Chemotherapy and radiotherapy in the management of gastric cancer

Investigations into the impact of non-coding RNA on the sensitivity of gastric cancer to radiotherapy

Non-coding RNAs (ncRNAs) are a newly discovered functional RNA different from messenger RNA, which can participate in regulating the occurrence and development of tumors. More and more research results show that ncRNAs can participate in the regulation of gastric cancer (GC) radiotherapy response, and its mechanism may be related to its effect on DNA damage repair, gastric cancer cell stemness, cell apoptosis, activation of epidermal growth factor receptor signaling pathway, etc. This article summarizes the relevant mechanisms of ncRNAs regulating the response to radiotherapy in gastric cancer, which will be directly important for the introduction of ncRNAs particularly microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) into clinical medicine as biomarkers and therapeutic targets.

Chinese herbal medicine combined with oxaliplatin-based chemotherapy for advanced gastric cancer: A systematic review and meta-analysis of contributions of specific medicinal materials to tumor response

Introduction: The incidence and mortality of gastric cancer ranks among the highest, and the 5-year survival rate of advanced gastric cancer (AGC) is less than 10%. Currently, chemotherapy is the main treatment for AGC, and oxaliplatin is an important part of the commonly used chemotherapy regimen for AGC. A large number of RCTs have shown that Chinese herbal medicine (CHM) combined with oxaliplatin-based chemotherapy can improve objective response rate (ORR) and disease control rate (DCR), reduce the toxic and side effects of chemotherapy. There is currently a lack of systematic evaluation of the evidence to account for the efficacy and safety of CHM combined with oxaliplatin-based chemotherapy in AGC. Therefore, we carried out this study and conducted the sensitivity analysis on the herbal composition to explore the potential anti-tumor efficacy. Methods: Databases of PubMed, EMBASE, CENTRAL, Web of Science, the Chinese Biomedical Literature Database, the China National Knowledge Infrastructure, the Wanfang database, and the Chinese Scientific Journals Database were searched from their inception to April 2022. RCTs evaluating the efficacy of CHM combined with oxaliplatin-based chemotherapy on AGC were included. Stata 16 was used for data synthesis, RoB 2 for quality evaluation of included RCTs, and GRADE for quality of synthesized evidence. Additional sensitivity analysis was performed to explore the potential anti-tumor effects of single herbs and combination of herbs. Results: Forty trials involving 3,029 participants were included. Most included RCTs were assessed as "Some concerns" of risk of bias. Meta-analyses showed that compare to oxaliplatin-based chemotherapy alone, that CHM combined with oxaliplatin-based chemotherapy could increase the objective response rate (ORR) by 35% [risk ratio (RR) = 1.35, 95% confidence intervals (CI) (1.25, 1.45)], and disease control rate (DCR) by 12% [RR = 1.12, 95% CI (1.08, 1.16)]. Subgroup analysis showed that compare to SOX, FOLFOX, and XELOX regimens alone, CHM plus SOX, CHM plus FOLFOX, and CHM plus XELOX could significantly increase the ORR and DCR. Sensitivity analysis identified seven herbs of Astragalus, Liquorice, Poria, Largehead Atractylodes, Chinese Angelica, Codonopsis, and Tangerine Peel with potentials to improve tumor response of oxaliplatin-based chemotherapy in AGC. Conclusion: Synthesized evidence showed moderate certainty that CHM plus oxaliplatin-based chemotherapy may promote improvement in tumor response in AGC. CHM treatment is safe for AGC. Due to the poor quality of included RCTs and small samplesizes, the quality of synthesized evidence was not high. Specific combinations of herbs appeared to produce higher contributions to ORR than the herb individually. Each of this seven above mentioned herbs has been shown in experimental studies to potentially contribute to the improvement of tumor response. To support this conclusion, these seven herbs are worthy of further clinical research. Systematic Review Registration: [http://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=262595], identifier [CRD42022262595].

Liver Metastases in Newly Diagnosed Gastric Cancer: A Population-Based Study from SEER

Purpose: Population-based data on the proportion and prognosis of liver metastases at diagnosis of gastric cancer are currently lacking. Besides, the treatment of gastric cancer with liver metastases is still controversial now.

Methods: Patients with gastric cancer and liver metastases (GCLM) at the time of diagnosis in advanced gastric cancer were identified using the Surveillance, Epidemiology, and End Result (SEER) database of the National Cancer Institute. Multivariable logistic and Cox regression were performed to identify predictors of the presence of GCLM at diagnosis and factors associated with all-cause mortality.

Results: We identified 3507 patients with gastric cancer and liver metastases at the time of diagnosis, representing 16.89% of the entire cohort and 44.12% of the subset with metastatic disease to any distant site. Among entire cohort, multivariable logistic regression identified thirteen factors (age, race, sex, original, tumor location, pathology grade, Lauren classification, T staging, N staging, tumor size, number of extrahepatic metastatic sites to bone, lung, and brain, insurance situation and smoking) as predictors of the presence of liver metastases at diagnosis. Median survival among the entire cohort with GCLM was 4.0 months (interquartile range: 1.0-10.0 mo). Patients receiving comprehensive therapy had longer median overall survival, of which the median survival was 12.0 months (interquartile range: 6.0-31.0 mo). Multivariable Cox model in SEER cohort confirmed nine factors (age, tumor location, Lauren classification, T staging, number of extrahepatic metastatic sites to bone, lung, and brain, surgery, chemotherapy, RSC and marital status) as independent predictors for overall survival.

Conclusions: The findings of this study provided population-based estimates of the proportion and prognosis for LM at time of GC diagnosis. These findings provide preventive guidelines for screening and treatment of LM in GC patients.

Prognostic analysis and liver metastases relevant factors after gastric and hepatic surgical treatment in gastric cancer patients with metachronous liver metastases: a population-based study

BACKGROUND

The prognosis for patients with liver metastases from gastric cancer is very poor. Nevertheless, standard therapeutic strategies have not been established yet. The impact of hepatic surgical treatment on survival of patients with metachronous liver metastases from gastric cancer still remains controversial.

METHODS

We conducted a retrospective analysis on records of 436 patients who received radical gastrectomy (with D2 lymphadenectomy, regardless of hepatic surgical treatment) for gastric cancer with metachronous (≥ 3 months after gastrectomy) liver metastases in our center between 2001 and 2016. All patients were followed until 2017/10/31 or withdrawn from the follow-up because of death.

RESULTS

The median interval for non-hepatic metastases of the 436 patients who underwent radical gastrectomy is 14 months. T (P = 0.041), N (P = 0.023) and lymphovascular invasion (P < 0.001) were independent predictors affecting liver metastases-free interval. The overall survival rates for the 436 patients were 44.5, 29.7, 16.3, and 16.3% at 1, 2, 3, and 5 years respectively since treatment of hepatic metastases, with a median survival time of 11 months. N (P = 0.025), extent of liver metastases (H) (H2 vs. H1, P = 0.036; H3 vs. H1, P < 0.001), and treatment of liver metastatic lesions (P < 0.001) were significant independent prognostic factors for survival after presence of liver metastases. Among H1 and H2 patients, median survival in hepatic surgical treatment group was significantly longer than that in systemic chemotherapy alone group (25 vs. 11 months, P = 0.015).

CONCLUSIONS

Liver examinations should be performed during the first 2 years after gastric surgery and continued for 5 years for high-risk patients. Active therapeutic strategies may prolong patients' survival compared with supportive treatment alone. Patients with H1, H2 metachronous liver metastases may be considered appropriate candidates for hepatic surgical treatment before embarking on systemic chemotherapy alone.

TRIAL REGISTRATION

ISRCTN Registry (Retrospectively registered; Reference number: 35067; Date: 02/04/2018).

Metastatic gastric cancer (MGC) patients: Can we improve survival by metastasectomy? A systematic review and meta-analysis

BACKGROUND

Prognosis with current management strategies continues to be dismal in metastatic gastric cancer (MGC) patients. We aimed to evaluate the role of metastasectomy in improving survival.

METHODS

A comprehensive search of MEDLINE, EMBASE, SCOPUS, and Cochrane central databases (1965 to present) was performed. All comparative studies measuring survival in MGC patients undergoing metastasectomy versus other therapies were included. Pooled risk ratios with corresponding 95% confidence intervals (CI) were calculated for survival at 1, 3, and 5 years.

RESULTS

Sixteen studies with 1712 patients (378 patients in metastasectomy, 1334 patients in other therapies) were eligible for the final meta-analysis. Median age was 63 years. For patients undergoing metastasectomy, a significant survival advantage was observed at 1 year (RR 0.52, CI 0.43-0.62), 3 year (RR 0.75 CI 0.67-0.83), and 5 year (RR 0.82, CI 0.74-0.91); mean increased difference in survival conferred by metastasectomy averaged between 9.3 and 15.7 months; P < 0.001 for all results. Age, ECOG status, and STROBE score did not contribute to differences in survival.

CONCLUSION

Metastasectomy is associated with increased survival at 1, 3, and 5 years in MGC patients. Large prospective randomized controlled trials are critically needed to evaluate the role of metastasectomy in MGC.

Isolation and characterization of circulating tumor cells from human gastric cancer patients

PURPOSE

Circulating tumor cells (CTCs) have been proved to be responsible for tumor metastasis and resistant to anticancer therapies. This study aims to isolate and characterize circulating tumor cells from human gastric cancer patients, and investigate characteristic differences between gastric CTCs and gastric cancer cell lines.

METHODS

We analyzed 31 cases of gastric cancer patients using anti-CD45 antibody-conjugated magnetic microbeads negative separation, combined with fluorescence activated cell sorter CD44 positive screening. Abilities of tumor formation, metastasis, invasion, migration, irradiation and drug sensitivity of CTCs and gastric cancer cell lines were detected and compared.

RESULTS

Of all the 31 patients, CD44(+)/CD45(-)CTCs were isolated in 14 patients, of which 3 cases were stage IIA, 2 cases stage IIB, 2 cases stage IIIC and 7 cases stage IV. The malignant behavior was demonstrated by both clonogenetic assay and tumor xenograft in nude mice. Compared with human gastric cancer cell lines, the migration and invasion abilities of CTCs increased to 3.21-12.6-fold and 2.3-6.7-fold, respectively (all p values <0.05). In addition, the metastatic potential of CTCs is much higher in vivo than that of the control. Furthermore, CTCs were found to be relatively sensitive to FU, cisplatin and paclitaxel, but relatively resistant to irradiation, oxaliplatin, cetuximab and trastuzumab.

CONCLUSIONS

CD44(+)/CD45(-) gastric CTCs were isolated and found to exhibit stronger malignant behavior when compared with human gastric cancer cell lines. Furthermore, CTCs cultured in vitro have potential implications in drug sensitivity screening for the future anticancer treatments.

MicroRNA-206 suppresses gastric cancer cell growth and metastasis

Gastric cancer is one of the leading causes of cancer death world-wide and carries a high rate of metastatic risk. In addition to other protein-coding oncogenes and tumor suppressor genes, microRNAs play an important role in gastric cancer tumorigenic progression. Here, we show that miR-206 is expressed at markedly low levels in a cohort of gastric tumors compared to their matching normal tissues, and in a number of gastric cancer cell lines. Down-regulation of miR-206 was particularly significant in tumors with lymphatic metastasis, local invasion, and advanced TNM staging. We find that forced expression of miR-206 suppressed the proliferation, colony-formation, and xenograft tumorigenesis of SCG-7901 cells, a line of gastric cancer cells. Forced expression of miR-206 also suppressed SCG-7901 cell migration and invasion, as well as metastasis in cell culture or tail-vein injected mouse models, respectively. The anti-metastatic effect of miR-206 is likely mediated by targeting metastasis regulatory genes STC2, HDAC4, KLF4, IGF1R, FRS2, SFRP1, BCL2, BDNF, and K-ras, which were drastically down-regulated by stable expression of exogenous miR-206 in SCG-7901 cells. Taken together, our results indicate that miR-206 is a tumor suppressor of gastric cancer acting at steps that regulate metastasis.

LY294002 may overcome 5-FU resistance via down-regulation of activated p-AKT in Epstein-Barr virus-positive gastric cancer cells

Background

As EBV-associated gastric cancer has unique features that are different from EBV (-) gastric cancer, EBV is considered to have a key role in gastric carcinogenesis. It has been reported that viral latent membrane protein 2A (LMP2A) in EBV-transformed tumor cells activates the phosphatidylinositol 3-kinase (PI3K)/AKT pathway, which provides a survival signal and chemo-resistance to cytotoxic anti-cancer drugs. This study was to evaluate anti-proliferative effect and cell cycle change when 5-FU and LY294002 (LY), a selective inhibitor of PI3K, were treated separately or combined with different schedules in EBV positive gastric cancer cell line, SNU-719.

Methods

After single treatment and sequential combination of 5-FU and LY, cytotoxic activity was measured by MTS assay. When 5-FU and LY were treated in single and sequential combinations, the expression of p-AKT, p-NFkB, p-p53 and bcl-2 was observed on different concentrations by Western blot analysis. We also investigated the effect on apoptosis and cell cycle distribution using flow cytometry. The LMP2A siRNA inhibition was done to confirm the reversal of decreased 5-FU activity and p-AKT.

Results

When 5-FU was sequentially combined with LY, the combination index (CI) value indicated synergistic anti-proliferative effect. The expression of p-AKT and p-NFκB was upregulated by 5-FU alone but sequential treatment of 5-FU and LY decreased the expression of both p-AKT and p-NFκB. When 5-FU was combined with LY, G0/G1 and sub G1 cell population (%) increased. When 5-FU was added to the cells transfected with LMP2A siRNA, its anti-proliferative effect increased and the expression of p-AKT decreased. In sequential combination of 5-FU and LY, the expression of p-p53 was increased and bcl-2 expression was diminished compared to 5-FU alone.

Conclusion

These data suggest that sequential combination of 5-FU and LY induce synergistic cytotoxicity and overcome intrinsic and acquired resistance of 5-FU via downregulation of activated p-AKT and mitochondria-dependent apoptosis in EBV gastric cancer cell line, SNU-719.

Advances in treatment of gastric cancer

Surgery is the first choice of treatment for gastric cancer. The development of micro-invasive surgery brings new challenges to gastric cancer therapy. The limited data indicate that laparoscopy operation can achieve the same therapeutic efficacy as laparotomy. New adjuvant chemotherapy contributes to the removal of statge Ⅲb or Ⅳ gastric cancer. Abdominal cavity heat therapy for gastric cancer has also achieved rather satisfactory therapeutic results. Study on microcosmic field of gastric cancer will provide more data on early diagnosis and treatment of gastric cancer. No standard treatment modalities for gastric cancer are available, though there are many. Therefore, further study is needed.

Palliative management of gastric cancer

Advanced gastric cancer and its palliative treatment have a long and interesting history. Today, gastric adenocarcinoma is the second leading cause of cancer death worldwide. Unfortunately, many cases are not diagnosed until late stages of disease, which underscores the importance of the palliative treatment of gastric cancer. Palliative care is best defined as the active total care of patients whose disease is not responsive to curative treatment. Although endoscopy is the most useful method for securing the diagnosis of gastric adenocarcinoma, computed tomography may be useful to assess local and distant disease. The main indication for the institution of palliative care is the presence of advanced gastric cancer for which curative treatment is deemed inappropriate. The primary goal of palliative therapy of gastric cancer patients is to improve quality, not necessarily length, of life. Four main modalities of palliative therapy for advanced gastric cancer are discussed: resection, bypass, stenting, and chemotherapy. The choice of modality depends on a variety of factors, including individual patient prognosis and goals, and should be made on case-by-case basis. Future directions include the discovery and development of serum or stool tumor markers aimed at prevention, improving prognostication and stratification, and increasing awareness and education.

Capecitabine: in advanced gastric or oesophagogastric cancer

The oral fluoropyrimidine capecitabine is metabolised preferentially in tumour tissue to the cytotoxic moiety fluorouracil. In a well designed phase III trial in patients with advanced gastric cancer, capecitabine plus cisplatin was noninferior to fluorouracil plus cisplatin in terms of progression-free survival (hazard ratio [HR] 0.81 [95% CI 0.63, 1.04]). In another similarly designed phase III trial in patients with oesophagogastric cancer (REAL 2), pooled capecitabine-based regimens were noninferior to pooled fluorouracil-based regimens in terms of overall survival (HR 0.86 [95% CI 0.80, 0.99]). These data are supported by randomised and noncomparative phase II trials in treatment-naive or pretreated patients with advanced gastric cancer or oesophagogastric cancer receiving capecitabine either as monotherapy or in combination with other antitumour agents. Given the nature of chemotherapy, capecitabine-based regimens were generally well tolerated, with the nature of treatment-related adverse events occurring with capecitabine-based regimens being similar to those of fluorouracil-based regimens.

Neurotoxicity of FOLFOX-4 as adjuvant treatment for patients with colon and gastric cancer: a randomized study of two different schedules of oxaliplatin

PURPOSE

The dose limiting toxicity of oxaliplatin (l-HOP) is neurotoxicity, which is characterized by an acute neuropathy and a clinically distinct chronic neuropathy. This randomized study evaluated if prolonged l-HOP infusion over the conventional l-HOP schedule was useful in reducing acute and possibly chronic l-HOP induced neurotoxicity in colon and gastric cancer patients receiving l-HOP-based regimen as adjuvant chemotherapy.

METHODS

Sixty-four patients were randomly assigned to group A (26 colon and 6 gastric cancer) and to group B (23 colon and 9 gastric cancer). Chemotherapy in both groups consisted of l-HOP 85 mg/m(2) i.v. only on day 1, with leucovorin 100 mg/m(2) i.v. as a 2-h infusion followed by bolus 5-fluorouracil (5-FU) 400 mg/m(2)/day and a 22-h infusion of 5-FU 600 mg/m(2)/day, repeated for two consecutive days every 2 weeks for a maximum of 12 cycles. Patients in group A received l-HOP as a continuous 6-h i.v. infusion, and patients in group B received l-HOP as the conventional 2-h i.v. infusion.

RESULTS

The percentage of patients presenting with grade >/=2 neurotoxicity was statistically lower in group A than in group B (28.1% vs. 59.3%: P = 0.02). There was a statistically lower percentage of cycles with grade >/=2 neurotoxicity in group A (6.1%) than in group B (18.5%) (P < 0.001).

CONCLUSIONS

This study suggests that l-HOP as a continuous 6-h infusion is useful in preventing and reducing acute l-HOP induced neurotoxicity in patients with colon and gastric cancer receiving FOLFOX-4 regimen as adjuvant treatment.

Molecular markers for gastric adenocarcinoma: an update

Gastric cancer is the second most common cancer worldwide. Treatment of localized gastric cancer relies primarily on surgical intervention, although growing evidence suggests that the addition of chemoradiation may improve disease-free intervals and overall survival. In this regard, the current high rates of recurrence and subsequent poor survival have prompted an ever-increasing use of multimodal strategies, even for early-stage disease. However, these therapies are often limited by debilitating toxicities and varying degrees of response efficacy. As a result, pharmacogenomics, the study of specific genetic and molecular signatures that may be predictive of treatment outcomes, has gained considerable interest. For example, studies have demonstrated that the expression of enzymes involved in the metabolism or conjugation of commonly used chemotherapy agents, such as fluoropyrimidines and cisplatin, can serve as surrogate markers predictive of chemotherapy response. Polymorphisms in the genes encoding these enzymes have also been identified and may further account for altered expression patterns, resulting in varied clinical responses. Future work is necessary to further refine the list of molecular genetic markers and to identify novel markers for prognostic and predictive purposes. Technologies such as microarray analysis may be useful in identifying new molecular genetic markers, and further work may determine whether these markers can be employed to help stratify patients into different multimodal treatment regimens.

Ganciclovir augments the lytic induction and apoptosis induced by chemotherapeutic agents in an Epstein-Barr virus-infected gastric carcinoma cell line

Epstein-Barr virus is an oncogenic herpesvirus and has been associated with several human malignancies, including gastric cancer. In Epstein-Barr virus-associated gastric cancer, Epstein-Barr virus is found in virtually all tumor cells, but rarely in normal epithelial cells, thus implying that Epstein-Barr virus-targeting therapies are likely to be an effective treatment strategy. Using the SNU-719 gastric cancer cell line, which is naturally infected with Epstein-Barr virus, we found that the chemotherapeutic agents, such as 5-fluorouracil, cis-platinum and taxol, induced the expressions of BMRF1, BZLF1 and BRLF1 proteins that are usually found in the lytic form of the virus. This effect was found to require various signal transduction pathways involving phosphatidylinositol 3' kinase, mitogen-activated protein/extracellular signal-regulated kinase, protein kinase C delta and p38 mitogen-activated protein kinase. Moreover, the combination of ganciclovir with these agents increased the lytic transformation and induced apoptosis in Epstein-Barr virus-associated gastric carcinoma. We conclude that ganciclovir enhances the therapeutic efficacy of 5-fluorouracil, cis-platinum and taxol in Epstein-Barr virus-positive gastric cancer cells. It is hoped that this information will be found useful during the establishment of treatment strategies for Epstein-Barr virus-associated gastric cancer.