Differentiated-type predominant mixed-histology-type early gastric cancer is a significant risk factor for endoscopic non-curative resection regardless of tumor size

Clinicopathological characteristics of early gastric cancer with different level of undifferentiated component and nomogram to predict lymph node metastasis

Background

Few studies showed that mixed type early gastric cancer (EGC) relates to higher risk of lymph node metastasis. We aimed to explore the clinicopathological feature of GC according to different proportions of undifferentiated components (PUC) and develop a nomogram to predict status of lymph node metastasis (LNM) in EGC lesions.

Methods

Clinicopathological data of the 4,375 patients who underwent surgically resection for gastric cancer in our center were retrospectively evaluated and finally 626 cases were included. We classified mixed type lesions into five groups (M1:0% < PUC ≤ 20%, M2:20%<PUC ≤ 40%, M3:40%<PUC ≤ 60%, M4:60%<PUC ≤ 80%, M5:80%<PUC < 100%). Lesions with 0% PUC were classified as pure differentiated group (PD) and lesions with 100% PUC were classified as pure undifferentiated group (PUD).

Results

Compared with PD, LNM rate was higher in group M4 and group M5 (p < 0.05 after Bonferroni correction). Differences of tumor size, presence of lymphovascular invasion (LVI), perineural invasion and invasion depth also exist between groups. No statistical difference of LNM rate was found in cases who met the absolute endoscopic submucosal dissection (ESD) indications for EGC patients. Multivariate analysis revealed that tumor size over 2 cm, submucosa invasion to SM2, presence of LVI and PUC level M4 significantly predicted LNM in EGC. With the AUC of 0.899(P < 0.05), the nomogram exhibited a good discrimination. Internal validation by Hosmer-Lemeshow test showed a good fitting effect in model (P > 0.05).

Conclusion

PUC level should be considered as one of the predicting risk factors of LNM in EGC. A nomogram that predicts the risk of LNM in EGC was developed.

Differentiated/undifferentiated mixed type is a prognostic factor for T2/T3 gastric cancer patients

OBJECTIVES

This work aimed to find the association of mixed-type histology and prognosis of T2/T3 GC patients.

METHODS

Eligible T2/T3 gastric cancer patients at our institution were identified. The histological types and risk factors affecting OS were examined. Survival differences were assessed by log-rank tests and Kaplan-Meier curves.

RESULTS

The study identified 972 T2/T3 gastric cancer patients, including 283 differentiated-type patients, 544 undifferentiated-type patients and 145 mixed type. Mixed-type histology was associated with shorter 5-year OS (DT vs UDT vs MT:57.5% vs 44.9% vs 39.6%, P = 0.002). MT histology can be predictive for prognosis of T2/T3 GC patients (HR for OS: 1.386, 95% CI: 1.028-1.868, P = 0.032), and its malignant potential is not inferior to UDT. In the subgroup analysis, MT can potentially be independent risk factor for non-distal GC patients (P = 0.010).

CONCLUSION

This study reported that mixed histology could be regarded as a potential prognostic factor for T2/T3 gastric cancer patients, especially for those with non-distal cancer. MT patients have higher incidence of metastasis and recurrence and had poorer prognosis than those with pure histological type. It is necessary for MT patients to have preoperative pathological examination for accurate histologic classification, so as to make the comprehensive treatment strategies..

Pitfalls in the Interpretation of Publications about Endoscopic Submucosal Dissection of Early Gastric Cancer with Undifferentiated-Type Histology

Endoscopic submucosal dissection (ESD) is a standard treatment for patients with gastrointestinal neoplasms with a negligible risk of lymph node metastasis. ESD enables en bloc resection of gastrointestinal neoplasms and organ preservation, thereby, avoiding surgical treatment. Although small (<2 cm) intramucosal early gastric cancer with undifferentiated-type histology (EGC-UH) without ulceration is included in the expanded criteria for ESD, controversies remain due to different biology and characteristics compared to EGC with differentiated-type histology. The authors previously presented studies about the technical feasibility of ESD for these lesions using a meta-analysis and retrospective multicenter analysis. However, many pitfalls were identified in the interpretation of studies analyzing histologic discrepancy, mixed-type histology, criteria-based analysis of therapeutic outcomes, interpretation of curative resection, and long-term clinical outcomes. In this review, the authors discuss pitfalls in the interpretation of publications on ESD for EGC-UH.

Endoscopic submucosal dissection of early gastric cancer with mixed-type histology: Protocol for a systematic review and meta-analysis

BACKGROUND

Endoscopic submucosal dissection (ESD) is a primary treatment for the early gastric cancer (EGC) who have a negligible risk of lymph node metastasis satisfying specific criteria. These criteria are histologically categorized by EGC with differentiated-type histology (EGC-DH) and undifferentiated-type histology (EGC-UH). However, gastric cancer is histologically heterogenous and there has been no specific criteria for EGC with mixed-type histology (EGC-MH). Moreover, therapeutic outcomes of ESD for EGC-MH have not been clearly described.

METHODS

We will search the core databases (MEDLINE (through PubMed), the Cochrane Library, and Embase) from their inception to November 2018 using pre-established searching strategy by 2 independent evaluators. The P.I.C.O. is as follows; Patients: who have EGC-MH, Intervention: ESD, Comparison: none, Outcome: at least one among the rate of complete resection, curative resection, en bloc resection, recurrence or procedure-related adverse event that enabled an evaluation of feasibility of ESD. All types of study design will be sought and publications in English with full-text will be included. The risk of bias will be assessed using the ROBINS-I tool. Descriptive data synthesis is planned and quantitative synthesis will be used if the included studies are sufficiently homogenous (pooled therapeutic outcomes data with 95% confidence intervals). Publication bias will be assessed with quantitative analyses if more than 10 articles are enrolled.

RESULTS

The results will provide evidence for validity of current ESD criteria in addition to the technical feasibility of ESD for EGC-MH.

CONCLUSION

This study will provide evidence of ESD for EGC-MH.