Chemotherapy for operable gastric cancer: current perspectives

Optimizing the Choice for Adjuvant Chemotherapy in Gastric Cancer

Simple Summary

Gastric cancer is the fourth largest cause of tumor-related death worldwide. Despite advances in the management of resectable cancer and improvements in early diagnosis, especially in east Asia where screening campaigns are actively performed, many patients experience recurrence and die because of the disease. Adjuvant systemic chemotherapy is administered after radical surgery in order to reduce the risk of recurrence and death. The modality of administration and regimens of chemotherapy in this setting are different between Eastern and Western countries. In Asia, adjuvant chemotherapy is traditionally given after surgery, while in Europe it is commonly scheduled after preoperative chemotherapy and surgery (perioperative chemotherapy), and in Northern America it is usually combined with radiotherapy (chemoradiotherapy). All these approaches are sustained by well-designed phase III clinical studies, and none may be considered superior to the others in the absence of head-to-head comparisons. The identification of predictive and/or prognostic factors could help to select patients at higher risk of recurrence and those more likely to receive a benefit from the adjuvant treatment. This would allow clinicians to avoid the administration of undue toxicity to non-responder patients and even to reduce the cost of unnecessary treatment.

Abstract

Advances in the management of gastric cancer have improved patient survival in the last decade. Nonetheless, the number of patients relapsing and dying after a diagnosis of localized gastric cancer is still too high, even in early stages (10% in stage I). Adjuvant systemic chemotherapy has been proven to significantly improve outcomes. In the present article we have critically reviewed the clinical trials that guide the current clinical practice in the adjuvant treatment of patients affected by resectable gastric cancer, focusing on the different approaches worldwide, i.e., adjuvant chemotherapy, adjuvant chemoradiotherapy, and perioperative chemotherapy. We also delineate the clinical–pathological characteristics that are commonly taken into account to identify patients at a higher risk of recurrence and requiring adjuvant chemotherapy, and also describe novel biomarkers and therapeutic agents that might allow personalization of the treatment.

Optimising Multimodality Treatment of Resectable Oesophago-Gastric Adenocarcinoma

Simple Summary

Oesophageal (food pipe) and stomach cancers are amongst the hard-to-treat cancers that result in significant illness and deaths around the globe. Over the last few decades, there has been remarkable progress in the treatment of these cancers as a result of advances in diagnosis, surgical techniques, systemic therapy and radiotherapy. However, even if caught in the early stages, most patients with these cancers will unfortunately have their cancers come back, usually becoming widespread and difficult to treat. Therefore, optimising the early treatment strategy of these cancers is essential to improve the outcome and reduce the risk of recurrence. There are currently various geographically influenced standard of care management practices of early stomach and oesophageal cancers, ranging from using chemotherapy before and after surgery to the use of combined chemoradiotherapy before surgery and more recently the use of immunotherapy after surgery. However, it is not very clear if one strategy is significantly better than the others and there are some ongoing studies aiming to directly compare these treatment options. In addition, our understanding of the molecular and genetic features of these cancers can help improve our clinical practice and inform our choice of the best treatment strategy for the individual patient.

Abstract

Oesophago–gastric adenocarcinoma remains a leading cause of cancer-related morbidity and mortality worldwide. Although there has been an enormous progress in the multimodality management of resectable oesophago–gastric adenocarcinoma, most patients still develop a recurrent disease that eventually becomes resistant to systemic therapy. Currently, there is no global consensus on the optimal multimodality approach and there are variations in accepted standards of care, ranging from preoperative chemoradiation to perioperative chemotherapy and, more recently, adjuvant immune checkpoint inhibitors. Ongoing clinical trials are aimed to directly compare multimodal treatment options as well as the additional benefit of targeted therapies and immunotherapies. Furthermore, our understanding of the molecular and genetic features of oesophago–gastric cancer has improved significantly over the last decade and these data may help inform the best approach for the individual patient, utilising biomarker selection and precision medicine.

Adapting and Surviving: Intra and Extra-Cellular Remodeling in Drug-Resistant Gastric Cancer Cells

Despite the significant recent advances in clinical practice, gastric cancer (GC) represents a leading cause of cancer-related deaths in the world. In fact, occurrence of chemo-resistance still remains a daunting hindrance to effectiveness of the current approach to GC therapy. There is accumulating evidence that a plethora of cellular and molecular factors is implicated in drug-induced phenotypical switching of GC cells. Among them, epithelial-mesenchymal transition (EMT), autophagy, drug detoxification, DNA damage response and drug target alterations, have been reported as major determinants. Intriguingly, resistant GC phenotype may be the result of GC cell-induced tumor microenvironment (TME) remodeling, which is currently emerging as a key player in promoting drug resistance and overcoming cytotoxic effects of drugs. In this review, we discuss the possible mechanisms of drug resistance and their involvement in determining current GC therapies failure.

Multimodality treatment of potentially curative gastric cancer: geographical variations and future prospects

After much controversy, multimodality therapy is now accepted worldwide as the gold standard for treatment of resectable bulky localized gastric cancer. There is significant regional variation in the style of multimodality treatment with adjuvant chemoradiation the North American standard, neoadjuvant chemotherapy preferred in Europe and Australasia, whilst adjuvant chemotherapy is preferred in Asia. With further standardization of surgery and D1+/D2 resections increasingly accepted world wide, and in particular in the West, as the surgical standard of care for potentially curable disease, it is timely to reassess the multimodality regimes being used. The challenge in the use of multimodality therapy is how current outcomes can be standardized and improved further. Recent studies indicate that mere intensification of the regime in time, dosage or addition of further agents does not improve localized gastric cancer outcomes. More novel strategies including early commencement of adjuvant therapies, intra-peritoneal chemotherapy or assessing neoadjuvant response with positron emission tomography scanning may give improvements in outcomes. The introduction of targeted therapies means that the adjuvant use of biological agents needs to be explored. By proper assessment of the patient's co-morbidities, full tumour staging, and a better understanding of the tumour's molecular pathology, multimodality therapy for gastric adenocarcinoma may be individualized to optimize the likelihood of cure.

Anticarcinogenic effects of products of heat-processed ginsenoside Re, a major constituent of ginseng berry, on human gastric cancer cells

Ginsenoside Re is a triol type triterpene glycoside and is abundantly present in ginseng berry. In the present study, we verified that ginsenoside Re can be transformed into less-polar ginsenosides, namely, Rg2, Rg6, and F4, by heat-processing. The products of heat-processed ginsenoside Re inhibited phosphorylation of CDK2 at Thr160 by upregulation of p21 level, resulting in S phase arrest. The products of heat-processed ginsenoside Re also activated caspase-8, caspase-9, and caspase-3, followed by cleavage of PARP, a substrate of caspase-3, in a dose-dependent manner. Concurrently, alteration of mitochondrial factors such as Bcl-2 and Bax was also observed. Moreover, pretreatment with Z-VAD-fmk abrogated caspase-8, -9, and -3 activations by the products of heat-processed ginsenoside Re. We further confirmed that the anticancer effects of the products of heat-processed ginsenoside Re in AGS cells are mainly mediated via generation of less-polar ginsenosides Rg6 and F4.

Stereospecific anticancer effects of ginsenoside Rg3 epimers isolated from heat-processed American ginseng on human gastric cancer cell

Background

Research has been conducted with regard to the development of methods for improving the pharmaceutical effect of ginseng by conversion of ginsenosides, which are the major active components of ginseng, via high temperature or high-pressure processing.

Methods

The present study sought to investigate the anticancer effect of heat-processed American ginseng (HAG) in human gastric cancer AGS cells with a focus on assessing the role of apoptosis as an important mechanistic element in its anticancer actions.

Results and Conclusion

HAG significantly reduced the cancer cell proliferation, and the contents of ginsenosides Rb1 and Re were markedly decreased, whereas the peaks of less-polar ginsenosides [20(S,R)-Rg3, Rk1, and Rg5] were newly detected. Based on the activity-guided fractionation of HAG, ginsenoside 20(S)-Rg3 played a key role in inducing apoptosis in human gastric cancer AGS cells, and it was generated mainly from ginsenoside Rb1. Ginsenoside 20(S)-Rg3 induced apoptosis through activation of caspase-3, caspase-8, and caspase-9, as well as regulation of Bcl-2 and Bax expression. Taken together, these findings suggest that heat-processing serves as an increase in the antitumor activity of American ginseng in AGS cells, and ginsenoside 20(S)-Rg3, the active component produced by heat-processing, induces the activation of caspase-3, caspase-8, and caspase-9, which contributes to the apoptotic cell death.