Analysis of postoperative morbidity and mortality following surgery for gastric cancer. Surgeon volume as the most significant prognostic factor

Current status of lymph node dissection in gastric cancer

Gastrectomy with lymph node (LN) dissection has been regarded as the standard surgery for gastric cancer (GC), however, the rational extent of lymphadenectomy remains controversial. Though gastrectomy with extended lymphadenectomy beyond D2 is classified as a non-standard gastrectomy, its clinical significance has been evaluated in many studies. Although hard evidence is lacking, D2 plus superior mesenteric vein (No. 14v) LN dissection is recommended when harbor metastasis to No. 6 nodes is suspected in the lower stomach, and dissection of splenic hilar (No. 10) LN can be performed for advanced GC invading the greater curvature of the upper stomach, and D2 plus posterior surface of the pancreatic head (No. 13) LN dissection may be an option in a potentially curative gastrectomy for cancer invading the duodenum. Prophylactic D2+ para-aortic nodal dissection (PAND) was not routinely recommended for advanced GC patients, but therapeutic D2 plus PAND may offer a chance of cure in selected patients, preoperative chemotherapy was considered as the standard treatment for GC with para-aortic node metastasis. There has been no consensus on the extent of lymphadenectomy for the adenocarcinoma of the esophagogastric junction (AEG) so far. The length of esophageal invasion can be used as a reference point for mediastinal LN metastases, and the distance from the esophagogastric junction to the distal end of the tumor is essential for determining the optimal extent of resection. The quality of lymphadenectomy may influence prognosis in GC patients. Both hospital volume and surgeon volume were important factors for the quality of radical gastrectomy. Centralization of GC surgery may be needed to improve prognosis.

Efficacy of Endoscopic Vacuum-Assisted Closure Treatment for Postoperative Anastomotic Leak in Gastric Cancer

Background/Aims

Endoscopic vacuum-assisted closure (EVAC) has been attempted as new nonsurgical treatment for anastomotic leakage. We aimed to evaluate the clinical outcomes of EVAC and compare its efficacy with the self-expandable metallic stent (SEMS) for postgastrectomy leakage.

Methods

Between January 2007 and February 2018, 39 patients underwent endoscopic treatment for anastomotic leakage after gastric cancer surgery. Of them, 28 patients were treated with SEMS, seven with EVAC after SEMS failure, and four with EVAC. We retrospectively compared the clinical characteristics and therapeutic outcomes between EVAC (n=11) and SEMS (n=28).

Results

The median follow-up duration was 17 months (interquartile range, 9 to 26 months) in both groups. In comparison of clinical characteristics between two groups, only the median size of the leak was larger in the EVAC group than in the SEMS group (2.1 cm vs 1.0 cm; p<0.001). All EVAC cases healed successfully; however, two cases (7.1%) failed to heal in the SEMS group. Anastomotic stricture occurred one case (9.1%) in EVAC and four cases (14.3%) in SEMS within 1 year after endoscopic treatment. The median treatment duration of EVAC was shorter than that of SEMS (15 days vs 36 days; p<0.001). Median weight loss after therapy was similar in both groups (8.0 kg in EVAC vs 9.0 kg in SEMS; p=0.356).

Conclusions

EVAC can be effective endoscopic treatment for postgastrectomy anastomotic leakage. Substantial leakage could be an important clinical factor for considering EVAC as a treatment option. Large randomized controlled trials are needed to confirm the efficacy of EVAC.

Tac2-N serves an oncogenic role and promotes drug resistance in human gastric cancer cells

Gastric cancer is one of the most common types of malignancy worldwide. Tac2-N (TC2N) has been reported to serve as either an oncogene or tumor suppressor in numerous different types of cancer; however, the role of TC2N in gastric cancer remains poorly understood. The present study aimed to investigate the role of TC2N in gastric cancer and reveal its regulatory mechanism. A Cell Counting Kit-8 assay was used to analyze the cell proliferation rate, while wound healing and Transwell Matrigel assays were performed to determine the cell migratory and invasive abilities, respectively. Cell cycle distribution was determined by flow cytometric analysis, and the expression levels of TC2N, P-glycoprotein (P-gp), cyclin D1, CDK4, cyclin E1, MMP2, MMP9 and N-Myc downstream regulated gene 1 were analyzed using reverse transcription-quantitative PCR or western blotting. Bioinformatics analysis revealed a high expression of TC2N in patients with gastric cancer. The experimental results revealed that TC2N expression levels were significantly unregulated in gastric cancer cell lines. The knockdown of TC2N in AGS cells significantly inhibited the cell proliferation rate and induced cell cycle arrest at the G0/G1 phase, while downregulating cyclin E1, cyclin D1 and CDK4 expression levels. The knockdown of TC2N also inhibited cell migration and invasion. Furthermore, the knockdown of TC2N improved the sensitivity of AGS cells to cisplatin, paclitaxel and 5-fluorouracil, and downregulated the protein expression levels of P-gp. By contrast, TC2N overexpression exerted the opposite effects in AGS cells. In conclusion, the findings of the present study indicated that the genetic knockdown of TC2N may inhibit cell proliferation, migration and invasion, while inducing cell cycle arrest in the G1/S phase and reversing the drug resistance of AGS cells, which may be partly through inhibiting P-gp expression levels. Thus, TC2N may serve as a novel diagnostic marker and therapeutic target for patients with gastric cancer.

MiR-183 affects biological behaviors of gastric cancer SGC-7901 cells by regulating the Wnt/β-catenin signaling pathway

BACKGROUND

MiR-183 is lowly expressed in various tumor tissues such as gastric cancer, breast cancer, and bladder cancer, and plays a role as a tumor suppressor gene. However, its mechanism of action in gastric cancer is still not fully understood. Studies have shown that miR-183 can inhibit the growth, migration, and invasion of osteosarcoma cells by regulating the Wnt/β-catenin signaling pathway, and the high activation of the Wnt/β-catenin signaling pathway is closely related to the occurrence and metastasis of gastric cancer. However, it is still unclear whether miR-183 affects the biological behaviors of gastric cancer cells by regulating the Wnt/β-catenin signaling pathway.

AIM

To investigate the effect of miR-183 on the biological behaviors of gastric cancer cells and the possible mechanism involved.

METHODS

qRT-PCR was used to detect the expression of miR-183 in different gastric cancer cell lines. After gastric cancer SGC-7901 cells were transfected with miR-183 mimic or miR-NC, the transfection efficiency was detected by qRT-PCR, the proliferation of SGC-7901 cells was detected by MTT proliferation assay, the apoptosis of SGC-7901 cells was detected by flow cytometry, and the invasion and migration of SGC-7901 cells were detected by Transwell assay. Western blot was used to detect the expression of apoptosis-related and Wnt/β-catenin signaling pathway-related proteins. The SRC-7901 cells overexpressing miR-183 were treated with Wnt/β-catenin signaling pathway agonist lithium chloride to observe the changes in biological behaviors of SGC-7901 cells.

RESULTS

Compared with normal gastric mucosal epithelial GES-1 cells, the expression of miR-183 was significantly decreased in the four gastric cancer cell lines (P < 0.05). The expression level of miR-183 was significantly increased in SGC-7901 cells transfected with miR-183 mimic (P < 0.05). After overexpression of miR-183, the proliferation of SGC-7901 cells decreased (P < 0.05), the apoptosis rate and the protein expression of Bax and cleaved Caspase-3 increased (P < 0.05), and cell migration and invasion decreased (P < 0.05). The expression levels of β-catenin, p-GSK-3β, and cyclin D1 proteins were down-regulated (P < 0.05), and the expression level of GSK-3β protein was up-regulated (P < 0.05). Activation of the Wnt/β-catenin signaling pathway partially reversed the inhibitory effect of miR-183 overexpression on the proliferation, invasion, and migration of SGC-7901 cells and the promotive effect on cell apoptosis (P < 0.05).

CONCLUSION

MiR-183 inhibits the proliferation, invasion, and migration of human gastric cancer SGC-7901 cells and promotes cell apoptosis possibly by inhibiting the Wnt/β-catenin signaling pathway.