Sentinel node mapping during laparoscopic distal gastrectomy for gastric cancer

Prognostic impact of fluorescent lymphography on gastric cancer

BACKGROUND

Fluorescent lymphography-guided lymphadenectomy (FL) for gastric cancer is gaining popularity. However, its impact on prognosis is not known. This study aimed to assess the prognostic impact of FL in gastric cancer patients.

MATERIALS AND METHODS

This study retrospectively analyzed 5678 gastric cancer patients who underwent gastrectomy from 2013 to 2017. The survival was compared between the FLFL group and the conventional lymphadenectomy (non-FL group) using 1:1 propensity score matching after exclusion. Patients in the FL group underwent gastrectomy with systematic lymphadenectomy after endoscopic peritumoral injection of indocyanine green the day before surgery.

RESULTS

After propensity score matching, the FL and non-FL groups each had 1064 patients with similar demographic and clinicopathological characteristics. All matched variables had a standardized mean difference under 0.1. The FL group showed a significantly higher number of retrieved lymph nodes (56.2±20.1) than the non-FL group (46.2±18.2, P <0.001). The FL group also had more stage III patients ( P= 0.044) than the non-FL group. The FL group demonstrated higher overall survival ( P= 0.038) and relapse-free survival ( P= 0.036) in stage III compared with the non-FL group. However, no significant differences in overall and relapse-free survival were observed between the two groups for stages I ( P= 0.420 and P= 0.120, respectively) and II ( P= 0.200 and P= 0.280, respectively).

CONCLUSION

FL demonstrated a higher survival in stage III gastric cancer patients by the more accurate staging resulting from larger lymph node retrieval. Thus, given its potential to improve prognostication by enhancing staging accuracy, it is recommended as an option to consider the use of FL in clinical practice.

Use of Carbon Nanoparticles to Improve the Efficiency of Harvesting Lymph Nodes in Rectal Cancer

BACKGROUND

The accurate determination of lymph node status in patients with rectal cancer requires harvesting a certain number of lymph nodes. This study investigated whether using carbon nanoparticles (CNs) could improve the efficiency of harvesting lymph nodes in rectal cancer patients.

MATERIALS AND METHODS

Data from patients with rectal cancer treated with radical resection were collected from Nanfang Hospital between January 2014 and June 2021. Patients in the CN group received a CN suspension 1 day before surgery, which was endoscopically injected around the tumor. A 1:1 case-matched study was performed using the propensity score. The efficiency of harvesting lymph nodes was investigated by comparing the number of total nodes, total time, and percentage of nodes <5 mm in size between the CN and non-CN groups.

RESULTS

A total of 768 patients were included, with 246 patients who underwent CN injection and 522 patients who did not. After matching, 246 pairs of patients were analyzed. After matching, the number of total nodes of each sample was significantly higher in the CN group than in the non-CN group ( P <0.001). The total time for node detection ( P <0.001) was significantly shorter in the CN group. The percentage of nodes <5 mm in size was increased significantly in the CN group ( P <0.001). Among patients with clinical staging I/II, the difference in positive LNs was significant (21.79% vs. 11.95%, P =0.029).

CONCLUSIONS

The application of CNs improved the efficiency of harvesting lymph nodes during rectal cancer surgery.

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.

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.

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

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

Sentinel node biopsy using blue dye and technetium99 in advanced gastric cancer: anatomical drainage and clinical application

Lymph node metastases are an independent prognosis factor in gastric carcinoma (GC) patients. Radical lymphadenectomy can improve survival but it can also increase surgical morbidity. As a principle, sentinel node (SN) navigation surgery can avoid unnecessary lymphadenectomy without compromising prognosis. In this pilot study, 24 patients with untreated GC were initially screened for SN navigation surgery, of which 12 were eligible. Five patients had T2 tumors, 5 had T3 tumors and 2 had T1 tumors. In 33% of cases, tumor diameter was greater than 5.0 cm. Three hundred and eighty-seven lymph nodes were excised with a median of 32.3 per patient. The SN navigation surgery was feasible in all patients, with a median of 4.5 SNs per patient. The detection success rate was 100%. All the SNs were located in N1 and N2 nodal level. In 70.9% of cases, the SNs were located at lymphatic chains 6 and 7. The SN sensitivity for nodal staging was 91.6%, with 8.3% of false negative. In 4 patients who were initially staged as N0, the SNs were submitted to multisection analyses and immunohistochemistry, confirming the N0 stage, without micrometastases. In one case initially staged as negative for nodal metastases based on SN analyses, metastases in lymph nodes other than SN were found, resulting in a 20% skip metastases incidence. This surgery is a reproducible procedure with 100% detection rate of SN. Tumor size, GC location and obesity were factors that imposed some limitations regarding SN identification. Results from nodal multisection histology and immunohistochemistry analysis did not change initial nodal staging.

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.

Could the immune response in the sentinel lymph nodes of gastric cancer patients be the key to tailored surgery?

BACKGROUND

Precise detection of downstream, nonsentinel lymph node metastases is the key to implementation of the sentinel lymph node concept in gastric cancer. To overcome the problem of complex lymphatic drainage, micrometastases, and skip metastases, we investigated the feasibility of tumor cell detection in sentinel lymph nodes, using flow cytometry as well as studied immune suppression in the sentinel lymph node as a potential marker of downstream lymph node metastases.

METHODS

In 21 patients with gastric cancer, the sentinel lymph nodes extracted during operation subjected to frozen sections and flow cytometry. The tumor cells were defined with the cell surface markers CEACAM and EpCAM. Simultaneously, the cell densities of different subsets of T cells were determined.

RESULTS

The sensitivity and specificity of the determination of nodal status with flow cytometry for tumor cell detection was 100% and 63%, respectively, as seen in frozen sections. Correlations with nonsentinel lymph node metastases were seen for CD127(low)CD25(high) and CD45(neg)CD127(low)CD25(high) cell densities, relative proportion of CD45RA(neg)CD127(low)CD25(high) cells, frozen sections results, lymphangial invasion, and tumor size (P ≤ .043 each). Multivariate analysis identified the relative proportions of CD45RA(neg)CD127(low)CD25(high) cells as the only significant predictor for downstream nonsentinel lymph node metastases (P = .028; 95% confidence interval, 1.107-5.780). The predictive value of combined detection of flow cytometry tumor cells and the relative proportion of CD45RA(neg)CD127(low)CD25(high) cells for nodal stage determination was 91%.

CONCLUSION

Combined detection of tumor cells and CD45RA(neg)CD127(low)CD25(high) cells in sentinel lymph nodes with flow cytometry predicts accurately nonsentinel lymph node metastases.

A multicenter study of using carbon nanoparticles to show sentinel lymph nodes in early gastric cancer

BACKGROUND

Lymph node metastasis occurs in approximately 10% of early gastric cancer. Preoperative or intra-operative identification of lymph node metastasis in early gastric cancer is crucial for surgical planning. The purpose of this study was to evaluate the feasibility of using carbon nanoparticles to show sentinel lymph nodes (SLNs) in early gastric cancer.

METHODS

A multicenter study was performed between July 2012 and November 2014. Ninety-one patients with early gastric cancer identified by preoperative endoscopic ultrasonography were recruited. One milliliter carbon nanoparticles suspension, which is approved by Chinese Food and Drug Administration, was endoscopically injected into the submucosal layer at four points around the site of the primary tumor 6-12 h before surgery. Laparoscopic radical resection with D2 lymphadenectomy was performed. SLNs were defined as nodes that were black-dyed by carbon nanoparticles in greater omentum and lesser omentum near gastric cancer. Lymph node status and SLNs accuracy were confirmed by pathological analysis.

RESULTS

All patients had black-dyed SLNs lying in greater omentum and/or lesser omentum. SLNs were easily found under laparoscopy. The mean number of SLNs was 4 (range 1-9). Carbon nanoparticles were around cancer in specimen. After pathological analysis, 10 patients (10.99%) had lymph node metastasis in 91 patients with early gastric cancer. SLNs were positive in 9 cases and negative in 82 cases. In pathology, carbon nanoparticles were seen in lymphatic vessels, lymphoid sinus, and macrophages in SLNs. When SLNs were positive, cancer cells were seen in lymph nodes. The sensitivity, specificity, and accuracy of black-dyed SLNs in early gastric cancers were 90, 100, and 98.9 %, respectively. No patient had any side effects of carbon nanoparticles in this study.

CONCLUSIONS

It is feasible to use carbon nanoparticles to show SLNs in early gastric cancer. Carbon nanoparticles suspension is safe for submucosal injection.

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.

Sentinel lymph node in oesophageal cancer-a systematic review and meta-analysis

BACKGROUND

Sentinel lymph nodes (SLNs) have been used to predict regional lymph node metastasis in patients with melanoma and breast cancer. However, the validity of the SLN hypothesis is still controversial for oesophageal cancer. We performed this meta-analysis to evaluate the feasibility and accuracy of radio-guided SLN mapping for oesophageal cancer.

METHODS

A systematic search was conducted using MEDLINE, PubMed, EMBASE, Current Contents Connect, Cochrane library, Google scholar, Science Direct, and Web of Science. Original data was abstracted from each study and used to calculate a pooled event rates and 95% confidence interval (95% CI).

RESULTS

The search identified 23 relevant articles. The overall detection rate was 0.93 (95% CI: 0.894-0.950), sensitivity 0.87 (95% CI: 0.811-0.908), negative predictive value 0.77 (95% CI: 0.568-0.890) and the accuracy was 0.88 (95% CI: 0.817-0.921). In the adenocarcinoma cohort, detection rate was 0.98 (95% CI: 0.923-0.992), sensitivity 0.84 (95% CI: 0.743-0.911) and the accuracy was 0.87(95% CI: 0.796-0.913). In the squamous cell carcinoma group, detection rate was 0.89 (95% CI: 00.792-0.943), sensitivity 0.91 (95% CI: 0.754-0.972) and the accuracy was 0.84 (95% CI: 0.732-0.914).

CONCLUSIONS

It is possible to identify and obtain a SLN before neoadjuvant therapy in oesophageal cancer. However, further work is needed to optimize radiocolloid type, refine the technique and develop a quick and accurate way to determine SLN status intraoperatively. This technique has to be further evaluated before it can be applied widely.

Early gastric cancer and dysplasia

Since the concept of early gastric cancer was first described in Japan in 1962, its treatment has evolved from curative surgical resection to endoscopic resection, initially with polypectomy to more recently with endoscopic submucosal dissection. As worldwide experience with these endoscopic techniques evolve and gain acceptance, studies have confirmed its comparable effectiveness with historical surgical outcomes in carefully selected patients. The criteria for endoscopic resection have expanded to offer more patients improved quality of life, avoiding the morbidity and mortality associated with surgery. This article summarizes the evolutional role of endoscopic and surgical therapy in early gastric cancer.

Animal model for training in sentinel lymph node biopsy of the stomach through combined methods

PURPOSE

Create and validate a proposed animal model for training in sentinel lymph node biopsy of the stomach.

METHODS

In thirty-two rabbits, through a laparotomy, they received a subserosal injection of 0.1 ml of phytate labeled with technetium-99m (0.2 mCi) in the anterior wall of the gastric corpus, followed by 0.2 ml of Blue Patent V(®) 2.5%, through the same puncture site. Suspicious lymph nodes were searched in vivo at five, ten and 20 minutes, both visually (Blue Patent stained lymph nodes) and with a manual gamma radiation detector (to detect suspected radioactive lymph nodes). After 20 minutes, was performed resection of these for further evaluation of radioactivity (ex vivo) and histological study.

RESULTS

Lymph nodes were identified in 30 rabbits (Average of 2.2 lymph nodes per animal). Of the 90 suspected lymph nodes that occurred in the study, 70 cases (77.8%) were histologically confirmed for lymphoid tissue. Of these, the majority were located in the periesophageal region of the gastric fundus. The sample presented a mortality rate of 6.25% and nine complications related to the method, which interfered in the identification of the lymph nodes.

CONCLUSION

The animal model for sentinel node biopsy in rabbit stomachs proved to be feasible, with low complexity and reproduced the difficulties encountered for gastric lymph node biopsy in humans, being adequate for surgical training.

What is the accuracy of sentinel lymph node biopsy for gastric cancer? A systematic review

BACKGROUND

In gastric cancer, the utility of sentinel lymph node (SLN) biopsy has not been established. SLN may be a good predictor of the pathological status of other lymph nodes and thus the necessity for more extensive surgery or lymph node dissection. We aimed to identify and synthesize findings on the performance of SLN biopsies in gastric cancer.

METHODS

Electronic literature searches were conducted using Medline, EMBASE, and the Cochrane Central Register of Controlled Trials from 1998 to 2009. Titles and abstracts were independently rated for relevance by a minimum of two reviewers. Techniques, detection rates, accuracy, sensitivity, specificity, and false-negative rates (FNRs) were analyzed. Analysis was performed based on the FNR.

RESULTS

Twenty-six articles met our inclusion criteria. SLN detection using the dye method (DM) was reviewed in 18 studies, the radiocolloid method (RM) was used in 12 studies, and both dye and radiocolloid methods (DUAL) were used in 5 studies. The DM had an overall calculated FNR of 34.7% (95% confidence interval [CI] 21.2, 48.1). The RM had an overall calculated FNR of 18.5% (95% CI 9.1, 28.0). DUAL had an overall calculated FNR of 13.1% (95% CI -0.9, 27.2).

CONCLUSION

Application of the SLN technique may be practical for early gastric cancer. The use of DUAL for identifying SLN may yield a lower FNR than either method alone, although statistical significance was not met.

Minimally invasive approaches for gastric cancer-Japanese experiences

Since development of laparoscopy-assisted distal gastrectomy with lymph node dissection in 1991 in Japan, laparoscopic gastrectomy (LAG) is improving and evolving. Recently, advanced LAG techniques including D2 lymph node dissection or anastomosis after total gastrectomy have been developed. Retrospective and prospective multicenter studies have been conducted for early and non-early gastric cancers to establish high-quality evidence. This review summarizes the current trends of minimally invasive approaches for gastric cancer based on current Japanese experiences.

A decade in gastric cancer curative surgery: Evidence of progress (1999-2009)

To investigate the progress in evidence-based surgical treatment of non-metastatic gastric cancer, we reviewed the last ten years’ literature. The data used in this review were identified by searches made on MEDLINE, Current Contents, PubMed, and other references taken from relevant original articles (on prospective and retrospective studies) concerning gastric cancer surgery. Only papers published in English between January 1999 and December 2009 were selected. Data from ongoing studies were obtained in December 2009, from the trials registry of the United States National Institutes of Health (http://www.clinicaltrial.gov). The citations list was presented according to evidence based relevance (i.e., randomized controlled trials, prospective studies, retrospective series). In the last ten years, many challenges have been faced relating to the extension of gastric resection and nodal dissection as well as surgical timing, but we found only limited evidence, regardless of latitude of study. The ongoing phase-III trials may provide answers that will be valid for the coming decades, and which may bring definitive answers for the currently unresolved questions.

Gastric adenocarcinoma surgery and adjuvant therapy

Gastric adenocarcinoma is one of the most common causes of death worldwide. Surgical resection remains the mainstay of therapy, offering the only chance for complete cure. Resection is based on the principles of obtaining adequate margins, with the extent of lymphadenectomy remaining controversial. Neoadjuvant and adjuvant therapies are used to reduce local recurrence and improve long-term survival. This article reviews the literature and provides a summary of surgical management options and neoadjuvant/adjuvant therapies for gastric adenocarcinoma.

Diagnostic value of sentinel lymph node biopsy in gastric cancer: a meta-analysis

BACKGROUND

The possible application and validity of the sentinel lymph node (SLN) concept in gastric cancer (GC) is still debated. A systematic review to evaluate the diagnostic value of SLN biopsy (SLNB) in GC is urgently needed.

METHODS

A systematic review of relevant literatures was performed in PubMed, Embase, and The Cochrane Library. A random-effect model was used to pool the data, and subgroup analysis was used to explain the heterogeneities.

RESULTS

A total of 38 included studies (2,128 patients) were included. The pooled SLN identification rate, sensitivity, negative predictive value, and accuracy were 93.7% (95% confidence interval [95% CI]: 91.1-95.6%), 76.9% (95% CI: 71.6-81.4%), 90.3% (95% CI: 86.9-92.9%), and 92.0% (95% CI: 89.9-93.7%), respectively. Subgroup analysis showed that early T stage, combined tracers, submucosal injection method, conventional open surgery, and usage of immunohistochemistry were associated with higher SLN identification rate and sensitivity.

CONCLUSIONS

SLNB in GC is technically feasible with an acceptable sensitivity. However, further studies are needed to confirm the best procedure and standard criteria.

Sentinel lymph node biopsy for gastric cancer: Where do we stand?

Development of sentinel node navigation surgery (SNNS) and advances in minimally invasive surgical techniques have greatly shaped the modern day approach to gastric cancer surgery. An extensive body of knowledge now exists on this type of clinical application but is principally composed of single institute studies. Certain dye tracers, such as isosulfan blue or patent blue violet, have been widely utilized with a notable amount of success; however, indocyanine green is gaining popularity. The double tracer method, a synchronized use of dye and radio-isotope tracers, appears to be superior to any of the dyes alone. In the meantime, the concepts of infrared ray electronic endoscopy, florescence imaging, nanoparticles and near-infrared technology are emerging as particularly promising alternative techniques. Hematoxylin and eosin staining remains the main method for the detection of sentinel lymph node (SLN) metastases. Several specialized centers have begun to employ immunohistochemical staining for this type of clinical analysis but the equipment costs involving the associated ultra-rapid processing systems is limiting its widespread application. Laparoscopic function-preserving resection of primary tumor from the stomach in conjunction with lymphatic basin dissection navigated by SLN identification represents the current paramount of SNNS for early gastric cancer. Patients with cT3 stage or higher still require standard D₂ dissection.

Is the sentinel node biopsy clinically applicable for limited lymphadenectomy and modified gastric resection in gastric cancer? A meta-analysis of feasibility studies

BACKGROUND

Sentinel node biopsies (SNBs) have been clinically applied in melanoma and breast cancer for limited lymphadenectomy. However, the use of SNB remains controversial in gastric cancer due to unsatisfactory sensitivity and variability. This meta-analysis was performed to determine the sensitivity of SNB in gastric cancer and to identify factors that improve its sensitivity.

METHODS

Feasibility studies on SNB in gastric cancer were searched for from 2001 to 2009 in Pubmed, Cochrane, and Embase. Forty-six reports, which included 2,684 patients, were found. Estimated sensitivities, detection rates, and negative (NPV), and positive predictive values (PPV) were calculated using a random effects model. Inter-study heterogeneity, meta-regression, and subgroup analysis for sensitivity was performed.

RESULTS

The estimated sensitivity, detection rate, NPV, and PPV were 87.8%, 97.5%, 91.8%, and 38.0%, respectively, with significant inter-study heterogeneity (P < 0.0001). However, no significant contributor to heterogeneity was identified. By subgroup analysis, sensitivity was found to depend significantly on the number of SNs harvested.

CONCLUSIONS

SNB in gastric cancer is probably not clinically applicable for limited lymphadenectomy due its unsatisfactory sensitivity and heterogeneity between practicing surgeons. To improve sensitivity, more than four SNs should be harvested, and a tumor specific SNB method should be developed.

Lymph node metastasis of gastric cancer

Despite a decrease in incidence in recent decades, gastric cancer is still one of the most common causes of cancer death worldwide [1]. In areas without screening for gastric cancer, it is diagnosed late and has a high frequency of nodal involvement [1]. Even in early gastric cancer (EGC), the incidence of lymph node (LN) metastasis exceeds 10%; it was reported to be 14.1% overall and was 4.8 to 23.6% depending on cancer depth [2]. It is important to evaluate LN status preoperatively for proper treatment strategy; however, sufficient results are not being obtained using various modalities. Surgery is the only effective intervention for cure or long-term survival. It is possible to cure local disease without distant metastasis by gastrectomy and LN dissection. However, there is no survival benefit from surgery for systemic disease with distant metastasis such as para-aortic lymph node metastasis [3]. Therefore, whether the disease is local or systemic is an important prognostic indicator for gastric cancer, and the debate continues over the importance of extended lymphadenectomy for gastric cancer. The concept of micro-metastasis has been described as a prognostic factor [4-9], and the biological mechanisms of LN metastasis are currently under study [10-12]. In this article, we review the status of LN metastasis including its molecular mechanisms and evaluate LN dissection for the treatment of gastric cancer.

Treatment strategy for early gastric cancer

Gastric cancer ranks the second leading cause of cancer-specific mortality worldwide. With a poor prognosis, 5-year survival rate of gastric cancer is less than 20%-25% in the USA, Europe, and China [1]. However, early gastric cancer(EGC) offers an excellent (over 90%) chance of cure based on surgical resection [2]. As the increasing detection of EGC, more treatment options have been developed both curatively and minimally invasively to maintain a good quality of life(QOL). One of the advanced therapeutic techniques is endoscopic dissection. Improvements in surgical treatment include minimizing lymph node dissection, reconstruction methods, laparoscopy-assisted surgery, and sentinel node navigation surgery(SNNS) [3]. With technological advances, even Natural Orifice Transluminal Endoscopy Surgery (NOTES) and robotic surgery are expected to represent the next revolution [4]. However, there still remains much dispute among these treatments, which arouses further clinical trials to verify. Update of the treatments, controversial indications, prognosis and current strategies for EGC are discussed in this review.

Sentinel lymph node biopsy in early breast cancer surgery--working with the risks of vital blue dye to reap the benefits

AIMS

Sentinel lymph node biopsy (SLNB) is an important method of staging early breast cancer because of the inherent benefits it confers on patients in terms of arm function and quality of life. Its success depends on a high level of accuracy in detecting the sentinel node. This is achieved by a dual mapping technique that employs a radio-labelled nanocolloid and a vital blue dye. The vital dyes however carry the risk of anaphylaxis, and as more surgeons employ SLNB in their daily practice, a proportionate rise in the number of anaphylactic reactions can be expected. A comprehensive review of risks and benefits associated with using vital blues dyes has not been published and therefore a retrospective review was undertaken of the different levels of anaphylaxis associated with vital dyes as well as their benefits in SLNB.

METHODS

An OVID MEDLINE search was performed of the English published literature using appropriate search terms to find published trial data and case series that focused on adverse reactions to vital blue dyes.

RESULTS

The risk of severe anaphylaxis (grade 3) can be as low as 0.06%, and up to 0.4% for patients undergoing SLNB when data is analysed from large trials. Furthermore, adverse reactions associated with blue dyes are reversible with appropriate management.

CONCLUSIONS

Surgeons should continue to use vital dyes to ensure that SLNB remains a highly sensitive procedure.

Sentinel lymph node biopsy in gastric cancer: possible applications and limits

AIMS

To explore the feasibility and accuracy of sentinel lymph node (SLN) biopsy in gastric cancer.

PATIENTS AND METHODS

Twenty-nine patients with clinical T1 and T2 N0 M0 gastric cancer less than 5 cm in diameter underwent SLN biopsy with the intraoperative Patent blue method. The procedure continued with radical gastrectomy and D2 lymphadenectomy. We investigated all technical aspects of the blue dye technique and determined the accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of the SLN technique.

RESULTS

SLNs were detected in 28 of 29 patients; the total number of excised SLNs was 45, with a median of two (range 1-3). Seventeen patients had metastatic SLN, with 21 lymph nodes retrieved. Twenty-two patients had SLNs located at the first level. Four patients had SLNs at the second level, one at the first and second levels, and one at the first and third levels. Five patients had false negative SLNs. The ability of SLN biopsy to predict the status of the other lymph nodes was summarised by an accuracy of 75%, a sensitivity of 75%, a specificity of 75%, a positive predictive value of 88%, and a negative predictive value of 55%.

CONCLUSIONS

Our study demonstrates that pick-up SLN biopsy in gastric cancer is technically feasible but has very low sensitivity. Regarding the utility of SLN navigation when attempting to detect the nodal basin, the high rate of false negative SLNs and lymph node level jumping warrant further studies with a large accrual before the method can be introduced into daily practice.

R0 resection in the treatment of gastric cancer: Room for improvement

Gastric carcinoma is one of the most frequent malignancies in the world and its clinical behavior especially depends on the metastatic potential of the tumor. In particular, lymphatic metastasis is one of the main predictors of tumor recurrence and survival, and current pathological staging systems reflect the concept that lymphatic spread is the most relevant prognostic factor in patients undergoing curative resection. This is compounded by the observation that two-thirds of gastric cancer in the Western world presents at an advanced stage, with lymph node metastasis at diagnosis. All current therapeutic efforts in gastric cancer are directed toward individualization of therapeutic protocols, tailoring the extent of resection and the administration of preoperative and postoperative treatment. The goals of all these strategies are to improve prognosis towards the achievement of a curative resection (R0 resection) with minimal morbidity and mortality, and better postoperative quality of life.

Sentinel node mapping guided by indocyanine green fluorescence imaging during laparoscopic surgery in gastric cancer

BACKGROUND

Indocyanine green (ICG) fluorescence imaging has recently been reported as a new method for sentinel node (SN) mapping in several types of cancers. In this study, we determined the possible usefulness of SN mapping guided by ICG fluorescence imaging during laparoscopy-assisted gastrectomy (LAG) for gastric cancer.

METHODS

Our series consisted of 77 patients with cT1- or cT2-stage gastric cancer who had undergone LAG (LAG group; 38 patients) or conventional open gastrectomy (OG group; 39 patients). Intraoperative SN mapping guided by ICG fluorescence imaging was conducted with a charge-coupled device camera with a light-emitting diode as the light source and a cut filter as the detector.

RESULTS

The detection rate and mean number of fluorescent nodes (FNs) were 94.7% and 7.9, respectively, in the LAG group, and 94.9% and 7.2, respectively, in the OG group. The accuracy and false-negative rates were 97.2% (35 of 36 cases) and 25% (1 of 4), respectively, in the LAG group, and 91.9% (34 of 37) and 23.1% (3 of 13), respectively, in the OG group. Among 33 LAG group patients and 27 OG group patients without FN metastasis, lymph node metastasis was found only in non-SNs located in the same lymphatic basin as the detected FNs.

CONCLUSIONS

SN mapping guidance by ICG fluorescence imaging could be useful for predicting the lymph node metastasis in gastric cancer, even during LAG. Our data suggest that dissection of the lymphatic basin containing FNs with laparoscopic surgery may be a promising approach as a new type of minimally invasive surgery for patients with cT1- or cT2-stage gastric cancer having no metastasis in FNs.

The role of laparoscopy for gastric surgery in the West

The only potentially curative treatment available for gastric adenocarcinoma is surgical resection. However, many controversies exist regarding treatment strategy, including whether the laparoscopic approach is appropriate. Many reports of laparoscopic techniques for cancer resection have shown oncologic equivalency to the open technique, with the known benefits of the minimally invasive approach, such as decreased pain, length of hospital stay, blood loss, and complications. The Eastern experience with laparoscopic gastrectomy has been extensive, associated with the increased incidence of early gastric cancers. However, in the West, laparoscopic approaches for gastric cancer have been more slowly accepted, largely due to the lower incidence of gastric cancer in this part of the world. Therefore, we aimed to review the technical feasibility and oncologic efficacy of the laparoscopic versus open approach to resection for gastric adenocarcinoma in the West. Review of the literature demonstrates that laparoscopic gastrectomy is a safe technique with short-term oncologic results that are equivalent in terms of margin status and lymph node retrieval and are associated with additional benefits of the minimally invasive approach, although long-term follow up is necessary. Laparoscopic gastrectomy for adenocarcinoma, similar to findings in the East, resulted in a decreased length of hospital stay, decreased narcotic use, fewer complications, and equivalent short-term oncologic outcomes. It appears that the minimally invasive approach for gastric resection of adenocarcinoma is safe and satisfies oncologic requirements, and is justified for use in selected patients.

Current status of sentinel lymph node biopsy in adenocarcinoma of the distal esophagus, gastric cardia, and proximal stomach

The resection of the adenocarcinoma of the esophagogastric junction should be considered to the extent of the lymphatic drainage. This, on the other hand, depends on the possible lymphatic metastasizing. As an adenocarcinoma of the esophagogastric junction is located along the borderline between two visceral cavities (mediastinal/abdominal), it can, in principle, metastasize in both cavities. There is not, however, an imaging (CT, MRI, PET) that can adequately assure the detection of a beginning lymph node metastasis in particular. The sentinel lymph node biopsy could provide the beginning of a solution in this case. The initial results, with all of the necessary accompanying technical work, have been encouraging. The paper presented here provides an introduction to the challenge of the SLNB and the background of a specialized surgical therapy of the AEG. If a lymph nodal metastasis can be definitely confirmed or ruled out, many patients could be spared an unnecessary lymphadenectomy. This is especially important at the AEG because minimizing the evasiveness of the surgery with adequate radical oncological resection (e.g., without thoracotomy) would mean a substantial reduction of postoperative mortality.

Gastric cancer

Gastric cancer is the second most frequent cause of cancer death worldwide, although much geographical variation in incidence exists. Prevention and personalised treatment are regarded as the best options to reduce gastric cancer mortality rates. Prevention strategies should be based on specific risk profiles, including Helicobacter pylori genotype, host gene polymorphisms, presence of precursor lesions, and environmental factors. Although adequate surgery remains the cornerstone of gastric cancer treatment, this single modality treatment seems to have reached its maximum achievable effect for local control and survival. Minimally invasive techniques can be used for treatment of early gastric cancers. Achievement of locoregional control for advanced disease remains very difficult. Extended resections that are standard practice in some Asian countries have not been shown to be as effective in other developed countries. We present an update of the incidence, causes, pathology, and treatment of gastric cancer, consisting of surgery, new strategies with neoadjuvant and adjuvant chemotherapy or radiotherapy, or both, novel treatment strategies using gene signatures, and the effect of caseload on patient outcomes.

Gastric cancer

Gastric cancer is the second most frequent cause of cancer death worldwide, although much geographical variation in incidence exists. Prevention and personalised treatment are regarded as the best options to reduce gastric cancer mortality rates. Prevention strategies should be based on specific risk profiles, including Helicobacter pylori genotype, host gene polymorphisms, presence of precursor lesions, and environmental factors. Although adequate surgery remains the cornerstone of gastric cancer treatment, this single modality treatment seems to have reached its maximum achievable effect for local control and survival. Minimally invasive techniques can be used for treatment of early gastric cancers. Achievement of locoregional control for advanced disease remains very difficult. Extended resections that are standard practice in some Asian countries have not been shown to be as effective in other developed countries. We present an update of the incidence, causes, pathology, and treatment of gastric cancer, consisting of surgery, new strategies with neoadjuvant and adjuvant chemotherapy or radiotherapy, or both, novel treatment strategies using gene signatures, and the effect of caseload on patient outcomes.

Supplementation of endoscopic submucosal dissection with sentinel node biopsy performed by natural orifice transluminal endoscopic surgery (NOTES) (with video)

BACKGROUND

Endoscopic submucosal dissection (ESD) is proving to be effective for the resection of selected early gastric and colon cancers. Its application and appropriateness could be extended if a means of determining lymphatic dissemination without recourse to a conventional operation could be provided.

OBJECTIVE

To demonstrate the feasibility of companion sentinel node biopsy (SNB) by natural orifice transluminal endoscopic surgery (NOTES) concurrent with intraluminal ESD in both the sigmoid colon and stomach.

DESIGN

Acute porcine model.

INTERVENTION

Arbitrarily selected mucosal foci were targeted for combined NOTES-SNB and ESD in the sigmoid and stomach of 2 separate anesthetized animals. NOTES peritoneal access was obtained either transgastrically or transvaginally. A second intraluminal endoscope was passed either orally or rectally, as appropriate, to perform submucosal injection for lymphatic mapping under direct vision of the NOTES endoscope. This endoscope then identified the first-order draining (sentinel) nodes and allowed their excisional biopsy. The sigmoid was retracted by magnetic assistance as required, while torque of an intraluminal gastroscope manipulated the stomach. After retrieval of the nodes, 1-cm and 1.5-cm specimens were resected from the sigmoid and stomach, respectively, by conventional ESD. At procedure end, necropsy was performed.

RESULTS

All sentinel nodes were identified, underwent biopsy, and were retrieved intact. ESD was subsequently readily performed without complication. SNB completeness and ESD quality were confirmed postprocedure.

LIMITATIONS

Experimental model with limited sample size.

CONCLUSIONS

Although not yet appropriate for human use, this proposal merits serious consideration as a potential means of augmenting the effectiveness and appropriateness of ESD techniques for GI neoplasia.

Lymph nodes and gastric cancer

Worldwide, gastric cancer is one of the top three leading causes of cancer mortality, but incidence and presentation vary geographically. Currently, surgery is the only possible cure. Nodal status is an important prognostic indicator for gastric cancer, and despite results of randomized controlled trials, debate continues over the importance of aggressive lymphadenectomy.

Gastric lymphatic mapping for sentinel node biopsy by natural orifice transluminal endoscopic surgery (NOTES)

BACKGROUND

Sentinel node biopsy is proposed as sufficiently reliable in determining the lymph node status of early gastric cancer to justify curtailed resection margins if negative. Its performance by natural orifice transluminal endoscopic surgery (NOTES) could therefore expand the patient cohort able to undergo solely endoscopic resection of their primary.

METHODS

A transvaginal NOTES technique was utilized in six pigs (mean weight 30 kg). The posterior colpotomy and pneumoperitoneum was created by a standard double-channel flexible videoendoscope which was then used to perform peritoneoscopy. Concomitant gastroscopy allowed selection of a site along the greater curvature for lymphatic mapping by submucosal injection of methylene blue (3 ml). Furthermore, torque upon this endoscope allowed the posterior surface of the stomach and retrogastric space to become accessible to the transvaginal endoscope. In surveying the mapping in vivo, the intraperitoneal scope could follow blue-stained efferent lymphatic channels to their first-order draining nodes (i.e., sentinel nodes). Conventional instruments worked down the scope's channels were then used to perform the excisional biopsy. At procedure end, the animals underwent immediate laparotomy to ensure the safety and adequacy of the procedure.

RESULTS

Each procedure was technically successful. Colpotomy, pneumoperitoneum, and peritoneoscopy were promptly achieved (mean 8 min). Post injection, blue efferent lymphatic channels were immediately appreciable in every animal. Five animals had sentinel nodes in their retropyloric region while the last mapped cephalad towards the esophagogastric junction. Two animals had alternative drainage channels identifying additional sentinel nodes. All blue nodes were dissected cleanly by the intraperitoneal scope and retrieved intact per vaginam. Mean lymphadenectomy time was 19 min. At laparotomy, there was no hematoma, ongoing hemorrhage, or visceral injury in any pig. There were no residual, missed stained nodes or channels.

CONCLUSION

NOTES sentinel node biopsy for the stomach is technically accomplishable in this experimental model. This proof of concept should encourage serious consideration of its applicability to clinical practice.

Sentinel node mapping during laparoscopic distal gastrectomy for gastric cancer

BACKGROUND

The goal of this study was to evaluate the feasibility and accuracy of sentinel node (SN) mapping with endoscopic submucosal blue dye injection during laparoscopic distal gastrectomy for gastric cancer.

METHODS

Thirty-four patients affected by gastric adenocarcinoma without gross clinical serosal invasion and distant metastasis were prospectively enrolled. At the start of the surgery, 2 ml of 2% patent blue was endoscopically injected into the submucosal layer at four points around the site of the primary tumor. Sentinel nodes were defined as nodes that were stained by the blue dye within 5-10 min after the dye injection. After identification and removal of sentinel lymph nodes, each patient underwent laparoscopic distal gastrectomy with D1 (n = 2) or D2 (n = 32) lymphadenectomy.

RESULTS

Of the 34 patients, 14 had positive nodules (41%). SNs were detectable as blue nodes in 27 (80%) of 34 patients. The mean number of dissected lymph nodes per patient was 31 +/- 10 (range = 16-64) and the mean number of blue nodes was 1.5 (range = 1-4). Only five (sensitivity 36%) of 14 N(+) patients had at least one metastatic lymph node among the SNs identified. In these 14 patients the sentinel node was traced in 12 cases. Sentinel node status diagnosed the lymph node status with 74% accuracy. In early gastric cancer (n = 18), three patients had lymph node metastasis. These early gastric cancer patients with nodal metastases had at least one metastatic lymph node among the SNs identified (sensitivity 100%).

CONCLUSIONS

Blue dye SN mapping during laparoscopic distal gastrectomy seems to be a feasible and accurate diagnostic tool for detecting lymph node metastasis in patients with early-stage gastric cancer in which the accuracy of the method was 100%. However, in more advanced gastric cancer the results are not satisfactory. Validation of this method requires further studies on technical issues, including selection of the tracers.