Submucosal Invasive Gastric Cancer Research Articles

Reduced DEFA5 Expression and STAT3 Activation Underlie the Submucosal Invasion of Early Gastric Cancers

Introduction: Submucosal invasion is a core hallmark of early gastric cancer (EGC) with poor prognosis. However, the molecular mechanism of the progression from intramucosal gastric cancer (IMGC) to early submucosal-invasive gastric cancer (SMGC) is not fully understood. The objective of this study was to identify genes and pathways involved in the submucosal invasion in EGC using comprehensive gene expression analysis. Methods: Gene expression profiling was performed for eight cases of IMGC and eight cases of early SMGC with submucosal invasion ≥500 μm. To validate the findings of gene expression analysis and to examine the gene expression pattern in tissues, immunohistochemical (IHC) staining was performed for 50 cases of IMGC and SMGC each. Results: Gene expression analysis demonstrated that the expression levels of small intestine-specific genes were significantly decreased in SMGC. Among them, defensin alpha 5 (DEFA5) was the most downregulated gene in SMGC, which was further validated in SMGC tissues by IHC staining. Gene set enrichment analysis showed a strong association between SMGC, the JAK-STAT signaling pathway, and the upregulation of STAT3-activating cytokines. The expression of phosphorylated STAT3 was significant in the nucleus of tumor cells in SMGC tissues but not in areas expressing DEFA5. Conclusion: The results of this study strongly suggest that the downregulation of DEFA5 and the activation of STAT3 play a significant role in the submucosal invasion of EGC.

Clinical feasibility and oncologic safety of primary endoscopic submucosal dissection for clinical submucosal invasive early gastric cancer.

This study aimed to evaluate the clinical feasibility and oncologic safety of primary endoscopic submucosal dissection for cT1bN0M0 gastric cancer by identifying patients who had undergone curative resection after endoscopic submucosal dissection and patients who had undergone primary surgery but could be treated with endoscopic submucosal dissection. A single-center retrospective cohort study was conducted on patients with cT1bN0M0 gastric cancer (size: ≤ 30mm) and differentiated histology from January 2007 to May 2017. Submucosal invasion was evaluated using conventional endoscopy and endoscopic ultrasonography. Patients were divided into the primary endoscopic submucosal dissection and primary surgery groups according to initial treatment. Curative resection rate was 65.0% (91/140) in the primary endoscopic submucosal dissection group. Of patients in the primary surgery group, 49.1% (82/167) were considered eligible for endoscopic submucosal dissection. No differences in en bloc resection rate were observed between pT1a and pT1b gastric cancers after endoscopic submucosal dissection (97.8 vs. 97.9%). However, the negative horizontal margin rate was higher in pT1a gastric cancer than pT1b gastric cancer (98.9 vs. 91.3%). There was no difference in overall survival among the curative treatment groups (log rank P = 0.310). In this study, 173 (56.4%) out of 307 patients with cT1bN0M0 gastric cancer could avoid unnecessary surgery if primary endoscopic submucosal dissection was used. Based on these findings, it is necessary to add an appropriate indication for endoscopic submucosal dissection in patients with cT1b gastric cancer. Further management could be determined based on pathologic findings after primary endoscopic submucosal dissection.

Preceding endoscopic submucosal dissection in submucosal invasive gastric cancer patients does not impact clinical outcomes

Submucosal deep invasion of gastric cancer (T1b2; depth of submucosal invasion ≥ 500 μm) is a risk factor for lymph node metastasis and, thus, is one of the criteria for curative treatment. Our aim was to evaluate the specific influence of endoscopic submucosal dissection (ESD) on the prognosis of patients with T1b2 gastric cancer. This was a retrospective analysis of 248 consecutive patients, with 252 pT1b2 gastric cancer lesions, who underwent ESD prior to additional surgery (Group A, n = 101) or surgery only (Group B, n = 147). After propensity score-matching (for sex, age, tumor diameter and gross type), we compared pathological characteristics between the 2 groups and the prognosis over a follow-up period ≥ 60 months. Compared to Group B, patients in Group A were older, with a higher proportion of men. The proportion of depressed and undifferentiated type tumors was greater in Group B than A, with larger tumor size and depth of submucosal invasion as well. There was no incidence of local recurrence, but distant metastasis was identified in 5% of cases in Group A and 3% in Group B. After propensity score-matching, there were no difference in the 5-year overall survival rate between Group A and B (87.5% vs. 91.2%, respectively), nor in the 5-year disease-specific survival rate (96.3% vs. 96.4%, respectively). ESD prior to surgery for T1b2 gastric cancer did not adversely affect clinical outcomes after additional surgery.

Lymphovascular invasion in early gastric cancer: impact of ancillary D2-40 and elastin staining on interobserver agreement.

Lymphatic invasion (LI) and venous invasion (VI) are the strongest risk factors for lymph node metastasis in patients with early gastric cancer, and may predict their prognosis. We aimed to investigate interobserver agreement among pathologists before and after adding ancillary staining for diagnosing LI and VI in this setting. This retrospective study included 100 specimens of submucosal invasive gastric cancer from 100 patients treated using endoscopic resection. Three pathologists (expert, intermediate and trainee experience levels) independently evaluated individual LI and VI status using haematoxylin and eosin (H&E)-stained slides, and re-evaluated their decisions by reviewing corresponding D2-40-stained and elastin-stained slides. Interobserver agreement was assessed using κ statistics. With the ancillary D2-40 staining, there was an improved agreement for LI diagnoses between the expert and intermediate pathologist (H&E κ=0.78, D2-40 κ=0.85) and between the expert and trainee pathologist (H&E κ=0.37, D2-40 κ=0.56). With the ancillary elastin staining, there was an improved agreement for VI diagnoses between the expert and intermediate pathologists (H&E κ=0.25, elastin κ=0.63) and between the expert and trainee pathologists (H&E κ=0.29, elastin κ=0.45). With both the ancillary D2-40 and elastin staining there was an improved interobserver agreement for LI and VI diagnoses, regardless of the pathologist's experience. This ancillary staining may be useful in improving the accuracy of LI and VI diagnoses, helping to improve the risk stratification of early gastric cancer patients.

Exploring the possibility of endoscopic submucosal dissection for clinical submucosal invasive early gastric cancers.

The current standard treatment modality for clinical submucosal invasive (cT1b) early gastric cancer (EGC) is surgery. However, there are discrepancies in T staging between pre- and post-operative findings, and in cases of overestimation, patients may lose the opportunity to preserve the stomach. The aim of this study was to analyze surgical outcomes of cT1b EGC and determine the pre-treatment factors favoring ESD. Patients who underwent gastrectomy for cT1b EGC with a tumor size of 30mm or less in diameter and differentiated-type histology were retrospectively reviewed from January 2010 to December 2014. According to the final surgical pathologic results, two groups were classified: patients whose pathologic results qualified for current ESD indication (ESD-qualified group, n = 203) and patients whose pathologic results made them ineligible for ESD (ESD-disqualified group, n = 261). The preoperative clinical characteristics were compared. Forty-three percent of the patients (203/464) who underwent gastrectomy for cT1b EGC qualified for ESD; their endoscopic lesion tended to be smaller than 20mm in size and located in the distal part of stomach. In addition, the ESD-qualified group showed a significantly higher proportion of well-differentiated tubular adenocarcinoma on endoscopic biopsy and of the flat/depressed type in the endoscopic evaluation. Forty-three percent of the patients with cT1b EGC who underwent gastrectomy had a chance to preserve their stomach by ESD. Therefore, pre-treatment factors such as endoscopic lesion size, location, histology, and gross type should be considered for treatment modality selection for cT1b EGC.

Expansion of lymph node metastasis in mixed-type submucosal invasive gastric cancer

Mixed-type early gastric cancer (differentiated and undifferentiated components) incurs a higher risk of lymph node metastasis than pure-type early gastric cancer (only differentiated or only undifferentiated components). Therefore, we investigated the expansion of lymph node metastasis in mixed-type submucosal invasive gastric cancer in order to establish the most appropriate treatment for mixed-type cancer. We retrospectively analyzed 279 consecutive patients with submucosal invasive gastric cancer who underwent curative gastrectomy for gastric cancer between 1996 and 2015. We classified the patients into the mixed-type and pure-type groups according to histologic examination and evaluated the expansion of lymph node metastasis. The rate of lymph node metastasis was 23.7% (66/279) in the total patients, 36.4% (36/99) in the mixed-type group, and 16.6% (30/180) in the pure-type group. The significant independent risk factors for lymph node metastasis were tumor size ≥2.0cm(P=0.014), mixed-type gastric cancer (P<0.001), and lymphatic invasion (P<0.001). Lymphatic invasion and lymph node metastasis had a strong relationship in mixed-type group. The rates of no. 7 lymph node metastasis in the total patients and mixed-type group were 2.9% (8/279) and 5.1% (5/99), respectively; the rates of no. 8a lymph node metastasis were 1.4% (4/279) and 4.0% (4/99), respectively. Mixed histological type is an independent risk factor for lymph node metastasis. Lymph node metastasis in mixed-type gastric cancer involves expansion to the no. 7 and no. 8a lymph nodes. Therefore, lymphadenectomy for mixed-type submucosal invasive gastric cancer requires D1+ or D2 dissection.

Long-term oncological outcomes of submucosal manipulation during non-curative endoscopic submucosal dissection for submucosal invasive gastric cancer: a multicenter retrospective study in Japan

Sufficient information is not available on the extent to which lymph node metastasis (LNM) and prognosis are affected by submucosal manipulation during endoscopic submucosal dissection (ESD) for submucosal invasive gastric cancer (SMGC). We aimed to identify the effects of submucosal manipulation during ESD on LNM and prognosis in patients with SMGC. From 19 institutions in Japan, 2526 patients who failed to meet the current curative criteria for ESD between 2000 and 2011 were recruited. After exclusion, 1969 patients were remained. Based on the treatment strategy after ESD, 1064 patients underwent additional radical surgery. A total of 890 of 1064 patients with SMGC, LNM and cancer recurrence, and prognosis were retrospectively reviewed. The median follow-up duration was 67months. A total of 214 patients had SM1 (depth of tumor invasion from the muscularis mucosae <500μm) invasive cancer and 676 patients had SM2 (depth of tumor invasion from the muscularis mucosae ≥500μm) invasive cancer. LNM was found in 84 patients (9.4%), and 14 patients (1.6%) developed cancer recurrence. The 3-year and 5-year overall survival rates were 96.1 and 91.7%, respectively. The 3-year and 5-year disease-specific survival rates were 99.3 and 98.5%, respectively. The rates of LNM and cancer recurrence, and prognosis of patients who underwent additional radical surgery after non-curative ESD for SMGC were excellent. Submucosal manipulation during ESD for SMGC does not seem to enhance the risk for LNM or worsen the prognosis compared to surgical series.

The value of diagnostic endoscopic submucosal dissection for patients with clinical submucosal invasive early gastric cancer

The standard treatment for clinical submucosal invasive (cT1b) early gastric cancer is gastrectomy. However, Japanese gastric cancer treatment guidelines list endoscopic submucosal dissection (ESD) as an option for treating limited early gastric cancer cases. ESD can be curative depending on the pathological characteristics of resected specimens. Thus, we aimed to clarify the benefits and disadvantages of preceding ESD for early gastric cancer. We retrospectively analyzed patients who underwent ESD or curative gastrectomy for cT1b gastric cancer with differentiated adenocarcinoma 30mm or less in diameter. Patients who underwent ESD irrespective of undergoing gastrectomy were assigned to the ESD group (n=107), and those who underwent gastrectomy without undergoing ESD were assigned to the non-ESD group (n=181). Clinicopathological characteristics were assessed, and the short-term and long-term outcomes of patients were compared. The criteria for curative resection were satisfied by 83 patients (28.8%), and preceding ESD did not affect the surgical outcomes of gastrectomy. Two patients (1.9%) who underwent ESD had an unscheduled total gastrectomy. The en bloc and complete resection rates of ESD were 99.0% and 84.1% respectively. Nine patients (8.4%) experienced intraprocedure perforation and postprocedure bleeding caused by ESD. Overall survival (hazard ratio 1.38; P=0.302) and cause-specific survival (hazard ratio 0.96; P=0.944) were comparable between groups. The stomach was preserved in 28.8% of patients, and preceding ESD did not show obvious disadvantages. Therefore, diagnostic ESD should be considered as an initial treatment for limited cT1b gastric cancer cases.

Risk factors associated with difficult gastric endoscopic submucosal dissection: predicting difficult ESD.

Endoscopic submucosal dissection (ESD) is a widely accepted treatment for superficial gastric neoplasms. Difficult ESD can lead to complications, such as bleeding and perforation. To predict difficult ESD procedures, we analyzed the factors associated with difficult ESD. The medical records of 1052 ESD procedures were retrospectively reviewed. Difficult ESD was defined by any one of three end points: longer procedure time (≥60min), piecemeal resection, incomplete (R1) resection, or gastric wall perforation. To determine the factors associated with difficult ESD, clinical and pathologic features and endoscopic findings were analyzed. The rates of en bloc resection and curative (R0) resection were 93.3 and 92.4%, respectively. The mean procedure time was 27.7±16.7min. After multivariate analysis, larger tumor size (≥20mm) was an independent risk factor for longer procedure time (OR 4.1, P<0.001), for piecemeal resection (OR 2.3, P=0.003) and incomplete (R1) resection (OR 2.1, P=0.005). Location of the lesion (upper third) was an independent risk factor for longer procedure time (OR 5.8, P<0.001), for piecemeal resection (OR 4.1, P<0.001) and incomplete (R1) resection (OR 4.5, P<0.001). Submucosal fibrosis was an independent risk factor for longer procedure time (OR 9.7, P<0.001), for piecemeal resection (OR 2.4, P<0.001) and incomplete (R1) resection (OR 2.6, P<0.001). Finally, submucosal invasive gastric cancer was an independent risk factor for piecemeal resection (OR 2.6, P=0.008), for perforation (OR 19.3, P=0.001) and for incomplete (R1) resection (OR 2.7, P=0.001). Difficult ESD procedures are a function of the lesion size and location, submucosal fibrosis, and submucosal invasive cancer. When a difficult ESD procedure is expected, appropriate preparations should be considered, including consultation with more experienced endoscopists.

The ratio of major and minor axis by EUS as a possible predictive marker for the diagnosis of submucosal invasive gastric cancer.

9 Background: The aim of this study was to evaluate the efficacy of the ratio of major and minor axis by endoscopic ultrasonography (EUS) as a possible predictive marker for the diagnosis of submucosal invasive gastric cancer. Methods: Between March 2014 and December 2014, the medical records of 51 patients with unclear distinction between mucosal and submucosal gastric cancer were retrospectively reviewed. Patient and tumor characteristics, accuracy rate and factors associated with correct diagnosis of submucosal invasive tumor in Ratio for gastric cancer were analyzed. Results: The mean age was 62.0 ± 12.6 (range, 35-79 years) and the male to female ratio was 1:0.45. The mean tumor size was 25.8 ± 14.7 mm. The overall accuracy was 60.7% (31/51) using the EUS and 82.3% (42/51) using the EUS ratio index (p = 0.045). The sensitivity, specificity, positive predictive value and negative predictive value to submucosal gastric cancer were 68.1, 55.1, 53.5, 65.9% using the EUS and 81.8,82.7,78.2,85.7% using the EUS ratio index, respectively. In the multivariate analysis, differentiated (Odds ratio [OR]: 1.42, 95% confidence interval [CI]: 0.95-1.89), no ulceration (OR: 1.96, 95% CI: 1.49-2.43), and deep submucosal invasion ( &gt; 500 μm, OR: 2.77, 95% CI: 2.16-3.34) were independent factors, associated with correct diagnosis of submucosal invasive tumor in Ratio for gastric cancer (p &lt; 0.05) Conclusions: The ratio of major and minor axis by endoscopic ultrasonography (EUS ratio index) might be a possible predictive marker for the diagnosis of submucosal invasive gastric cancer.

Non-curative endoscopic resection does not always lead to grave outcomes in submucosal invasive early gastric cancer.

Endoscopic submucosal dissection (ESD) has been widely performed for the treatment of early gastric cancer (EGC). The aim of this study is to examine the effectiveness of ESD in submucosal invasive gastric cancers (SM-GC), with a special focus on patients who underwent non-curative resection. Data for 1,246 patients who underwent ESD for treatment of EGC at six medical centers in Daegu-Gyeongbuk, Korea, between February 2003 and May 2010 were collected. After retrospective analysis of ESD databases, 118 patients were enrolled and classified into three groups: (1) EGC with submucosal invasion less than 500 μm (SM1-GC) that met the expanded criteria (EC) (SM1 EC, n = 42); (2) SM1-GC that did not meet the EC (SM1 non-EC, n = 38); and (3) EGC with submucosal invasion greater than 500 μm (SM2-GC, n = 38). The en bloc and complete resection rates did not differ significantly among the three groups. However, the curative resection rate was significantly better in the SM1 EC group (69.0%) compared to that in SM1 non-EC and SM2-GC groups (0% in both cases). Out of a total of 118 patients, 89 (75.4%) underwent non-curative resection, and cancer recurrence was observed in 9 (9/89, 10.1%). We analyzed the survival rate in these non-curative patients and the overall survival and disease-free survival did not differ significantly between patients that were treated with additional surgical resection and those that were simply followed up after ESD. Non-curative resection in SM-GC does not always lead to cancer recurrence. Thus, if additional surgery cannot be performed because of the patient's unsuitable condition or refusal, a close follow-up with endoscopy can be considered as an alternative for carefully selected patients. Moreover, as the ESD technology continues to evolve, it might be possible to expand the criteria for curative ESD in patients with SM-GC.

Is endoscopic submucosal dissection an effective treatment for operable patients with clinical submucosal invasive early gastric cancer?

Gastrectomy with lymph node dissection is the gold standard curative treatment for clinical submucosal invasive early gastric cancer (cSM EGC), but a relatively small number of operable patients with cSM EGC have undergone endoscopic submucosal dissection (ESD) instead because they refused surgery. The aim of this study was to determine the effectiveness of ESD in these operable patients. The therapeutic outcomes of ESD were retrospectively assessed for 38 patients with 38 operable cSM EGC lesions who initially refused surgery at the National Cancer Center Hospital, Tokyo, from January 1999 to December 2008. The en bloc resection rate was 84.2% (32 lesions) and the complete (R0) resection rate was 63.2% (24 lesions). A total of 33 lesions (86.8%) involved submucosal invasion on pathology. Resection was non-curative in 34 patients (89.5%), 22 of whom (64.7%) underwent subsequent gastrectomy after the need for such surgery was carefully explained to them again. The median follow-up period was 73.2 months (range 3-115 months). Local recurrence was detected in one patient, distant metastasis in two patients, and both local recurrence and distant metastasis were detected in one patient. None of these four patients with recurrence (10.5%) had undergone surgery when their recurrent disease was detected and all of them died from gastric cancer. The 5-year cause-specific survival rate for all patients was 91.8%. The 5-year cause-specific survival rate for all patients was lower than the previously reported rate of 96.7% for pathologically submucosal invasive EGC patients after gastrectomy; therefore, ESD appears to have been an ineffective treatment for operable patients with cSM EGC.

Clinical validity of endoscopic submucosal dissection for submucosal invasive gastric cancer: a single-center study

The 2010 Japanese Gastric Cancer Association guidelines for the treatment of submucosal invasive gastric cancer (SM-GC) specify size 30mm or less, differentiated-dominant histology, lack of vessel involvement, and submucosal invasion of less than 500μm (SM1) as expanded criteria for curative endoscopic resection. Our purpose in this study was to confirm the validity of the expanded indications for curative endoscopic submucosal dissection (ESD) of SM-GC. The study subjects were 173 patients with SM-GC resected by ESD at Hiroshima University Hospital between April 2002 and September 2010, including 99 patients for whom 3-plus years' follow-up information was available. Post-ESD outcomes were compared between cases of SM1-GC that met the expanded ESD criteria, those that did not, and SM2-GC cases. Complete resection was achieved for 93.2% of the SM1-GCs that met the expanded criteria. There was neither metastasis to lymph nodes or other organs nor local recurrence among the SM1-GCs. Disease-specific survival did not differ significantly between patients that were simply followed up after ESD and those that were treated by additional surgical resection. Our outcome data support the clinical validity of ESD without additional surgical resection for SM1-GCs that meet the expanded criteria.

Clinical Outcomes of Endoscopic Submucosal Dissection for Undifferentiated or Submucosal Invasive Early Gastric Cancer

Background/AimsEarly gastric cancer (EGC) that is undifferentiated or shows submucosal invasion has not been generally accepted as an indication for endoscopic treatment. But recently, experiences with endoscopic submucosal dissection (ESD) for undifferentiated EGC or submucosal invasive (SM) EGC have increased. The aim of this study was to evaluate clinical outcomes of ESD for EGC with undifferentiation or submucosal invasion.MethodsBetween August 2005 and August 2009, among 210 EGCs treated using ESD at our hospital, 18 lesions were diagnosed as undifferentiated gastric cancer and 41 as SM gastric cancer. A retrospective analysis was done on the medical records of these patients.ResultsMean follow-up periods were 19.39±11.2 months. During the follow-up period, local recurrence was noted in 4 lesions. Local recurrence rates of the EGC groups (group 1, mucosal cancer with undifferentiation; group 2, SM cancer with differentiation; group 3, SM cancer with undifferentiation) were 10%, 4.5%, and 50%, respectively. Groups 1 and 2 were not significantly different in local recurrence rates compared to the mucosal cancer with differentiation group (p=0.061, p=0.125, respectively). The undifferentiated EGC group was significantly lower in curability using ESD than the differentiated EGC group (55.6% vs. 89.6%, p=0.000). The curability of the SM EGC group was lower than the mucosal EGC group (36.6% vs. 98.9%).ConclusionsComplete resection using ESD is difficult in undifferentiated and SM gastric cancers. SM cancer with undifferentiation should be treated immediately by salvage operation. For mucosal cancer with undifferentiation or SM cancer with differentiation, one should consider careful short-term follow-up.

ENDOSCOPIC SUBMUCOSAL DISSECTION FOR SUBMUCOSAL INVASIVE GASTRIC CANCER AND CURABILITY CRITERIA

The aims of the present study were to evaluate the feasibility of endoscopic submucosal dissection (ESD) as curative treatment for node-negative submucosal invasive early gastric cancer (EGC) and to consider further expansion of the curability criteria for submucosal invasive EGC. A total of 977 EGC in 855 patients treated by ESD were enrolled. They were divided into intramucosal cancer (M); minimally submucosal invasive cancer (<500µm from the muscularis mucosa) (SM1); and deeper submucosal invasive cancer (>500µm from the muscularis mucosa) (SM2). The technical feasibility of ESD for SM1 and M were compared, and the clinical prognosis of SM1 was evaluated. Furthermore, the volume of carcinoma invading to the submucosal layer, which we called the SM volume index, was calculated virtually to analyze its correlation with lymphatic-vascular invasion. There were no statistical differences in technical outcomes and complications between M and SM1. Curative resection rates were significantly better in M than in SM1 (M, 92.6%; SM1, 63.8%). No local recurrences and distant metastases were found in 48 SM1 patients declared to have undergone curative resections. Most cases (72.0%) with successful ESD but non-curative resection exceeded 30mm in maximum size, and no local recurrences and metastases were found in these patients. The SM volume index of these cases was comparatively small. The technical and theoretical validity of ESD for SM1 was validated. The possibility of further expansion of the curability criteria for submucosal invasive cancers was suggested by the evaluation of the SM volume index.

Predicting the absence of lymph node metastasis of submucosal invasive gastric cancer: Expansion of the criteria for curative endoscopic resection

Objective. The conditions upon which endoscopic resection (ER) can be considered curative for submucosal invasive gastric cancer remain controversial; thus, unnecessary surgery is sometimes performed after ER. Our purpose is to evaluate the significance of several clinicopathological factors for predicting the absence of lymph node (LN) metastasis of submucosal invasive gastric cancer and thus determining cases in which ER can be considered curative. Patients and methods. The study group comprised 220 patients with submucosal invasive gastric cancer that was resected surgically or endoscopically. Patients treated by ER underwent additional surgical resection. The presence of LN metastasis was evaluated in all patients, retrospectively. Results. LN metastasis was detected in 37 (16.8%) of the 220 patients. Independent risk factors for LN metastasis were width of submucosal invasion >6000 μm, lymphatic involvement, undifferentiated type at the deepest invasive portion, depth of submucosal invasion >1000 μm, and tumor diameter >30 mm. The group of 36 patients with submucosal invasion to a depth of ≤1000 μm, tumor diameter ≤30 mm, differentiated type as the dominant histologic type, and absence of vessel involvement was entirely free of LN metastasis (95% confidence interval, 0–8.0%). Conclusions. Taken together, the five independent risk factors may allow expansion of the criteria for determining whether ER for submucosal invasive gastric cancer has been curative.

W1561: Expansion of Curative Condition After Endoscopic Resection for Submucosal Invasive Gastric Cancer

Endoscopic resection (ER) is a therapeutic but simulataneously a total excisional biopsy technique. The AIM of this study is to evaluate the significance of several clinicopathological features in prediction of lymph node (LN) metastasis of submucosal gastric cancer and to examine the feasibility of expansion curative condition after ER for submucosal gastric cancer.

A case of submucosal invasive gastric cancer based on diffuse cystic malformation treated by endoscopic submucosal dissection

A case of submucosal invasive gastric cancer based on diffuse cystic malformation treated by endoscopic submucosal dissection

Mixed-histologic-type submucosal invasive gastric cancer as a risk factor for lymph node metastasis: feasibility of endoscopic submucosal dissection

Mixed-histologic-type submucosal invasive gastric cancer as a risk factor for lymph node metastasis: feasibility of endoscopic submucosal dissection

Mixed-histologic-type submucosal invasive gastric cancer as a risk factor for lymph node metastasis: feasibility of endoscopic submucosal dissection

The clinicopathologic features of gastric cancers containing a mixture of differentiated-type and undifferentiated-type components remain uninvestigated. We evaluated the risk of lymph node metastasis and the feasibility of endoscopic submucosal dissection (ESD) for the treatment of mixed-histologic-type gastric cancers. We histologically classified 376 cases of gastric cancer with submucosal invasion into four types (differentiated type, differentiated-type-predominant mixed type, undifferentiated-type-predominant mixed type, and undifferentiated type) and studied the clinicopathologic relations of each type to lymph node metastasis. Lymphatic invasion was evaluated by D2-40 immunostaining. The overall prevalence of lymph node metastasis in gastric cancer with submucosal invasion was 16.5% (62/376). The prevalence of lymph node metastasis was 36.5% (23/63) in undifferentiated-type-predominant mixed type, which was significantly higher than those in the other three types (P < 0.001 vs. differentiated type, P = 0.013 vs. differentiated-type-predominant mixed type, and P = 0.003 vs. undifferentiated type). Lymphatic invasion, a depth of invasion of 500 microm or more from the lower margin of the muscularis mucosae (SM2), tumor size above 30 mm, and undifferentiated-type-predominant mixed histologic type were independent risk factors for lymph node metastasis. Submucosal cancers without these four risk factors were free of lymph node metastasis (0/41; 95 % confidence interval 0%-8.6%). Undifferentiated-type-predominant mixed-type gastric cancer with submucosal invasion carries a high risk of lymph node metastasis. ESD can be indicated for gastric cancer with submucosal invasion provided that the following conditions indicating a low risk of metastasis are met: a depth of invasion of no more than 500 microm or more from the lower margin of the muscularis mucosae (SM1), no lymphatic invasion, a tumor size of no more than 30 mm, and a proportion of undifferentiated components below 50%.