Analysis of sentinel node involvement in gastric cancer

The Results of Sentinel Node Mapping for Patients with Clinically Early Staged Gastric Cancer Diagnosed with pT2/deeper Tumors

BACKGROUND

Sentinel node (SN) mapping based on the SN concept has been applied to early gastric cancer. However, it is still controversial whether or not the oncological safety is ensured in case pathological stage was advanced in these patients. The aim of this study was to investigate the validity of SN mapping in patients with clinically early staged gastric cancer diagnosed with pT2/deeper tumors.

METHODS

We retrospectively analyzed 40 patients with a diagnosis of cT1N0 or cT2N0 single-lesion gastric cancer who were shown to have pT2 or deeper tumors after gastrectomy with SN mapping. We adopted a dual-tracer method using a radioactive colloid and blue dye to detect SNs. The diagnostic accuracy and distribution of SNs at each tumor site were analyzed.

RESULTS

Of the 40 patients, 24 (60%) were postoperatively diagnosed as pT2, and 16 (40%) as pT3 or T4. SNs were detected in all patients. The false negative rate was 9% (1/11), and in that patient, the non-SN metastasis was observed within the SN basin. Diagnostic accuracy was 98% (39/40). Overall distribution of SNs was similar to that for patients with early gastric cancer. No significant differences in overall and recurrence-free survival were observed between the patients who underwent standard gastrectomy and those who underwent function-preserving gastrectomy, based on the results of SN mapping.

CONCLUSIONS

Our results confirmed validity of SN mapping for patients with clinically early staged gastric cancer diagnosed with pT2/deeper tumors after gastrectomy. Closed surveillance without additional surgical treatment is an option for these patients.

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.

Long-term outcome following sentinel node navigation surgery for cT1 gastric cancer

Sentinel node navigation surgery (SNNS) has become a standard procedure for early-stage melanoma and breast cancer. However, very few studies have evaluated the long-term clinical outcomes following SNNS for gastric cancer. The present study analyzed 51 patients with cT1 gastric cancer who underwent SNNS at our hospital. Sentinel nodes (SNs) were identified using the dual tracer method. Patients underwent limited gastrectomy with SN station dissection when the SNs were reported as pathologically negative during surgery. When SNs were pathologically positive, standard gastrectomy with D2 lymphadenectomy was performed. Out of the 51 cases, 42 cases (82%) were pathologically diagnosed as SN-negative using a frozen section. The surgical procedures included segmental gastrectomy (n=33) and local resection (n=9). A total of 9 patients (18%) had lymph node metastasis in SNs. The mean observation period was 3,125±167 days, and the 5-year overall survival rate was 98%. There was no recurrence, and body weight loss was minimal following the SNNS. Remnant gastric cancer developed in 4 (8%) of the 50 patients except total gastrectomy. Thus, SNNS was a useful procedure for cT1 gastric cancer from the long-term clinical outcomes, though metachronous gastric cancer should paid further attention to.

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.

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.

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.

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

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

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.

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.

Intraoperative imaging-guided cancer surgery: from current fluorescence molecular imaging methods to future multi-modality imaging technology

Cancer is a major threat to human health. Diagnosis and treatment using precision medicine is expected to be an effective method for preventing the initiation and progression of cancer. Although anatomical and functional imaging techniques such as radiography, computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) have played an important role for accurate preoperative diagnostics, for the most part these techniques cannot be applied intraoperatively. Optical molecular imaging is a promising technique that provides a high degree of sensitivity and specificity in tumor margin detection. Furthermore, existing clinical applications have proven that optical molecular imaging is a powerful intraoperative tool for guiding surgeons performing precision procedures, thus enabling radical resection and improved survival rates. However, detection depth limitation exists in optical molecular imaging methods and further breakthroughs from optical to multi-modality intraoperative imaging methods are needed to develop more extensive and comprehensive intraoperative applications. Here, we review the current intraoperative optical molecular imaging technologies, focusing on contrast agents and surgical navigation systems, and then discuss the future prospects of multi-modality imaging technology for intraoperative imaging-guided cancer surgery.

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.

Digestive cancer surgery in the era of sentinel node and epithelial-mesenchymal transition

Lymph node involvement is one of the most important prognostic indicators of carcinoma of the digestive tract. Although the therapeutic impact of lymphadenectomy has not been proven and the number of retrieved nodes cannot be considered a measure of successful cancer surgery, an adequate lymph node count should be guaranteed to accurately assess the N-stage through the number of involved nodes, lymph node ratio, number of negative nodes, ratio of negative to positive nodes, and log odds, i.e., the log of the ratio between the number of positive lymph nodes and the number of negative lymph nodes in digestive carcinomas. As lymphadenectomy is not without complications, sentinel node mapping has been used as the rational procedure to select patients with early digestive carcinoma in whom nodal dissection may be omitted or a more limited nodal dissection may be preferred. However, due to anatomical and technical issues, sentinel node mapping and nodal basin dissection are not yet the standard of care in early digestive cancer. Moreover, in light of the biological, prognostic and therapeutic impact of tumor budding and tumor deposits, two epithelial-mesenchymal transition-related phenomena that are involved in tumor progression, the role of staging and surgical procedures in digestive carcinomas could be redefined.

Prognosis of patients with gastric cancer and solitary lymph node metastasis

AIM: To investigate the relationship of solitary lymph node metastasis (SLNM) and age with patient survival in gastric cancer (GC).

METHODS: The medical records databases of China’s Beijing Cancer Hospital at the Peking University School of Oncology and Shanghai Tenth People’s Hospital affiliated to Tongji University were searched retrospectively to identify patients with histologically proven GC and SLNM who underwent surgical resection between October 2003 and December 2012. Patients with distant metastasis or gastric stump carcinoma following resection for benign disease were excluded from the analysis. In total, 936 patients with GC + SLNM were selected for analysis and the recorded parameters of clinicopathological disease and follow-up (range: 13-2925 d) were collected. The Kaplan-Meier method was used to stratify patients by age (≤ 50 years-old, n = 198; 50-64 years-old, n = 321; ≥ 65 years-old, n = 446) and by metastatic lymph node ratio [MLR < 0.04 (1/25), n = 180; 0.04-0.06 (1/25-1/15), n = 687; ≥ 0.06 (1/15), n = 98] for 5-year survival analysis. The significance of intergroup differences between the survival curves was assessed by a log-rank test.

RESULTS: The 5-year survival rate of the entire GC + SLNM patient population was 49.9%. Stratification analysis showed significant differences in survival time (post-operative days) according to age: ≤ 50 years-old: 950.7 ± 79.0 vs 50-64 years-old: 1697.8 ± 65.9 vs≥ 65 years-old: 1996.2 ± 57.6, all P < 0.05. In addition, younger age (≤ 50 years-old) correlated significantly with mean survival time (r = 0.367, P < 0.001). Stratification analysis also indicated an inverse relationship between increasing MLR and shorter survival time: < 0.04: 52.8% and 0.04-0.06: 51.1% vs≥ 0.06: 40.5%, P < 0.05. The patients with the shortest survival times and rates were younger and had a high MLR (≥ 0.06): ≤ 50 years-old: 496.4 ± 133.0 and 0.0% vs 50-65 years-old: 1180.9 ± 201.8 and 21.4% vs≥ 65 years-old: 1538.4 ± 72.4 and 37.3%, all P < 0.05. The same significant trend in shorter survival times and rates for younger patients was seen with the mid-range MLR group (0.04-0.06), but the difference between the two older groups was not significant. No significant differences were found between the age groups of patients with MLR < 0.04. Assessment of clinicopathological parameters identified age group, Borrmann type, histological type and tumor depth as the most important predictors of the survival rates and times observed for this study population.

CONCLUSION: GC patients below 51 years of age with MLR of SLNM above 0.06 have shorter life expectancy than their older counterparts.

Early gastric cancer and dysplasia

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

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.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

One-step nucleic acid amplification (OSNA) for the application of sentinel node concept in gastric cancer

PURPOSE

This study was designed to apply safely the sentinel node navigation surgery (SNNS) to the malignancies, an accurate and prompt intraoperative diagnosis of SN is essential, and micrometastasis has been frequently missed by conventional frozen sections. Recently, a novel molecular-based rapid diagnosis for the lymph node (LN) metastases has been developed using (OSNA) in breast cancer, which takes approximately 30 min to obtain a final result. We evaluated the efficacy of OSNA in terms of the intraoperative diagnosis of LN metastasis in patients with gastric cancer.

METHODS

A total of 162 LNs dissected from 32 patients with gastric cancer was included in this study; 45 LNs were pathologically diagnosed as metastatic LNs and 117 LNs were negative. The LNs were bisected; halves were examined with H&E stain, and the opposite halves were subjected to OSNA analyses of CK19 mRNA. The CK19 mRNA expression was examined in the positive or negative metastatic LNs, and the correlation between the tumor volume and CK19 mRNA expression in the metastatic LNs was examined.

RESULTS

The CK19 mRNA expressions in the positive metastatic LNs were significantly higher than those of negative LNs. When 250 copies/μl was set as a cutoff value, the concordance rate was 94.4%, the sensitivity was 88.9%, and the specificity was 96.6%. The OSNA expression was significantly correlated with the estimated tumor volumes in the metastatic LNs.

CONCLUSIONS

The OSNA method is feasible and acceptable for detecting LN metastases in patients with gastric cancer. This should be applied for the intraoperative diagnosis in the SN-navigation surgery in gastric cancer.

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

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

Limited gastrectomy with dissection of sentinel node stations for early gastric cancer with negative sentinel node biopsy

OBJECTIVE

To evaluate the early results of sentinel node (SN)-navigated limited surgery for early gastric cancer.

SUMMARY BACKGROUND DATA

False-negative results of SN biopsy cannot be ignored in gastric cancer surgery. Previous studies suggest that dissection of lymph node stations where SNs belong (SN stations) may minimize the possibility of leaving metastasis behind in SN-navigated surgery.

METHODS

Patients with T1N0M0 gastric cancer <4 cm were informed about the SN-navigated limited surgery from 2003 to 2008. SNs were identified using radioisotope and dye methods. When the SN biopsy by frozen section was negative, limited gastrectomy with dissection of SN stations was performed. Patients with SN stations limited to either the lesser or greater curvature underwent a wedge resection unless it would cause a strong deformity of the stomach. A sleeve gastrectomy was performed in other cases.

RESULTS

Six of the 60 enrolled patients chose a standard gastrectomy. Sixteen patients were excluded after laparotomy due to a T2-T3 tumor or tumor location. Three patients with positive SN biopsy underwent D2 gastrectomy, and 35 with negative SN biopsy underwent limited gastrectomy with dissection of SN stations; wedge resection in 8 and sleeve gastrectomy in 27. There were no operative mortalities or morbidities. All patients undergoing the limited surgery had no lymph node metastasis by postoperative pathology, and survived without any recurrence. The average area of the resected stomach for limited surgery was significantly smaller than that for standard procedures (92 +/- 50 vs. 189 +/- 64 cm, P < 0.001).

CONCLUSIONS

SN-navigated limited gastrectomy with dissection of SN stations for T1N0M0 gastric cancer was considered safe and acceptable although long-term follow-up is mandatory.