Undifferentiated Early Gastric Cancer Research Articles

Feasibility of expanded indication for endoscopic submucosal dissection in undifferentiated early gastric cancer

Objective To evaluate the feasibility of expanded indication for endoscopic submucosal dissection (ESD) in undifferentiated early gastric cancer, to investigate the risk factors of lymph node metastasis (LNM), so as to provide the theoretical evidence for the choice of treatment. Methods From June 2007 to December 2018, at the Affiliated Hospital of Qingdao University, the clinical and pathological data of 807 patients with undifferentiated early gastric cancer and undergoing gastrectomy plus lymphadenectomy were retrospectively analyzed. Chi-square test was performed to analyze the correlation between clinicopathologic characteristics of early gastric cancer and LNM. Multivariate logistic regression model was used to analyze the independent risk factor of LNM. Results LNM was found in 17.2% (139/807) patients with undifferentiated early gastric cancer. And no LNM was detected in 110 patients who met the expanded indication of ESD. The results of univariate analysis indicated that LNM was significantly associated with increased carcinoembryonic antigen (CEA), tumour size, gross type, ulcer, invasion depth, lymphovascular invasion and perineural invasion (χ2=4.500, 13.332, 16.611, 6.083, 51.064, 0.564 and 17.006, all P 500 μm ; OR=3.014, 95%CI 1.753 to 5.181, P<0.01) were independent risk factors of LNM in early gastric cancer. Conclusions The expanded ESD indication of undifferentiated early gastric cancer is applicable for endoscopic treatment considering the low risk of LNM. In early undifferentiated gastric cancer, maximum diameter of tumor over 20 mm, lymphovascular invasion, submucosal superficial and deep invasion are the independent risk factors of LNM. Key words: Endoscopic submucosal dissection; Risk factor; Undifferentiated early gastric cancer; Expanded indication; Lymph node metastasis

Endoscopic Resection of Undifferentiated-type Early Gastric Cancer.

Early detection of gastric cancer is crucial because the survival rate can be improved through curative treatment. Although surgery and gastrectomy with lymph node dissection remain as the gold standard for curative treatment, early gastric cancer (EGC) with negligible risk of lymph node metastasis can be treated with endoscopic resection (ER), such as endoscopic submucosal dissection. Among gastric cancers, undifferentiated-type cancer is distinguished from differentiated-type cancer in various aspects in terms of clinical features and pathophysiology. The undifferentiated-type cancer is also known to be associated with an aggressive behavior and a poor prognosis. Therefore, the indication of ER for undifferentiated EGC is limited compared with differentiated-type. Recent studies have reported that ER for undifferentiated EGC is safe and shows favorable short- and long-term outcomes. However, it is necessary to understand the details of the research results and to selectively accept them. In this review, we aimed to evaluate the current practice guidelines and the short-term and long-term outcomes of ER for undifferentiated type EGC.

Possible indication of endoscopic resection in undifferentiated early gastric cancer

Endoscopic resection for early gastric cancer (EGC) without lymph node metastasis may be a valuable treatment option. To date, endoscopic resection for undifferentiated EGC is being investigated. We evaluated the risk of lymph node metastasis in undifferentiated EGC by examining the preoperative endoscopic findings and operated pathologic specimen. The medical records of patients who underwent surgical resection because of undifferentiated EGC between November 2008 and December 2015 were reviewed retrospectively. The risk factors associated with lymph node metastasis and the lymph node metastasis rate in the expanded indication of undifferentiated EGC were evaluated. A total of 376 patients with undifferentiated EGC (233 signet ring cell type and 143 poorly differentiated type) were analyzed. Lymph node metastasis was found in 9.8% of the patients. Among the patients who met the expanded criteria (59 patients), only one patient had lymph node metastasis (signet ring cell type without ulceration and 15 mm in size). The risk factors associated with lymph node metastasis were lesion size >20 mm (OR 3.013), scar deformity (OR 2.248), surface depression (OR 2.360), submucosal invasion (OR 3.427), and lymphovascular invasion (OR 6.296). Before endoscopic resection of undifferentiated EGC, careful selection of patients should be considered. The undifferentiated EGC with size ≥15 mm, scar deformity, surface depression, submucosal invasion, and lymphovascular invasion should be considered surgical resection instead of endoscopic resection.

Expanding the indication of endoscopic submucosal dissection for undifferentiated early gastric cancer is safe or not?

Endoscopic submucosal dissection (ESD) has gained more popularity in the treatment of early gastric cancer (EGC). Although there is a lack of confirmed evidence for the feasibility of ESD for undifferentiated EGC. The aim of the study was to investigate the feasibility of ESD with expanded indications for undifferentiated EGC patients. Data from patients with undifferentiated EGC (including signet-ring cell carcinoma, mucinous adenocarcinoma, mixed adenocarcinoma, and poorly differentiated adenocarcinoma) who underwent radical surgical resection were retrospectively reviewed. The relationship between the clinical parameters and the incidence of lymph node metastasis (LNM) was investigated. A total of 517 patients were included in this study. The results showed that LNM was significantly associated with ulceration, tumor size, depth of invasion, lymphatic invasion, vascular invasion, and perineural invasion. Multivariate stepwise logistic regression analysis revealed that tumor size (OR=1.61, 95% CI=1.03-2.52, P=0.0367), depth of tumor invasion (OR=2.77, 95% CI=1.66-4.63, P=0.0001), and lymphatic invasion (OR=14.74, 95% CI=1.58-137.36, P=0.0182) were independent risk factors for LNM. In the patients who would be included under the new proposed guidelines for ESD, including men with mucosal tumors ≤2cm and without ulceration or lymphatic or venous infiltration, LNM was present in 11.9% (14/118). Caution to be exercised in expanding application of ESD should be carefully weighed in undifferentiated EGC.

Risk factors of lymph node metastasis or lymphovascular invasion for early gastric cancer: a practical and effective predictive model based on international multicenter data

BackgroundMost lymph node metastasis (LNM) models for early gastric cancer (EGC) include lymphovascular invasion (LVI) as a predictor. However, LVI must be confirmed by postoperative pathology. In this study, we aimed to develop a model for predicting the risk of LNM/LVI in EGC using preoperative factors.MethodsEGC patients who underwent radical gastrectomy at Fujian Medical University Union Hospital and Sun Yat-sen University Cancer Center (n = 1460) were selected as the training set. The risk factors of LNM/LVI were investigated. Data from the International study group on Minimally Invasive surgery for GASTRIc Cancer trial (n = 172) were selected as the validation set.ResultsIn the training set, the incidence of LNM/LVI was 21.6%. The 5-year cancer-specific survival rates of patients with and without LNM/LVI were 92.4 and 95.0%, respectively, with significant difference (P = 0.030). Multivariable logistic regression analysis showed that the four independent risk factors for LNM/LVI were female, tumor larger than 20 mm, submucosal invasion and undifferentiated tumor histological type (all P < 0.05); the area under the curve (AUC) was 0.694 (95% confidence interval [CI]: 0.659–0.730). Patients were divided into low-risk, intermediate-risk, high-risk and extremely high-risk groups by recursive partitioning analysis; the incidences of LNM/LVI were 5.4, 12.6, 24.2 and 37.8%, respectively (P < 0.001). The AUC of the validation set was 0.796 (95%CI, 0.662–0.851) and the predictive performance of the LNM/LVI risk in the validation set was consistent with that in the training set.ConclusionsThe risk of LNM/LVI in differentiated mucosal EGC is low, which indicated that endoscopic resection is a treatment option. The risk of LNM/LVI in undifferentiated mucosal EGC and submucosa EGC are high and gastrectomy with lymph node dissection is suggested.

Endoscopic features of submucosal invasion in undifferentiated type early gastric cancer sized less than 2 cm without ulceration.

76 Background: The prediction of invasion depth is important to decide the treatment modality for the undifferentiated type early gastric cancer (EGC) when size is less than 2 cm and had no ulceration. We aimed to identify the endoscopic features associated with submucosal invasion in the undifferentiated type EGC that meet the criteria of size and status of ulcer in the endoscopic submucosal dissection (ESD). Methods: A total of 120 patients with undifferentiated type EGC who received ESD or operation from August 2008 to December 2017 were enrolled in this study. All lesions met the ESD criteria except the invasion depth. We retrospectively reviewed endoscopic features of tumor before the resection and depth of invasion after resection. Results: In 120 undifferentiated EGCs, the mucosal and submucosal cancer were 97 and 23 lesions, respectively, In univariable analysis, discolor change, upper third location, the presence of deep/wide erosion were associated with submucosal invasion. Multivariable analysis revealed that upper/middle third location (odds ratio [OR] 8.0, 95% confidence interval [CI] 1.2-55.0; OR 7.9, 95% CI 1.8-35.1), erosion or polypoid (OR 41.8, 95% CI 4.1-427.9), and elevated type (OR 20.9, 95% CI 2.5-173.8) were significant risk factors. In 112 patients received gastrectomy with lymph nodes dissection, lymph node metastases were found in four cases (three mucosal cancer and one submucosal cancer). However, there was no lymph node metastasis in the lesions meeting the expanded ESD indication. Conclusions: The careful decision of treatment modality is needed for undifferentiated type EGC with erosion or elevated gross type located on the upper/middle third, although the tumor size and ulcer status meet the ESD indication.

Endoscopic submucosal dissection versus surgery for undifferentiated-type early gastric cancer: A meta-analysis.

111 Background: It is still controversial to treat undifferentiated early gastric cancer by endoscopic submucosal dissection (ESD). Therefore, we aimed to perform a meta-analysis to investigate long-term outcomes of ESD and surgery for undifferentiated early gastric cancer. Methods: PubMed, Cochran Library, and EMBASE were used to search for relevant researches comparing endoscopic submucosal dissection and surgery for undifferentiated early gastric cancer. The methodological quality of the included publications was evaluated using the Risk of Bias Assessment tool for Non-randomized Studies. The overall survival rate, recurrence rate, adverse event rate, and complete resection rate were explored, and the odds ratio (OR) and 95% confidence interval (CI) were estimated. Results: This meta-analysis enrolled five studies, with 376 and 1148 participants undergoing ESD and surgery, respectively. Overall survival rate did not show significant difference between ESD and surgery group (OR 0.57, 95% CI 0.18 – 1.83, P = 0.34). However, ESD was associated with higher recurrence rate (OR 11.57, 95% CI 5.07 – 26.39, P &lt; 0.001) and lower complete resection rate (OR 0.03, 95% CI 0.01 – 0.11, P &lt; 0.001). Adverse event rate was similar between two groups (OR 0.95, 95% CI 0.46 – 1.96, P = 0.88). Conclusions: Despite higher recurrence rate and lower complete resection rate, ESD demonstrated similar overall survival rate and adverse event rate in the treatment of undifferentiated early gastric cancer compared to surgery.

Long-term clinical outcomes of endoscopic vs. surgical resection for early gastric cancer with undifferentiated histology.

The efficacy of endoscopic submucosal dissection (ESD) for undifferentiated early gastric cancer (UD EGC) is controversial due to the relatively high risk of lymph node metastasis. We compared long-term clinical outcomes of UD EGC between ESD and surgical resection groups. We retrospectively reviewed the medical records of patients with UD EGC treated by either ESD or surgical resection between January 2007 and December 2014. Long-term clinical outcomes were compared between the two groups in terms of survival. A total of 1147 patients were enrolled with median follow-up duration of 59.1 months. ESD and surgical resections were performed in 126 and 1021 patients respectively. Additional surgery was performed in 22 patients after ESD. There were no significant differences in overall survival [total, p = 0.641; propensity score matching (PSM), p = 0.330; expanded criteria, p = 0.512]. Although the disease-free survival rate was lower in ESD group because of the higher rate of metachronous cancer development (total, p < 0.001; PSM, p = 0.001), the difference was not significant in the group within expanded criteria (p = 0.071). ESD could be a comparable treatment option with surgical resection for UD EGC within expanded criteria in terms of long-term survival. It is mandatory to establish a meticulous indication of ESD for UD EGC considering the risk of lymph node metastasis.

Risk Factors for Lymph Node Metastasis in Undifferentiated Early Gastric Cancer

The indication for endoscopic resection is differentiated gastric cancer ≤ 2 cm in size without an ulcer, of which the depth of invasion is clinically diagnosed as tumor confined to the mucosa. Endoscopic resection is not indicated for undifferentiated gastric intramucosal carcinoma, which is associated with a high rate of lymph node metastasis. This study aimed to analyze the factors associated with lymph node metastasis and to determine the validity of endoscopic resection in patients with undifferentiated early gastric cancer (EGC). This study included 141 patients who underwent gastrectomy with lymph node dissection for undifferentiated EGC. The clinicopathological findings were retrospectively analyzed to identify the factors associated with lymph node metastasis. According to the depth of tumor invasion, lymph node metastasis was observed in 13 patients (9.2%), including three with intramucosal carcinoma (3.6%) and ten with submucosal invasive carcinoma (17.2%). Univariate analysis identified tumor size (p = 0.038), depth of tumor invasion (p = 0.008), and lymphovascular invasion (LVI) (p = 0.0002) as risk factors for lymph node metastasis. On multivariate analysis, LVI (p = 0.002) was identified as the only independent risk factor for lymph node metastasis. The use of endoscopic resection for the undifferentiated EGC should be considered carefully for patients with LVI because of the risk for lymph node metastasis.

Endoscopic Indication of Endoscopic Submucosal Dissection for Early Gastric Cancer Is Not Compatible with Pathologic Criteria in Clinical Practice.

The inappropriate selection of patients with early gastric cancer (EGC) for endoscopic submucosal dissection (ESD) may lead to additional surgery because of a non-curative resection. This study was performed to assess the accuracy of clinical decisions in ESD for EGC. A total of 607 cases of EGC treated by ESD were prospectively enrolled from January 2011 to June 2014 at a single academic hospital. The 607 EGCs were divided into three groups (overestimated, same-estimated, and underestimated) based on pre-procedure endoscopic findings (indication) and pathological diagnosis after ESD (criteria). We evaluated the discrepancy rates between pre-procedure indication and pathological criteria, and then analyzed the pre-procedure factors that could influence the occurrence of the discrepancies. The absolute, expanded, and beyond the expanded indication has its accuracy on curability criteria in 87%, 77.6%, and 55.6% of cases, respectively. The ratio of overall indication-criteria discrepancies was 250/607 (41.2%). The curability was significantly lower in the underestimated group compared to the overestimated and same-estimated groups (41.6% vs. 94.6%, 94.4%, p < 0.001). In multivariate analysis examining the predictive factors for discrepancies in the 598 EGCs with absolute/expanded indications, the endoscopic size ≥ 20mm [odds ratio (OR) 2.493, confidence interval (CI) 1.546-4.022, p < 0.001], presence of ulcers (OR 1.712, CI 1.070-2.738, p = 0.025), patient age < 60years (OR 1.689, CI 1.044-2.733, p = 0.033), and undifferentiated type EGC on forceps biopsy (OR 5.397, CI 2.027-14.369, p = 0.001) were all associated with discrepancies. Indication judged by pre-procedural endoscopy is not sufficiently accurate to be used as a good measurement for post-procedural criteria.

E‐Poster Presentations ‐ C) Endoscopy

E‐Poster Presentations ‐ C) Endoscopy

Predictive factors to diagnosis undifferentiated early gastric cancer after endoscopic submucosal dissection.

It is difficult to predict precisely whether the lesion corresponds to endoscopic resection indication. Furthermore, discrepancy may occur between endoscopic forceps biopsy (EFB) and finally resected specimen, which may be diagnosed as undifferentiated cancer and additional surgery may be required. Our study aimed to evaluate predictive factors to diagnose undifferentiated cancer after endoscopic submucosal dissection (ESD).Among the 532 patients diagnosed by ESD between January 2009 and December 2015, 557 early gastric cancer (EGC) cases were studied. Factors predicting diagnosis of undifferentiated cancer and clinical outcomes of the lesions were retrospectively analyzed.Among the 557 cases with EGC, 535 (96.1%) were diagnosed as differentiated cancer and 22 (3.9%) as the undifferentiated type with ESD. Tumor size was larger (mean size 20.67 vs 13.59 mm, P < .001) and age was lower (60.24 vs 64.50 years, P < .001) in the group with undifferentiated cancer. En bloc resection rate was similar (95.5% vs 95.9%, P = .886), but the complete resection rate was lower (72.7% vs 92.4%, P < .001) in the group with undifferentiated cancer. On multivariate analysis, tumor size ≥10 mm (OR = 11.340, P = .032), age <55 years (OR = 5.972, P = .004), surface redness (OR = 11.562, P = .024), and whitish discoloration (OR = 35.368, P < .001) were predominantly associated with undifferentiated cancer.Young age (<55 years), large tumor size (≥10 mm), surface redness, and whitish discoloration are predictors of undifferentiated cancer, and lesions with these features detected need to be treated cautiously.

A case report of prostate cancer metastasis to the stomach resembling undifferentiated-type early gastric cancer

BackgroundOccurrence of metastatic cancer to the stomach is rare, particularly in patients with prostate cancer. Gastric metastasis generally presents as a solitary and submucosal lesion with a central depression.Case presentationWe describe a case of gastric metastasis arising from prostate cancer, which is almost indistinguishable from the undifferentiated-type gastric cancer. A definitive diagnosis was not made until endoscopic resection. On performing both conventional and magnifying endoscopies, the lesion appeared to be slightly depressed and discolored area and it could not be distinguished from undifferentiated early gastric cancer. Biopsy from the lesion was negative for immunohistochemical staining of prostate-specific antigen, a sensitive and specific marker for prostate cancer. Thus, false initial diagnosis of an early primary gastric cancer was made and endoscopic submucosal dissection was performed. Pathological findings from the resected specimen aroused suspicion of a metastatic lesion. Consequently, immunostaining was performed. The lesion was positive for prostate-specific acid phosphatase and negative for prostate-specific antigen, cytokeratin 7, and cytokeratin 20. Accordingly, the final diagnosis was a metastatic gastric lesion originating from prostate cancer.ConclusionIn this patient, the definitive diagnosis as a metastatic lesion was difficult due to its unusual endoscopic appearance and the negative stain for prostate-specific antigen. We postulate that both of these are consequences of hormonal therapy against prostate cancer.

Probe-based confocal laser endomicroscopy in the margin delineation of early gastric cancer for endoscopic submucosal dissection.

We evaluated probe-based confocal laser endomicroscopy (pCLE) in the margin delineation of early gastric cancer (EGC) for endoscopic submucosal dissection in comparison with white-light imaging with chromoendoscopy (CE). We conducted a prospective, randomized controlled study from November 2013 to October 2014 in a tertiary referral hospital. A total of 101 patients scheduled for endoscopic submucosal dissection due to differentiated EGC were randomized into pCLE and CE groups (pCLE 51, CE 50). Markings were made by electrocautery at the proximal and distal tumor margins, as determined by either pCLE or CE. The distance from the marking to the tumor margin was measured in the resected specimen histopathologically and was compared between the two groups by a linear mixed model. Among 104 lesions, 80 lesions with 149 markings (pCLE 68, CE 81) were analyzed after excluding undifferentiated EGCs (n=8) and unidentifiable markings (n=13). Although the complete resection rate showed no difference between the groups (94.6% vs 93.2%, P=1.000), the median distance from the marking to the margin was shorter in the pCLE group (1.3 vs 1.8mm, P=0.525) and the proportion of the distance <1mm was higher (43.9% vs 27.6%, P=0.023) in the pCLE group. Finally, subgroup analysis with superficial flat lesions (18 lesions, 31 marking dots) showed a significantly decreased distance in the pCLE group (0.5 vs 3.1mm, P=0.007). Among EGCs with superficial flat morphology, in which the accurate evaluation of lateral extent is difficult with CE, pCLE would be useful for more precise margin delineation.

Clinical outcome after endoscopic submucosal dissection for early gastric cancer of absolute and expanded indication.

This study evaluated the clinical outcome of endoscopic submucosal dissection (ESD) in minute submucosa (SM) invasion or undifferentiated early gastric cancer (EGC) and analyzed factors related to local recurrence after ESD.We retrospectively reviewed the chart of EGC patients, who underwent ESD at our tertiary hospital between January 2009 and 2015. The patients’ characteristics and clinical outcomes were compared among an absolute indication, minute SM invasion, and undifferentiated EGC group.Of 885 total patients, 729 composed the absolute indication group; 65, the differentiated, SM invasion group; and 51, the undifferentiated, confined mucosa group. Follow-up was conducted for average (± standard deviation) 34.12 (± 10.6) months; as compared to the absolute indication group, both en bloc resection and curative resection rate were low in the other 2 groups, but there were no significant differences in procedure-related complication, local recurrence, and survival rate. Comparing the cases of ESD performed at our hospital from 2005 to 2009 with those performed between 2009 and 2015, en bloc resection (80.5% vs 89.1%, P = .001) and curative resection rate (86.2% vs 92.1%, P = .011) were higher in the latter study. Noncurative resection and tumor size of more than 2 cm were factors associated with local recurrence.ESD in minute SM invasion or undifferentiated EGC showed an unfavorable short-term outcome as compared to that in the absolute indication group, but there were no differences in local recurrence and overall survival rate. Therefore, in minute SM invasion or undifferentiated EGC patients, ESD could be recommended as a therapeutic option.

Risk factors of lymph node metastasis in undifferentiated early gastric cancers.

171 Background: The aims of this retrospective study were to analyze risk factors of lymph node metastasis undifferentiated-type early gastric cancer (UD-type EGC) and to select the suitable patient for endoscopic resection. Methods: We analyzed 368 patients who had undergone gastrectomy with lymphadenectomy for UD-type EGC between November 2001 and July 2016 at the Yeouido St. Mary’s Hospital. Using clinicopathological factors of patient age, size, an endoscopic macroscopic tumor form, ulceration, depth, histology, lymphatic involvement (LI) and venous involvement (VI), LNM risk was examined and stratified by univariate analysis and multivariate analysis. Results: Of the 368 patients, the lymph node metastases rate in patients with EGC was 48 patients (13%). 204 (55 %) had mucosal cancers and 164 (45 %) had submucosal cancers. Univariate analysis revealed &gt; 60 age, &gt; 2 cm, submucosal(sm), poorly cohesive carcinoma as significant prognostic factors. On multivariate analysis, &gt; 60 age (odd ratio , 2.20; 95% confidence interval, 1.19~4.06), submucosal(odd ratio , 9.38; 95% confidence interval, 4.08~21.56), poorly cohesive carcinoma (odd ratio, 0.33; 95% confidence interval, 0.12~0.86) were independent risk factors for lymph node involvement. Conclusions: LNM-related factors in undiff-EGC were age, depth and pathology. We proposed that risk factors for metastases should be considered when choosing surgery for EGC.

Applicability of endoscopic submucosal dissection for undifferentiated early gastric cancer: Mixed histology of poorly differentiated adenocarcinoma and signet ring cell carcinoma is a worse predictive factor of nodal metastasis

BackgroundEndoscopic submucosal dissection (ESD) is not considered an appropriate treatment for undifferentiated early gastric cancer (UEGC) due to the higher risk of nodal metastases. We aimed to investigate predictive factors for nodal metastases in UEGCs, determine whether the tumor histology is an independent factor for it, and explore whether ESD is applicable for UEGC. MethodsWe reviewed the medical records of 1837 patients who underwent curative gastrectomy for poorly differentiated adenocarcinoma, signet ring cell carcinoma, and a mixed type of both tumors between 2008 and 2012. ResultsNodal metastases were found in 208 (11.3%) patients. Multivariate analysis revealed that lymphovascular invasion and tumor histology were significantly associated with nodal metastases in mucosal cancers, the rates of which were higher in mixed type tumors (6.3%) than in the other two types (2.0–2.5%; p = 0.005). No nodal metastases were observed in poorly differentiated adenocarcinomas <2 cm and signet ring cell carcinomas <1 cm without lymphovascular invasion and confined to the mucosa. ConclusionMixed type tumors should not be considered for endoscopic resection. ESD might be applicable for mucosal tumors with poorly differentiated adenocarcinoma <2 cm and signet ring cell carcinoma <1 cm without lymphovascular invasion.

A Risk-prediction Model Based on Lymph-node Metastasis for Incorporation Into a Treatment Algorithm for Signet Ring Cell-type Intramucosal Gastric Cancer.

The aim of the study was to develop a reliable and easy-to-use risk-scoring system (RSS) to predict lymph-node metastasis (LNM) and determine the feasibility of endoscopic submucosal dissection for mucosa-confined signet ring cell carcinomas (SRCs). Fewer LNM and better survival rates have been reported for early gastric SRCs compared with other undifferentiated early gastric cancers (EGCs). Data from 1544 patients with mucosa-confined SRCs were reviewed. Stepwise logistic regression analysis determined the independent predictors of LNM. Risk scores were based on the final predictive factors for LNM, and performance was internally validated using a split-sample approach. External validation was also performed in an independent dataset (n = 208) to assess the discriminatory power of the RSS. The overall LNM incidence was 3.8% (57/1544). Three risk factors (tumor size ≥1.7 cm, tumors of elevated type, and lymphatic-vascular involvement) were significantly associated with LNM. These factors were incorporated into the RSS, and were assigned scores ranging from 0 to 4. The area under the receiver-operating characteristic curve for predicting LNM after internal and external validation was 0.68 (95% confidence interval, 0.0793-0.2865) and 0.686 (95% confidence interval, 0.618-0.748), respectively. A score of 2 points was the optimal cut-off value for LNM prediction, and the overall diagnostic accuracy was 96%. LNM were found in 2.9% and 23.8% of the low and high-risk groups of the RSS, respectively. A RSS may help to predict LNM and evaluate endoscopic submucosal dissection feasibility in patients with intramucosal SRC.

Low Incidence of Synchronous or Metachronous Tumors after Endoscopic Submucosal Dissection for Early Gastric Cancer with Undifferentiated Histology.

BackgroundGastric cancer with undifferentiated histology has different clinicopathologic characteristics compared to differentiated type gastric cancer. We aimed to compare the risk of synchronous or metachronous tumors after curative resection of early gastric cancer (EGC) via endoscopic submucosal dissection (ESD), according to the histologic differentiation of the primary lesion.MethodsClinicopathological data of patients with initial-onset EGC curatively resected via ESD between January 2007 and November 2014 in a single institution were reviewed. We analyzed the incidence of synchronous or metachronous tumors after ESD with special reference to the differentiation status of the primary lesion.ResultsOf 1,560 patients with EGC who underwent curative resection via ESD, 1,447 had differentiated type cancers, and 113 had undifferentiated type cancers. The cumulative incidence of metachronous or synchronous tumor after ESD was higher in the differentiated cancer group than in the undifferentiated cancer group (P = 0.008). Incidence of metachronous or synchronous tumor was 4.8% and 1.2% per person-year in the differentiated and undifferentiated cancer groups, respectively. The Cox proportional hazard model revealed that undifferentiated cancers were associated with a low risk of synchronous or metachronous tumors after adjusting for confounding variables (hazard ratio [95% confidence interval] = 0.287 [0.090–0.918]).ConclusionsThe rate of synchronous or metachronous tumors after curative ESD was significantly lower for undifferentiated cancers compare to differentiated cancers. These findings suggest that ESD should be actively considered as a possible treatment for undifferentiated type EGCs.

Clinical Outcomes of Endoscopic Submucosal Dissection in Patients under 40 Years Old with Early Gastric Cancer

Background/Aims: The clinicopathologic features of gastric cancer in young patients are different from those of older patients. However, endoscopic submucosal dissection (ESD) is performed regardless of age. The purpose of this study was to characterize younger patients (≤40 years) who underwent ESD for early gastric cancer (EGC) and analyze the results of ESD. Materials and Methods: From January 2006 to June 2014, 55 patients aged 40 years or younger with newly diagnosed EGC under- went ESD at two tertiary hospitals. The clinicopathologic features of EGC and clinical outcomes of ESD in these young patients were reviewed retrospectively. Results: A total 55 patients with 57 EGC lesions underwent ESD. Female sex, superficial flat or depressed lesions, and un- differentiated histology were more common in younger patients than in older patients in our institutional ESD cohort. The en bloc resection rate was 92.7% and the complete resection rate was 94.5%. Although there was a high proportion of undifferentiated can- cer in the younger patient group, the curative resection rate was 72.7%. Among 15 patients with non-curative resection, 4 patients underwent additional surgery and 1 patient underwent argon plasma coagulation at the ESD ulcer margin. Eight patients were placed under close surveillance without additional treatment, and no recurrent tumors developed, with a median follow-up period of 37.2±23.6 months. Conclusions: Younger EGC patients who underwent ESD showed the typical characteristics seen in younger patients with gastric cancer. ESD in younger EGC patients showed comparable outcomes to those in patients with undifferentiated EGC in general. (Korean J Helicobacter Up Gastrointest Res 2016;16:139-146)