Interim results of sentinel node biopsy during laparoscopic gastrectomy: possible role in function-preserving surgery for early cancer

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.

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

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

Interventional nuclear medicine: a focus on radioguided intervention and surgery

Within interventional nuclear medicine (iNM) a prominent role is allocated for the sub-discipline of radioguided surgery. Unique for this discipline is the fact that an increasing number of clinical indications (e.g. lymphatic mapping, local tumor demarcation and/or tumor receptor targeted applications) have been adopted into routine care. The clinical integration is further strengthened by technical innovations in chemistry and engineering that enhance the translational potential of radioguided procedures in iNM. Together, these features not only ensure ongoing expansion of iNM but also warrant a lasting clinical impact for the sub-discipline of radioguided surgery.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Recent advances in nuclear and hybrid detection modalities for image-guided surgery

Introduction: Radioguided surgery is an ever-evolving part of nuclear medicine. In fact, this nuclear medicine sub-discipline actively bridges non-invasive molecular imaging with surgical care. Next to relying on the availability of radio- and bimodal-tracers, the success of radioguided surgery is for a large part dependent on the imaging modalities and imaging concepts available for the surgical setting. With this review, we have aimed to provide a comprehensive update of the most recent advances in the field. Areas covered: We have made an attempt to cover all aspects of radioguided surgery: 1) the use of radioisotopes that emit γ, β+, and/or β- radiation, 2) hardware developments ranging from probes to 2D cameras and even the use of advanced 3D interventional imaging solutions, and 3) multiplexing solutions such as dual-isotope detection or combined radionuclear and optical detection. Expert opinion: Technical refinements in the field of radioguided surgery should continue to focus on supporting its implementation in the increasingly complex minimally invasive surgical setting, e.g. by accommodating robot-assisted laparoscopic surgery. In addition, hybrid concepts that integrate the use of radioisotopes with other image-guided surgery modalities such as fluorescence or ultrasound are likely to expand in the future.

Sentinel lymph node mapping procedure in T1 colorectal cancer: A systematic review of published studies

OBJECTIVE

to investigate the role of sentinel lymph node mapping procedure in T1 Colorectal cancer.

BACKGROUND

The incidence of T1 Colorectal cancer is increasing thanks to screening and awareness campaigns. The issue concerning T1 is when to consider a local treatment curative or when it is necessary a radical resection. The histopathological features of resected polyps are able to predict the nodal spread but the value of specificity is increasingly a problem of these predictors. The sentinel lymph node procedure could be a solution.

METHODS

A systematic review was performed following PRISMA guidelines and using "sentinel node", "lymph nodes", and "colorectal cancer" as search terms in PubMed and Embase databases. References from included studies, review articles, and editorials were cross-checked. The risk of bias and quality of the included studies were assessed using the QUADAS-2 tool. The primary outcome was sentinel lymph node accuracy rate and the secondary outcome was sentinel lymph node detection rate for T1 Colorectal cancer.

RESULTS

A total of 12 studies (108 patients) met inclusion and exclusion criteria, 8 were monocentric cohort studies and 4 were multicentric cohort studies. The rate of sentinel lymph node accuracy in T1 colorectal cancer varies from 89% to 100%. Only 1 false negative was found. In 7 of these 12 studies (71 patients) the detection rate of T1 colorectal cancer was reported and showed a variation from 92% to 100%. Even in this case, only 1 case of failed procedure was found.

DISCUSSION

The literature on this topic agrees on that sentinel lymph node mapping, differently from breast cancer and melanomas should not be used for therapeutic purposes in colorectal cancer, but mainly to refine staging. The reason is the low sensitivity of this procedure with an accompanying high false negative rate. However, the data refers mainly to advanced stages of the disease because there are few data available on the earlier stages and in particular related to T1. Isolating the data related only to T1, the false negative rate seems to be very low. Additional studies are necessary, but a decisional role of sentinel lymph node mapping on the treatment of T1 Colorectal cancer is possible in the future.

Intraoperative Sentinel Node Mapping in the Colon: Potential and Pitfalls

Sentinel lymph node mapping (SLNM) may play a significant role in future delivery of colon cancer surgery because of an increase in early-stage, node-negative disease due to national bowel cancer screening programmes. Traditionally, colon lymphatic drainage has not been thought relevant as the operative approach cannot be tailored. Recent advances in local and endoscopic risk-reducing interventions for colonic malignancy have caused a rethink in approach. SLNM was initially attempted with blue dye techniques with limited success. Technological improvement has allowed surgeons to use near-infrared (NIR) light and NIR active tracers such as indocyanine green. This review provides an overview of the current status of intraoperative lymph node mapping in the colon, identifies challenges to the delivery of the techniques, and discusses potential solutions that may help SLNM play a role in improving the delivery of surgical care for patients with colon cancer.

[Micrometastasis in Gastric Cancer]

Although the incidence and mortality rate of gastric cancer have been steadily declining, gastric cancer is still the fourth most common cancer in the world and more than 50% of cases occur in Eastern Asia. In Korea, gastric cancer is the second most common cancer and third cause of cancer related death. The standard surgical procedure for resectable advanced gastric cancer is D2 lymphadenectomy with radical gastrectomy. Even though R0 resection was completed, recurrence is relatively common, and contributes to the limited survival of the patients in gastric cancer. As a clinically relevant factor for detection of the recurrence, the presence of isolating tumor cells has been introduced and it is so called as 'micrometastasis'. Numerous immunohistochemistry and molecular studies have shown that micrometastasis can be demonstrated not only in lymph nodes but also in such body compartments as the bone marrow, peritoneal cavity and blood. Herein, we review the current knowledge and evidence of the prognostic significance of micrometastasis in peritoneal, lymph node, bone marrow. Also, we discuss the current state of research on the circulating tumor cell in peripheral blood.

A pilot study to assess near infrared laparoscopy with indocyanine green (ICG) for intraoperative sentinel lymph node mapping in early colon cancer

BACKGROUND

Previous attempts at sentinel lymph node (SLN) mapping in colon cancer have been compromised by ineffective tracers and the inclusion of advanced disease. This study evaluated the feasibility of fluorescence detection of SLNs with indocyanine green (ICG) for lymphatic mapping in T1/T2 clinically staged colonic malignancy.

METHODS

Consecutive patients with clinical T1/T2 stage colon cancer underwent endoscopic peritumoral submucosal injection of indocyanine green (ICG) for fluorescence detection of SLN using a near-infrared (NIR) camera. All patients underwent laparoscopic complete mesocolic excision surgery. Detection rate and sensitivity of the NIR-ICG technique were the study endpoints.

RESULTS

Thirty patients mean age = 68 years [range = 38-80], mean BMI = 26.2 (IQR = 24.7-28.6) were studied. Mesocolic sentinel nodes (median = 3/patient) were detected by fluorescence within the standard resection field in 27/30 patients. Overall, ten patients had lymph node metastases, with one of these patients having a failed SLN procedure. Of the 27 patients with completed SLN mapping, nine patients had histologically positive lymph nodes containing malignancy. 3/9 had positive SLNs with 6 false negatives. In five of these false negative patients, tumours were larger than 35 mm with four also being T3/T4.

CONCLUSION

ICG mapping with NIR fluorescence allowed mesenteric detection of SLNs in clinical T1/T2 stage colonic cancer. CLINICALTRIALS.GOV: ID: NCT01662752.

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.

Clinical significance of the anterosuperior lymph nodes along the common hepatic artery identified by sentinel node mapping in patients with gastric cancer

BACKGROUND

The sentinel node (SN) concept is safely applied and validated in early gastric cancer. Gastric lymph nodes are divided into five basins with the main gastric arteries, and the anterosuperior lymph nodes with the common hepatic artery (No. 8a) are classified in the right gastric artery (r-GA) basin. Although No. 8a are considered to have lymphatic flow from the r-GA basin, there might be additional multiple lymphatic flows into No. 8a. The aim of this study is to analyze the lymphatic flows to No. 8a and to investigate the clinical significance of No. 8a as a sentinel node (SN No. 8a).

METHODS

Four hundred and twenty-nine patients with cT1N0 or cT2N0 gastric cancer underwent SN mapping. We used technetium-99 tin colloid solution and blue dye as a tracer.

RESULTS

We detected SN No. 8a in 35 (8.2 %) patients. In these patients, we detected SN No. 8a with SNs that belonged to the left gastric artery (l-GA) basin (66 %), right gastroepiploic artery (r-GEA) basin (54 %), and right gastric artery (r-GA) basin (46 %). In addition, celiac artery lymph nodes were detected as SNs significantly more frequently. Function-preserving surgery was performed significantly less often in patients with SN No. 8a (p =0.018).

CONCLUSIONS

We found that SN No. 8a seemed to have lymphatic flow not only from the r-GA basin, but also from the l-GA basin or r-GEA basin. When SN No. 8a are detected, we should be careful to perform function-preserving surgery, even in SN-negative cases.

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

BACKGROUND

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

METHODS

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

RESULTS

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

DISCUSSION

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Comparison of the Diagnostic Value Between Real-Time Reverse Transcription-Polymerase Chain Reaction Assay and Histopathologic Examination in Sentinel Lymph Nodes for Patients With Gastric Carcinoma

OBJECTIVES

Sentinel lymph node (SLN)-based diagnosis in gastric cancers has shown varied sensitivities and false-negative rates in several studies. Application of the reverse transcription-polymerase chain reaction (RT-PCR) in SLN diagnosis has recently been proposed.

METHODS

A total of 155 SLNs from 65 patients with cT1-2, N0 gastric cancer were examined. The histopathologic results were compared with results obtained by real-time RT-PCR for detecting molecular RNA (mRNA) of cytokeratin (CK)19, carcinoembryonic antigen (CEA), and CK20.

RESULTS

The sensitivity and specificity of the multiple marker RT-PCR assay standardized against the results of the postoperative histological examination were 0.778 (95% confidence interval [CI], 0.577-0.914) and 0.781 (95% CI, 0.700-0.850), respectively. In comparison, the sensitivity and specificity of intraoperative diagnosis were 0.819 (95% CI, 0.619-0.937) and 1.000 (95% CI, 0.972-1.000), respectively. The positive predictive value of the multiple-marker RT-PCR assay was 0.355 (95% CI, 0.192-0.546) for predicting non-SLN metastasis, which was lower than that of intraoperative diagnosis (0.813, 95% CI, 0.544-0.960).

CONCLUSIONS

The real-time RT-PCR assay could detect SLN metastasis in gastric cancer. However, the predictive value of the real-time RT-PCR assay was lower than that of precise histopathologic examination and did not outweigh that of our intraoperative SLN diagnosis.

Sentinel node mapping in adenocarcinoma of the esophagogastric junction

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Current status and scope of lymph node micrometastasis in gastric cancer

Recently, lymph node micrometastasis has been evaluated for its prognostic value in gastric cancer. Lymph node micrometastasis cannot be detected via a usual pathologic examination, but it can be detected by using some other techniques including immunohistochemistry and reverse transcription-polymerase chain reaction assay. With the development of such diagnostic techniques, the detection rate of lymph node micrometastasis is constantly increasing. Although the prognostic value of lymph node micrometastasis remains debatable, its clinical impact is apparently remarkable in both early and advanced gastric cancer. At present, studies on the prognostic value of lymph node micrometastasis are evolving to overcome its current limitations and extend the scope of its application.

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.

Suitability of sentinel node mapping as an index of metastasis in early gastric cancer following endoscopic resection

BACKGROUND

When pathological diagnosis following endoscopic resection (ER) for early gastric cancer (EGC) suggests probable lymph node metastasis, additional surgery with lymphadenectomy should be performed. The sentinel node (SN) concept has yet to be applied to tumors following ER. The aim of this study was to evaluate the feasibility of SN navigation surgery for such tumors.

METHODS

Forty patients diagnosed with EGC lesions <4 cm in diameter underwent gastrectomy with SN mapping following ER. A technetium-99 m tin colloid solution and a dye were injected into the submucosal layer around the post-ER scar in all four abdominal quadrants. We then compared the SN distribution and metastases among the patients who underwent ER and controls (n = 192).

RESULTS

SNs were identifiable in all patients, and the mean number of SNs per case was 4.9. The location of the SN basin was similar in the patients who underwent ER and the controls. One patient (3 %) whose primary tumor had invaded the submucosal layer had a metastatic SN. The median time from ER to surgery was 73 days. No postoperative recurrence was observed in any patient over a median follow-up of 1,023 days.

CONCLUSIONS

Our findings suggest that the SN basin is not greatly affected by ER. The SN concept could be suitable for tumors following ER, but conventional gastrectomy with lymphadenectomy involving the SN basin should be used at present.

Sentinel node navigation surgery in patients with early gastric cancer

Clinical application of sentinel node (SN) mapping in patients with early gastric cancer has been a controversial issue for years. However, a recent meta-analysis and a prospective multicenter trial of SN mapping for early gastric cancer have shown acceptable SN detection rates and accuracy of determination of lymph node status. A dual-tracer method that utilizes radioactive colloids and blue dyes is currently considered the most reliable method for the stable detection of SNs in patients with early gastric cancer. However, new technologies such as indocyanine green infrared or fluorescence imaging might revolutionize the SN mapping procedures in gastric cancer. For early-stage gastric cancer such as cT1N0, for which a better prognosis can be potentially achieved through conventional surgical approaches, the establishment of individualized, minimally invasive treatments that may retain the patients' quality of life should be the next surgical challenge. Although there are many unresolved technical issues, laparoscopic SN biopsy with laparoscopic minimized gastrectomy or endoscopic mucosal resection/endoscopic submucosal dissection could be a promising strategy to achieve this goal.

Sentinel node and mechanism of lymphatic metastasis

The validity and clinical usefulness of the sentinel node (SN) concept for breast cancer has been confirmed, and individualized limited surgery based on diagnosis of SN metastasis is presently performed. In the future, SN navigation surgery (SNNS) will be actively applied to the treatment of early gastric cancer, and an intraoperative real-time reverse transcription-polymerase chain reaction (RT-PCR) assay to detect SN micrometastasis of gastric cancer is under development. Not only anatomical factors, but also many other factors such as local immunosuppression in the SN and lymphoangiogenesis may be involved in development of SN micrometastasis, and clarification of the mechanisms of metastasis and development of treatment methods are awaited. (*English Translation of J Jpn Col Angiol 2008; 48: 137-142.).

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.

Laparoscopy-assisted proximal gastrectomy with sentinel node mapping for early gastric cancer

BACKGROUND

Laparoscopy-assisted proximal gastrectomy (LAPG) remains a relatively uncommon procedure because of certain technical issues, such as curability, safety, and retention of postoperative patients' quality of life. The aim of the present study was to evaluate the feasibility of a newly developed LAPG procedure for early-stage proximal gastric cancer.

METHODS

We enrolled 37 consecutive patients who were preoperatively diagnosed with cT1N0M0 primary gastric cancer in the upper third of the stomach with the primary tumor diameter less than 4 cm. Laparoscopy-assisted proximal gastrectomy with sentinel node (SN) mapping and esophagogastric anastomosis with a circular stapler and transoral placement of the anvil was attempted.

RESULTS

The LAPG procedure was completed in 36 patients. It was converted to laparoscopy-assisted total gastrectomy in one patient because one SN detected intraoperatively was positive for metastasis by intraoperative pathological diagnosis. There were no severe postoperative complications in any patient. Only one patient (3%) complained of mild reflux symptoms immediately after operation, which were graded endoscopically as B by the Los Angeles Classification of gastroesophageal reflux disease; however, the symptoms were controlled well by a proton-pump inhibitor. Sentinel nodes were detected successfully in 37 (100%) of our patients. The mean number of dissected lymph nodes and identified SNs per case was 29.7 and 5.8, respectively. The sensitivity of prediction of nodal metastasis (including isolated tumor cells) and diagnostic accuracy based on SN status were 100% (3/3) and 100% (37/37), respectively. All patients have been free from recurrence for a median follow-up period of 26 months.

CONCLUSIONS

This study reveals that our novel LAPG approach is curative and represents a feasible minimally invasive surgical procedure with minimal morbidity and postoperative reflux esophagitis in patients with upper-third early-stage gastric cancer.

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.

Minimally invasive approaches for gastric cancer-Japanese experiences

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

Precise pathologic examination decreases the false-negative rate of sentinel lymph node biopsy in gastric cancer

BACKGROUND

Gastric cancer has been identified as a target for sentinel lymph node (SLN) navigational surgery. Although accurate evaluation of SLNs is essential for applying the SLN concept to gastric cancer surgery, there is no standardized pathologic examination protocol for SLNs in gastric cancer.

METHODS

A total of 231 SLNs from 69 patients with cT1-2, N0 gastric cancer were prospectively examined in this study. During the operation, SLNs were sliced at 2-mm intervals, and frozen sections were analyzed by hematoxylin and eosin (HE) staining in 35 patients or HE staining with rapid immunohistochemistry (IHC) for pancytokeratin (CK) in 34 patients. HE staining and CK IHC were performed postoperatively on each remaining SLN. Non-SLNs were evaluated with 2 levels of HE slides and 1 CK IHC.

RESULTS

Of 35 patients, metastasis was identified in 10 patients by intraoperative HE staining, and in 12 patients by postoperative HE staining and CK IHC. Two patients had isolated tumor cells (ITCs) detectable by postoperative CK IHC; these patients had non-SLN metastasis. We enrolled another 34 patients and examined 147 SLNs by frozen HE and rapid IHC. In this cohort, 26 patients with negative SLNs by intraoperative examination did not have non-SLN metastasis even after deeper sectioning and CK IHC of non-SLNs (sensitivity, 100%; false negative value, 0%).

CONCLUSIONS

Our study indicated that precise and detailed intraoperative examination decreases the false-negative rate of SLN biopsy. ITCs in SLNs should not be overlooked, and rapid IHC can be helpful for detecting ITCs intraoperatively.

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.

High FOXP3+ regulatory T-cell density in the sentinel lymph node is associated with downstream non-sentinel lymph-node metastasis in gastric cancer

Background:

We aimed to evaluate the immunologic nature of sentinel lymph nodes (SLNs) in gastric cancer patients and to determine whether it can predict non-SLN metastasis.

Methods:

Sentinel lymph node samples were collected from 64 gastric carcinoma patients who had undergone gastrectomy with SLN biopsy. One representative SLN sample was selected from each patient and was subjected to immunostaining for CD8, CD57, FOXP3, and DC-LAMP. The numbers of marker-positive cells in each sample were counted. The relationships between various immune cell densities and clinicopathologic parameters or metastasis status of SLNs and non-SLNs were sought.

Results:

High FOXP3+ Treg density of the SLN was found to be significantly associated with the presence of metastasis in either SLNs or non-SLNs. DC-LAMP+ cell density of the SLN was the highest at the isolated tumours cell level, and this decreased along with an increase in tumour metastasis in either SLNs or non-SLNs. Univariate and multivariate logistic regression models revealed that high FOXP3+ Treg density of the SLN was an independently significant predictor of non-SLN metastasis.

Conclusions:

This study is the first to indicate an important role of SLNs in metastatic dissemination of gastric cancer. Our findings suggest that Tregs could be a new therapeutic target for regulating the metastasis of gastric cancer.

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.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Localized resection for colon cancer

Localized resection of early stage colon cancer is increasingly technically feasible by truly minimally invasive means. Such techniques as endoscopic submucosal dissection (ESD) and Natural Orifice Transluminal Endoscopic Surgery (N.O.T.E.S.) now raise the prospect of focused intraluminal and transmural resection of small primary tumors without abdominal wall transgression. The potential clinical benefit that patients may accrue from targeted dissection as definitive treatment in place of radical operation is not yet definitively proven but may be considerable at least in the short-term. However, oncological propriety and outcomes must be maintained. In particular methods by which regional nodal staging can be assured if standard operation is avoided need still to be established. Sentinel node mapping is one such putative means of doing so that deserves serious consideration from this perspective as it performs a similar function for breast cancer and melanoma and because there is already considerable evidence to suggest the technique in colonic neoplasia may be at its most accurate in germinal disease. In addition, it may already be employed by laparoscopy while solely transluminal means of its deployment are advancing. While the confluence of operative technologies and techniques now coming on-stream has the potential to precipitate a dramatic shift in the paradigm for the management of early stage colonic neoplasia, considerable confirmatory study is required to ensure that oncology propriety and treatment efficacy is maintained so that patient benefit may be maximized.

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.

Sentinel node biopsy for the individualization of surgical strategy for cure of early-stage colon cancer

INTRODUCTION

The requirement for nodal analysis currently confounds the oncological propriety of focused purely endoscopic resection for early-stage colon cancer and complicates the evolution of innovative alternatives such as natural orifice transluminal endoscopic surgery (NOTES) and its hybrids. Adjunctive sentinel node biopsy (SNB) deserves consideration as a means of addressing this shortfall.

METHODS

Data from two prospectively maintained databases established for multicentric studies of SNB in colon cancer that employed similar methodologies were pooled to establish technique potency selectively in T1/T2 disease (both overall and under optimized conditions) and to project potential clinical impact.

RESULTS

Of 891 patients with T1-4, M0 intraperitoneal colon cancer, 225 had T1/T2 disease. Sentinel nodes were either not found or were falsely negative in 18 patients with T1/T2 cancers (8%) as compared with 17% (112/646) in those with T3/T4 disease (P = 0.001). Negative predictive value (NPV) in the former exceeded 95%, while sensitivity [including immunohistochemistry (IHC)] was 81%. In the 193 patients with T1/T2 disease recruited from those centers contributing >22 patients, sensitivity was 89% and NPV 97%. Thus, in this cohort, SNB could have correctly prompted localized resection (obviating en bloc mesenteric dissection) in 75% (144) of patients, including 59 with T1 lesions potentially amenable to intraluminal resection alone as their definitive treatment. Forty-four patients (23.4%) would still have conventional resection, leaving three patients (1.6% overall) understaged (11% false-negative rate).

CONCLUSION

These findings support the further investigation of SNB as oncological augment for localized resective techniques. Specific prospective study should pursue this goal.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

OBJECTIVE

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

DESIGN

Acute porcine model.

INTERVENTION

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

RESULTS

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

LIMITATIONS

Experimental model with limited sample size.

CONCLUSIONS

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

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 guided by indocyanine green fluorescence imaging in gastric cancer

OBJECTIVE

In this study, we determined the possible usefulness of sentinel node (SN) mapping guided by indocyanine green (ICG) fluorescence imaging in the management of gastric cancer.

SUMMARY BACKGROUND DATA

ICG fluorescence imaging system has recently been developed for obtaining biochemical information from living tissues.

METHODS

Our series consisted of 56 patients with gastric cancer who underwent standard gastrectomy with lymphadenectomy. Two milliliters of ICG solution (0.5%) was injected into the submucosa around the tumor endoscopically before the operation or into the subserosa intraoperatively. ICG fluorescence imaging was conducted using a charge-coupled device camera with a light-emitting diode having a wavelength of 760 nm as the light source and a cut filter to filter out light with wavelengths below 820 nm as the detector.

RESULTS

SNs were detected in 54 (96.4%) of the 56 patients, and the mean number of SNs was 7.2 +/- 7.0. Even SNs that were not green in color could be easily and clearly visualized by ICG fluorescence imaging. cT1-stage cancers were associated with a significantly higher accuracy rate (97.2% vs. 72.2%, P = 0.0127) than cT2-or cT3-stage cancers. Preoperative ICG injection was associated with a significantly higher incidence of cT1-stage cancers (87.1% vs. 40.0%, P = 0.0004), a larger mean number of SNs (9.9 +/- 7.5 vs. 4.1 +/- 5.0, P < 0.0001), a higher accuracy rate (100% vs. 73.9%, P = 0.0039), and a lower false negative rate (0% vs. 60.0%, P = 0.0345) as compared with intraoperative ICG injection.

CONCLUSIONS

This study shows that ICG fluorescence imaging allows highly sensitive image-guided intraoperative SN mapping in cases of gastric cancer. Our data suggest that SN mapping guided by ICG fluorescence imaging might be useful for predicting the metastatic status in lymph nodes in cases of gastric cancer, especially those with cT1-stage cancer.

Ancillary N.O.T.E.S. procedures for early stage gastric cancer

The potential for performing truly scarless, safe surgery that at the same time may be less morbid is tempting both patients and physicians alike to seriously consider Natural Orifice Transluminal Endoscopy Surgery (NOTES) for a range of clinical applications. Given the move towards gastric-preservation by minimally invasive techniques for definitive management of early gastric cancer, this radical approach may find a niche within future clinical care paradigms for early stage malignant lesions of the stomach. Indeed already selected T1,N0 adenocarcinoma is being treated and even cured by advanced endoscopic techniques such as Endoscopic Submucosal Dissection. NOTES may initially therefore find a role in furthering the application of such endeavour by ensuring oncological providence in the treatment of those T1 lesions with higher risk of lymphatic metastases that currently are advised to lie outwith the scope of pure endoscopic resection (for reasons of oncological propriety rather than technical capacity). One such means NOTES could supplement ESD is by providing for direct sampling of sentinel nodes from the perigastric lymph basins. Subsequently perhaps a NOTES technique may develop capable of performing localized, full-thickness gastric wedge or sleeve resection for T2,N0 adenocarcinoma (and indeed perhaps other pathologies such as small gastrointestinal stromal tumors). This review examines how advancing technology along with progressive surgical thinking and innovation could lead to NOTES becoming absorbed into clinical care pathways for early gastric malignancy.

[Not Available]

M. Pocard, J.-C. Sabourin In theory, the concept of sentinel lymph node (SLN) biopsy can be applied to cancer surgery for all solid cancers. Yet sentinel lymph node biopsy has not become a standard part of gastrointestinal cancer surgery. It has been of value in the assessment of small early-stage gastric cancers, but has only achieved widespread practice in Japan. Studies of SLN biopsy in colon cancer have not shown it to be a reliable predictor of N+ status and therefore don't permit the omission of lymph node dissection in selected cases. On the other hand, as a form of intra-operative lymph node mapping, dye injection of the SLN may demonstrate aberrant lymphatic drainage and could occasionally permit the sparing of a middle colic artery whose sacrifice would otherwise be dictated by standard drainage patterns. SLN biopsy may have prognostic usefulness by demonstrating micrometastases; careful serial sectioning focussed on the SLN may detect nests of metastatic cells on HE staining, thereby converting a tumor from Stage I (TxN0M0) to Stage II (TxN1M0). This finding has been noted in 10-15% of cases. However, the prognostic value of micrometastases detected only by immunohistochemical staining or PCR has not been demonstrated. For cancers of the anal canal, SLN biopsy of inguinal nodes has been tested as a means of establishing the indications for inguinal lymph node dissection.