Detection of micrometastases in sentinel node navigation surgery for gastric cancer

The histopathological evaluation based on the indocyanine green fluorescence imaging of regional lymph node metastasis of splenic flexural colon cancer by near-infrared observation

PURPOSE

The purpose of this study was to investigate the relationship between the fluorescence on indocyanine green fluorescent imaging (ICG-FI) and the histopathological findings of regional lymph node (LN) metastasis of splenic flexural colon cancer.

METHODS

From July 2013 to December 2018, consecutive patients with splenic flexural colon cancer with a preoperative diagnosis of N0 who underwent laparoscopic surgery were enrolled. The distribution of cancer sites in metastatic LNs (completely/not completely occupied by metastatic foci) was evaluated with hematoxylin and eosin-stained preparations. We compared the relationship between the distribution of cancer site and fluorescence of paraffin block in metastatic LNs.

RESULTS

Seventy-two patients were enrolled, of whom 13 (18.1%) had metastatic LNs. A total of 25 metastatic LNs were evaluated. The median short axis of the occupied LNs was 4.5 mm, which was significantly larger than that of the non-occupied LNs (3.0 mm; p = 0.036). In the near-infrared observation of the paraffin block, the completely occupied LNs showed no fluorescence, regardless of the LN size, but 8 of 10 non-occupied LNs showed fluorescence (p < 0.001). Even the non-occupied LNs that showed fluorescence, the cancer site did not show fluorescence.

CONCLUSIONS

The occupied LNs showed no fluorescence, but 80% of the non-occupied LNs showed fluorescence. Even in non-occupied LNs that showed fluorescence, the cancer site did not show fluorescence. This demonstrated LN dissection should not be omitted, even if no fluorescence is noted on intraoperative ICG-FI.

Occult Tumour Cells in Lymph Nodes from Gastric Cancer Patients: Should Isolated Tumour Cells Also Be Considered?

INTRODUCTION

Regional lymph node metastasis is an important prognostic factor for patients with gastric cancer. Occult tumour cells (OTCs), including either micrometastases (MMs) or isolated tumour cells (ITCs), may be a key factor in the development of cancer recurrence in pN0 patients.

AIMS

We aimed to determine the frequency and prognostic significance for disease recurrence of OTCs.

MATERIALS AND METHODS

This retrospective cohort study included all consecutive patients with pN0 gastric adenocarcinoma between January 2000 and December 2011 (n = 73). Immunohistochemistry using the pan-cytokeratin antibody AE1/AE3 was used to detect OTCs in 1257 isolated lymph nodes.

RESULTS

OTCs were identified in 30 patients (41%), including 20 cases with MMs (27%) and 10 cases with ITCs (14%). Disease recurrence and cancer-related death were observed in 24 (33%) and 20 patients (27%), respectively, and both were significantly associated with the detection of OTCs. A significant difference was also observed for the mean survival time between patients with OTCs and those without OTCs [100 vs 158 months (p = 0.015)]. The presence of OTCs was statistically significantly associated with the Lauren classification, tumour size and lymphatic permeation. Multivariate analyses revealed that only age, T stage and the presence of ITCs in lymph nodes were independent factors for recurrence. The presence of ITCs increased the risk for recurrence by 11.1-fold.

CONCLUSIONS

In a significant proportion of patients diagnosed as stage pN0, OTCs may be identified in lymph nodes if carefully searched for, which can negatively affect their prognosis. The presence of ITCs was found to be an independent factor for recurrence and after proper validation should be considered during lymph node assessment for prognosis definition.

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

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

Risk factors for lymph node metastasis in non-sentinel node basins in early gastric cancer: sentinel node concept

BACKGROUND

Sentinel node (SN) concept is being applied to early gastric cancer. However, when SNs are positive for metastasis, it is unclear how often LNs in other LN basins show metastasis. We aimed to investigate LN metastasis possibility in LN basins without SNs (non-SN basins). We determined risk factors for metastasis in non-SN basins and identified a prediction model for non-SN basin metastasis using classification and regression tree (CART) analysis.

METHODS

We enrolled 550 patients who were diagnosed with cT1N0M0 or cT2N0M0 gastric cancer with a single lesion and underwent SN mapping. We adopted a dual-tracer method using a radioactive colloid and blue dye to detect SNs.

RESULTS

Of all, 45 (8.2%) patients had SN metastasis; we divided them into two groups: LN metastasis positive and LN metastasis negative in non-SN basins. Univariate analysis showed that the groups differed significantly regarding lymphatic invasion (p = 0.007), number of identified SNs (p = 0.032), and macrometastasis in SN basins (p = 0.005). The CART decision tree for predicting LN metastasis in non-SN basins had area under the curve value of 0.86. Moreover, there were significantly differences in cancer-specific survival (CSS) between the two groups (p = 0.028).

CONCLUSIONS

Macrometastasis in SN basins, lymphatic invasion, and number of identified SNs ≥ 5 are risk factors for LN metastasis in non-SN basins among gastric cancer patients. We identified a prediction model with CART analysis; patients with macrometastasis in SN basins and lymphatic invasion were considered to be at the highest risk for LN metastasis.

Quantitative assessment of fluorescence intensity of ICG in sentinel nodes in early gastric cancer

BACKGROUND

The sentinel node (SN) detection by dual tracer method using indocyanine green (ICG) and a radioisotope (RI) has been recommended for early gastric cancer. However, institutions are limited due to radioactivity in the RI method. The greatest advantage of the RI method is that it objectively assesses RI uptake as a numerical value. The aim of the present study was to verify the usefulness of ICG fluorescence intensity in SN.

METHODS

Seventeen patients with early gastric cancer were enrolled in this study. RI uptake by each lymph node was measured using Navigator GPS and fluorescence nodes were identified using the hyper eye medical system (HEMS). Fluorescence intensity in fluorescence nodes was evaluated using ICG intensity imaging software (Mizuho, Japan) of the HEMS.

RESULTS

The total number of dissected lymph nodes was 227, with an average of 13.3 per patient. The numbers of HN, FN-S, and FN-B were 64, 77, and 34. RI uptake was significantly greater by FN-S than by non-FN-S (P = 0.0016). The median fluorescence intensity value was higher in HN than in non-HN (P < 0.001). A correlation was observed between RI uptake and fluorescence intensity. Dissecting FNs with fluorescence intensity levels of 1-6 resulted in 92.1% dissection of HNs.

CONCLUSION

It is possible that the evaluation of fluorescence intensity is useful for selected SNs instead of RI tracer. If fluorescence intensity is measurable in surgery, an infrared fluorescence method using ICG may be useful and safe for the detection of SN in early gastric cancer.

The Detection of Messenger RNA for Carcinoembryonic Antigen and Cytokeratin 20 in Peritoneal Washing Fluid in Patients with Advanced Gastric Cancer

Background/Aims

Peritoneal micrometastasis is known to play an important role in the recurrence of gastric cancer. However, its effects remain equivocal. Herein, we examine the messenger RNA (mRNA) as tumor markers, carcinoembryonic antigen (CEA), and cytokeratin 20 (CK20), in peritoneal washing fluid. Moreover, we evaluate whether these results could predict the recurrence of gastric cancer following curative resection.

Methods

We prospectively enrolled 132 patients with gastric cancers, who had received an operation, between January 2010 and January 2013. The peritoneal lavage fluid was collected at the operation field and semi-quantitative PCR was performed using the primers for CEA and CK20. We excluded patients with stage IA (n=28) early gastric cancer, positive cytologic examination of peritoneal washings (n=7), and those who were lost during follow up (n=18).

Results

A total of 79 patients with gastric cancers were enrolled, and the mean follow-up period was 39.95±19.25 months (range, 5-72 months). According to the multivariate analysis, T4 stage at the initial diagnosis was significantly associated with recurrence. All cases of recurrence were CEA positive and 6 cases were CK20 positive. The positive and negative predictive values of CEA were 32.0% and 100%, respectively, whereas those of CK20 were 37.5% and 71.4%, respectively. Disease free survival of CK20-negative cases was 36.17±20.28 months and that of CK20-positive cases was 32.06±22.95 months (p=0.39).

Conclusions

It is unlikely that the real time polymerase chain reaction results of mRNA for CEA and CK20 in peritoneal washing fluid can predict recurrence. However, negative results can convince surgeons to perform curative R0 resection.

Sentinel node navigation in gastric cancer: new horizons for personalized minimally invasive surgical oncology?

Complete (R0) resection and regional lymph nodes (LNs) dissection represent undoubtedly the basic surgical tools for patients with gastric cancer. It is reported that the LN metastasis rate in patients with early gastric cancer (EGC) is approximately 15-20%. Therefore, the innovative clinical application of sentinel node navigation surgery (SNNS) for EGC might be able to prevent unnecessary LN dissection as well as to reduce significantly the volume of gastric resection. Recent evidence suggests that double tracer methods appear superior compared to single tracer techniques. However, the researchers' interest is now focused on the identification of new LN detection methods utilizing sophisticated technology such as infrared ray endoscopy, fluorescence imaging and near-infrared technology. Despite its notable limitations, hematoxylin-eosin is still considered the mainstay staining for assessing the metastatic status of LNs. In this review, we summarize the current evidences and we provide the latest scientific information assessing safety, efficacy and potential limitations of the innovative sentinel node (SN) navigation technique for gastric cancer. We try also to provide a "view" towards a future potential application of personalized minimally invasive surgery in gastric cancer field.

Auxiliary diagnosis of lymph node metastasis in early gastric cancer using quantitative evaluation of sentinel node radioactivity

BACKGROUND

Sentinel node (SN) mapping using dye and radioisotope (RI) tracer has been reported to be feasible in cases of early gastric cancer. Because accurate diagnosis of micrometastasis is sometimes difficult in the limited time available during surgery, a faster and simpler method of improving the intraoperative diagnostic precision of lymph node metastasis is needed. The amount of tracer deposited in an SN can be determined from its radioactivity; however, the significance of the RI count has not been fully discussed. We investigated the clinical impact of the RI count when used as an adjunct to conventional lymph node dissection when diagnosing lymphatic metastasis in cases of early gastric cancer.

METHODS

From 2008 to 2009, patients with clinically diagnosed T1N0M0 gastric cancers who underwent gastrectomy and SN mapping were enrolled. SNs were examined by intraoperative and postoperative pathology. The RI count was measured for each SN with a handheld gamma probe; the correlation between nodal metastasis and the RI count was assessed.

RESULTS

A total of 308 SNs were harvested from 72 patients. Patients with SN metastasis had significantly higher total RI counts than those without SN metastasis (p = 0.007). Among cases with SN metastasis, RI counts were also significantly elevated in metastasis-positive nodes, stations, and basins. In these cases, the most of SNs having the highest RI count in each case had metastasis including isolated tumor cells.

CONCLUSION

In early gastric cancer patients, a high RI count from an SN was correlated with lymph node metastasis. Therefore, RI counting may aid efficient pathological diagnosis and focused lymph node dissection.

CA19-9 serum levels predict micrometastases in patients with gastric cancer

Background

We explored the prognostic value of the up-regulated carbohydrate antigen (CA19-9) in node-negative patients with gastric cancer as a surrogate marker for micrometastases.

Patients and methods

Micrometastases were determined using reverse transcription quantitative polymerase chain reaction (RT-qPCR) for a subgroup of 30 node-negative patients. This group was used to determine the cut-off for preoperative CA19-9 serum levels as a surrogate marker for micrometastases. Then 187 node-negative T1 to T4 patients were selected to validate the predictive value of this CA19-9 threshold.

Results

Patients with micrometastases had significantly higher preoperative CA19-9 serum levels compared to patients without micrometastases (p = 0.046). CA19-9 serum levels were significantly correlated with tumour site, tumour diameter, and perineural invasion. Although not reaching significance, subgroup analysis showed better five-year survival rates for patients with CA19-9 serum levels below the threshold, compared to patients with CA19-9 serum levels above the cut-off. The cumulative survival for T2 to T4 node-negative patients was significantly better with CA19-9 serum levels below the cut-off (p = 0.04).

Conclusions

Preoperative CA19-9 serum levels can be used to predict higher risk for haematogenous spread and micrometastases in node-negative patients. However, CA19-9 serum levels lack the necessary sensitivity and specificity to reliably predict micrometastases.

Sentinel lymph node navigation surgery for gastric cancer: Does it really benefit the patient?

Sentinel lymph node (SLN) navigation surgery is accepted as a standard treatment procedure for malignant melanoma and breast cancer. However, the benefit of reduced lymphadenectomy based on SLN examination remains unclear in cases of gastric cancer. Here, we review previous studies to determine whether SLN navigation surgery is beneficial for gastric cancer patients. Recently, a large-scale prospective study from the Japanese Society of Sentinel Node Navigation Surgery reported that the endoscopic dual tracer method, using a dye and radioisotope for SLN biopsy, was safe and effective when applied to cases of superficial and relatively small gastric cancers. SLN mapping with SLN basin dissection was preferred for early gastric cancer since it is minimally invasive. However, previous studies reported that limited gastrectomy and lymphadenectomy may not improve the patient’s postoperative quality of life (QOL). As a result, the benefit of SLN navigation surgery for gastric cancer patients, in terms of their QOL, is limited. Thus, endoscopic and laparoscopic limited gastrectomy combined with SLN navigation surgery has the potential to become the standard minimally invasive surgery in early gastric cancer.

Occult Tumor Cells in Lymph Nodes of Patients with Gastric Cancer: A Systematic Review on Their Prevalence and Predictive Role

BACKGROUND AND AIMS

The presence of lymph node (LN) metastasis is a key prognostic factor for gastric adenocarcinoma. However, even among patients without LN metastasis (N0), recurrence may occur. In some of these cases, occult tumor cells (OTC) are thought to play an important role. We aimed to determine the prevalence of OTC and its clinical relevance.

METHODS

We conducted a systematic review of studies in English published until September 2013 that addressed OTC prevalence and/or its clinical relevance. The studies were retrieved from the MEDLINE database.

RESULTS

We included 42 studies. The most frequently used methods for detecting OTC were immunohistochemical examination (IHC) and/or polymerase chain reaction (PCR) with a wide range of markers. Using IHC for OTC detection, in patients and in LN, the prevalence varied from 9 to 88% and 0.4 to 42%, respectively. With PCR, it ranged from 17 to 46% in patients, and from 3 to 33% in LN. In the studies assessing the predictive role of OTC in gastric cancer recurrence (n=24), 8 studies found no statistical association, while 18 concluded that OTC presence was associated with poorer prognosis. However, only 6 studies presented a significantly different 5-year survival rate between patients with and without LN micrometastasis.

CONCLUSIONS

OTC seems to occur in gastric cancer patients with a variable prevalence, depending on the definition, methods and setting. The majority of the retrieved studies (75%) evaluating the predictive role of OTC conclude that its presence is associated with a worse prognosis.

A new stage of sentinel node navigation surgery in early gastric cancer

Sentinel node (SN) navigation surgery is expected to realize organ- and function-preserving surgery with SN mapping, and has been applied in operations for breast cancer and melanoma. But there has been no definite evidence for the SN concept in gastric cancer. A prospective multicenter trial to confirm the SN concept for gastric cancer conducted by the Japan Society of Sentinel Node Navigation Surgery reported that the SN detection rate, sensitivity of positive SNs, and accuracy of nodal status are 97.5% (387/397), 93% (53/57), and 99% (383/387), respectively. A detailed analysis of the trial suggested that strictly the "lymphatic basin concept" rather than the "SN concept" was confirmed in early gastric cancer. The Japan Society of Sentinel Node Navigation Surgery started a new trial of function-preserving gastrectomy with lymphatic basin dissection (LBD) for early gastric cancer without metastasis in SNs on the basis of this promising outcome of the trial. It is supposed that LBD guarantees curability in SN navigation surgery for early gastric cancer. Full-thickness resection or endoscopic submucosal dissection in combination with laparoscopic LBD will soon be a new treatment option for early gastric cancer.

Visualization of Lymph/Blood Flow in Laparoscopic Colorectal Cancer Surgery by ICG Fluorescence Imaging (Lap-IGFI)

PURPOSE

In laparoscopic colorectal cancer (Lap-CRC) surgery, determination of a suitable mesentery division line and the appropriate degree of lymphadenectomy by tracing the blood supply is critical. We performed visualization of the lymph and blood flow by laparoscopic indocyanine green (ICG) fluorescence imaging (Lap-IGFI).

METHODS

ICG is injected into the submucosa near the tumor via colonoscopy, and the lymph flow is observed. Intestinal blood flow is evaluated by administering ICG intravenously.

RESULTS

For lymph flow, visualization of the main lymph node basin helped to determine the surgical division line for cases in which the blood flow was not completely visualized. Lap-IGFI changed the surgical plan of the lymphadenectomy in 23.5 %. In our experience, the metastatic rate of ICG-positive nodes was 10.0 %, and the metastatic rate of ICG-negative nodes was 5.3 %. Furthermore, there were no metastatic nodes that were ICG negative more than 5 cm from the tumor. For blood flow, the blood flow distribution of the intestinal wall from the last branch of the vasa recta of the anastomotic site was clearly visualized and proved useful in choosing the extent of intestinal resection. Lap-IGFI changed the surgical plan of the extensive intestinal resection in 16.7 %.

CONCLUSIONS

Lap-IGFI can noninvasively provide detailed lymph and blood flow information and is a useful device to aid in the accurate identification of individual patients' lymph drainage. This helps dictate adequate lymphadenectomy and the extent of intestinal resection in Lap-CRC surgery.

Assessment of sentinel node concept in esophageal cancer based on lymph node micrometastasis

PURPOSE

The clinical significance of lymph node micrometastasis remains unclear in patients with esophageal cancer. Therefore, accurate assessment of lymph node status including micrometastasis is important when performing sentinel node (SN) navigation surgery. The purpose of the present study was to investigate the adequacy of SN concept based on lymph node micrometastasis determined by immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR) in patients with esophageal cancer.

METHODS

A total of 57 patients with esophageal cancer who were preoperatively diagnosed as having T1-T2 (cT1-T2) and N0 (cN0) were enrolled. They underwent standard esophagectomy with lymph node dissection. One day before surgery, a total of 3 mCi of 99mTechnetium-tin colloid was endoscopically injected into the submucosa around the tumor. During the operation, radioisotope uptake in the lymph nodes was measured using Navigator GPS. All dissected lymph nodes were investigated by RT-PCR using the double marker of CEA and SCC, hematoxylin-eosin (HE) staining, and IHC.

RESULTS

Node-positive incidence identified by HE and IHC was 12.3% (7/57) and 19.3% (11/57), respectively. RT-PCR demonstrated micrometastasis in four of 46 patients without nodal metastasis determined by HE staining and IHC. No non-SN metastases were found in 42 patients without micrometastasis identified by IHC and RT-PCR of SN. Accuracy and false negative rates were 100% (57/57) and 0% (0/42), respectively.

CONCLUSIONS

SN concept might be acceptable in patients with cT1-T2 and cN0 esophageal cancer, even in the presence of micrometastasis identified by IHC and RT-PCR.

Evaluation of focused sentinel lymph node RT-qPCR screening for micrometastases with the use of the Maruyama computer program

Background

In this preliminary study, we investigated the sensitivity and specificity of reverse transcriptase (RT)-qPCR lymph node (LN) metastases detection, the accuracy of intraoperative dye navigation, and the incidence of micrometastasis (MM) detection with this protocol, compared to other published studies.

Methods

A total of 23 patients were enrolled in the study. The first stained LN was analyzed using RT-qPCR for carcinoembryonic antigen (CEA) and cytokeratin 20 (CK-20) expression, as markers for MM involvement. The Maruyama computer program was used to determine the most likely first metastatic site. These results were compared with the actual staining patterns to evaluate whether the first draining LN was extracted. We analyzed the correlations between MM and tumor characteristics. The incidence of MM detected with the present method was compared to other studies, as markers of the accuracy of the present protocol.

Results

At 35 threshold cycles, the RT-qPCR had a negative predictive value of 100 % and a positive predictive value of 83.3 %. MM were detected in 4 out of 14 node-negative patients (28.6 %). The extracted sentinel LN coincided in 76.9 % of cases with the most probable first metastatic LN predicted by the Maruyama program. MM were found more frequently in these ‘high-risk’ LNs. Significant differences were found in the Lauren’s histological type distribution and the age distribution among the MM-positive and MM-negative groups.

Conclusion

Our preliminary results confirm that RT-qPCR is an accurate method of MM detection, that the dye navigation enables the determination of the first draining LN, and that the incidence of MM detection with this focused sentinel LN protocol is comparable to other studies.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

The efficiency of micrometastasis by sentinel node navigation surgery using indocyanine green and infrared ray laparoscopy system for gastric cancer

BACKGROUND

The clinical application of sentinel node navigation surgery (SNNS) for patients with gastric cancer requires accurate intraoperative diagnosis of lymph node metastasis. However, the clinical significance of the diagnosis of lymph node micrometastasis for gastric cancer has not been established. In this study, we evaluated lymph nodes dissected during SNNS by immunohistochemistry with anti-cytokeratin antibody (IHC) staining for gastric cancer to investigate the usefulness of SNNS.

PATIENTS AND METHODS

The subjects were 130 patients with gastric cancer (3,381 lymph nodes) who underwent SNNS with infrared ray observation and lymph node dissection of D1+α or more. The dissected lymph nodes were stained with IHC (CAM 5.2), and the results were compared with intra- and postoperative diagnoses by hematoxylin and eosin (H&E) staining. In addition, the association of metastatic lymph nodes and ICG-positive lymph nodes was examined.

RESULTS

The number of patients (lymph nodes) with lymph node metastasis by HE and IHC staining was 16 (52 nodes) and 31 (91 nodes), respectively. Fifteen patients (27 nodes) diagnosed with pN0 by HE staining were diagnosed to be metastatic by IHC staining. The tumor depth of these patients was pT1 in ten patients (m, 3; sm, 7) and pT2 in five (mp, 4; ss, 1). Regarding the histological type, three patients were classified as well-differentiated type, while six patients each had moderately and poorly differentiated types. The grade of lymphatic invasion was ly0 in 5, ly1 in 6, and ly2 in 4, respectively. Histological assessment of 27 IHC-positive and HE-negative cells indicated 5 single cells, 16 clusters, and 6 micrometastases. These lymph nodes were all included in the sentinel nodes (SN) identified during surgery. All but one patient (0.8%) were recurrence-free at 2-8 years after surgery (median 74.7 months). The one patient developed anastomotic recurrence 4.5 years after the first operation and died.

CONCLUSION

Since all 27 lymph nodes in 15 patients with metastasis by IHC staining but not by HE staining were micrometastasis or less and included in the SN, ICG-positive lymphatic basin dissection by SNNS with infrared ray observation seems to be an adequate method of lymph node dissection for gastric cancer.

CHFR: a key checkpoint component implicated in a wide range of cancers

CHFR (Checkpoint with Forkhead-associated and RING finger domains) has been implicated in a checkpoint regulating entry into mitosis. However, the details underlying its roles and regulation are unclear due to conflicting lines of evidence supporting different notions of its functions. We provide here an overview of how CHFR is thought to contribute towards regulating mitotic entry and present possible explanations for contradictory observations published on the functions and regulation of CHFR. Furthermore, we survey key data showing correlations between promoter hypermethylation or down-regulation of CHFR and cancers, with a view on the likely reasons why different extents of correlations have been reported. Lastly, we explore the possibilities of exploiting CHFR promoter hypermethylation status in diagnostics and therapeutics for cancer patients. With keen interest currently focused on the association between hypermethylation of CHFR and cancers, details of how CHFR functions require further study to reveal how its absence might possibly contribute to tumorigenesis.

Lymph node, peritoneal and bone marrow micrometastases in gastric cancer: Their clinical significance

The 7th TNM classification clearly states that micrometastases detected by morphological techniques (HE stain and immunohistochemistry) should always be reported and calculated in the staging of the disease (pN1mi or M1), while patients in whom micrometastases are detected by non-morphological techniques (e.g., flow cytometry, reverse-transcriptase polymerase chain reaction) should still be classified as N0 or M0. In gastric cancer patients, micrometastases have been detected in lymph nodes, the peritoneal cavity and bone marrow. However, the clinical implications and/or their prognostic significance are still a matter of debate. Current literature suggests that lymph node micrometastases should be encountered for the loco-regional staging of the disease, while skip lymph node micrometastases should also be encountered in the total number of infiltrated lymph nodes. Peritoneal fluid cytology examination should be obligatorily performed in pT3 or pT4 tumors. A positive cytology classifies gastric cancer patients as stage IV. Although a curative resection is not precluded, these patients face an overall dismal prognosis. Whether patients with a positive cytology should be treated similarly to patients with macroscopic peritoneal recurrence should be evaluated further. Gastric cancer cells are detected with high incidence in the bone marrow. However, the published results make comparison of data between groups almost impossible due to severe methodological problems. If these methodological problems are overcome in the future, specific target therapies may be designed for specific groups of patients.

Molecular detection of sentinel node micrometastases in patients with clinical N0 gastric carcinoma with real-time multiplex reverse transcription-polymerase chain reaction assay

PURPOSE

Described is a novel real-time multiplex reverse transcription-polymerase chain reaction (RT-PCR) assay suitable for intraoperative detection of micrometastasis (MM) in sentinel nodes (SNs) dissected from patients with clinical N0 (cN0) gastric carcinoma.

METHODS

One hundred three patients with gastric cancer, who were preoperatively diagnosed with cN0 and clinical T1 or T2, were enrolled. The patients underwent SN mapping followed by standard radical gastrectomy with lymph node dissection. In addition to all SNs, non-SNs (NSNs) within the SN lymphatic basin and NSN from a different lymphatic basin were randomly sampled. All SNs and NSNs were examined by routine histologic diagnosis and RT-PCR for the expression of cytokeratin (CK) 19, CK20, and carcinoembryonic antigen (CEA).

RESULTS

The RT-PCR assay and histologic examination were performed in 512 SNs and 299 NSNs from 103 patients. Pathologic l lymph node metastasis was revealed in 13 (12.6%) of 103 patients. All metastatic lymph nodes were identified within SNs. SNs of these 13 patients had positive findings on RT-PCR. Twenty-eight (27.2%) of 103 patients had negative histopathology but positive findings on RT-PCR. In 7 patients (6.8%), SNs were negative but NSNs were positive on RT-PCR. RT-PCR-positive NSNs were present in the same station as corresponding SNs in 3 of these 7 patients and in the same basin as SNs in 4 patients.

CONCLUSIONS

The real-time multiplex RT-PCR assay is a useful tool for the detection of MM in SNs and NSNs in patients with gastric cancer.

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.

The extent of lymph node dissection for gastric cancer: a critical appraisal

The extent of lymphadenectomy during therapeutic gastrectomy for gastric cancer remains a protracted and controversial issue. While traditionally extended lymphadenectomy is performed in Eastern Asia, limited lymphadenectomy is advocated by most western surgeons. Two large western randomized trials, meta-analyses and a recent systematic review were unable to demonstrate overall benefit from extended lymphadenectomy. In this review, the currently available data on this topic are critically evaluated, while ongoing studies and future perspective are discussed.

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.

Routine modified D2 lymphadenectomy performance in pT1-T2N0 gastric cancer

AIM: To evaluate routine modified D2 lymphadenectomy in gastric cancer, based on immunohistochemically detected skip micrometastases in level II lymph nodes.

METHODS: Among 95 gastric cancer patients who were routinely submitted to curative modified D2 lymphadenectomy, from January 2004 to December 2008, 32 were classified as pN0. All level I lymph nodes of these 32 patients were submitted to immunohistochemistry for micrometastases detection. Patients in whom micrometastases were detected in the level I lymph node stations (n = 4) were excluded from further analysis. The level II lymph nodes of the remaining 28 patients were studied immunohistochemically for micrometastases detection and constitute the material of the present study.

RESULTS: Skip micrometastases in the level II lymph nodes were detected in 14% (4 out of 28) of the patients. The incidence was further increased to 17% (4 out of 24) in the subgroup of T1-2 gastric cancer patients. All micrometastases were detected in the No. 7 lymph node station. Thus, the disease was upstaged from stage IA to IB in one patient and from stage IB to II in three patients.

CONCLUSION: In gastric cancer, true R0 resection may not be achieved without modified D2 lymphadenectomy. Until D2+/D3 lymphadenectomy becomes standard, modified D2 lymphadenectomy should be performed routinely.

Influencing factors and clinical significance of the metastatic lymph nodes ratio in gastric adenocarcinoma

Background

To investigate influencing factors of the metastatic lymph nodes ratio (MLR) and whether it is related to survival in patients with gastric adenocarcinoma.

Methods

We retrospectively evaluated the clinical features of 121 patients with gastric adenocarcinoma enrolled in our hospital between 2000 and 2007. The receiver operating characteristic (ROC) curve was used to determine the cutoff of the MLR, and CK20 immunohistochemical staining was used to detect micrometastasis of the lymph nodes.

Results

The areas under the ROC curve of MLR used to predict the death of 3-year and 5-year postoperative patients were 0.826 ± 0.053 and 0.896 ± 0.046. Thus MLR = 30.95% and MLR = 3.15% were designated as cutoffs. The MLR was then classified into three groups: MLR₁ (MLR<3.15%); MLR₂(3.15% ≤ MLR ≤ 30.95%); and MLR₃ (MLR>30.95%). We found that patients with a higher MLR demonstrated a much poorer survival period after radical operation than those patients with a lower MLR (P = 0.000). The COX model showed that MLR was an independent prognostic factor (P = 0.000). The MLR could also discriminate between subsets of patients with different 5-year survival periods within the same N stage (P < 0.05). The MLR has been shown to be 34.7% (242/697) by HE staining and 43.5% (303/697) by CK staining (P = 0.001). The clinicopathological characteristics of lymph vessel invasion and the depth of invasion could significantly affect the MLR.

Conclusion

MLR is an independent prognostic factor in gastric cancer. The combined ROC curve with MLR is an effective strategy to produce a curve to predict the 3-year and 5-year survival rates.