 group were identified to present the significant lower survival rate than those in the peri-gastric group, and to present the similar median overall survival (OS) to those in the extra-gastric group. In addition, patients with extra-gastric LN except No. 7 LN metastases failed to show any superiority of survival outcomes, compared with those with extra-gastric LN metastases including the No. 7 LN metastasis.

Conclusions

The No. 7 LN metastases had the crucial survival implications. Nevertheless, the No. 7 LN failed to be considered as the predictive LN for the extra-gastric LN metastases in gastric cancer (GC).

Evaluation of postoperative quality of life by PGSAS-45 following local gastrectomy based on the sentinel lymph node concept in early gastric cancer

BACKGROUND

The usefulness of sentinel node navigation surgery (SNNS) for early gastric cancer has been demonstrated in a multicenter prospective study. However, quality of life (QOL) after local resection remains unclear. This present study investigated QOL after local resection and distal gastrectomy.

METHODS

We examined 69 patients who underwent laparoscopic distal gastrectomy (LADG) (n = 44) and laparoscopic local resection (LLR) (n = 25) in our hospital between September 2011 and May 2018. We conducted a combination of laparoscopic and endoscopic approaches to neoplasia with non-exposure technique (CLEAN-NET) with SNNS as LLR. All patients had pStage I or II and none had received adjuvant chemotherapy. We evaluated QOL using the postgastrectomy syndrome assessment scale questionnaire (PGSAS-45) 1, 6, and 12 months after surgery.

RESULTS

In PGSAS-45, no significant differences were observed between LLR and LADG at 1 and 6 months after surgery. At 12 months, the LLR group scored better for some of the subscales (SS). In the endoscopic evaluation, the LLR group showed significant improvements in residual gastritis at 6 months (P = 0.006) and esophageal reflux and residual gastritis at 12 months (P = 0.021 and P = 0.017). A significant difference was observed in the prognostic nutritional index, which was assessed using serum samples, between the two groups at 6 months (P = 0.028). The body weight ratio was better in the LLR group than in the LADG group at 6 and 12 months (P = 0.041 and P = 0.007, respectively).

CONCLUSIONS

CLEAN-NET with SNNS preserved a better QOL and nutrition status than LADG in patients with early gastric cancer.

Sentinel node mapping for post-endoscopic resection gastric cancer: multicenter retrospective cohort study in Japan

BACKGROUND

Standard gastrectomy with systematic lymphadenectomy as an additional surgery after endoscopic resection (ER) causes a deterioration in long-term quality of life. If the sentinel lymph node (SN) basin concept can be applied in post-ER gastric cancer, minimal surgery can be applied without reducing the curability. This retrospective multicenter cohort study aimed to verify the validity of the SN basin concept in post-ER gastric cancer.

PATIENTS AND METHODS

Individual data of 132 patients who underwent SN mapping after ER were collected from 8 university hospitals in Japan from 2001 to 2016. Tracers were injected endoscopically in the submucosal layer at four sites around the post-ER scar. We compared the SN basin distribution of post-ER gastric cancer with that of 275 patients with non-ER gastric cancer.

RESULTS

Two cases of SN were unidentified, both involving a single tracer (SN detection rate: 98.5%). Nine cases (6.8%) of lymph node metastasis were found, of which eight had a metastatic lymph node within the SNs and one had a non-SN metastasis within the SN basin. The diagnostic sensitivity of SN mapping for lymph node metastasis was 88.9% in post-ER group and 95.7% in non-ER group (P = 0.490); the accuracy was 99.2% and 99.6% (P = 0.539), respectively. Regarding the SN basin, no significant intergroup differences were found regardless of the primary tumor location.

CONCLUSIONS

Our findings clarified the feasibility of SN mapping based on the SN basin concept in patients with gastric cancer who previously underwent ER.

Nonexposed wall-inversion surgery as a novel local resection method for neoplasms in the gastrointestinal tract

Nonexposed wall-inversion surgery was invented for the treatment of node-negative gastrointestinal tumors that are difficult to be resected using the endoluminal approach alone. The advantages of this surgery include 1. full-thickness resection procedure of gastrointestinal wall with minimum necessary tumor-negative margins and 2. less risk of bacterial contamination and tumor seeding into the abdominal cavity. We conducted a PubMed search to select relevant articles published until the end of October 2019 for pooled case analyses using the keyword “nonexposed wall-inversion surgery,” Based on our search, we enrolled the data of 88 gastric lesions and 1 duodenal lesion retrieved from 7 case report articles and 4 original articles of clinical cases. The gastric lesions consisted of 59 gastrointestinal stromal tumors, 7 ectopic pancreases, 5 leiomyomas, 3 early gastric cancers, and 14 others, with a mean maximal tumor diameter of 25.0 mm. In 5 lesions (5.7%), intraoperative perforation was performed, and 2 lesions (2.3%) were retrieved by the transabdominal route. All 4 major postoperative complications (4.5%) were managed without resurgical interventions. The duodenal case, neuroendocrine tumor, measuring 13 mm in size, was curatively resected without complications. Nonexposed wall-inversion surgery appears to be an acceptable treatment for node-negative gastric and duodenal tumors; however, further accumulation of cases is necessary to confirm the feasibility.

Laparoscopic sentinel node navigation surgery versus laparoscopic gastrectomy with lymph node dissection for early gastric cancer: short-term outcomes of a multicentre randomized controlled trial (SENORITA)

BACKGROUND

Sentinel node navigation surgery reduces the extent of gastric and lymph node dissection, and may improve quality of life. The benefit and harm of laparoscopic sentinel node navigation surgery (LSNNS) for early gastric cancer is unknown. The SENORITA (SEntinel Node ORIented Tailored Approach) trial investigated the pathological and surgical outcomes of LSNNS compared with laparoscopic standard gastrectomy (LSG) with lymph node dissection.

METHODS

The SENORITA trial was an investigator-initiated, open-label, parallel-assigned, non-inferiority, multicentre RCT conducted in Korea. The primary endpoint was 3-year disease-free survival. The secondary endpoints, morbidity and mortality within 30 days of surgery, are reported in the present study.

RESULTS

A total of 580 patients were randomized to LSG (292) or LSNNS (288). Surgery was undertaken in 527 patients (LSG 269, LSNNS 258). LSNNS could be performed according to the protocol in 245 of 258 patients, and a sentinel node basin was detected in 237 (96·7 per cent) Stomach-preserving surgery was carried out in 210 of 258 patients (81·4 per cent). Postoperative complications occurred in 51 patients in the LSG group (19·0 per cent) and 40 (15·5 per cent) in the LSNNS group (P = 0·294). Complications with a Clavien-Dindo grade of III or higher occurred in 16 (5·9 per cent) and 13 (5·0 per cent) patients in the LSG and LSNNS groups respectively (P = 0·647).

CONCLUSION

The rate and severity of complications following LSNNS for early gastric cancer are comparable to those after LSG with lymph node dissection. Registration number: NCT01804998 ( http://www.clinicaltrials.gov).

Utility of the one-step nucleic acid amplification assay in sentinel node mapping for early gastric cancer patients

BACKGROUND

To safely perform minimized gastrectomy based on sentinel node (SN) concept for early gastric cancer patients, intraoperative diagnostic accuracy is indispensable. This study aimed to evaluate the clinical utility of the one-step nucleic acid amplification (OSNA) assay in the intraoperative diagnosis of SN metastasis in early gastric cancer patients compared with that of histopathological examination.

METHODS

We conducted a prospective study using the OSNA assay for 43 patients with cT1N0M0 gastric cancer undergoing gastrectomy with SN mapping. All the SNs and selected non-SNs were examined by routine histopathological diagnosis, and the OSNA assay.

RESULTS

We performed permanent histopathology (PH) in 1732 lymph nodes (LNs) (286 SNs and 1446 non-SNs) obtained from 43 patients. We also evaluated 439 LNs (286 SNs and 153 non-SNs) with the OSNA assay in addition to PH. Intraoperative histopathology (IH) was performed in 214 LNs (213 SNs and 1 non-SN). PH revealed LN metastasis in 6 patients (14%), all of whom showed positive SNs by PH. The diagnostic accuracy to predict the LN status based on the SN concept by histological examination was 100%. The concordance rate between the OSNA assay and the PH and IH were 0.970 and 0.981 respectively. Discordant results between PH and OSNA assay were observed in 13 LNs. The sensitivity and specificity of the OSNA assay compared with those of PH were 0.636, and 0.988, and compared with those of IH were 0.800, and 0.995.

CONCLUSION

Our results suggest that the OSNA assay is a useful and convenient tool for the intraoperative detection of SN metastasis in early gastric cancer patients.

Assessment of lymphatic flow based on the sentinel node concept in early gastric adenocarcinoma that satisfies expanded endoscopic resection criteria

BACKGROUND

Even though indications for endoscopic resection (ER) in early gastric cancer are determined based on the potential risk of lymph node metastasis, the criteria for ER remain controversial. Sentinel node (SN) mapping for early gastric cancer can help determine regional lymphatic flow patterns. The aim of this study was to assess lymphatic flow according to the SN concept in patients with early gastric cancer, especially those who satisfy the expanded criteria for ER.

METHODS

We retrospectively enrolled 301 patients diagnosed with pT1 adenocarcinoma who had undergone gastrectomy with SN mapping and had no lymphovascular invasion. Patients were categorized into six groups based on oncological assessment. We analyzed lymphatic flow, including the number of identified SN and SN basin, and the rate of SN metastasis in each group.

RESULTS

Of the 301 patients, 128 (42.5%) met the criteria for ER, with 18 in the absolute group and 110 in the expanded group; 173 (57.5%) were assigned to the surgical group. SN metastasis rate tended to be higher in surgical group patients than in ER criteria patients. In the expanded criteria group, the sub-group of patients with intramucosal, undifferentiated adenocarcinoma measuring 20 mm or less had a significantly greater number of identified SNs (p = 0.013) and SN basins (p = 0.032). Furthermore, SN metastasis was observed only in this group.

CONCLUSIONS

Patients with intramucosal, nonulcerated, undifferentiated adenocarcinoma measuring 20 mm or less could develop a lymphatic network. For these patients, careful follow-up is required after ER.

Burgeoning study of sentinel-node analysis on management of early gastric cancer after endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) represents an organ-preserving alternative to surgical resection of early gastric cancer. However, even with ESD yielding en-bloc resection specimens, there are concerns regarding tumor spread such as with larger lesions, ulcerated lesions, undifferentiated pathology and submucosal invasion. Sentinel node navigational surgery (SNNS) when combined with ESD offers a minimally invasive alternative to the traditional extended gastrectomy and lymphadenectomy if lack of lymph node spread can be confirmed. This would have a clear advantage in terms of potential complications and quality of life. However, SNNS, though useful in other malignancies such as breast cancer and melanoma, may not have a sufficient sensitivity for malignancy and negative predictive value in EGC to justify this as standard practice after ESD. The results of SNNS may improve with greater standardization and more involved dissection, technological innovations and more experience and validation such that the paradigm for post-ESD resection of EGC may change and include SNNS.

The significance of preoperative serum carcinoembryonic antigen levels in the prediction of lymph node metastasis and prognosis in locally advanced gastric cancer: a retrospective analysis

Background

In this study, we aimed to investigate the preoperative serum carcinoembryonic antigen (CEA) in the diagnosis of positive lymph node metastasis (LNM), and to evaluated the relationship between CEA and survival in patients with locally advanced gastric cancer (LAGC).

Methods

The significance of the preoperative serum CEA level for the diagnose of LAGC and prediction of LNM was determined using the receiver operating characteristic (ROC) curve. The areas under the ROC of CEA were compared with those of other tumor markers or imaging examination including CT and MRI. Logistic regression was utilized to identify the risk factors predicting positive LNM. Independent prognosis factors were evaluated using univariate and multivariate COX regression analyses.

Results

The ROC curves showed that the AUCs of CEA, CA199, and CA125 for diagnosing LAGC were 0.727, 0.594, and 0.566. When used to predict LNM, the AUC of CEA, CA199 and CA125 were 0.696, 0.531, and 0.588. Logistic regression analysis demonstrated that preoperative serum CEA were significantly associated with positive LNM. On combining imaging examination with CEA, the sensitivity and specificity were 85.3 and 79.4%, respectively, with the AUC equal to 0.853. The combination of CEA and imaging examination preformed the highest levels of AUC and sensitivity for diagnosing LNM, which is significantly higher than using either of them alone. Although patients with abnormal CEA have a poor prognosis, two models of multivariate analysis showed that CEA was not the independent prognosis factor for survival.

Conclusions

CEA can be used to diagnose gastric cancer and determine whether it has LNM. Moreover, combined with CEA could improve the diagnostic sensitivity of imaging examination for lymph node involvement.

Minimally invasive approaches for early gastric cancer in East Asia: current status and future perspective

East Asia is well known as a region with higher incidences of gastric cancer compared with the rest of the world. This region has also experienced a rise in the detection of early gastric cancer (EGC) for the past three decades. The success of nationwide screening programs conducted in Japan or South Korea, increasing public awareness of gastric cancer, improved diagnostic ability of gastroenterologists and the aging population of modern societies may all contribute to the increase in EGC detection rates. Along with the increasing diagnosis of EGC, several key advances in the minimally invasive approach to EGC treatment have been made. Endoscopic resection is an ideal procedure for lesions without lymph node involvement, and its indications have expanded based on the results of prospective studies. Laparoscopic surgery with lymph node dissection has been becoming a standard treatment for EGC patients. Additionally, robot-assisted surgery is penetrating the field of gastric cancer surgery as surgeons pursue a more accurate minimally invasive approach with reduced morbidity rates. However, prolonged operation time and high cost remain problems to be solved for robot-assisted surgery. In this context, function-preserving surgery has become ever more important and should be considered as a method to enhance patients' quality of life after a gastrectomy for EGC. Pylorus-preserving gastrectomy or proximal gastrectomy is more frequently employed in East Asia and strategies that employ sentinel node (SN) navigation to personalize function-preserving surgery in clinical practice are emerging as several prospective studies investigate its efficacy.

Detection of indocyanine green fluorescence to determine tumor location during laparoscopic gastrectomy for gastric cancer: Results of a prospective study

INTRODUCTION

In laparoscopic gastrectomy, a method to locate the margin of an early-stage cancerous lesion that is invisible from the serosal surface and impalpable during laparoscopic procedures is needed to determine an appropriate transection line. We conducted a prospective study to develop a new marking method using preoperative submucosal injection of indocyanine green (ICG).

METHODS

Patients undergoing laparoscopic gastrectomy for T1 gastric cancer were recruited. The first 11 patients comprised the learning set and the subsequent 18 patients the validation set. ICG was endoscopically injected in the submucosal layer of the stomach approximately 1 cm away from the tumor edge 1 or 3 days before surgery. The diameters of the visualized ICG were compared with those of a conventional marking method using India ink in 10 historical controls.

RESULTS

In the learning set, the optimal amount of ICG was determined to be 0.1 mL at a concentration of 0.5 mg/mL. In the validation set, the same procedure was repeated. No technical problems or adverse reactions related to ICG injection were observed. In all cases, ICG was successfully detected, and negative surgical margins were pathologically confirmed. The mean long diameter of the visualized ICG fluorescence measured at the mucosal surface of the stomach was significantly smaller in the current study than in the historical controls in whom India ink was used (21 vs 52 mm, P < 0.0001).

CONCLUSIONS

The preoperative submucosal ICG marking was safely performed and successfully detected without excessive blurring during laparoscopic gastrectomy.

A nodal diagnosis by computed tomography is unreliable for patients who need additional gastrectomy after endoscopic submucosal dissection

PURPOSE

T1 gastric cancer is treated by endoscopic submucosal dissection (ESD) or surgery, considering the risk of lymph node metastasis. Additional gastrectomy is necessary when the pathological specimens after ESD show some risk of lymph node metastasis. Preoperative computed tomography (CT) after ESD sometimes reveals enlarged lymph nodes, which should prompt surgeons to select D2 over D1/D1+. However, whether or not CT after ESD is reliable remains unclear.

METHODS

Patients who underwent radical gastrectomy for clinical T1 between April 2015 and June 2019 were enrolled. The patients were classified into those who underwent CT after ESD (group A) and those who underwent CT before primary surgery or ESD (group B). The accuracy of the nodal diagnosis was compared between groups.

RESULTS

A total of 650 patients (group A; 81, group B; 569) were examined. The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value (group A vs. group B) were 77.8% vs. 84.2%, 0.0% vs. 15.9%, 84.0% vs. 95.7%, 0.0% vs. 38.2%, and 91.3% vs. 87.1%, respectively. The false-positive rate was 100% in group A and 61.8% in group B (p = 0.011).

CONCLUSIONS

A nodal diagnosis by CT is unreliable for patients who need additional gastrectomy after ESD.

The Methods of Lymph Node Examination Make a Difference to Node Staging and Detection of N3b Node Status for Gastric Cancer

Background: The number of retrieved lymph nodes (RLNs) affects the likelihood of detecting metastatic lymph nodes (MLNs) for gastric cancer (GC), but the retrieval of LNs is not satisfactory worldwide. There is no standard for LN examination.

Methods: We retrospectively analyzed 2,163 patients diagnosed with GC who underwent surgery at Nanfang Hospital between October 2004 and September 2016. According to the methods of LN examination, patients were classified into two groups: LN detection by pathologists (pathologist group) and LN examination by surgicopathologic team (surgicopathologist group). The relationship between RLNs and LN staging accuracy as well as the factors influencing the detection of MLNs were evaluated.

Results: There were 472 males in pathologist group and 467 males in surgicopathologist group. The number of RLNs and MLNs in surgicopathologist group was significantly higher than that in pathologist group (RLNs: 53.8 ± 20.9 vs. 18.8 ± 11.5, p < 0.001; MLNs: 5.6 ± 9.8 vs. 3.9 ± 5.7, p < 0.001). Notably, the detection of N3b node status was significantly improved in surgicopathologist group [83 (11.9%) vs. 34 (4.8%), p < 0.001]. Additionally, the detection rate of N3b status gradually increased from 0 in patients with 1-16 RLNs to 16.6% in patients with more than 49 RLNs. The MLNs detected increased gradually from 2.3 ± 3.0 in patients with 1-16 RLNs to 7.3 ± 11.7 in patients with more than 49 RLNs. Univariate and multivariate analyses indicated that LN examination by surgicopathologic team, more advanced pT, tumor size ≥5 cm and combined organ(s) resection were related to detecting more MLNs.

Conclusions: The retrieval of nodes immediately postoperatively by the surgicopathologic team could significantly improve the number of RLNs, detect more MLNs, and screen more patients with N3b node status.

Development of Magnetic Probe for Sentinel Lymph Node Detection in Laparoscopic Navigation for Gastric Cancer Patients

New laparoscopic sentinel lymph node navigation using a dedicated magnetic probe and magnetic nanoparticle tracer for gastric cancer patients allows minimally invasive surgeries. By identifying the sentinel lymph nodes containing magnetic nanoparticles, patients can avoid excessive lymph node extraction without nuclear facilities and radiation exposure. This paper describes the development of the laparoscopic magnetic probe, ACDC-probe, for laparoscopic sentinel lymph node identification utilizing the nonlinear response of the magnetic nanoparticles magnetized by an alternating magnetic field with a static magnetic field. For highly sensitive detection, the ratio of static to alternating magnetic fields was optimized to approximately 5. The longitudinal detection length was approximately 10 mm for 140 μg of iron, and the detectable amount of iron was approximately 280 ng at a distance of 1 mm. To demonstrate the feasibility of laparoscopic detection using the ACDC-probe and magnetic tracers, an experiment was performed on a wild swine. The gastric sentinel lymph node was clearly identified during laparoscopic navigation. These results suggest that the newly developed ACDC-probe is useful for laparoscopic sentinel lymph node detection and this magnetic technique appears to be a promising method for future sentinel lymph node navigation of gastric cancer patients.

History and future perspectives in Japanese guidelines for endoscopic resection of early gastric cancer

Japanese guidelines for gastric cancer treatment were first published in 2001 for the purpose of showing the appropriate indication for each treatment method, thereby reducing differences in the therapeutic approach among institutions, and so on. With the accumulation of evidence and the development and prevalence of endoscopic submucosal dissection (ESD), the criteria for the indication and curability of endoscopic resection (ER) for early gastric cancer (EGC) have expanded. However, several problems still remain. Although a risk-scoring system (eCura system) for predicting lymph node metastasis (LNM) may help treatment decision in patients who do not meet the curative criteria for ER of EGC, which is referred to as eCura C-2 in the latest guidelines, additional gastrectomy with lymphadenectomy may be excessive for many patients, even those at high risk for LNM. Less-invasive function-preserving surgery, such as non-exposed endoscopic wall-inversion surgery with laparoscopic sentinel node sampling, may overcome this problem. In addition, further less-invasive treatment, such as ER with chemotherapy, should be established for patients who prefer not to undergo additional gastrectomy.

Sentinel lymph node detection for gastric cancer: Promise or pitfall?

At present, optimal surgery for gastric cancer is still under debate, especially the extent of lymph node dissection. Gastrectomy with D1/D2 lymphadenectomy is standard treatment for resectable advanced gastric cancer. However, in early gastric cancer without lymph node metastasis, gastrectomy with D1/D2 lymphadenectomy may not be unnecessary, which could increases morbidity and mortality and reduces the quality of life (QOL). Therefore, the concept of sentinel lymph node could be applied in gastric cancer. But due to the complexity of gastric lymphatic drainage, there are still many issues under debate, such as suitable tracers, the method of mapping and collecting and the oncologic safety of sentinel node navigation surgery (SNNS). In addition, skip metastasis and unreliability of intraoperative pathological diagnosis are two main reasons for false negative cases. In this review, we summarize the current status and controversy of sentinel lymph node detection in gastric cancer, attempting to help with practical application. Further, we hold opinion that we should be cautious about performing sentinel lymph node detection in gastric cancer before an accurate and effective method occurs.

[Fluorescence-guided detection of lymph node metastases of gastrointestinal tumors]

A correct lymph node (LN) staging is essential in oncological surgery. Indocyanine green (ICG) near-infrared fluorescence (NIRF) guided sentinel lymph node (SLN) navigation is a relatively novel technique. The aim of this review is to analyze the impact of ICG-NIRF on identification of LN metastases of gastrointestinal tumors. The Scopus and PubMed/MEDLINE literature databases were searched and 20 studies were included. The ICG-NIRF navigation of LN has been shown to enable and improve LN detection in gastrointestinal tumors; however, the mean detection, sensitivity, accuracy and false negative rates show substantial variation. This could be due to both the heterogeneous techniques applied and to the low retention of ICG by lymph nodes. Fluorescence imaging to identify LN drainage is a promising tool to improve oncological outcomes. Nonetheless, the technique requires further development in terms of hardware, software and fluorophores, which are currently being investigated.

[Does sentinel lymph node identification has indication in digestive cancers?]

Despite being a standard of care in several cancers, sentinel lymph node (SLN) is not widespread in digestive cancers. European guidelines do not recommend its use for any digestive cancers. Particularity of the lymphatic vessel, intimately linked to blood vessel, may explain part of this phenomenon. Nevertheless, more indication could arise in the near future with the early diagnosis of tumor induced by cancer screening. Ruling out the lymphatic invasion could allow preserving the organ currently resected because of risk of lymph node positivity. This procedure is well studied in early gastric cancer in Korea and Japan. Several study have demonstrated that, a dual-tracer (isotopic and dye) allows to accurately identify the SLN. A randomized phase 3 trial is currently active in Korea to evaluate the oncological results of the procedure. Similar indication could arise for T1 tumor of the low-rectum, but currently available data are insufficient to recommend its use outside of a study. SLN may also be used to detect aberrant lymphatic drainage (rectum, ileum) but have been tested so far only in a few dozen of patients. Finally, SLN is disappointing in colon cancer, due to its low sensitivity and the absence of modification of the surgical procedure induced.

Survival outcomes after sentinel node navigation surgery for early gastric cancer

AIM

This study evaluated the prognosis after sentinel node navigation surgery (SNNS) for early gastric cancer.

METHODS

For 100 patients who underwent SNNS (between August 13, 2003 and December 17, 2018) at our hospital, the survival outcomes were investigated.

RESULTS

(a) SN were detected with a diagnostic accuracy of 0.98. (b) Of seven patients who had positive SN metastasis, three underwent standard gastrectomy with D2 lymph node dissection. Among them, one patient died of recurrence (bone) and the other two patients were alive 4.5 and 14.7 years after surgery. The remaining four patients with positive SN who underwent diminished gastrectomy with lymphatic basin dissection at their request are alive 2.8, 6.0, 6.9 and 10.8 years after surgery without recurrence. (c) No patients who underwent diminished gastrectomy died of gastric cancer after surgery. (d) In the period following diminished gastrectomy, one patient underwent total gastrectomy and five patients underwent endoscopic submucosal dissection, and they survived for longer than 5 years. (e) As a result of SNNS, the gastric cancer-specific cumulative 5-year survival rate was 98.5%.

CONCLUSIONS

Diminished gastrectomy during SNNS resulted in a satisfactory prognosis. However, regular follow-up after surgery is needed to detect secondary cancer of the remaining stomach.

Sentinel Node Navigation in Gastric Cancer: Where Do We Stand?

BACKGROUND

Early gastric cancer (EGC) is more common nowadays and is related a to low percentage of lymph node metastasis. For this reason, there is enormous interest to implicate minimally invasive approaches. Recently, special efforts have been made towards a potential intraoperative (real-time) lymph node metastasis (LNM) assessment, as nodal disease status could not be identified with precision before or during surgery. In this direction, accurate prediction of the LNM status through sentinel LN mapping has been attempted, as an approach to the intraoperative detection of sentinel lymph nodes (SLNs). A careful literature search was conducted in order to clarify the potential clinical application of SN biopsy in the gastric cancer field.

CONCLUSION

The real clinical application of SN biopsy in gastric cancer treatment has been more than challenging due to the "complicated" nature of gastric lymphatic drainage and the high possibility of "skip" metastasis phenomenon. Notably, sophisticated technical aspects, such as the preferred tracer used and the potential "ideal" method to verify the presence of metastases in the resected SLNs, made SN biopsy application in gastric cancer field extremely demanding. Assessing the potential role of SN navigation for gastric cancer treatment in the era of advanced technology, where the minimally invasive surgical approaches are in the top of the scientific interest, it has to be highlighted that SN navigation for gastric cancer is a topic that remains highly controversial, and the need for future clinical trials on this topic is obvious.

A prediction model for lymph node metastasis in early-stage gastric cancer: Toward tailored lymphadenectomy

BACKGROUND

The aim of this study was to develop a prediction model for the presence and location of lymph node metastasis (LNM) in early gastric cancer.

METHOD

We reviewed medical records of 4 929 patients who underwent radical gastrectomy for early gastric cancer. Variables of age, sex, lymphatic invasion, depth of invasion, location, gross type, differentiation, and tumor size were analyzed. Logistic regression analysis was used to determine independent predictors of LNM at each LN station.

RESULT

Overall incidence of LNM was 9.1% (448/4 929 patients). For the presence of LNM, risk factors of age, sex, lymphatic invasion, depth of invasion, anatomical part, gross ulceration, size, and tumor differentiation were significantly associated with LNM. The area under the curve (AUC) for predicting LNM after validation was 0.834 for the test set. For the location of LNM, age, sex, lymphatic invasion, depth of invasion, anatomical part, circumferential portion, gross type, differentiation, and tumor size were significantly associated with LNM. The AUC of each LN station was favorable with the test set.

CONCLUSION

Predicting the location of metastatic LNs appeared to be possible in patients with early gastric cancer.

Prospective feasibility study for single-tracer sentinel node mapping by ICG (indocyanine green) fluorescence and OSNA (one-step nucleic acid amplification) assay in laparoscopic gastric cancer surgery

BACKGROUND

The double-tracer method has been established for sentinel node (SN) mapping in gastric cancer surgery. However, there remain several unresolved issues that prevent its widespread use in clinical practice. In this study, we aimed to demonstrate the feasibility of single-tracer SN mapping in laparoscopic surgery for gastric cancer, using indocyanine green (ICG) fluorescence imaging with a one-step nucleic acid amplification (OSNA) assay intraoperatively.

METHODS

Patients with clinical T1N0M0 gastric adenocarcinoma preoperatively were considered for inclusion if they had a single primary lesion 4 cm or less in maximal diameter. Immunohistochemical staining with the anti-cytokeratin 19 antibody was performed on preoperative biopsy specimens, and patients with faint positive reactions were excluded. Intraoperatively, single-tracer SN biopsy with ICG fluorescence imaging was performed, followed by laparoscopic gastrectomy with modified D1+ or D2 lymph node dissection.

RESULTS

Twenty eligible patients underwent SN biopsy and laparoscopic gastrectomy. SNs were identified in 17 cases (85%), with a median number of three SNs per patient. The median times for SN mapping and OSNA assay were 19 and 35 min, respectively. OSNA assay detected one metastatic lymph node, but all other nodes were negative. No adverse effects were observed in relation to SN mapping.

CONCLUSIONS

Single-tracer SN mapping by ICG fluorescence imaging with intraoperative diagnosis by OSNA assay is feasible and safe. SNs can be identified in most patients, without producing false-negative results. Further clinical trial to demonstrate the sensitivity is ongoing.

Gastric lymphatic flows may change before and after endoscopic submucosal dissection: in vivo porcine survival models

BACKGROUND AND STUDY AIM

Standard gastrectomy with lymphadenectomy is recommended following endoscopic submucosal dissection (ESD) due to the risk of lymph-node metastasis for resected cancers. However, when lymphatic flows remain unchanged after ESD, a minimally invasive function-preserving surgery based on the sentinel node (SN) concept may be applicable. In this study, using porcine survival models, we aimed to investigate whether gastric lymphatic flows were modified following ESD.

METHODS

Twelve pigs, each with one simulating lesion 3 cm in size, were used. Indocyanine green (ICG) fluid was endoscopically injected into the submucosa in four quadrants surrounding the lesion. Following laparoscopic observation of lymphatic flows, the lesions were resected by ESD. After 4 weeks, ICG fluid was injected in four quadrants surrounding the scar and lymphatic flows were observed in the same manner as the initial procedure. The distribution of lymphatic flows, including stained SNs, was compared.

RESULTS

In ten lesions (83.3%), the distribution of flows remained unchanged. However, in one lesion, the flow along the right gastric epiploic artery (R-GEA) disappeared on the lesser curvature of the middle stomach. In addition, in one lesion, the flow along R-GEA emerged on the lesser curvature of the lower stomach.

CONCLUSIONS

Our study revealed that, despite ESD, lymphatic flows remained unchanged in most parts of the stomach. The SN concept may be applied after ESD, except for lesions on the lesser curvature. However, in the case of the lesser curvature, special care must be given to the SN concept.

A homogenized approach to classify advanced gastric cancer patients with limited and adequate number of pathologically examined lymph nodes

Background

The prognosis of gastric cancer patients with a limited number of pathologically examined lymph nodes (eLN, < 16) is dismal compared to those with adequately eLN (≥ 16), yet they are still classified within the same subgroups using the American Joint Committee on Cancer (AJCC) staging system. We aimed at formulating an easy-to-adopt and clinically reliable stratification approach to homogenize the classification for these two categories of patients.

Methods

Patients staged according to the 8th AJCC pathological nodal (N) and tumor-node-metastasis (TNM) classification were stratified into a Limited and Adequate eLN cohort based on their number of pathologically examined LNs. The statistical differences between the 5-year overall survival (OS) rates of both cohorts were determined and based on which, patients from the Limited eLN cohort were re-classified to a proposed modified nodal (N′) and TNM (TN′M) classification, by matching their survival rates with those of the Adequate eLN cohort. The prognostic performance of the N′ and TN′M classification was then compared to a formulated lymph-node-ratio-based nodal classification, in addition to the 8th AJCC N and TNM classification.

Results

Significant heterogeneous differences in 5-year OS between patients from the Limited and Adequate eLN cohort of the same nodal subgroups were identified (all P < 0.001). However, no significant differences in 5-year OS were observed between the subgroups N0, N1, N2, and N3a of the Limited eLN cohort when compared with N1, N2, N3a, and N3b from the Adequate eLN cohort, respectively (P = 0.853, 0.476, 0.114, and 0.230, respectively). A novel approach was formulated in which only patients from the Limited eLN cohort were re-classified to one higher nodal subgroup, denoted as the N′ classification. This re-classification demonstrated superior stratifying and prognostic ability as compared to the 8th AJCC N and lymph-node-ratio classification (Akaike information criterion values [AIC]: 12,276 vs. 12,358 vs. 12,283, respectively). The TN′M classification also demonstrated superior prognostic ability as compared to the 8th AJCC TNM classification (AIC value: 12,252 vs. 12,312).

Conclusion

The proposed lymph node classification approach provides a clinically practical and reliable technique to homogeneously classify cohorts of gastric cancer patients with limited and adequate number of pathologically examined lymph nodes.

Sentinel Lymph Node Sampling for Early Gastric Cancer-Preliminary Results of A North American Prospective Study

INTRODUCTION

Although endoscopic resection for early gastric cancer is well established, anatomical resection with regional lymphadenectomy is recommended for lesions at high risk for occult lymph node metastasis (e.g., lymphovascular invasion, poor grade, and deep submucosal invasion). However, 75-95% high-risk early gastric cancer (HR-EGC) patients ultimately have node-negative disease and could potentially have undergone organ-sparing resection. Due to the inadequacy of standard modalities to reliably rule out nodal metastases in HR-EGC patients, sentinel lymph node (SLN) sampling was developed in Asia with promising results. However, the applicability of this technique in the West has been brought into question due to potential differences in tumor histology and body habitus. This prospective study aimed to test SLN sampling for North American EGC patients.

METHODS

All patients with biopsy-confirmed T0-2 N0-1 M0 gastric adenocarcinoma at the Montreal General Hospital-McGill University Health Centre were eligible for enrollment. Esophageal and GEJ cancers were excluded due to the high rate of intrathoracic lymph node involvement. Peritumoral submucosal injection with T⁹⁹ radiocolloid was performed endoscopically 24-30 h prior to surgery. Methylene blue dye injection was performed after induction of anesthesia. SLN basins were identified as those having > 10% of baseline tumor radiation signal or blue color, or both. After basins were individually removed, standard laparoscopic anatomical resection was then performed with D2 lymphadenectomy. ( ClinicalTrials.gov identifier: NCT03049345). Data are presented as median (interquartile range).

RESULTS

From July 2016-April 2018, 253 patients with esophagogastric adenocarcinoma were evaluated. Of these, 10 met inclusion criteria (90% male, age 66(30) years). Subtotal gastrectomy was performed in nine patients (90%) and length of stay was 4 (2) days. At least one SLN basin was identified in nine cases (90%). The median #SLN basins identified was 2(2) with a median of 5(5) total SLNs retrieved per patient. In the one case for which no SLN basins were identified, only blue dye injection was used, whereas SLNs were identified in all cases using the dual tracer method. Final T-stage was pT1b/T2 in four (40%), pT1a in two (20%), and Tx in four (40%). Two patients (20%) had lymph node metastases on final pathological analysis, both of which were identified by SLN sampling (accuracy 100%; false negative rate 0%). No adverse events related to SLN retrieval were identified.

CONCLUSIONS

This study represents the first prospective feasibility evaluation of sentinel lymph node sampling for early gastric cancer in North America with promising preliminary results. The dual tracer method was superior to single agent blue dye in identifying sentinel nodal basins. Considerable further study is necessary to verify the safety and utility of SLN mapping in North American patients with early gastric adenocarcinoma.

Perioperative complications and outcome after surgery for treatment of gastric carcinoma in dogs: A Veterinary Society of Surgical Oncology retrospective study of 40 cases (2004-2018)

OBJECTIVE

To describe the clinical characteristics, perioperative complications, and outcomes in dogs surgically treated for gastric carcinoma.

STUDY DESIGN

Multi-institutional retrospective case series.

ANIMALS

Forty client-owned dogs with histologically confirmed gastric carcinoma.

METHODS

Medical records were reviewed for preoperative diagnostics, surgery, histopathology, postoperative complications, adjuvant chemotherapy, disease progression, and survival. Variables were assessed for associations with outcome by using Cox proportional hazards regression analysis.

RESULTS

Surgical treatment included partial gastrectomy (28 dogs), Billroth I (9 dogs), subtotal gastrectomy (2 dogs), and submucosal resection (1 dog). Major postoperative complications occurred in 8 of 40 dogs, including septic peritonitis secondary to dehiscence in 4 dogs. The median progression free interval was 54 days, and the median survival time (MST) was 178 days (range, 1-1902). According to multivariable analysis results, experiencing an intraoperative complication was associated with an increased risk of death (hazard ratio [HR] 3.5, 95% CI 1.1-9.8, P = .005), and administration of adjuvant chemotherapy correlated with an improved survival (HR 0.4, 95% CI 0.2-0.9, P = .03).

CONCLUSION

In this population of dogs, MST exceeded historically reported data, major postoperative complication rates were comparable to established literature, and administration of adjuvant chemotherapy was associated with improved survival.

CLINICAL SIGNIFICANCE

Results from this study may be used to counsel owners more accurately regarding prognosis for dogs undergoing surgical excision for gastric carcinoma.

Establishment of a model of sentinel lymph node metastasis using immunodeficient swine

Lymph node metastasis occurs via the migration of cancer cells through the lymphatic system. Sentinel lymph node (SLN) biopsy is a common diagnostic strategy. SLNs have been studied using healthy rodents and large animals without metastasis. Here we used immunodeficient swine to establish a model of lymph node metastasis. We used RAG2-knockout immunodeficient swine. A431 human epithelial carcinoma cells expressing green fluorescent protein were injected subcutaneously into the posterior sides of the auricle, forelimb and hindlimb of knockout swine. Indigo carmine dye was injected subcutaneously 8 weeks after tumour cell transplantation. SLNs were extracted, observed using a stereoscopic fluorescence microscope and analysed histologically using haematoxylin and eosin staining, and immunohistochemistry. Lymphoid follicles were found in wild-type swine, and a few aggregated lymphocytes and immature lymphoid follicles were observed in knockout swine. Fluorescence in the lymph nodes indicated metastasis of tumour cells to the lymph nodes. Tumour cells replaced lymph node architectures, showed high-grade nuclear atypia and formed irregular tumour nests. Our model may be useful for the preclinical validation of diagnostic methods and minimally invasive treatment of metastatic cancer.

Laparoscopic endoscopic cooperative surgery (LECS) for the gastrointestinal tract: Updated indications

Laparoscopic and endoscopic cooperative surgery (LECS) is a procedure combining laparoscopic gastric resection with endoscopic submucosal dissection for local resection of gastric tumors with appropriate, minimal surgical resection margins. The LECS concept was initially developed from the classical LECS procedure for gastric submucosal tumor resection. Many researchers reported that classical LECS was a safe and feasible technique for resection of gastric submucosal tumors, regardless of tumor location, including the esophagogastric junction. Recently, LECS was approved for insurance coverage by Japan's National Health Insurance plan and widely applied for gastric submucosal tumor resection. However, the limitations of classical LECS are the risk of abdominal infection, scattering of tumor cells in the abdominal cavity, and tumor cell seeding in the peritoneum. The development of modified LECS procedures, such as inverted-LECS, non-exposed endoscopic wall-inversion surgery, a combination of laparoscopic and endoscopic approaches to neoplasia with a non-exposure technique, and closed-LECS, has almost resolved these drawbacks. This has led to a recent increase in the indication of modified LECS to include patients with gastric epithelial neoplasms. The LECS concept is also beginning to be applied to tumor excision in other organs, such as the duodenum, colon and rectum. Further evolution of LECS procedures is expected in the future. Sentinel lymph node mapping could also be combined with LECS, resulting in a portion of early gastric cancers being treated by LECS with sentinel node mapping.

Radiomics Signature on Computed Tomography Imaging: Association With Lymph Node Metastasis in Patients With Gastric Cancer

Background: To evaluate whether radiomic feature-based computed tomography (CT) imaging signatures allow prediction of lymph node (LN) metastasis in gastric cancer (GC) and to develop a preoperative nomogram for predicting LN status.

Methods: We retrospectively analyzed radiomics features of CT images in 1,689 consecutive patients from three cancer centers. The prediction model was developed in the training cohort and validated in internal and external validation cohorts. Lasso regression model was utilized to select features and build radiomics signature. Multivariable logistic regression analysis was utilized to develop the model. We integrated the radiomics signature, clinical T and N stage, and other independent clinicopathologic variables, and this was presented as a radiomics nomogram. The performance of the nomogram was assessed with calibration, discrimination, and clinical usefulness.

Results: The radiomics signature was significantly associated with pathological LN stage in training and validation cohorts. Multivariable logistic analysis found the radiomics signature was an independent predictor of LN metastasis. The nomogram showed good discrimination and calibration.

Conclusions: The newly developed radiomic signature was a powerful predictor of LN metastasis and the radiomics nomogram could facilitate the preoperative individualized prediction of LN status.

Prospective Multicenter Feasibility Study of Laparoscopic Sentinel Basin Dissection after Endoscopic Submucosal Dissection for Early Gastric Cancer: SENORITA 2 Trial Protocol

Purpose

Although standard radical gastrectomy is recommended after noncurative resection of endoscopic submucosal dissection (ESD) for early gastric cancer in most cases, residual tumor and lymph node metastasis have not been identified after surgery. The aim of this study is to evaluate the feasibility of sentinel node navigation surgery after noncurative ESD.

Materials and Methods

This trial is an investigator-initiated, multicenter prospective phase II trial. Patients who underwent ESD for clinical stage T1N0M0 gastric cancer with noncurative resections were eligible. Qualified investigators who completed the prior phase III trial (SENORITA 1) are exclusively allowed to participate. In this study, 2 detection methods will be used: 1) intraoperative endoscopic submucosal injection of dual tracer, including radioisotope and indocyanine green (ICG) with sentinel basins detected using gamma-probe; 2) endoscopic injection of ICG, with sentinel basins detected using a fluorescence imaging system. Standard laparoscopic gastrectomy with lymphadenectomy will be performed. Sample size is calculated based on the inferior confidence interval of the detection rate of 95%, and the calculated accrual is 237 patients. The primary endpoint is detection rate, and the secondary endpoints are sensitivity and postoperative complications.

Conclusions

This study is expected to clarify the feasibility of laparoscopic sentinel basin dissection after noncurative ESD. If the feasibility is demonstrated, a multicenter phase III trial will be initiated to compare laparoscopic sentinel node navigation surgery versus laparoscopic standard gastrectomy in early gastric cancer after endoscopic resection.

Trial Registration

ClinicalTrials.gov Identifier: NCT03123042.

Precision surgical approach with lymph-node dissection in early gastric cancer

The gravest prognostic factor in early gastric cancer is lymph-node metastasis, with an incidence of about 10% overall. About two-thirds of early gastric cancer patients can be diagnosed as node-negative prior to treatment based on clinic-pathological data. Thus, the tumor can be resected by endoscopic submucosal dissection. In the remaining third, surgical resection is necessary because of the possibility of nodal metastasis. Nevertheless, almost all patients can be cured by gastrectomy with D1+ lymph-node dissection. Laparoscopic or robotic gastrectomy has become widespread in East Asia because perioperative and oncological safety are similar to open surgery. However, after D1+ gastrectomy, functional symptoms may still result. Physicians must strive to minimize post-gastrectomy symptoms and optimize long-term quality of life after this operation. Depending on the location and size of the primary lesion, preservation of the pylorus or cardia should be considered. In addition, the extent of lymph-node dissection can be individualized, and significant gastric-volume preservation can be achieved if sentinel node biopsy is used to distinguish node-negative patients. Though the surgical treatment for early gastric cancer may be less radical than in the past, the operative method itself seems to be still in transition.

Long-term outcome following sentinel node navigation surgery for cT1 gastric cancer

Sentinel node navigation surgery (SNNS) has become a standard procedure for early-stage melanoma and breast cancer. However, very few studies have evaluated the long-term clinical outcomes following SNNS for gastric cancer. The present study analyzed 51 patients with cT1 gastric cancer who underwent SNNS at our hospital. Sentinel nodes (SNs) were identified using the dual tracer method. Patients underwent limited gastrectomy with SN station dissection when the SNs were reported as pathologically negative during surgery. When SNs were pathologically positive, standard gastrectomy with D2 lymphadenectomy was performed. Out of the 51 cases, 42 cases (82%) were pathologically diagnosed as SN-negative using a frozen section. The surgical procedures included segmental gastrectomy (n=33) and local resection (n=9). A total of 9 patients (18%) had lymph node metastasis in SNs. The mean observation period was 3,125±167 days, and the 5-year overall survival rate was 98%. There was no recurrence, and body weight loss was minimal following the SNNS. Remnant gastric cancer developed in 4 (8%) of the 50 patients except total gastrectomy. Thus, SNNS was a useful procedure for cT1 gastric cancer from the long-term clinical outcomes, though metachronous gastric cancer should paid further attention to.