Adjuvant chemoradiation for gastric carcinoma: State of the art and perspectives

From twilight to starlight? Debating the role of chemoradiotherapy in gastric cancer in the D2 dissection era

Patients affected by resectable locally advanced gastric cancer (GC) should receive perioperative chemotherapy as a standard of care. However, an additional benefit of adjuvant chemoradiation (CRT) has been negated by modern trials in the era of extended surgical dissection, and CRT is currently only considered on an individual basis in case of suboptimal resection. However, the dismal prognosis of GC and the modest treatment completion rates of perioperative chemotherapy have pushed to reconsider CRT, particularly as a preoperative treatment, in light of modern treatment techniques, advances in the understanding of the immune landscape and development of targeted agents. The aim of this review is to critically assess the historical role of CRT, the limitations of current evidence and to debate its potential role in an integrated neoadjuvant strategy for patients with resectable GC.

Multi-modal analysis for accurate prediction of preoperative stage and indications of optimal treatment in gastric cancer

BACKGROUND

Accurate preoperative clinical staging of gastric cancer helps determine therapeutic strategies. However, no multi-category grading models for gastric cancer have been established. This study aimed to develop multi-modal (CT/EHRs) artificial intelligence (AI) models for predicting tumor stages and optimal treatment indication based on preoperative CT images and electronic health records (EHRs) in patients with gastric cancer.

METHODS

This retrospective study enrolled 602 patients with a pathological diagnosis of gastric cancer from Nanfang hospital retrospectively and divided them into training (n = 452) and validation sets (n = 150). A total of 1326 features were extracted of which 1316 radiomic features were extracted from the 3D CT images and 10 clinical parameters were obtained from electronic health records (EHRs). Four multi-layer perceptrons (MLPs) whose input was the combination of radiomic features and clinical parameters were automatically learned with the neural architecture search (NAS) strategy.

RESULTS

Two two-layer MLPs identified by NAS approach were employed to predict the stage of the tumor showed greater discrimination with the average ACC value of 0.646 for five T stages, 0.838 for four N stages than traditional methods with ACC of 0.543 (P value = 0.034) and 0.468 (P value = 0.021), respectively. Furthermore, our models reported high prediction accuracy for the indication of endoscopic resection and the preoperative neoadjuvant chemotherapy with the AUC value of 0.771 and 0.661, respectively.

CONCLUSIONS

Our multi-modal (CT/EHRs) artificial intelligence models generated with the NAS approach have high accuracy for tumor stage prediction and optimal treatment regimen and timing, which could facilitate radiologists and gastroenterologists to improve diagnosis and treatment efficiency.

Overview of Chemotherapy for Gastric Cancer

Gastric cancer (GC) is one of the most clinically challenging cancers worldwide. Over the past few years, new molecular-targeted agents and immunotherapy have markedly improved GC prognosis. Human epidermal growth factor receptor 2 (HER2) expression is a key biomarker in first-line chemotherapy for unresectable advanced GC. Further, the addition of trastuzumab to cytotoxic chemotherapy has extended the overall survival of patients with HER2-positive advanced GC. In HER2-negative GC, the combination of nivolumab, an immune checkpoint inhibitor, and a cytotoxic agent has been demonstrated to prolong the overall survival of GC patients. Ramucirumab and trifluridine/tipiracil, which are second- and third-line treatments for GC, and trastuzumab deruxtecan, an antibody-drug conjugate for HER2-positive GC, have been introduced in clinics. New promising molecular-targeted agents are also being developed, and combination therapy comprising immunotherapy and molecular-targeted agents is expected. As the number of available drugs increases, it is important to understand the target biomarkers and drug characteristics and select the optimal therapy for each patient. For resectable disease, differences in the extent of standard lymphadenectomy between Eastern and Western countries have led to different standard treatments: perioperative (neoadjuvant) and adjuvant therapy. This review aimed to summarize recent advances in chemotherapy for advanced GC.

Is there still a place for radiotherapy in gastric cancer?

Stomach cancer is an aggressive disease and represents a global health problem. The majority of patients with localised disease present with locally advanced cancer that requires multimodality treatment. Chemoradiotherapy delivered after D2 gastrectomy has been evaluated in a number of clinical studies and best evidence, thus far, does not support its use in the post-operative setting. Data from currently recruiting and ongoing trials with exploratory translational endpoints are eagerly awaited to direct the use of chemoradiotherapy in the neoadjuvant setting. Radiotherapy can be effective in the palliation of symptoms associated with advanced gastric cancer. Furthermore, Stereotactic Body Radiotherapy has the potential to provide long term disease control in a proportion of gastric cancer patients with oligometastatic liver disease.

PINTology: A short history of the lncRNA LINC-PINT in different diseases

LINC-PINT is a p53-induced long intergenic noncoding transcript that plays a crucial role in many diseases, especially cancer. This long noncoding RNA (lncRNA) gene produces in total 102 (LNCipedia) alternatively spliced variants (LINC-PINT:1 to LINC-PINT:102). The functions of known variants include RNA transcripts, host transcripts for circular RNA (circRNA) generation and as sources for the translation of short peptides. In most human tumors, LINC-PINT is down-regulated where it serves as a tumor suppressor. However, the diversity of its functions in other maladies signifies its general clinical importance. Current LINC-PINT molecular functions include RNA-protein interactions, miRNA sponging and epigenetic modulation with these mechanisms operating in different cellular contexts to exert effects on biological processes ranging from DNA damage responses, cell cycle and growth arrest, senescence, cell migration and invasion, and apoptosis. Genetic polymorphisms in LINC-PINT have also been functionally associated with cancer and other pathologies including the autoimmune diseases pemphigus foliaceus and arthritis. Hence, LINC-PINT shows great potential as a clinical biomarker, especially for the diagnosis and prognosis of cancer. In this review, we explore the current knowledge highlighting the distinctive molecular functions of LINC-PINT in specific cancers and other disease states. This article is categorized under: RNA in Disease and Development > RNA in Disease.

Intensity-modulated radiotherapy with more than 60 Gy improved the survival of inoperable patients with locally advanced esophageal squamous cell carcinoma: A population-based real-world study

Intensity-modulated radiotherapy (IMRT) is widely applied during the treatment of esophageal squamous cell carcinoma (ESCC), but the optimal radiation dose still lacks a consensus. The aim of this study was to explore the optimal radiation dose for inoperable locally advanced ESCC patients treated with IMRT in a real-world clinical setting.A total of 90 inoperable ESCC patients with locally advanced stages of II-IVA treated with IMRT in our institute between February 1, 2014 and June 30, 2019 were included in this retrospective study. Sixty patients had received >60 Gy (high dose group) and 30 patients had received ≤60 Gy (low dose group). The median radiation dose was 66 Gy (range: 61-70 Gy) and 50.2 Gy (range: 40-60 Gy), respectively. Concurrent chemotherapies were platinum-based regimens.The median progression free survival (PFS) and overall survival (OS) of all patients were 7.6 and 14.1 months, respectively. Patients in the high dose group exhibited a significantly better PFS (1-year PFS 34.6% vs 22.8%; 2-year PFS 11.9% vs 0%, P = .008) and OS (1-year OS 57.5% vs 39.5%; 2-year OS 31.4% vs 15.8%, P = .007). The median PFS in the high and low dose groups were 8.1 and 6.1 months, and the median OS were 15.4 and 8.5 months, respectively. Multivariate Cox analysis showed that radiation dose (>60 Gy vs ≤60 Gy) was independently prognostic factor for OS (HR: 0.44; 95% CI: 0.22-0.89; P = .021), but not for PFS (HR: 0.56; 95% CI: 0.31-1.02; P = .058). There was no significant difference in treatment-related toxicities of grade ≥3 between the 2 groups (P = .402).This retrospective study confirmed that higher radiation dose (>60 Gy) resulted in better survival outcomes for inoperable patients with locally advanced ESCC treated with IMRT.

Trimodality treatment in gastric and gastroesophageal junction cancers: Current approach and future perspectives

Gastric and gastroesophageal junction (GEJ) cancers represent an aggressive group of malignancies with poor prognosis even when diagnosed in relatively early stage, with an increasing incidence both in Asia and in Western countries. These cancers are characterized by heterogeneity as a result of different pathogenetic mechanisms as shown in recent molecular analyses. Accordingly, the understanding of phenotypic and genotypic correlations/classifications has been improved. Current therapeutic strategies have also advanced and moved beyond surgical extirpation alone, with the incorporation of other treatment modalities, such as radiation and chemotherapy (including biologics). Chemoradiotherapy has been used as postoperative treatment after suboptimal gastrectomy to ensure local disease control but also improvement in survival. Preoperative chemoradiotherapy/chemotherapy has been employed to increase the chance of a successful R0 resection and pathologic complete response rate, which is associated with improved long-term outcomes. Several studies have defined various chemotherapy regimens to accompany radiation (before and after surgery). Recently, addition of immunotherapy after trimodality of gastroesophageal cancer has produced an advantage in disease-free interval. Targeted agents used in the metastatic setting are being investigated in the early setting with mixed results. The aim of this review is to summarize the existing data on trimodality approaches for gastric and GEJ cancers, highlight the remaining questions and present the current research effort addressing them.

Shifting sands: the role of radiotherapy for patients with gastric and gastroesophageal adenocarcinoma

Gastric adenocarcinoma, a leading cause of cancer-related mortality worldwide, is treated primarily with surgical resection in the non-metastatic setting. However, the optimal role and sequencing of adjunctive therapies, including radiotherapy (RT) as well as systemic therapy, remains unclear. A complex milieu of trials spanning several decades has evaluated different treatment strategies for gastric cancer, including the role of RT. In this review, we summarize the trial-level evidence for the diverse gastric cancer treatment paradigms. Despite initial success, postoperative RT has not shown a clear benefit in modern prospective studies in the setting of more aggressive surgical nodal dissection. On the other hand, the role of preoperative RT in optimizing oncologic outcomes for gastric cancer patients remains relatively under-explored; ongoing trials assessing preoperative RT aim to illuminate the optimal treatment strategy for non-metastatic gastric cancer patients.

Roles of Nrf2 in Gastric Cancer: Targeting for Therapeutic Strategies

Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2) is a specific transcription factor with potent effects on the regulation of antioxidant gene expression that modulates cell hemostasis under various conditions in tissues. However, the effects of Nrf2 on gastric cancer (GC) are not fully elucidated and understood. Evidence suggests that uncontrolled Nrf2 expression and activation has been observed more frequently in malignant tumors, including GC cells, which is then associated with increased antioxidant capacity, chemoresistance, and poor clinical prognosis. Moreover, Nrf2 inhibitors and the associated modulation of tumor cell redox balance have shown that Nrf2 also has beneficial effects on the therapy of various cancers, including GC. Based on previous findings on the important role of Nrf2 in GC therapy, it is of great interest to scientists in basic and clinical tumor research that Nrf2 can be active as both an oncogene and a tumor suppressor depending on different background situations.

Cascades between miRNAs, lncRNAs and the NF-κB signaling pathway in gastric cancer (Review)

Gastric cancer is a common digestive tract malignancy that is mainly treated with surgery combined with perioperative adjuvant chemoradiotherapy and biological targeted therapy. However, the diagnosis rate of early gastric cancer is low and both postoperative recurrence and distant metastasis are thorny problems. Therefore, it is essential to study the pathogenesis of gastric cancer and search for more effective means of treatment. The nuclear factor-κB (NF-κB) signaling pathway has an important role in the occurrence and development of gastric cancer and recent studies have revealed that microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are able to regulate this pathway through a variety of mechanisms. Understanding these interrelated molecular mechanisms is helpful in guiding improvements in gastric cancer treatment. In the present review, the functional associations between miRNAs, lncRNAs and the NF-κB signaling pathway in the occurrence, development and prognosis of gastric cancer were discussed. It was concluded that miRNAs and lncRNAs have complex relations with the NF-κB signaling pathway in gastric cancer. miRNAs/target genes/NF-κB/target proteins, signaling molecules/NF-κB/miRNAs/target genes, lncRNAs/miRNAs/NF-κB/genes or mRNAs, lncRNAs/target genes/NF-Κb/target proteins, and lncRNAs/NF-κB/target proteins cascades are all important factors in the occurrence and development of gastric cancer.

Effects of 8-Amino-Isocorydine, a Derivative of Isocorydine, on Gastric Carcinoma Cell Proliferation and Apoptosis

Background

Isocorydine (ICD) has anticancer effects; however, its suboptimal bioactivity has driven the production of ICD derivatives, including 8-amino-isocorydine (8-NICD).

Objective

This study explored the antitumor effects of 8-NICD on a variety of tumor cell lines to detect tumors sensitive to 8-NICD and investigated the mechanisms by which it suppresses tumor cell growth.

Methods

Human gastric carcinoma (GC) cells (MGC-803) were used to evaluate the effects of 8-NICD on cell proliferation and apoptosis. The in vivo action of 8-NICD in a nude mouse xenograft model was also investigated. The antioxidant activity of 8-NICD was evaluated using a 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay.

Results

8-NICD exerted significant antitumor activity against several tumor cell lines with IC₅₀ between 8.0 and 142.8 µM and was not toxic to healthy fibroblasts and epithelial cells at concentrations up to 100 µM. Moreover, 8-NICD strongly inhibited the proliferation of MGC803 cells without causing toxicity to human umbilical vein endothelial cells with a selectivity index of 19.2 and arrested MGC803 cells in the S phase. Further, the percentages of apoptotic MGC-803 and BGC823 cells increased in a concentration-dependent manner, and the expression of apoptosis regulator Bax increased, whereas that of Bcl-2 decreased in response to 8-NICD treatment. Further, 8-NICD significantly suppressed MGC-803 tumor growth in nude mice. In addition, 8-NICD was a potent scavenger of radicles in a 1,1-diphenyl-2-picrylhydrazyl (IC₅₀ = 11.12 µM) antioxidant assay.

Conclusions

These results suggest that 8-NICD exerts significant antitumor effects on GC cells by inducing apoptosis and cell cycle arrest and is a promising candidate anti-GC drug. The particularly high sensitivity of MGC803 cells suggest that the potential of 8-NICD to treat GC should be further explored. (Curr Ther Res Clin Exp. 2021; 82:XXX–XXX)

Cone Beam CT-Based Daily Adaptive Planning or Defined-Filling Protocol for Neoadjuvant Gastric Cancer Radiation Therapy: A Comparison

Purpose

This study aimed to investigate, in the setting of neoadjuvant gastric irradiation with integrated boost, whether cone beam computed tomography (CBCT)-based adaptive radiation therapy compared with a defined-filling protocol would be beneficial in terms of feasibility and achieving daily reproducible dose volume indexes of the planning target volume (PTV) and organs at risk (OARs) and workflow.

Methods and materials

Planning computed tomography (PCT) and 25 CBCT scans of a previously treated patient were used, and neoadjuvant therapy of gastric carcinoma was simulated offline. PTVs and OARs were defined per the TOPGEAR protocol (PTV: 45 Gy/1.8 Gy), and an integrated boost (gross tumor volume [GTV]: 50.4 Gy/2.016 Gy) was added. The patient followed a filling regimen consisting of 12-hour fasting followed by 200 mL of water intake (2 glasses of water) immediately before irradiation. OARs and PTVs were newly contoured on each CBCT. Nonrigid registration of PCT and CBCT scans was performed. Nonadapted plans were recalculated on each CBCT (R-CBCT). Furthermore, an adapted plan was created for the new anatomy (A-CBCT). Dose parameters and comparison of R-CBCT and A-CBCT for the kidneys, liver, and heart were analyzed using a paired t test.

Results

A total of 200 plans for R-CBCT and A-CBCT were obtained. Mean gastric volumes were 277.32 cm³ (±54.40 cm³) in CBCT scans and 519.2 cm³ in PCT. Mean doses to the PTV did not differ meaningfully within the CBCT scans, with an average of 1.54%. The D₉₅ improved in GTV coverage by 5.26% compared with the R-CBCT plan. Mean heart, liver, and right kidney doses were reduced with the A-CBCT plan by 35.74%, 10.71% and 29.47%, respectively. The R- and A-CBCT comparison for GTV and OARs was significantly different in all cases (P < .0001).

Conclusions

Adaptive radiation therapy through deformable registration represents an important tool in neoadjuvant gastric irradiation, encompassing daily variability and organ motion, compared with the defined-filling protocol while improving OAR sparing.

Harnessing DNA Replication Stress for Novel Cancer Therapy

DNA replication is the fundamental process for accurate duplication and transfer of genetic information. Its fidelity is under constant stress from endogenous and exogenous factors which can cause perturbations that lead to DNA damage and defective replication. This can compromise genomic stability and integrity. Genomic instability is considered as one of the hallmarks of cancer. In normal cells, various checkpoints could either activate DNA repair or induce cell death/senescence. Cancer cells on the other hand potentiate DNA replicative stress, due to defective DNA damage repair mechanism and unchecked growth signaling. Though replicative stress can lead to mutagenesis and tumorigenesis, it can be harnessed paradoxically for cancer treatment. Herein, we review the mechanism and rationale to exploit replication stress for cancer therapy. We discuss both established and new approaches targeting DNA replication stress including chemotherapy, radiation, and small molecule inhibitors targeting pathways including ATR, Chk1, PARP, WEE1, MELK, NAE, TLK etc. Finally, we review combination treatments, biomarkers, and we suggest potential novel methods to target DNA replication stress to treat cancer.

Patterns of recurrence after curative D2 resection for gastric cancer: Implications for postoperative radiotherapy

BACKGROUND

High-quality randomized controlled trials have demonstrated the benefit of radiotherapy (RT) in patients with radical resected gastric cancer (GC), however, utilization rates of postoperative RT remain remarkably low. Patterns, incidences, and time of recurrence provide biological bases for clinical monitoring of GC patients and guiding potential complementary therapies. Thus, the aim of this study is to understand the location of locoregional recurrence which may allow individualized RT strategies and minimize radiation-related toxic effects.

METHODS

A relatively large sample of GC patients in a single institution who had undergone curative D2 resection was retrospectively reviewed and the relevant recurrence patterns were illustrated. Independent recurrence-related risk factors were analyzed by logistic regression analysis. New logistic regression models were further developed to predict the probability of recurrence.

RESULTS

Overall, among 776 GC patients who had continuous and complete follow-up data, 300 cases relapsed after curative resection. Lymphovascular invasion, lymph node metastases, and tumor stage were indicators for early recurrence. Peritoneal, regional, local, and distant recurrence initially occurred in 51 (6.6%), 151 (19.4%), 56 (7.2%), and 164 (21.1%) patients, respectively. Among patients with regional recurrence, the most common sites were lymph node stations 16a2, 8, 12, 16b1, and 9. Remnant stomach recurrence was not so prominent that it seemed reasonable to be excluded from an irradiation field for patients with negative surgical/pathologic margins.

CONCLUSIONS

For GC patients who underwent radical D2 resection, distant and regional recurrences were still common. Besides, optimizing regional control of lymph nodes outside the D2 dissected area was crucial for rational design of the RT field. Furthermore, the new logistic regression models might act as useful tools to evaluate recurrence risk and determine which patients should receive postoperative chemoradiotherapy.

Computed tomography texture analysis in patients with gastric cancer: a quantitative imaging biomarker for preoperative evaluation before neoadjuvant chemotherapy treatment

PURPOSE

The aim of the study is to explore the role of computed tomography texture analysis (CT-TA) for predicting clinical T and N stages and tumor grade before neoadjuvant chemotherapy treatment in gastric cancer (GC) patients during the preoperative period.

MATERIALS AND METHODS

CT images of 114 patients with GC were included in this retrospective study. Following pre-processing steps, textural features were extracted using MaZda software in the portal venous phase. We evaluated and analyzed texture features of six principal categories for differentiating between T stages (T1,2 vs T3,4), N stages (N+ vs N-) and grades (low-intermediate vs. high). Classification was performed based on texture parameters with high model coefficients in linear discriminant analysis (LDA).

RESULTS

Dimension-reduction steps yielded five textural features for T stage, three for N stage and two for tumor grade. The discriminatory capacities of T stage, N stage and tumor grade were 90.4%, 81.6% and 64.5%, respectively, when LDA algorithm was employed.

CONCLUSION

CT-TA yields potentially useful imaging biomarkers for predicting the T and N stages of patients with GC and can be used for preoperative evaluation before neoadjuvant treatment planning.

Fucoidan suppresses the gastric cancer cell malignant phenotype and production of TGF-β1 via CLEC-2

The sulfated polysaccharide fucoidan displays excellent anticancer properties with low toxicity in many kinds of cancers. However, its detailed pharmacological effect and mechanism of action in gastric carcinoma remains unclear. In this study, we found that fucoidan could suppress gastric cancer (GC) cell growth, as well as cell migration and invasion. A cytokine expression screen demonstrated that transforming growth factor beta 1 (TGF-β1) secretion was decreased in fucoidan-treated cells. Fucoidan has been reported to be a platelet agonist for the C-type lectin-like receptor 2 (CLEC-2), and our previous research found that upregulation of CLEC-2 inhibited GC progression. Here, we confirmed that fucoidan, combined with CLEC-2, significantly increased CLEC-2 expression in GC cells via the transcription factor caudal type homeobox transcription factor 2, an important regulator of gut homeostasis. In addition, the inhibitory effect of fucoidan on the GC cell malignant phenotype and TGF-β1 secretion could be restored by knocking down CLEC-2. Thus, our data suggest that fucoidan targets CLEC-2 to exert antitumorigenesis and antimetastatic activity, suggesting that fucoidan is a promising treatment for gastric carcinoma.

EphA2-to-YAP pathway drives gastric cancer growth and therapy resistance

Yes-associated protein (YAP) is a transcriptional coactivator that promotes cell proliferation, stem cell maintenance and tissue homeostasis. The YAP activity is primarily regulated through an inhibitory phosphorylation by the serine/threonine kinases of Hippo pathway. Here, we show that receptor tyrosine kinase (RTK) erythropoietin-producing hepatocellular receptor A2 (EphA2) interacts with and phosphorylates YAP protein, leading to stabilization, nuclear translocation and activation of YAP in gastric cancer (GC) cells. EphA2 induces chemotherapy-resistance by increasing YAP stability and nuclear YAP protein. Knockdown of YAP blocks EphA2-induced tumor growth in GC xenograft mouse models. Importantly, the coactivation of EphA2 and YAP is manifested in clinical human GC, and is related to GC recurrence. Thus, our results establish a novel EphA2-to-YAP pathway that drives GC growth, progression and therapy-resistance, targeting this pathway would be an efficient way for the treatment of GC, particularly chemotherapy-resistant GC.

Strategy for improved therapeutic efficiency of curcumin in the treatment of gastric cancer

Gastric cancer is a common oncological disease. Although enormous efforts have been expended, possible therapeutic modalities are still limited. For this reason, new therapeutic approaches and agents are highly requested and intensively developed. One strategy is the application of natural agents, such as curcumin, with proven anticancer effects and low toxicity for patients. Therefore, this review discusses the potential application of curcumin in the therapy of gastric cancer and its potential incorporation in therapeutic regimens. Because one of the largest impediments for widespread curcumin application is its limited bioavailability (caused mainly by its very low water solubility), studied strategies (drug delivery systems and curcumin derivatization) aimed to solve this obstacle are discussed in more detail.