Sentinel node biopsy using dye and isotope double tracers in early gastric cancer

Recent Advances in Sentinel Node Navigation Surgery for Early Gastric Cancer

Maintaining the postoperative quality of life (QOL) while ensuring curability without overtreatment is important in the treatment of early gastric cancer. Postoperative QOL is anticipated to be maintained through minimally invasive function-preserving gastrectomy in early gastric cancer. The concept of the sentinel lymph node (SN) basin is essential to maintain the curability of early gastric cancer using minimally invasive function-preserving gastrectomy. However, additional resection after surgery is difficult to perform in gastric cancer. Thus, the SN basin theory is important. Recently, a multicenter randomized phase III trial in South Korea (SENORITA trial) proved that laparoscopic sentinel node navigation surgery (LSNNS) for stomach preservation results in better postoperative QOL compared with standard gastrectomy in patients with early gastric cancer. LSNNS contributes to patients' QOL based on the concept that curability is not impaired. A multicenter nonrandomized phase III trial is ongoing in Japan, and oncologic safety is expected to be demonstrated. LSNNS has been established as a treatment option for selected patients with early gastric cancer, and its application will become widespread in the future.

Tracers in Gastric Cancer Surgery

The treatment of gastric cancer mainly depends on radical gastrectomy. Determination of appropriate surgical margins and adequate lymph node (LN) resection are two major surgical steps that directly correlate with prognosis in gastric cancer. Due to the expanding use of minimally invasive procedures, it is no longer possible to locate tumors and LNs through touch. As an alternative, tracers have begun to enter the field due to their capacities for intraoperative visualization. Herein, we summarize the application of contemporary tracers in gastric cancer surgery, including isosulfan blue, methylene blue, patent blue, indocyanine green, carbon particles, and radioactive tracers. Their mechanisms, administration methods, detection efficiency, and challenges, as well as perspectives on them, are also outlined.

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.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Resection of distal gastric tube cancer with sentinel node biopsy: a case report and review of the literature

Background

The frequency of gastric tube cancershas increased with advances in surgical techniques and improvement of survival rates in patients with esophageal cancer. However, a standard surgical treatment has not yet been established. Total resection of the gastric tube with lymphadenectomy has been considered a radical treatment, while repeat surgery with both laparotomy and thoracotomy has been associated with severe complications, including anastomotic leakage, recurrent nerve paralysis, bronchotracheal injury, and damage to other organs.

Case presentation

We present a successful case of a gastric tube cancer that was treated with surgical resection in combination with sentinel node biopsy. The tumor was diagnosed as a type 0-IIc lesion with ulceration, and was located proximal to the pyloric ring. Endoscopic submucosal dissection was not indicated because the primary lesion was submucosally invasive, and undifferentiated. By the dye-guided method, sentinel nodes were detected along the right gastroepiploic artery and vein. Intraoperative pathological examination revealed no metastasis of the sentinel nodes. Resection of the distal gastric tube was safely performed with a Roux-en-Y reconstruction, preserving the right gastroepiploic artery and vein and the perfusion of the proximal gastric tube.

Conclusion

We suggest distal resection of the gastric tube with sentinel node biopsy as a novel surgical method for a cT1N0 gastric tube cancer located in the abdomen.

Minimally invasive surgery for gastric cancer treatment: current status and future perspectives

Minimally invasive surgery, which has been extensively used to treat gastric adenocarcinoma, is now regarded as one of the standard treatments for early gastric cancer, and its suitability for advanced gastric cancer is being investigated. The use of cutting-edge techniques for minimally invasive surgery enables surgeons to deliver various treatment options to minimize a patient's distress and to maintain oncologic safety. Ongoing multicenter prospective studies aim to validate the efficacy of these surgical techniques and to expand the indications of minimally invasive surgery for the treatment of gastric cancer. In this review, we summarize the current status and issues regarding minimally invasive surgery for the treatment of gastric cancer.

How much progress has been made in minimally invasive surgery for gastric cancer in Korea?: a viewpoint from Korean prospective clinical trials

Gastric cancer is the most common cancer in Korea. Because the incidence of gastric cancer is still high even with early detection and because of developments in surgical instruments and technological advances, minimally invasive surgery has rapidly become an accepted treatment for gastric cancer in Korea. Many Korean gastric surgeons have contributed to the rapid adaptation of minimally invasive surgery for gastric cancer: not only the Korean Laparoscopic Gastrointestinal Surgery Study (KLASS) group, but also other expert surgeons after the 2000s. Thanks to their vigorous efforts involving active learning, education, workshops, academic communications, and international communications with active laparoscopic gastric surgeons in Korea, numerous results and well-designed large-scale clinical studies have been published or are actively ongoing, thus increasing its wide acceptance as an option for gastric cancer. Now, Korea has become one of the leading countries using minimally invasive surgery for the treatment of gastric cancer. This review article will summarize the current status and issues, as well as the clinical trials that have finished or are ongoing, regarding minimally invasive surgery for gastric cancer in Korea.

Sentinel node navigation surgery in gastric cancer: Current status

The theory behind using sentinel node mapping and biopsy in gastric cancer surgery, the so-called sentinel node navigation surgery, is to limit the extent of surgical tissue dissection around the affected organ and subsequently the accompanied morbidity. However, obstacles on the clinical correspondence of sentinel node navigation surgery in everyday practice have occasionally alleviated researchers’ interest on the topic. Only recently with the widespread use of minimally invasive surgical techniques, i.e., laparoscopic gastric cancer resections, surgical community’s interest on the topic have been unavoidably reflated. Double tracer methods appear superior compared to single tracer techniques. Ongoing research is now focused on the invention of new lymph node detection methods utilizing sophisticated technology such as infrared ray endoscopy, florescence imaging and near-infrared technology. Despite its notable limitations, hematoxylin/eosin is still the mainstay staining for assessing the metastatic status of an identified lymph node. An intra-operatively verified metastatic sentinel lymph node will dictate the need for further conventional lymph node dissection. Thus, laparoscopic resection of the gastric primary tumor combined with the appropriate lymph node dissection as determined by the process of sentinel lymph node status characterization represents an option for early gastric cancer. Patients with T3 or more advanced disease should still be managed conventionally with resection plus standard lymph node dissection.

Sentinel lymph node biopsy in esophageal cancer: an essential step towards individualized care

Lymph node status is the most important prognostic factor in esophageal cancer. Through improved detection of lymph node metastases, using the sentinel lymph node concept, accurate staging and more tailored therapy may be achieved. This review article outlines two principle ways in which the sentinel lymph node concept could dramatically influence current standard of care for patients with esophageal cancer. We discuss three limitations to universal acceptance of the technique, and propose next steps for increasing enthusiasm amongst physicians and surgeons including the development of a universal tracer, and improved contrast agents with novel dual-modality 'visibility'.

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

PURPOSE

Complicated gastric lymphatic drainage potentially undermines the utility of sentinel node (SN) biopsy in patients with gastric cancer. Encouraged by several favorable single-institution reports, we conducted a multicenter, single-arm, phase II study of SN mapping that used a standardized dual tracer endoscopic injection technique.

PATIENTS AND METHODS

Patients with previously untreated cT1 or cT2 gastric adenocarcinomas < 4 cm in gross diameter were eligible for inclusion in this study. SN mapping was performed by using a standardized dual tracer endoscopic injection technique. Following biopsy of the identified SNs, mandatory comprehensive D2 or modified D2 gastrectomy was performed according to current Japanese Gastric Cancer Association guidelines.

RESULTS

Among 433 patients who gave preoperative consent, 397 were deemed eligible on the basis of surgical findings. SN biopsy was performed in all patients, and the SN detection rate was 97.5% (387 of 397). Of 57 patients with lymph node metastasis by conventional hematoxylin and eosin staining, 93% (53 of 57) had positive SNs, and the accuracy of nodal evaluation for metastasis was 99% (383 of 387). Only four false-negative SN biopsies were observed, and pathologic analysis revealed that three of those biopsies were pT2 or tumors > 4 cm. We observed no serious adverse effects related to endoscopic tracer injection or the SN mapping procedure.

CONCLUSION

The endoscopic dual tracer method for SN biopsy was confirmed as safe and effective when applied to the superficial, relatively small gastric adenocarcinomas included in this study.

Laparoscopic gastrectomy for gastric cancer

Laparoscopic gastrectomy for gastric cancer is rapidly becoming popular because of the technical developments and the accumulated data of laparoscopic surgery in gastric cancer patients. The aim of this review is to present the current body of evidence and to highlight controversial issues of laparoscopic gastrectomy for gastric cancer. Laparoscopic distal gastrectomy (LDG) provides better or comparable outcomes compared to conventional open distal gastrectomy (ODG) in terms of short-term results. The long-term survival of LDG is expected to be comparable to that of ODG in early-stage gastric cancer, and an ongoing Korean multicenter randomized controlled trial (KLASS-01) will provide more clear evidence. Laparoscopic total gastrectomy is still selectively performed compared to LDG, and there is still debate on the safety of the laparoscopic esophagojejunostomy technique. Laparoscopic pylorus-preserving gastrectomy seems to be preferred for early gastric cancer in the middle third of the stomach in terms of functional advantages and comparable oncologic outcome. Evidence for LDG for advanced gastric cancer is still insufficient and the issue of lack of generalization still remains, even after ongoing multicenter randomized controlled trials have revealed clinical evidence. Laparoscopic sentinel node navigation surgery is still experimental and the surgical procedure has yet to be standardized. Robotic gastrectomy is feasible for early gastric cancer in terms of similar outcome, but is much more expensive in comparison to laparoscopic surgery. Its benefit over the conventional laparoscopic gastrectomy has not yet been proven.

Minor gastric resections with modified lymphadenectomy in early gastric cancer with negative sentinel node

OBJECTIVE

To study the sentinel lymph node in early gastric cancer as a diagnostic method of unsuspected lymph node metastasis, which may allow the performance, in those with negative lymph nodes, of smaller gastric resections with limited lymphadenectomy.

METHODS

We studied seven patients with early gastric cancer treated at the Hospital Universitário Clementino Fraga Filho, Federal University of Rio de Janeiro, from September 2008 to May 2011, who underwent sentinel lymph node exams, performed by intraoperative peritumoral endoscopic injection of patent blue dye.

RESULTS

We found an average of three sentinel nodes per patient. The frozen biopsy of lymph nodes was negative for metastases, which allowed the realization of atypical gastric resection in three cases and antrectomy with BI reconstruction in four. The performed lymphadenectomy was modified D1. There was no operative mortality. The duration of postoperative follow-up ranged from five to 37 months, without evidence of recurrence. One patient developed a second early tumor 13 months after the initial surgery and underwent total gastrectomy.

CONCLUSION

The sentinel lymph node in early gastric cancer proved to be an effective method for the evaluation of nodal metastases in seven patients and allowed for smaller gastric resections and limited lymphadenectomies. These minor procedures reduce the risk of postoperative complications, maintaining, on the other hand, the oncological radicality that is required in the treatment of 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-Korean experience

Laparoscopic surgery in Korea increased rapidly because of the early detection of gastric cancer by the development of diagnostic tools and nationwide screening. The Korean Laparoscopic Gastrointestinal Surgery Study Group (KLASS group) played a leading role in various projects related with minimally invasive surgery. The justification of minimally invasive procedures including robotic surgery, sentinel-node biopsy, or single-port surgery/Natural Orifice Transluminal Endoscopic Surgery (NOTES) must be predetermined by the clinical trial before a wide application, and the medical industry as well as surgeons should have great responsibility.

History of minimally invasive surgery for gastric cancer in Korea

Laparoscopic gastrectomy was begun in 1995 in Korea. But, there was 4 years gap to reactivate in 1999. High incidence of gastric cancer and increasing proportion of early cancer through national screening program along with huge effort and enthusiasm of laparoscopic gastric surgeon, and active academic exchange with Japanese doctors contributed development of laparoscopic gastrectomy in Korea. Study group activity of Korean Laparoscopic Gastrointestinal Surgery Study (KLASS) group and Collaborative Action for Gastric Cancer (COACT) group were paramount to evoke large scale multicenter clinical study and various well performed clinical studies. This review encompasses mainly international publications about this area so far in Korea.

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.

The peak-standardized uptake value (P-SUV) by preoperative positron emission tomography-computed tomography (PET-CT) is a useful indicator of lymph node metastasis in gastric cancer

BACKGROUND AND OBJECTIVES

Little data is currently available on the usefulness of peak-standardized uptake value (P-SUV) by positron emission tomography-computed tomography (PET-CT) in gastric cancer. The purpose of the present study was to evaluate the value of PET-CT for the preoperative evaluation of patients with gastric cancer. The aim of this study was to assess the relation of between primary tumor P-SUV, as determined by preoperative PET-CT, and lymph node metastasis in gastric cancer.

METHODS

From December 2007 to March 2010, we analyzed the PET-CT of 147 patients that underwent gastrectomy for gastric cancer. P-SUV in PET-CT were measured by single nuclear medicine physician. Statistical analysis was performed to determine relations between clinicopathologic parameters including P-SUV and lymph node metastasis using the chi-square test, the independent t-test, and using logistic regression analysis.

RESULTS

Age, tumor depth, tumor size, and lymph node metastasis were found to be associated with primary tumor P-SUV by PET-CT (P=0.009, <0.001, <0.001, and <0.001, respectively). No association was found between P-SUV and tumor histology or tumor location (P=0.099). Advanced gastric cancer was found to have a higher P-SUV than early gastric cancer, and a higher P-SUV was found to be associated with lymph node metastases by both univariate and multivariate analysis.

CONCLUSIONS

P-SUV of primary tumor could be an independent indicator of lymph node metastasis in gastric cancer. Gastric surgeons should pay more attention to the dissection of lymph nodes when primary tumors have higher P-SUV values by PET-CT.

Computed tomography lymphography for the detection of sentinel nodes in patients with gastric carcinoma

The sentinel node (SN) concept has been found to be feasible in gastric cancer. However, the lymphatic network of gastric cancer may be more complex, and it may be difficult to visualize all the SN distributed in unexpected areas by conventional modalities. In this study, we evaluate the feasibility and efficacy of CT lymphography for the detection of SN in gastric cancer. A total 24 patients with early gastric cancer were enrolled in the study. Three modalities (CT lymphography, dye and radioisotope [RI] methods) were used for the detection of SN. The images of CT lymphography were obtained at 10 min after injection of contrast agents. The SN were successfully identified by CT lymphography in 83.3% of patients; detection rates by the dye and RI methods were 95% and 100%, respectively. Most patients, in whom SN were successfully detected by CT lymphography, had positive results at 5 min after injection of the contrast material. The SN stations detected by CT lymphography were consistent with or included those detected by dye and/or RI methods. In conclusion, CT lymphography for the detection of SN in gastric cancer is feasible and has several advantages. However, based on this initial experience, CT lymphography had a relatively low detection rate compared with conventional methods, and further efforts will be necessary to improve the detection rate and widen the clinical application of CT lymphography for the detection of SN in gastric cancer.

Preoperative imaging of sentinel lymph nodes in gastric cancer using CT lymphography

PURPOSE

Preoperative identification of the sentinel lymph node (SLN) in gastric cancer (GC) patients may have great advantages for the minimally invasive treatment. This study was performed to evaluate the possibility of preoperative SLN detection using CT lymphography.

MATERIALS AND METHODS

Fourteen patients with early GC were enrolled. CT images were obtained before and at 1, 3, and 5 minutes after endoscopic submucosal peritumoral injection of 2 mL iopamidol. For patients with clearly identified SLNs, to make comparisons with the CT lymphography results, intraoperative SLN detection was performed using subserosally injected Indocyanine green (ICG) lymphography and ex vivo ICG and iopamidol lymphography using mammography was also performed.

RESULTS

CT lymphography clearly visualized draining lymphatics and SLNs in 4 (28.6%) out of 14 patients. All clearly visualized SLNs (one to three SLNs per patient) under preoperative imaging were detected in the same location by intraoperative ICG lymphography and ex vivo ICG and iopamidol lymphography using mammography. All preoperative SLN detections were observed with the primary tumors in the lower third of the stomach.

CONCLUSION

Although our study demonstrated a SLN detection rate of less than 30%, CT lymphography with radio-contrast showed potential as a method of preoperative SLN detection for GC.

The accuracy of sentinel node mapping according to T stage in patients with gastric cancer

BACKGROUND

Sentinel lymph node (SLN) mapping has been recently introduced to the field of gastric cancer. To the best of our knowledge, no study has dealt with the accuracy of SLN mapping according to the T stage of the primary tumor. The aim of the present study was to evaluate SLN status according to the T stage of the primary tumors.

METHODS

Eighty patients with gastric cancer underwent SLN mapping with patent blue dye during gastric resection.

RESULTS

Forty-seven patients underwent distal subtotal gastrectomy; 17 patients, proximal gastrectomy; 14, total gastrectomy; and 2, gastric stump resection. SLNs were stained in 61/80 patients (76.3%). The number of stained SLNs varied from 1 to 16 (mean, 3.3). Patients undergoing proximal gastrectomy had a mean of 3 stained SLNs, whereas patients undergoing distal subtotal gastrectomy had a mean of 2.8 stained SLNs. In 55/61 patients (90.2%) with stained SLNs a positive correlation was found between the presence of metastases and stained or non-stained SLNs. Ten out of 11 patients (90.9%) with T1 tumors (mean, 3.27 SLNs per patient) and 15/17 patients with T2 tumors (88.2%; mean, 3 SLNs per patient) had stained SLNs as compared to only 33/48 (68.8%) of patients with T3 tumors (mean, 3.3 SLNs per patient). The positive predictive value of the SLN mapping was 100%, the negative predictive value was 76.9%, and sensitivity was 85.4%.

CONCLUSION

While in T1 and T2 tumors sentinel node mapping may be of assistance in the decision-making process regarding the extent of lymphadenectomy (sensitivity, 100%; negative predictive value, 90%-100%), SLN mapping in patients with T3 tumors will be misleading in a third of the patients and should not be attempted.

Factors associated with detection failure and false-negative sentinel node biopsy findings in gastric cancer: results of prospective single center trials

BACKGROUND AND OBJECTIVES

The factors associated with successful sentinel node biopsy (SNB) are limited in gastric cancer despite a wide range of sensitivities reported. This study was performed to identify the factors associated with detection failure and SNB false-negativity in gastric cancer.

METHODS

SNB was performed on 156 gastric cancer patients from May 2002 to April 2007 at the Korean National Cancer Center during three consecutive prospective trials. Indications for SNB were determined preoperatively in cT1-2N0 patients. Dissected SNs and non-SNs after D2 lymphadenectomy were pathologically evaluated for metastasis. Clinical, pathological, and technical factors were analyzed for detection failure and false-negativity.

RESULTS

SNs were detected in 147 patients (94.2%) and the median number of SNs detected per patient was 3 (1-12). Twenty-five of 37 with nodal metastasis were diagnosed by SNB (sensitivity, 67.6%). Surgeon's inexperience (<or=30 procedures) and a male patient gender were significantly associated with detection failure (P = 0.014 and 0.031, respectively). A small number of SNs (<or= 3) was found to be significantly associated with false-negativity (P = 0.027).

CONCLUSIONS

SNB requires experience for successful detection and should be performed cautiously in male patients. Harvesting of more than three SNs is warranted to reduce false-negatives when diagnosing nodal metastasis.

A comprehensive overview of radioguided surgery using gamma detection probe technology

The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology.

Sentinel node mapping and skip metastases in patients with early gastric cancer

OBJECTIVES

This study was designed to identify the characteristics of patients with early gastric cancers that have skip metastases.

BACKGROUND

The possibility of lymph node metastasis is the most important factor to consider when deciding on the resection procedure for patients with early gastric cancer.

METHODS

From February 2003 through July 2008, 739 patients with early gastric adenocarcinoma underwent gastric resection at the National Cancer Center, Korea, and were included in this study. Patients with skip metastases were analyzed and compared with those without skip metastases.

RESULTS

Skip metastases were found in 2.8% of patients with early gastric cancer. Tumor size and the presence of lymphatic invasion were associated with skip metastases by both univariate and multivariate analysis. All skip metastases were metastases to the extraperigastric lymph nodes that skipped across the perigastric lymph nodes. Sixteen patients (66.7%) with these metastases had metastatic lymph nodes at No. 7, 8, and 9 stations.

CONCLUSIONS

Tumor size should be considered during sentinel lymph node mapping to prevent false-negative results in patients with early gastric cancer. If sentinel nodes are not found in the perigastric lymph nodes, No. 7, 8, and 9 stations should be explored for prevention of false-negative sentinel node mapping results.

Feasibility of laparoscopic sentinel basin dissection for limited resection in early gastric cancer

BACKGROUND

The clinical applications of sentinel node (SN) biopsies in early gastric cancer are limited because of low sensitivity. Sentinel basin (SB) dissection has been suggested as alternative to SN biopsy to improve sensitivity. The aim of this study was to examine the feasibility of laparoscopic SB dissection.

METHODS

Twenty-one gastric adenocarcinoma patients of cT1N0 were enrolled. Technetium 99 m human serum albumin and indocyanine green were injected into the submucosal layer around tumor using an intraoperative endoscope. Green-stained or radioactive lymphatic basins were detected and defined as SBs. After laparoscopic SB dissection, laparoscopy-assisted gastrectomy with D2 lymphadenectomy was performed. Dissected SB nodes and non-SB nodes were evaluated for metastasis pathologically.

RESULTS

The SB detection rate was 95.2%. Numbers of SBs were one in 6, two in 10, and three in 4 patients. The mean number of SB nodes was 7.0. Two patients with lymph node metastasis were diagnosed by SB dissection. Mean time of laparoscopic SB dissection procedure was 15.2 min.

CONCLUSIONS

Above findings suggest that laparoscopic SB dissection is technically feasible, and it might have better sensitivity than SN biopsy. However, the validity of this procedure should be evaluated in a larger series before being clinically applied.

Which biopsy method is more suitable between a basin dissection and pick-up biopsy for sentinel nodes in laparoscopic sentinel-node navigation surgery (LSNNS) for gastric cancer?

BACKGROUND

Sentinel-node navigation surgery (SNNS) for breast cancer and melanoma has been accepted as a reasonable oncologic surgery worldwide. On the other hand, in gastric cancers that do metastasize well to the lymph node, the use of SNNS has been approached with care and performed in only limited cases. Some obstacles still have to be overcome, such as the shortcomings of SN tracers and the technical limitations of laparoscopic SN detection. The aims of this study were to determine whether laparoscopic SNNS is possible, and which biopsy method is more suitable for SN tracers, in gastric cancer, preoperatively diagnosed as < or =T2 and with < or =4-cm-sized lesions.

MATERIALS AND METHODS

Between January 2005 and October 2006, 92 consecutive patients that underwent LSNNS, using a combined indocyanine green and (99m)Tc-labeled tin colloid technique, were prospectively studied. SNs were laparoscopically removed by using two biopsy methods: a basin dissection and pick-up method, with the results of these two SN biopsy methods then compared with the final diagnosis obtained from a permanent section.

RESULTS

With the pick-up method, SNs were identified in 23 of 42 patients (54.8%); however, with basin dissection, the detection rate was 96% (48 of 50 patients). The average number of SNs detected by the two methods were 2.1 (range, 0-4) and 3.5 (range, 1-7), respectively. The sensitivities of the two methods were 66% (4/6) and 85.7% (12/14), with specificities of 100% (17/17) and 100% (34/34), respectively.

CONCLUSION

In gastric cancer, it was possible to perform LSNNS. At this moment, we believe the laparoscopic basin dissection technique with a dual-tracer injection, followed by SN detection on the back table, will be a reasonable procedure for gastric cancer, owing to the shortcomings related to the dye and radioisotope, the so-called "stained lymphatic duct only" and "shine-through phenomenon."

Detection of micrometastases in sentinel node navigation surgery for gastric cancer

Although lymph node metastasis is one of the important prognostic factors for patients with gastric cancer, the clinical significance of micrometastasis remains controversial. In the 6th edition of the TMN classification, micrometastases were classified as micrometastasis (MM) and isolated tumor cells (ITC) according to its greatest dimension. The accurate diagnosis of micrometastases is required when considering less invasive surgery, especially in early stage of gastric cancer. Since generating useful information about micrometastases by conventional RT-PCR is time-consuming, this procedure is not useful for rapid diagnosis during surgery. Recently some new methods of genetic diagnosis have reduced the amount of time required to obtain information about micrometastases in lymph nodes to 30-40 min. Such methodology can be clinically applied during less invasive surgery. The sentinel node (SN) concept has recently been applied to gastric cancer and SN navigation surgery (SNNS) is ideal for reduction of lymphadenectomy in patients with early gastric cancer. However, we should think about some conditions to establish SN concept for gastric cancer: the particle size of radioisotope, relationship between metastatic area and RI uptake, and the diagnosis of micrometastases by various method such as histological examination, immunostaining and RT-PCR. Here, we described the current status of MM and ITC in the lymph nodes and the SN concept in gastric cancer.

Preoperative lymphoscintigraphy for detection of sentinel lymph node in patients with gastric cancer--initial experience

BACKGROUND

Preoperative lymphoscintigraphy may be informative when assessing nodal status in patients with early gastric cancer, especially for surgeons who are scheduled to introduce or have just introduced SLN biopsy.

METHODS

A total of 80 patients with clinical T1N0M0 gastric cancer were injected with technetium-99 m tin-colloid and then underwent preoperative lymphoscintigraphy. The detection rate of SLN per lymphatic basin was determined on the basis of the results of confirmatory lymph node dissection.

RESULTS

By means of lymphoscintigraphy, 71 of 106 basins were found (67%; 95% confidence interval [CI], 57.2-75.9%). Patients were stratified into the following subgroups: successful (S; all basins visualized), partially successful (PS; some basins visualized), and unsuccessful (U; none visualized). The body mass index (BMI) was significantly higher in the U (24.0 +/- 2.5) than in the S (22.3 +/- 2.4) group (P = 0.037). All patients in the U group had a single basin. Multivariate analysis showed that BMI was associated with unsuccessful lymphoscintigraphy (OR, 1.43; 95% CI, 1.06-1.92; P = 0.019), whereas all factors were similar between the S and PS groups.

CONCLUSION

BMI affects SLN detection during lymphoscintigraphy. Unsuccessful lymphoscintigraphy suggests that SLNs are located in a single basin. When lymphoscintigraphy is positive, no preoperative factors can predict whether all lymphatic basins can be visualized.

Distribution of solitary lymph nodes in primary gastric cancer: A retrospective study and clinical implications

AIM: To investigate the distribution pathway of metastatic lymph nodes in gastric carcinoma as a foundation for rational lymphadenectomy.

METHODS: We investigated 173 cases with solitary or single station metastatic lymph nodes (LN) from among 2476 gastric carcinoma patients. The location of metastatic LN, histological type and growth patterns were analyzed retrospectively.

RESULTS: Of 88 solitary node metastases cases, 65 were limited to perigastric nodes (N₁), while 23 showed skipping metastasis. Among 8 tumors in the upper third stomach, 3 involved right paracardial LN (station number: No.1), and one in the greater curvature was found in No.1. In the 28 middle third stomach tumors, 10 were found in LN of the lesser curvature (No.3) and 6 in LN of the left gastric artery (No.7); 5 of the 20 cases on the lesser curvature spread to No.7, while 2 of the 8 on the greater curvature metastasized to LN of the spleen hilum (No.10). Of 52 lower third stomach tumors, 13 involved in No.3 and 19 were detected in inferior pyloric LN (No.6); 9 of the 29 cases along the lesser curvature were involved in No.6.

CONCLUSION: Transversal and skipping metastases of sentinel lymph nodes (SLN) are notable, and rational lymphadenectomy should, therefore, be performed.

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.

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.