Prognosis of Adjuvant SOX vs XELOX Chemotherapy for Gastric Cancer After D2 Gastrectomy in Chinese Patients

Inhibition of PI3K/Akt/mTOR Signaling Pathway Suppresses 5-Fluorouracil Resistance in Gastric Cancer

BACKGROUND

At present, 5-Fluorouracil (5-FU) is a crucial anti-cancer drug and is widely used for the treatment of various carcinomas, including gastric cancer (GC). The resistance of GC cells to 5-FU is still a matter of great concern.

OBJECTIVE

To illustrate the role of PI3K/Akt/mTOR signaling in regulating the cell cycle progression and migration of 5-FU-resistant GC cells.

MATERIAL AND METHODS

After the establishment of drug-resistant GC cell lines, the effects of 5-FU and/or BEZ235 (the dual inhibitor of PI3K and mTOR) on the activity of parental or drug-resistant GC cells were explored. The viability and localization of GC cells (MKN-45 and MKN-74) and their drug-resistant cells (MKN-45/R and MKN-74/R) were assessed using MTT assays and immunofluorescence staining. The impacts of 5-FU and/or BEZ235 on GC cell cycle progression and cell migration were assessed via flow cytometry analyses and wound healing assays, respectively. GC tissues were collected from patients with GC sensitive or refractory to 5-FU chemotherapy. RT-qPCR and western blot were conducted to measure PI3K, AKT, and mTOR levels in GC cells or tissues.

RESULTS

After 5-FU treatment, GC cells displayed 5-FU resistance and the viability of drug-resistant cells (MKN-45/R and MKN-74/R) was higher than that of parental cells (MKN-45 and MKN-74). The IC50 values for MKN-45 and MKN-45/R were 8.93 ug/ml and 140 ug/ml, and the values for MKN-74 and MKN-74/R were 3.93 ug/ml and 114.29 ug/ml. Additionally, the PI3K/Akt/mTOR signaling pathway was activated in drug-resistant GC cells and tumor tissues of patients refractory to 5-FU chemotherapy, as evidenced by high PI3K, Akt, and mTOR levels in MKN-45/R, MKN-74/R, and GC tissues resistant to 5-FU. BEZ235 promoted cell cycle arrest and suppressed the migration of GC cells. Moreover, the combination of BEZ235 and 5-FU led to more effective suppressive influence on cell cycle progression and cell migration relative to the single 5-FU or BEZ235 treatment.

CONCLUSIONS

Silencing of the PI3K/Akt/mTOR signaling pathway suppressed the 5-FU resistance of GC cells.

Prognostic Model of D2 Radical Gastrectomy Combined with Neoadjuvant Chemotherapy for Gastric Cancer

Purpose

The AJCC (the American Joint Committee on Cancer) ypTNM (post-neoadjuvant pathologic stage group) staging was established based on patients with lymphadenectomy scope less than D2 and did not include ypT0N0 patients with pathologically complete response (PCR). The purpose of this study was to construct a survival predictive model for gastric cancer patients after neoadjuvant chemotherapy and gastrectomy combined with D2 lymphadenectomy.

Patients and Methods

The multicenter data of 838 gastric cancer patients who received neoadjuvant chemotherapy and gastrectomy combined with D2 lymphadenectomy were analyzed retrospectively. These dual center patients were divided into training (n = 671, the Affiliated Hospital of Qingdao University) and validation (n = 167, Qingdao West Coast New Area Central Hospital) cohorts. Based on training cohort, univariate and multivariable COX regression analyses were performed to select the clinicopathological characteristics significantly correlating with overall survival and construct a nomogram. Based on training and validation cohorts, the distinguishing and calibrating capabilities of nomogram was evaluated by the receiver operating characteristic (ROC) curve, Harrell's concordance index (C-index), decision curve analysis (DCA) curve and calibration curve.

Results

Platelet-to-lymphocyte ratio (PLR), pathologic stage after neoadjuvant treatment: ypT and ypN stage, tumor regression grade (TRG) became independent variables intimately related to the prognosis and was used to construct nomograms of 3/5-year prognosis. The nomograms showed an accuracy in predicting OS (overall survival) rate, with area under the ROC curve (AUC) of 0.818 (95% CI = 0.753~0.883) and C-index of 0.801 (95% CI = 0.744~0.858) in validation cohort. Calibration curves showed satisfactory agreement between nomogram prediction and actual result, and DCA curves indicated the large positive net benefit and excellent clinical usefulness of nomogram.

Conclusion

This study successfully developed a nomogram to predict overall survival of gastric cancer patients after neoadjuvant chemotherapy and gastrectomy combined with D2 lymphadenectomy, which might have excellent predictive performance and clinical application value.

Real-World Study: A Powerful Tool for Malignant Tumor Research in General Surgery

Real-world study (RWS) is a method to draw conclusions by collecting and analyzing real-world data under a real clinical background. Compared with traditional randomized controlled trials (RCTs), RWSs are favored by clinicians because of their low cost and good extrapolation. In recent years, RWS has made remarkable achievements in the field of general surgery, especially in the drug treatment of advanced malignant tumors. Therefore, to further understand the main contents of the existing RWS and the application prospect of RWS in the future, this paper systematically reviews the clinical application of RWS in malignant tumors in general surgery in the past three years.

Comparison of S-1-based vs. capecitabine-based adjuvant chemotherapy for patients with gastric cancer: a systematic review and meta-analysis

BACKGROUND

S-1-based and capecitabine-based adjuvant treatments are proved efficacious for patients with gastric cancer, but conventional meta-analyses of the direct comparisons between two alternative adjuvant regimens to resection of GC have not been attempted.

AIM

The aim of this review was to compare the disease-free survival, overall survival and adverse events in patients receiving the S-1- and capecitabine-based adjuvant chemotherapies for treatment of gastric cancer (GC) patients undergoing resection.

METHODS

A search of the academic literature was performed in PUBMED, SCOPUS, CENTRAL and EMBASE databases along with manual search in relevant journals for studies in English, to identify comparative studies comparing the effect of S-1-based chemotherapy and capecitabine-based adjuvant chemotherapy (AC), used in combination with surgical resection for treatment of gastric cancer. Both qualitative and quantitative analyses was carried out for all the included studies. The hazard ratios (HR) of disease-free survival (DFS) and overall survival (OS) were pooled using generic inverse variance method. The included studies were assessed for risk of bias using ROBINS-E (risk of bias in non-randomized studies of exposures) tool.

RESULTS

Seven retrospective cohort studies, two prospective cohort studies and one randomized clinical trial were included. Both S-1- and capecitabine-based adjuvant chemotherapy for treatment of stage 2 or 3 gastric cancer had similar effects on the 3-year and 5-year DFS rates, overall survival and adverse events in the included studies. There was no difference in the adjusted hazard ratios (HR) of OS and DFS (0.86 95% CI (0.68, 1.09); p = 0.21 and 0.96 95% CI (0.75, 1.24), respectively). Oral mucositis was increasingly associated with S-1-based AC, while incidences of adverse events such as neutropenia, anaemia and thrombocytopenia were similar to those of capecitabine-based regimen. The quality of the included studies was found to be low to moderate.

CONCLUSION

S-1- and capecitabine-based adjuvant chemotherapies can be used interchangeably as an adjuvant chemotherapeutic regimen postradical gastrectomy with D2 lymph node dissection.