Comparison of Short-term and Three-year Oncological Outcomes Between Robotic and Laparoscopic Gastrectomy for Gastric Cancer: A Large Multicenter Cohort Study

OBJECTIVE

To compare the short-term and long-term outcomes between robotic gastrectomy (RG) and laparoscopic gastrectomy (LG) for gastric cancer.

BACKGROUND

The clinical outcomes of RG over LG have not yet been effectively demonstrated.

METHODS

This retrospective cohort study included 3599 patients with gastric cancer who underwent radical gastrectomy at eight high-volume hospitals in China from January 2015 to June 2019. Propensity score matching was performed between patients who received RG and LG. The primary end point was 3-year disease-free survival (DFS).

RESULTS

After 1:1 propensity score matching, 1034 pairs of patients were enrolled in a balanced cohort for further analysis. The 3-year DFS in the RG and LG was 83.7% and 83.1% ( P =0.745), respectively, and the 3-year overall survival was 85.2% and 84.4%, respectively ( P =0.647). During 3 years of follow-up, 154 patients in the RG and LG groups relapsed (cumulative incidence of recurrence: 15.0% vs 15.0%, P =0.988). There was no significant difference in the recurrence sites between the 2 groups (all P >0.05). Sensitivity analysis showed that RG had comparable 3-year DFS (77.4% vs 76.7%, P =0.745) and overall survival (79.7% vs 78.4%, P =0.577) to LG in patients with advanced (pathologic T2-4a) disease, and the recurrence pattern within 3 years was also similar between the 2 groups (all P >0.05). RG had less intraoperative blood loss, lower conversion rate, and shorter hospital stays than LG (all P >0.05).

CONCLUSIONS

For resectable gastric cancer, including advanced cases, RG is a safe approach with comparable 3-year oncological outcomes to LG when performed by experienced surgeons.

Loss of PTPN4 activates STAT3 to promote the tumor growth in rectal cancer

Colorectal cancer (CRC) is one of the most common types of malignant tumor. Many genetic factors have been proved to show high association with the occurrence and development of CRC and many mutations are detected in CRC. PTPN4/PTP‐MEG1 is a widely expressed non–receptor protein tyrosine phosphatase. Over the past three decades, PTPN4 has been demonstrated in the literature to participate in many biological processes. In this study, we identified a nonsense mutation of PTPN4 with a mutation ratio of 90.90% from 1 case of rectal cancer, leading to loss of function in PTPN4 gene. Several somatic mutations occurred in 5/137 rectal cancer samples from The Cancer Genome Atlas Rectum Adenocarcinoma (TCGA READ) database. Interestingly, we found that PTPN4 negative cytoplasm staining was more prone to lymphatic metastasis (N = 50, P = 0.0153) and low expression of PTPN4 in rectal cancer was highly associated with poor prognosis. Overexpression of PTPN4 suppressed the cell growth, and moreover, the loss of PTPN4 accelerated cell growth and boosted clonogenicity of CRC cells. Furthermore, we revealed that the deletion of PTPN4 promoted the tumor formation of NCM460 cells in vivo. In terms of the molecular mechanism, we demonstrated that PTPN4 dephosphorylates pSTAT3 at the Tyr705 residue with a direct interaction and suppresses the transcriptional activity of STAT3. In summary, our study revealed a novel mechanism that the tumorigenesis of colorectal cancer might be caused by the loss of PTPN4 through activating STAT3, which will broaden the therapy strategy for anti–rectal cancer in the future.

Overexpression of CREPT confers colorectal cancer sensitivity to fluorouracil

AIM

To investigate expression of cell cycle-related and expression-elevated protein in tumor (CREPT) in colorectal cancer (CRC) and determine its prognostic value in response to 5-fluorouracil (5-FU).

METHODS

The relative expression of CREPT in CRC tumor samples was determined using immunohistochemistry. The protein content in cell lines was analyzed by immunoblotting. Cell viability was measured with the CCK-8 assay. Cell cycle and apoptosis analyses were performed with flow cytometry.

RESULTS

CREPT was overexpressed in CRC tissues and correlated with histological grade. Clinicopathological analysis indicated that CREPT was positively related to tumor progression. Exogenous expression of CREPT stimulated cell proliferation and accelerated the cell cycle. More importantly, high expression of CREPT sensitized CRC cells to 5-FU treatment. Furthermore, we demonstrated that 5-FU elicited significant apoptosis in CREPT-positive cells.

CONCLUSION

Aberrant overexpression of CREPT contributes to tumorigenesis of CRC by promoting cell proliferation and accelerating the cell cycle, and confers sensitivity to 5-FU. CREPT is a potential prognostic biomarker for 5-FU in CRC.

Microsatellite instability of gastric cancer and precancerous lesions

OBJECTIVE

To investigate whether microsatellite instability (MSI) of gastric cancer and precancerous lesions were existed and its effect.

METHODS

Laser microdissection was used. Gastric, intestinal metaplasia, dysplasia and normal mucosa were collected respectively. Five microsatellite loci were selected and MSI was detected by denaturing high-performance liquid chromatography.

RESULTS

In the five microsatellite loci REF-positive phenotype, intestinal metaplasia MSI was 20.7%. Dysplasia MSI was 22.4%. Gastric MSI was 47.9%, and there was no MSI in normal gastric mucosa.

CONCLUSION

MSI gradually increased from precancerous lesions to gastric cancer. The early detection of MSI may be a potential early warning indicator for early diagnosis of gastric cancer.

Detection of microsatellite instability in gastric cancer and dysplasia tissues

OBJECTIVE

We aimed to investigate the association between gastric cancer and microsatellite instability (MSI) in the present study.

METHOD

Phenol-chloroform method was employed for DNA extraction from the cancer tissues of 65gastric cancer patients and the dysplasia tissues and normal control tissues of 32 non-gastric cancer patients. The microsatellite loci Bat25, Bat26, D2S123, D5S346 and D17S250 were detected by using PCR-SSCP silver staining technique, and the MSI of the gastric cancer tissues and the precancerous tissues was analyzed.

RESULTS

Of 65 gastric cancer cases, MSI was detected in 43 cases, with the detection rate of 66.2%. There were 13 cases showing MSI-H and 30 cases showing MSI-L, accounting for 30.2% and 69.8%, respectively. Among 32 cases of dysplasia tissues, MSI was detected in 10 cases, with the detection rate of 31.3%. Two cases of dysplasia tissues showed MSI-H and 8 cases showed MSI-L, accounting for 20.0% and 80.0%, respectively.

CONCLUSION

Gastric cancer patients had a high detection rate of MSI. It is speculated that MSI is another molecular mechanism of carcinogenesis and may serve as a sensitive diagnostic indicator of gastric cancer.

Impact of early postoperative enteral nutrition on clinical outcomes in patients with gastric cancer

The impact of early enteral nutrition (EEN) on clinical outcomes of gastric cancer patients was investigated. Three hundred pa-tients undergoing gastric cancer surgery from July 2010 to May 2014 were randomly divided into experimental and control groups (n = 150/group). Experimental group patients received enteral nutrition in water during the early postoperative period. Control group patients received conventional perioperative treatment. Patients' clinical outcomes, post-operative immune function, and nutritional statuses were compared, which revealed that the postoperative fever duration (80.2 ± 6.0 vs 88.1 ± 8.1 h, P < 0.05), anal exhaust time (78.8 ± 9.3 vs 85.3 ± 8.4 h, P < 0.05), and length of hospitalization (7.73 ± 2.13 vs 9.77 ± 1.76 days, P < 0.01) differed significantly. Treatment costs in thousands of dol-lars were 31.24 ± 3.21 for the experimental group and 35.61 ± 2.32 for the control group; this difference was statistically significant (P < 0.01). The incidence of postoperative complications did not significantly differ between the experimental and control groups [14.0% (21/150) vs 17.3% (26/150), P > 0.05]. At postoperative days 3 and 7, the CD3(+), CD4(+), natural killer cell, albumin, and prealbumin levels and CD4(+)/CD8(+) ra-tio were significantly higher in the experimental group than the control group (all P < 0.05). CD8(+) cell counts were significantly lower in the experimental group than the control group (P < 0.05). Postsurgical oral EEN can improve nutritional status and immune function and promote early recovery of intestinal function in patients with gastric cancer.

The postoperative clinical outcomes and safety of early enteral nutrition in operated gastric cancer patients

PURPOSE

This study investigated the impact of early enteral nutrition (EEN) on the clinical outcomes of gastric cancer patients after radical gastrectomy.

METHODS

Four hundred gastric cancer patients undergoing radical gastrectomy of any extend with D2 nodal dissection were randomly divided into an experimental and a control group with 200 cases in each group. Patients in the control group received postoperative parenteral nutrition (PN), while patients in the experimental group received postoperative EEN. After treatment, the clinical outcomes, postoperative immune function, and nutritional status of the two groups were evaluated.

RESULTS

The postoperative fever time, intestinal function recovery time, anal exhaust time, and the length of hospital stay for patients in the experimental group were significantly shorter than those of the control group. We did not find significant differences in anastomotic leak, postoperative ileus and regurgitation between the two groups. The activities of multiple immune cell types, including CD3⁺, CD4⁺, CD4⁺/CD8⁺, and natural killer (NK) cells, were significantly lower in both groups on postoperative day 1 when compared with the preoperative levels (p<0.05). The level of CD8⁺ was not significantly different between the two groups (p>0.05). After treatment, levels of CD3⁺, CD4⁺, CD4⁺/CD8⁺, and NK cells in the experimental group patients were 35.6 ± 4.2, 42.2 ± 3.0, 1.7 ± 0.3, and 27.3 ± 5.3%, respectively, on postoperative day 7, which were similar to the preoperative levels. The immune cell levels from the control group patients remained significantly lower when compared with preoperative values; in addition, these values were also significantly lower when compared with the EEN patients (p<0.05) CONCLUSION: For gastric cancer patients undergoing radical gastrectomy, the clinical outcome, immune function and nutritional status after EEN were significantly improved. These data suggest the widespread use of EEN in clinical practice.

A missense mutation (S3660L) in MLL3 gene influences risk of gastric cancer

PURPOSE

Several studies indicated that the expression level of MLL3 gene in gastric cancer tissue was associated with prognosis, and previous studies also suggested that genetic polymorphisms of MLL3 were related to the risk for gastric cancer. The present study aimed to investigate the association of a missense mutation (S3660L) in the MLL3 gene with gastric cancer risk in a Chinese population.

METHODS

In the present study, we identified a novel missense mutation in MLL3 gene (S3660L) by directly sequencing method in 48 gastric cancer patients. To further explore the relation between gastric cancer and this mutation, we selected 354 gastric cancer patients and 377 healthy control subjects and designed a case-control study.

RESULTS

We found that the AG genotype (14.9 vs 6.40%, odds ratio/OR=2.58, 95% CI: 1.33-4.54, p<0.001) and A allele (7.5 vs 3.2%, OR=2.46, 95% CI: 1.55~5.34, p<0.001) were common in the gastric cancer patients than in the control subjects.

CONCLUSION

We concluded that this novel missense (S3660L) mutation in MLL3 gene is likely to increase the gastric cancer risk.

[Clinical and pathological characteristics of Helicobacter pylori-associated chronic gastritis]

To define the clinical and pathological characteristics of Helicobacter pylori-associated gastritis, 173 patients with chronic gastritis, including 99 Hp-positive and 74 Hp-negative patients were studied. We found that there were no significant differences between Hp-positive and Hp-negative patients with regard to clinical symptoms, gastric acid secretion and serum basal gastrin level, whereas the grades of chronic gastritis and active gastritis were markedly higher in Hp-positive patients. 91.2% of patients with active gastritis had evidence of Hp infection. With the increase in Hp density, the proportion of high grades (II and III) gastritis tended to increase, especially the severe active gastritis. In addition, glandular atrophy and intestinal metaplasia in antral mucosa were significantly commoner in Hp-positive patients. There were no significant differences between the two groups in duodenogastric reflux rate, but the reflux rate over moderate degree in Hp-positive patients (19.59%) was somewhat lower that in Hp-negative patients (36.36%) (P = 0.09).

[An urease enzyme linked immunosorbent assay for detection of Helicobacter pylori infection]

A sensitive and specific serological diagnostic test for Helicobacter pylori infection has been developed and validated in 120 patients with dyspeptic symptoms undergoing endoscopy. This test is to use urease, a protein unique to H. pylori, as the basis for the enzyme linked immunosorbent assay (ELISA) that detects serum H. pylori urease antibodies. The ELISA mean optical density (OD) in H. pylori-positive group is higher than that in H. pylori-negative group (0.57 +/- 0.23 vs 0.24 +/- 0.15, P < 0.001), a cut-off 0.3 OD yields a sensitivity of 95% and a specificity of 93%. Serum absorption test showed that Escherichia coli, Klebsiella pneumonia, Proteus mirabilis, Yersinia enterocolotica, Pseudomonas aeruginosa cell lysate do not influence serum H. pylori urease antibody level, though they all have urease except E. coli. The result implied that H. pylori urease can be a good antigen to detect serum H. pylori antibody and it would be useful for epidemiological survey and routine diagnostic approach. Nearly half of the blood donors showed positive result with H. pylori urease antibody. It is suggested that H. pylori infection is quite common in the asymptomatic population.

[Duodenal ulcer disease: Helicobacter pylori and hyperchlorhydria]

Basal and pentagastrin-stimulated gastric acid secretion and basal serum gastrin level were investigated in 55 active duodenal ulcer patients with antral colonization with Helicobacter pylori (HP) and 17 patients without. Our study shows that basal (BAO) and pentagastrin-stimulated gastric acid secretion (MAO and PAO) were significantly higher in HP positive than in HP negative patients with duodenal ulcer disease. There were also a tendency to increase in basal serum gastrin concentration in HP positive patients. We suggest that antral HP increases antral gastrin release and gastric secretion. Increased acid secretion then causes duodenal ulcers by producing a low intraduodenal pH.

[Enzyme-linked immunosorbent assay for the serodiagnosis of Campylobacter pylori infection]

Antibody activities to campylobacter pylori in serum were estimated by an enzyme-linked immunosorbent assay (ELISA) to crude antigens, prepared by sonication of whole organisms obtained from bacterial culture in 100 patients with chronic gastritis. Significantly raised serum IgG antibody activities to C. pylori was found in colonised patients with gastritis, especially in patients with active gastritis. High activities were also found beyond the age of 30. In 6 patients cleared of C. pylori with furazolidone and/or colloidal bismuth subcitrate (De-NoL), serial testing has shown a fall in activity to normal level by 1/2 year in 4 patients. The specificity and sensitivity of the sero-diagnostic assay was 85.3% and 97% respectively. The positive and negative predictive values were 92.8% and 93.5% respectively. The results indicate that such a serodiagnostic assay could be used to screen patients with C. pylori colonisation in epidemiological surveys.

[Comparison of colloidal bismuth subcitrate with ranitidine in healing and relapse of Campylobacter pylori-associated duodenal ulcers]

Eighty patients with Campylobacter pylori-associated duodenal ulcer disease were randomly allocated to receive colloidal bismuth subcitrate (CBS)tablet 120 mg four times a day or ranitidine 150 mg twice daily in a trial comparing the effects of these drugs in short-term healing and post-healing relapse rates of duodenal ulceration. At 8 weeks 88.1% (37/42) of those on CBS and 92.1% (35/38) of those on ranitidine had ulcers healed. The difference is not significant. After ulcer healing, the cumulative rates of relapse, as determined endoscopically, for symptomatic and asymptomatic ulcers were 19.4% (6/31) for CBS and 46.7% (14/30) for ranitidine at 6 months (P less than 0.05) and 41.9% (13/31) for CBS and 73.3% (22/30) for ranitidine at 12 months (P less than 0.05). As campylobacter pylori was cleared in 35 of the 42 patients (83.3%) in the CBS group, while only one of the 38 patients (2.63%) in the ranitidine group (P less than 0.005), it is possible that the clearance of Campylobacter pylori by CBS is instrumental to the reduction of the rate of reulceration.

[Comparison of endoscopy and the milk 99mTc-EHIDA test in assessing duodenogastric reflux]

Duodenogastric reflux was estimated in 101 patients with chronic gastritis by means of endoscopy and milk 99mTc-EHIDA test. 61 patients (60.4%) were deemed to be duodenogastric reflux positive by endoscopy, as compared to 40 patients (39.6%) by milk 99mTc-EHIDA test. These differences are statistically significant (P less than 0.005). The discrepancy arises largely from the error in endoscopic estimation of duodenogastric reflux. In a group of 58 patients who were mild to moderate reflux positive by endoscopy, the assessment made by the milk 99mTc-EHIDA test was reflux positive in only 33 (57%). In other words more than 40% of the endoscopically reflux positive patients did not show reflux with 99mTc activity in the stomach. Measurement of the ratio of 99mTc activity in gastric aspirates to the total 99mTc activity injected intravenously was carried out in 13 patients. A perfect correlation was found between the ratio and the grading of duodenogastric reflux estimated by the milk 99mTc-EHIDA test. This finding suggests that by using the milk 99mTc-EHIDA test, duodenogastric reflux may be monitored semiquantitatively without recourse to a nasogastric tube. Furthermore, 10 patients were evaluated twice by the milk 99mTc-EHIDA test at intervals ranging from 3-14 days. In 8 patients the results were identical. This indicates the good reproducibility of the test. This study demonstrates that milk 99mTc-EHIDA test is a more physiological and more accurate method of studying duodenal contents in the stomach, than endoscopy.

[Effect of antacids on the bioavailability and therapeutic efficacy of cimetidine]

Five patients with duodenal ulcer received cimetidine and after an interval of four days cimetidine with antacid. Cimetidine in serum was analysed with high performance liquid chromatography. There was no significant difference in the values of the pharmacokinetic parameters of cimetidine (Cmax, tmax and AUC) when taking cimetidine alone and cimetidine plus antacid. 53 outpatients with endoscopically proven duodenal ulcer were evaluated in a randomized study, so as to compare the therapeutic effect of cimetidine and aluminum hydroxide gel plus cimetidine. 18 of 26 patient taking cimetidine alone (69.2%) and 19 of 27 patients taking cimetidine plus antacid (70.4%) had their ulcer completely healed after 4 weeks. The overall healing rates after 8 weeks for the groups taking cimetidine alone and cimetidine plus antacid were 80.0% and 92.6% respectively with no significant difference. This study indicates: (1) Simultaneous administration of aluminum hydroxide gel does not alter the bioavailability of cimetidine. (2) Combined administration of aluminum hydroxide gel and cimetidine does not alter the therapeutic effect of cimetidine in patients with duodenal ulcer.

[Clinical characteristics of bile reflux gastritis]

Thirty patients with bile reflux gastritis, proven by gastroscopy and Milk 99mTc-EHIDA Test, were studied and their clinical features were compared with those of patients with non-bile reflux gastritis. The symptoms were similar in both groups of patients, whereas histologically in bile reflux gastritis there were more hyperemia of mucosa, more obvious edema in lamina propria and more polymorphonuclear infiltration. Furthermore, in bile reflux gastritis the histological changes were more severe in the antrum and decreased in severity toward the cardia. Acid secretion was significantly lower in patients with bile reflux gastritis than in patients with non-bile reflux gastritis while the serum gastrin level was significantly higher in the former than in the latter group. The authors suggest that there may be a vicious cycle among duodenogastric reflux, low level of gastric acidity and high level of serum gastrin. When duodenogastric reflux occurs, not only the bile salts damage the gastric mucosa and subsequently cause the back diffusion of hydrogen ion but also the alkaline duodenal juice neutralizes the gastric acid, resulting in decrease of gastric acidity. The bile salts and low acidity can stimulate the release of serum gastrin which antagonizes the effects of cholecystokinin and secretin on pyloric tone and aggravates the duodenogastric reflux.

Failure of pancreatic polypeptide release in congenitally obese mice

Obesity can be reversed in ob/ob mice by parabiosis to lean littermates, by islet transplantation, and by injection of pancreatic polypeptide. These observations suggest that obese mice have functioning satiety centers but lack a circulating satiety factor of pancreatic origin which could be pancreatic polypeptide. This hypothesis has been difficult to test because antisera currently available do not cross-react with rodent pancreatic polypeptide. We have raised an antiserum against the biologically active carboxyl-terminal hexapeptide that measures mouse pancreatic polypeptide specifically. This antiserum has been used to compare circulating and tissue concentrations of pancreatic polypeptide in obese and lean mice. Although pancreatic contents were significantly (p less than 0.01) increased in obese mice (237 +/- 34 pmol/g) compared with lean littermates (107 +/- 20 pmol/g), no postprandial increase in circulating concentrations was observed in obese mice. The hypothesis that obese mice lack a satiety factor of pancreatic origin could be explained by the failure of release of pancreatic polypeptide.