Sentinel node biopsy for cT1 and cT2a gastric cancer

Medical Applications and Advancement of Near Infrared Photosensitive Indocyanine Green Molecules

Indocyanine green (ICG) is an important kind of near infrared (NIR) photosensitive molecules for PTT/PDT therapy as well as imaging. When exposed to NIR light, ICG can produce reactive oxygen species (ROS), which can kill cancer cells and pathogenic bacteria. Moreover, the absorbed light can also be converted into heat by ICG molecules to eliminate cancer cells. In addition, it performs exceptionally well in optical imaging-guided tumor therapy and antimicrobial therapy due to its deeper tissue penetration and low photobleaching properties in the near-infrared region compared to other dyes. In order to solve the problems of water and optical stability and multi-function problem of ICG molecules, composite nanomaterials based on ICG have been designed and widely used, especially in the fields of tumors and sterilization. So far, ICG molecules and their composite materials have become one of the most famous infrared sensitive materials. However, there have been no corresponding review articles focused on ICG molecules. In this review, the molecular structure and properties of ICG, composite material design, and near-infrared light- triggered anti-tumor, and antibacterial, and clinical applications are reviewed in detail, which of great significance for related research.

Mapping Lymph Node during Indocyanine Green Fluorescence-Imaging Guided Gastric Oncologic Surgery: Current Applications and Future Directions

Huge strides have been made in the navigation of gastric cancer surgery thanks to the improvement of intraoperative techniques. For now, the use of indocyanine green (ICG) enhanced fluorescence imaging has received promising results in detecting sentinel lymph nodes (SLNs) and tracing lymphatic drainages, which make it applicable for limited and precise lymphadenectomy. Nevertheless, issues of the lack of specificity and unpredictable false-negative lymph nodes were encountered in gastric oncologic surgery practice using ICG-enhanced fluorescence imaging (ICG-FI), which restrict its application. Here, we reviewed the current application of ICG-FI and assessed potential approaches to improving ICG-FI.

Mapping of the perigastric lymphatic network using indocyanine green fluorescence imaging and tissue marking dye in clinically advanced gastric cancer

BACKGROUND

Using indocyanine green (ICG) fluorescence imaging and tissue marking dyes (TMDs), perigastric lymphatic mapping and their pathological correlation were examined to see whether ICG staining covers all metastatic lymph nodes (LNs) in advanced gastric cancer (AGC).

METHODS

Patients with AGC who underwent open distal or total gastrectomy were enrolled. ICG was serially injected intraoperatively into the subserosa along the greater and lesser curvatures. Stomach specimens were examined under a near-infrared camera. ICG-stained LNs were named, excised, and tattooed with different colored TMDs to retrace the exact location after pathological examinations.

RESULTS

A total of 687 LNs and 69 LN stations were examined from 11 patients. The map of the perigastric lymphatic network showing the topography of ICG-stained and ICG-unstained LNs, including metastatic information, was successfully reconstructed. The average number of ICG-stained and ICG-unstained LNs were 23.6 ± 12.3 (37.8%) and 38.8 ± 17.1 (62.2%), respectively. LN metastases were present in 28 LN stations of 8 patients. Of 8 cases with LN metastases, 40% (11.1-75% per case) of metastatic LNs were stained by ICG. Of 28 metastatic LN stations, 21 (75.0%) were covered by ICG, and actual metastatic LNs were stained in 16 LN stations (57.1%). In 4/8 cases (50%), all metastatic LN stations showed ICG signals.

CONCLUSIONS

ICG fluorescence imaging and TMD are useful tools for visualizing the perigastric lymphatic network and retracing the exact location of ICG-stained LNs in AGC. However, ICG imaging is still not recommended for selective LN dissection in AGC because of the limited staining of perigastric LNs.

The accuracy of sentinel node biopsy by 99mTc-sodium phytate in patients with pancreatic cancer

Backgrounds/Aims

Pancreaticoduodenectomy is the only potentially curative treatment for pancreatic cancer. The identification of the first nodal drainage site (sentinel node) may improve the detection of metastatic nodes and can contribute to a less invasive surgery. We aimed to determine the accuracy of sentinel node mapping in patients with pancreatic cancer using intraoperative radiotracer injection technique.

Methods

At surgical exposure, peritumoral injection of 0.4-0.5 mci/0.5 ml of 99mTc- sodium phytate was performed. After tumor resection, sentinel nodes were investigated in the most common areas using a hand-held gamma probe. Any lymph node with in vivo count twice the background was considered as sentinel node, thus, it was removed and sent for pathological assessment. Then a standard lymph node dissection was performed for all patients.

Results

Fourteen patients with cancer in the head of the pancreas were included in this study. Overall, 180 lymph nodes were harvested with a mean of 11.6±4.7 lymph nodes per patient. In eight patients, at least one sentinel node could be identified (detection rate about 64%). False negative rate of the study was 3/5 (60%).

Conclusions

Our study revealed insufficient diagnostic accuracy and high false negative rate for sentinel lymph node mapping with 99mTc- sodium phytate in pancreatic cancer.

Simultaneous sentinel lymph node computed tomography and locoregional chemotherapy for lymph node metastasis in rabbit using an iodine-docetaxel emulsion

Purpose

A sentinel lymph node (SLN) tracer can gain multi-functionality by combining it with additional components. We developed a SLN tracer consisting of iodine and docetaxel and applied it as a theragnostic nanoparticle to simultaneously perform SLN computed tomography (CT) lymphography and locoregional chemotherapy of the draining lymphatic system.

Results

Docetaxel could be loaded in iodine emulsions at a drug-to-surfactant weight ratio as high as that in the drug formulation Taxotere^®. The particle size and drug concentration were stable during storage for up to 3 months in optimized nanoemulsions. Popliteal LN enhancement on CT was observed in all healthy rabbits (n=3) and VX2 tumor-implanted rabbits (n=6) 12 hours after injection. The rate of SLN metastasis was significantly lower in the treatment group (29.4%, 5/17) than in the non-treatment group (70.6%, 12/17) (P=0.038).

Material and Methods

We prepared a nanoemulsion carrying both iodine and docetaxel in a single structure by optimizing the composition of surfactants surrounding the inner iodized oil core. CT was performed 12 hours after subcutaneous injection of the emulsion in healthy rabbits (n=3) and VX2 tumor-implanted rabbits (n=6) for SLN imaging. Next, we tested the effect of treatment by histopathologically assessing the popliteal LN metastasis rate in VX2 tumor-implanted rabbits 7 days after subcutaneous injection of the emulsion (treatment group, n=17) and comparing it with that of non-treatment group rabbits (n=17).

Conclusions

We developed an iodine-docetaxel emulsion and demonstrated that it can be applied to simultaneously achieve CT SLN imaging and local chemotherapy against nodal metastasis.

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

OBJECTIVE

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Sentinel lymph node mapping for 385 gastric cancer patients

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Application of fluorescence in robotic general surgery: review of the literature and state of the art

The initial use of the indocyanine green fluorescence imaging system was for sentinel lymph node biopsy in patients with breast or colorectal cancer. Since then, application of this method has received wide acceptance in various fields of surgical oncology, and it has become a valid diagnostic tool for guiding cancer treatment. It has also been employed in numerous conventional surgical procedures with much success and benefit to the patient. The advent of minimally invasive surgery brought with it a new use for fluorescence in helping to improve the safety of these procedures, particularly for single-site procedures. In 2010, a near-infrared camera was integrated into the da Vinci Si System, creating a combination of technical and minimally invasive advantages that have been embraced by several experienced surgeons. The use of fluorescence, although useful, is considered challenging. Only a few studies are currently available on the use of fluorescence in robotic general surgery, whereas many articles have focused on its application in open and laparoscopic surgery. Many of these reports describe promising and satisfactory results, although with some shortcomings. The purpose of this article is to review the current status of the use of fluorescence in general surgery and particularly its role in robotic surgery. We also review potential uses in the future.

Sentinel lymph node navigation surgery for early stage gastric cancer

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

Evaluation of the novel near-infrared fluorescence tracers pullulan polymer nanogel and indocyanine green/γ-glutamic acid complex for sentinel lymph node navigation surgery in large animal models

BACKGROUND

This study aimed to examine tracers designed to overcome the disadvantages of indocyanine green (ICG), which disperses quickly to multiple lymph nodes, using a near-infrared (NIR) imaging system in animal models.

METHODS

Diluted ICG, ICG/poly-γ-glutamic acid (PGA) complex, and IRDye900-conjugated pullulan-cholesterol nanoprobe "near-infrared polynagogel" (NIR-PNG) were injected into the stomachs of dogs and pigs, and the patterns of dispersion were observed using an NIR imaging system. To compare retention times, fluorescence signals were evaluated in the stomach and small bowel of animals 1 week after injection.

RESULTS

A diluted concentration (~0.1 mg/ml) of ICG was optimal for NIR imaging compared with the conventional concentration (5 mg/ml) for visual inspection. When injected into the stomach, the signals of ICG and ICG/PGA complex were relatively large at the injection site, and signals were detected at multiple sentinel nodes and lymph nodes beyond them. The NIR-PNG signal intensity was relatively small at the injection site and limited to only one sentinel node with no additional node. When evaluated 1 week after injection, only the NIR-PNG signal was detected in the canine stomach, and the signal intensity at the lymph nodes of the porcine small bowel was the highest with NIR-PNG, followed by ICG/PGA complex and finally ICG.

CONCLUSION

NIR-PNG showed the best characteristics of less dispersion and longer retention in the sentinel nodes, and ICG/PGA complex remained longer than diluted ICG. These tracers could potentially be used as optimal tracers for sentinel node navigation surgery in gastric cancer.

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 navigation surgery for early stage gastric cancer

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

Sentinel node mapping of VX2 carcinoma in rabbit thigh with CT lymphography using ethiodized oil

OBJECTIVE

To assess the feasibility of computed tomography (CT) lymphography using ethiodized oil for sentinel node mapping in experimentally induced VX2 carcinoma in the rabbit thigh.

MATERIALS AND METHODS

This experiment received approval from the institutional animal use and care administrative advisory committee. Twenty-three rabbits with VX2 carcinoma in the thigh underwent CT before and after (1 hour, 2 hour) peritumoral injection of 2 mL ethiodized oil. After the CT examination, sentinel nodes were identified by peritumoral injection of methylene blue and subsequently removed. The retrieved sentinel and non-sentinel lymph nodes were investigated with radiographic and pathologic examinations. Based on the comparison of CT findings with those of radiographic and pathologic examinations, the diagnostic performance of CT for sentinel node identification was assessed.

RESULTS

All 23 rabbits showed 53 ethiodized oil retention nodes on post-injection CT and specimen radiography, and 52 methylene blue-stained nodes at the right femoroiliac area. Of the 52 blue-stained sentinel nodes, 50 nodes demonstrated ethiodized oil retention. Thus, the sentinel node detection rate of CT was 96% (50 of 52). On pathologic examination, 28 sentinel nodes in 17 rabbits (nodes/rabbit, mean ± standard deviation, 1.7 ± 0.6) harbored metastasis. Twenty seven of the 28 metastatic sentinel nodes were found to have ethiodized oil retention.

CONCLUSION

Computed tomography lymphography using ethiodized oil may be feasible for sentinel node mapping in experimentally induced VX2 carcinoma in the rabbit thigh.

Analysis of the lymphatic stream to predict sentinel nodes in gastric cancer patients

PURPOSE

To investigate the pattern of lymphatic drainage in gastric cancer patients to predict sentinel node placement according to tumor location.

METHODS

A total of 462 pT1 or T2 gastric adenocarcinoma patients with metastasis to 1-3 lymph nodes (LNs) who had undergone lymphadenectomy greater than D1+β were included in the study. The distribution of metastatic LNs was evaluated according to tumor longitudinal and circumferential location. The incidence rate of atypical metastasis (skip or transversal metastasis) and related clinicopathologic factors were analyzed.

RESULTS

The rates of skip and transversal metastasis were 15.8 % (73 of 462) and 10.3 % (23 of 224), respectively. Atypical metastasis was observed regardless of tumor location. Tumors that showed the most frequent atypical metastasis were located in the lower third and lesser curvature (LC) of the stomach (29.0 % for skip metastasis and 18.0 % for transversal metastasis). In uni- and multivariate analyses, an LC tumor was a risk factor for skip metastasis, and tumor located circumferentially in the LC or longitudinally in the lower third of the stomach was an independent risk factor for transversal metastasis. There was no correlation between tumor aggressiveness and atypical metastasis.

CONCLUSIONS

Tumors at any location had a chance of atypical metastasis; however, those located longitudinally in the lower or circumferentially at the LC had a significantly higher chance of atypical metastasis compared to other locations. When sentinel node navigation surgery is applied, special care should be taken with tumors at these locations to prevent false-negative results.

Early gastric cancer: feasibility of CT lymphography with ethiodized oil for sentinel node mapping

PURPOSE

To evaluate the feasibility of CT lymphography with ethiodized oil for sentinel node mapping in porcine stomachs and in patients with early gastric cancer.

MATERIALS AND METHODS

Approval for the animal study was obtained from the authors' institutional animal use and care administrative advisory committee, the clinical study was approved by the institutional review board, and informed consent was obtained from each participant. Five pigs underwent CT lymphography 1 hour after gastric subserosal injection of 1 mL ethiodized oil and sentinel node mapping with injection of 1 mL methylene blue. Ethiodized oil retention nodes were identified on the radiographic images of the gastric specimen and removed for histopathologic examination. In addition, 10 patients with early gastric cancer underwent CT lymphography with peritumoral injection of 1 mL ethiodized oil, followed by sentinel basin extirpation with CT and routine nodal dissection. The removed sentinel basins were examined by radiography. Histopathologic examination was performed for dissected nodes, including sentinel nodes.

RESULTS

In each of the five pigs, CT showed one perigastric ethiodized oil retention node. After harvesting the ethiodized oil retention node, blue-stained areas were identified in the five removed nodes and intranodal ethiodized oil was detected on histopathologic examination. In all 10 patients, CT lymphography with ethiodized oil successfully defined the sentinel basin with ethiodized oil retention nodes. CT lymphography revealed 20 ethiodized oil retention nodes. After basin extirpation, 28 and 46 nodes were detected on radiographic and histopathologic examinations. Histopathologic examination revealed that one patient had micrometastases at two sentinel nodes and another patient had isolated tumor cells at one sentinel node. No patient had metastasis in nonsentinel nodes.

CONCLUSION

CT lymphography with ethiodized oil may be a feasible method for sentinel node mapping in patients with early gastric cancer.

Sentinel lymph node mapping and biopsy using radioactive tracer in gastric cancer

BACKGROUND

Lymph node metastasis is one of the most important prognostic factors in gastric cancer survival. Sentinel lymph node (SLN) mapping and biopsy may reduce the extension of lymph node dissection by determination of lymph node involvement. The current study prospectively evaluates the feasibility and reliability of SLN biopsy in gastric cancer.

METHODS

A total of 30 patients with gastric cancer with a preoperative imaging stage of T1-T2 or T3, N0 and M0 were enrolled in the study. Furthermore, 2-16 h prior to each operation, (99m) Tc-sulphur colloid solution (0.5 mL, 2 mCi/mL) was endoscopically injected into the submucosal layer around the primary lesion. Lymph nodes were examined using a hand-held gamma probe. Subsequently, a total or subtotal gastrectomy and D2 lymphadenectomy was performed in each patient.

RESULTS

The success rate of SLN biopsy was 100%. Sensitivity, specificity, positive predictive value and negative predictive value were 91.7%, 100%, 100% and 75%, respectively. Both of the two false-negative cases were in the T3 group. In cases of T2 tumours, the sensitivity was 100%.

DISCUSSION

SLN biopsy using a gamma probe in early stage gastric cancer seems to be a safe, feasible and accurate procedure with high sensitivity in predicting regional lymph node involvement.

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.

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.

Sentinel lymph node biopsy to direct treatment in gastric cancer. A systematic review of the literature

Gastric cancer is one of the main causes of cancer-related deaths around the world. The prevalence of early gastric cancer (EGC) among all gastric cancers of 45-51% in Japan, but only 7-28% in Western countries. The prevalence of EGC is growing partly because of better diagnostics and screening programmes. Possible treatment options for EGC treatment are expanded by the introduction of endoscopic mucosal resection and endoscopic submucosal dissection Therefore, detailed knowledge about nodal metastatic risk is warranted. We performed a systematic review of the literature concerning studies investigating the role of sentinel lymph node biopsy in EGCr and whether there is enough proof to introduce SLN as a part of treatment for EGC in the Netherlands. Several detection substances (dye or radiocolloid) and injection methods (submucosal or subserosal) are investigated. An overall sensitivity percentage of 85.4% was found. In comparison, high and clinically sufficient percentages were observed for specificity (98.2%), negative predictive value (90.7%) and accuracy (94%). Subgroup analyses showed that the combination of dye and radiocolloid detection substances is the best method for sentinel lymph node detection in early gastric cancer. However, the precise method of sentinel lymph node biopsy in EGC has to be determined further. Large, randomized series should be initiated in Europe to address this issue.

Current trends and emerging future of indocyanine green usage in surgery and oncology: a literature review

Ever since Kitai first performed fluorescent navigation of sentinel lymph nodes (SLNs) using indocyanine green (ICG) dye with a charge-couple device and light emitting diodes, the intraoperative use of near infrared fluorescence has served a critical role in increasing our understanding in various fields of surgical oncology. Here the authors review the emerging role of the ICG fluorophore in the development of our comprehension of the lymphatic system and its use in SLN mapping and biopsy in various cancers. In addition, they introduce the novel role of ICG-guided video angiography as a new intraoperative method of assessing microvascular circulation. The authors attempt to discuss the promising potential in addition to assessing several challenges and limitations in the context of specific surgical procedures and ICG as a whole. PubMed and Medline literature databases were searched for ICG use in clinical surgical settings. Despite ICG's significant impact in various fields of surgical oncology, ICG is still in its nascent stages, and more in-depth studies need to be carried out to fully evaluate its potential and limitations.

Gastric lymphatic basin dissection for sentinel node biopsy using hybrid natural orifice transluminal endoscopic surgery (NOTES)

The aim of the present study was to describe a method of gastric lymphatic basin dissection for sentinel node biopsy using natural orifice transluminal endoscopic surgery with laparoscopic assistance (hybrid NOTES) in a porcine model. Lymph node dissection was performed in three healthy female domestic farm pigs (each around 40 kg) between October, 2007, and December, 2007. The pigs were administered a general anesthetic and laparoscopy-guided transvaginal colpotomy was performed. A two-channel endoscope was then inserted through the incision into the peritoneal cavity via the transvaginal route. An endoscope was inserted simultaneously into the mouth and indocyanine green solution was injected into the submucosal layer of the gastric wall at four sites. Dyed omentum and lymphatics were dissected using a laparoscopic dissector and the grasping forceps of a transvaginal endoscope. Lymphatics and omentum (mean 13.3 cm, range 8-20 cm) were removed transvaginally. The mean number of detected and resected sentinel nodes was 2.6 (range 1-4, diameter 2~12 mm). Sentinel lymphatic basin dissection was performed successfully and without intraoperative complications in all three cases. Hybrid NOTES is technically feasible, and this procedure may represent an alternative to laparoscopic sentinel lymph node dissection of the stomach.

Feasibility of laparoscopic partial gastrectomy with sentinel node basin dissection in a porcine model

BACKGROUND

This study aimed to evaluate the technical feasibility and safety of laparoscopic partial full-thickness gastrectomy with extensive sentinel node basin (SB) dissection in a porcine model before its application to gastric cancer without lymph node metastasis.

METHODS

A series of 10 pigs (30-37 kg) were used for a survival study approved by an animal use committee. The imaginary lesions were located in the greater curvature (n = 2), lesser curvature (n = 2), anterior wall (n = 2), posterior wall (n = 2), cardia (n = 1), and angle of the stomach (n = 1). The SBs were assumed to be located around each lesion in question. Laparoscopic partial gastrectomy and SB dissection were performed. Upper gastrointestinal series (UGIS) studies were performed with gastrograffin 5 days after the operation to detect possible stricture, leakage, and passage problems. The pigs were kept alive for 3 weeks, then killed.

RESULTS

The procedure was completed for all the pigs. Nine gastric wedge resections and one segmental resection of the stomach with several SB dissections were performed. The mean operation time was 102 min (70-150 min). The postoperative mean weight gain was 3.19 kg. There was no perioperative morbidity or mortality. The UGIS studies failed to detect leakage and stricture, but all the pigs exhibited delayed gastric emptying. Necropsies did not detect procedure-related complications.

CONCLUSIONS

As shown by a pig model, laparoscopic limited gastrectomy with SB dissection appears to be safe and technically feasible.

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.

Simultaneous indocyanine green and (99m)Tc-antimony sulfur colloid-guided laparoscopic sentinel basin dissection for gastric cancer

BACKGROUND

There are few reports on a dual dye and isotope approach using laparoscopy in gastric cancer sentinel node mapping. The aim of this study is to evaluate the feasibility of laparoscopic sentinel basin dissection for gastric cancer using simultaneous indocyanine green (ICG) and (99m)Tc-antimony sulfur colloid (ASC) injections.

METHODS

Sixty-eight patients were enrolled who had been diagnosed with cT1-T2 and cN0 stage gastric cancers. They underwent laparoscopic sentinel basin dissection between June 2005 and May 2008. ICG and (99m)Tc-tin colloid (separate injections in the first phase, n = 16) or ICG and (99m)Tc-ASC (simultaneous injections in the second phase, n = 52) were injected into the submucosa endoscopically. After performing the sentinel basin dissection, laparoscopy-assisted gastrectomy with curative lymphadenectomy was done. Green-stained or radioactive sentinel nodes (SNs) were analyzed by hematoxylin and eosin staining and by immunohistochemistry for cytokeratin.

RESULTS

SNs were identified in 62 of the 68 patients (91.2%; mean 3.3 per patient). Eighteen patients had lymph node metastases. The sensitivity and specificity were, respectively, 72.2 and 100% using the dye method and 83.3 and 100% by the isotope method. However, the dual dye/isotope procedure improved both sensitivity and specificity to 100%. Patients receiving this protocol had significantly more SNs than those receiving separate ICG and (99m)Tc-tin colloid injections (3.3 vs. 1.9, P = 0.008).

CONCLUSION

Simultaneous ICG and (99m)Tc-ASC-guided laparoscopic sentinel basin dissection is an effective tool for gastric cancer SN mapping, giving a high detection rate and excellent sensitivity.

Near-Infrared Fluorescence Imaging in Humans with Indocyanine Green: A Review and Update

Near-infrared (NIR) fluorescence imaging clinical studies have been reported in the literature with six different devices that employ various doses of indocyanine green (ICG) as a non-specific contrast agent. To date, clinical applications range from (i) angiography, intraoperative assessment of vessel patency, and tumor/metastasis delineation following intravenous administration of ICG, and (ii) imaging lymphatic architecture and function following subcutaneous and intradermal ICG administration. In the latter case, NIR fluorescence imaging may enable new discoveries associated with lymphatic function due to (i) a unique niche that is not met by any other conventional imaging technology and (ii) its exquisite sensitivity enabling high spatial and temporal resolution. Herein, we (i) review the basics of clinical NIR fluorescence imaging, (ii) survey the literature on clinical application of investigational devices using ICG fluorescent contrast, (iii) provide an update of non-invasive dynamic lymphatic imaging conducted with our FDPM device, and finally, (iv) comment on the future NIR fluorescence imaging for non-invasive and intraoperative use given recent demonstrations showing capabilities for imaging following microdose administration of contrast agent.

Sentinel node mapping with indocyanine green (ICG) and infrared ray detection in early gastric cancer: an accurate method that enables a limited lymphadenectomy

AIM

This study compares lymphatic mapping in early gastric cancer with ICG and infrared ray electronic endoscopy (IREE) to ICG alone. It examines the optimal method for intra-operative detection of metastases and shows long term follow up results.

METHODS

212 patients underwent the SN procedure with IREE and peritumoural ICG injection. Evaluated parameters were detection of sentinel nodes with IREE versus ICG alone, intra-operative detection rate of lymph node (LN) metastasis with node picking versus lymphatic basin dissection (LBD) and lymphatic drainage patterns.

RESULTS

34 patients had LN metastases. The SN identification rate and sensitivity for IREE versus ICG alone were 99.5 versus 85.8% and 97.0 versus 48.4% respectively. Intra-operative accuracy for detecting LN metastasis was 50% with node picking versus 92.3% with LBD. LN metastases were always in the SN basin. Lymphatic invasion and T-stage were risk factors for nodal metastases. Two patients showed recurrent disease. Both had a tumour with signet cell differentiation. One patient had a T3 tumour, the other patient had a tumour with a diameter of 85 mm.

CONCLUSION

The SN procedure with IREE can detect the SN and is better than ICG alone. LBD of the SN basin is required for accurate intra-operative diagnosis of metastases. LBD dissection based on IREE is a safe method of nodal dissection in patients with T1 or limited T2 tumours.

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.

Methylene blue-assisted lymph node dissection in combination with ex vivo sentinel lymph node mapping in gastric cancer

AIMS

Lymph node (LN) stage is still the strongest prognostic marker in potentially curable gastric cancer. Accuracy of histopathological lymph node assessment depends on the number of investigated LNs and detection rate of metastases and micrometastases. The aim was to perform a feasibility study employing intra-arterial methylene blue injection - a novel method to improve LN harvest - and ex vivo sentinel LN mapping.

METHODS AND RESULTS

A total of 33 cases were enrolled, including 14 retrospective cases that served as a control group. The methylene group showed a highly significant improved mean LN harvest compared with unstained cases, with 38 +/- 14 versus 21 +/- 10 LNs (P < 0.001), respectively. The detection rate of ex vivo sentinel mapping was 88%. No skip metastases occurred.

CONCLUSION

Both techniques have the potential to improve the accuracy of histopathological LN staging and can be combined successfully.

Lymphatic mapping with 99mTc-Evans Blue dye in sheep

OBJECTIVE

99mTc-Evans Blue (EB) is an agent that contains both radioactive and color signals in a single dose. Earlier studies in animal models have suggested that this agent when compared with the dual-injection technique of radiocolloid/blue dye can successfully discriminate the sentinel lymph node. The aim of this study was to investigate the potential of 99mTc-EB as an agent to map the lymphatic system in an ovine model.

METHODS

Doses of 99mTc-EB (23 MBq) containing EB dye (4 mg) were administered intradermally to the limbs of four anesthetized sheep, and they were then imaged over 20-30 min using a gamma camera. The study protocol was repeated using 99mTc-antimony trisulfide colloid (ATC) and Patent Blue V dye. The lymph nodes (popliteal, inguinal, and iliac for hind limbs or prescapular for fore limbs) were identified with a gamma probe during the operative exposure, then dissected and counted in a large volume counter.

RESULTS

Simple and complex (dual) drainage patterns were visible on the scans, and the sentinel node was more radioactive than higher tier nodes in a chain, for both radiotracers. For 99mTc-EB, maximum radioactive uptake was achieved at 3-6 min for popliteal lymph nodes, 12-14 min for iliac nodes, and 13-14 min for prescapular nodes. 99mTc-ATC resulted in maximum radioactive uptake at 4-6 min for popliteal lymph nodes, 13 min for an inguinal node, 13-20 min for iliac nodes, and 18 min for a prescapular node. Following 99mTc-EB injection, 15/15 lymph nodes harvested were all radioactive and blue. For 99mTc-radiocolloid/Patent Blue V injection, 8/14 nodes were radioactive and blue, and 6/14 nodes were radioactive only.

CONCLUSIONS

The soluble radiotracer 99mTc-EB appeared to be a useful lymphoscintigraphic agent in sheep, in which radioactive counts from superficial lymphatic channels and lymph nodes were sufficient for planar imaging. In comparison with 99mTc-antimony trisulfide colloid, both tracers discriminated the sentinel lymph node up to 50 min after administration; however, 99mTc-EB had the advantage of providing radioactive (gamma probe) and color signals simultaneously during the operative exposure.

Sentinel lymph node biopsy for gastrointestinal cancers

Sentinel lymph node biopsy (SLNB) in gastrointestinal-(GI)-tract cancer is not yet of clinical relevance. Nevertheless, the results in the upper GI-tract promise to be helpful to individualize the indication for surgical therapy. SLNB in colon cancer still fails to show high validity to predict the nodal status, but may be helpful to clarify the prognostic role of micrometastases/isolated tumor cells. In anal cancer SLNB is able to guide the indication for groin irradiation.

Technical limitations of lymph node mapping in pancreatic cancer

AIM

The high incidence of lymphatic and peri-neural invasion in pancreatic cancer results in poor loco-regional control. Radical pancreatico-duodenectomy may achieve better loco-regional control, but is accompanied by increasing morbidity. Our hypothesis was that if intra-operative mapping of pathological lymph nodes (LN) is technically feasible in pancreatic cancer, it would allow for selective radical resection.

METHODS

In an ethically approved and statistically powered feasibility study of 72 (stopped after 20% enrollment) patients with suspected pancreatic cancer undergoing resection, we injected methylene blue dye peri- and intra-tumorally and studied its progress to identify putative 'sentinel lymph node(s)'. The Kausch-Whipple procedure (or total pancreatectomy, if required) was carried out in addition to radical LN dissection, which was evaluated histopathologically according to the Japanese criteria.

RESULTS

Over 18 months, 14/16 patients prospectively recruited underwent lymph node mapping and a mean of 20 (range 11-37) LNs per patient were harvested. Methylene blue dye injection identified blue LN(s) in 4/14 patients, none of which were positive for malignant deposits, whilst 10/14 patients had LN metastases. The commonest stations for LN metastasis were 17A or B (9/10), 8A (2/10) and 6 (3/10). The median survival for the 13 patients with cancer was 22.3 months (IQR: 10.4-30 months).

CONCLUSION

Sentinel lymph node mapping is not technically feasible in pancreatic cancer.

Hyaluronic acid is a useful tool for intraoperative sentinel node detection in gastric cancer surgery

BACKGROUND

We assessed whether a mixture of hyaluronic acid (HA) and dye can facilitate dye-guided sentinel node (SN) mapping in gastric surgery. Although dye-guided, SN-navigated surgery is clinically applied for the treatment of early gastric cancer, there are still some practical problems. Because dyes are carried out from the SN within 20 to 30 minutes, it is sometimes difficult to detect SNs accurately, especially when they are located in a deep area in obese patients.

METHODS

Patent blue or ferumoxides, superparamagnetic iron nanocolloids, with or without HA, were injected into the gastrointestinal tract of the pig, and the time course of dye transfer through the lymphatic system of the pig mesentery was assessed.

RESULTS

When a mixture of HA and patent blue at a volume ratio of 1:4 was injected into the submucosal layer, the time to stain the SN did not differ from that with patent blue alone; however, HA markedly prolonged the time the blue dye was retained in the SN. Patent blue alone stained the efferent lymphatics of the SN and spread to other lymph nodes within 20 minutes after submucosal injection. At the same time point, in contrast, blue stain was restricted to a part of the SN, and the efferent lymphatics were not stained for 2 hours when patent blue was mixed with HA. When a mixture of HA and ferumoxides was used as the tracer, the ferumoxides were still observed in the mesenteric SN even at 2 days after injection. Iron staining showed that Fe was trapped primarily in cells in the peripheral sinus of the SN, suggesting that the iron nanoparticles were mostly incorporated by phagocytic macrophages in the SN within a few hours.

CONCLUSIONS

Our data indicate that a mixture with HA prolongs the stay of a dye tracer in the SN and thus enables easy and accurate detection of the SN. HA may be a useful tool to develop a more sophisticated SN mapping technique.

Efficacy of different technical procedures for sentinel lymph node biopsy in gastric cancer staging

BACKGROUND

The clinical impact of sentinel lymph node biopsy (SLNB) in gastric cancer is controversial. We performed a prospective trial to compare different methods: radiocolloid method (RM), dye method (DM), and both methods simultaneously (dual method, or DUM) for reliability and therapeutic consequences.

METHODS

RM and DM were applied in 35 gastric cancer patients. After endoscopic peritumoral injection of (99m)Tc-colloid and Patent Blue V, the positions of all blue sentinel lymph nodes (SLNs) were recorded, and the SLNs microscopically examined by hematoxylin and eosin, step sections, and immunohistochemistry.

RESULTS

RM, DM, and DUM identified the SLNs in 34 (97%) of 35 patients. The sensitivity for the prediction of positive lymph node status for RM was 22 (92%) of 24, for DM 16 (66%) of 24, and for DUM 22 (92%) of 24. In 7 of 17 (RM), 5 of 15 (DM), and 7 of 17 (DUM) patients classified as N0 by routine hematoxylin and eosin staining, micrometastases or isolated tumor cells were found in the SLN (upstaging) after focused examination. If only a limited lymph node dissection of the SLN basins would have been performed in patients, residual lymph node metastases were left in 9 of 24 (RM), in 7 of 34 (DM), and in 5 of 24 (DUM) of patients with node-positive disease.

CONCLUSIONS

Use of RM was superior. DUM did not further increase the sensitivity. A limited lymph node dissection-i.e., lymphatic basin in patients with SLN-positive disease-is associated with a high risk of residual metastases. Patients with negative SLNs may be selected for a limited surgical procedure if they meet certain criteria.

Gastroesophageal carcinoma: individualized surgical therapy

During the twentieth century, surgical management of gastroesophageal carcinoma was developed by an establishment of standard procedures with lymph node dissection according to the metastatic distribution. The "fear" of invisible micrometastasis caused surgeons to perform more aggressive resection with lymphadenectomy to control the disease locally. Although several promising results of extensive lymph node dissection have been reported, the prognostic benefits of extensive surgery have not been proven by prospective randomized trials. A novel technology to detect micrometastasis without extensive surgical resection is required to gastroesophageal carcinoma. The lymphatic mapping technique is one of the attractive candidates for a novel tool to approach this issue.