Neoadjuvant treatment of locally advanced esophageal and junctional cancer: the evidence-base, current key questions and clinical trials

Epigenetic regulation of ferroptosis in gastrointestinal cancers (Review)

Ferroptosis is a type of iron‑dependent cell death characterized by excessive lipid peroxidation and may serve as a potential therapeutic target in cancer treatment. While the mechanisms governing ferroptosis continue to be explored and elucidated, an increasing body of research highlights the significant impact of epigenetic modifications on the sensitivity of cancer cells to ferroptosis. Epigenetic processes, such as DNA methylation, histone modifications and non‑coding RNAs, have been identified as key regulators that modulate the expression of ferroptosis‑related genes. These alterations can either enhance or inhibit the sensitivity of gastrointestinal cancer (GIC) cells to ferroptosis, thereby affecting the fate of GICs. Drugs that target epigenetic markers for advanced‑stage cancer have shown promising results in enhancing ferroptosis and inhibiting tumor growth. This review explores the intricate relationship between epigenetic regulation and ferroptosis in GICs. Additionally, the potential of leveraging epigenetic modifications to trigger ferroptosis in GICs is investigated. This review highlights the importance of further research to elucidate the specific mechanisms underlying epigenetic control of ferroptosis and to advance the development of novel therapeutic approaches.

Targeting Radiation Resistance in Oesophageal Adenocarcinoma with Pyrazinib-Functionalised Gold Nanoparticles

Background/Objectives: Only 20-30% of oesophageal adenocarcinoma (OAC) patients achieve a complete response to neoadjuvant chemo-radiotherapy for locally advanced tumours. Enhancing the response to radiation therapy is critical for improving outcomes in this aggressive cancer. Pyrazinib (P3) is a promising compound with radiosensitizing, anti-angiogenic, anti-inflammatory, and anti-metabolic properties. However, its limited solubility and bioavailability have hindered its therapeutic potential.

METHODS

To overcome these limitations, pyrazinib was conjugated with gold nanoparticles (AuNP-P3), creating a novel formulation designed to enhance solubility, maintain bioactivity, and enable targeted delivery to tumour sites.

RESULTS

In an isogenic model of OAC radioresistance, AuNP-P3 significantly reduced the surviving fraction following irradiation, demonstrating its radiosensitizing properties. It also reduced mitochondrial metabolism and modulated the secretion of inflammatory mediators in both in vitro models of OAC radioresistance and human ex vivo OAC tumour explants. Furthermore, AuNP-P3 exhibited potent anti-angiogenic activity, significantly inhibiting blood vessel formation in vivo using zebrafish embryo models.

CONCLUSIONS

These results collectively confirm that P3, in its conjugated formulation with gold nanoparticles, retains its therapeutic properties, highlighting the potential of AuNP-P3 as a novel therapeutic radiosensitizer for oesophageal adenocarcinoma and supporting its further development for clinical applications.

Neoadjuvant radiotherapy combined with fluorouracil-cisplatin plus cetuximab in operable, locally advanced esophageal carcinoma: Results of a phase I-II trial (FFCD-0505/PRODIGE-3)

Background

Radiotherapy combined with fluorouracil (5FU) and cisplatin for locally advanced esophageal cancer is associated with a 20-25% pathologic complete response (pCR) rate. Cetuximab increases the efficacy of radiotherapy in patients with head and neck carcinomas. The aim of this phase I/II trial was to determine the optimal doses and the pCR rate with chemoradiotherapy (C-RT) plus cetuximab.

Methods

A 45-Gy radiotherapy regimen was delivered over 5 weeks. The phase I study determined the dose-limiting toxicity and the maximum tolerated dose of 5FU-cisplatin plus cetuximab. The phase II trial aimed to exhibit a pCR rate > 20 % (25 % expected), requiring 33 patients (6 from phase I part plus 27 in phase II part). pCR was defined as ypT0Nx.

Results

The phase I study established the following recommended doses: weekly cetuximab (400 mg/m2 one week before, and 250 mg/m2 during radiotherapy); 5FU (500 mg/m2/day, d1-d4) plus cisplatin (40 mg/m2, d1) during week 1 and 5. In the phase II part, 32 patients received C-RT before surgery, 31 patients underwent surgery, and resection was achieved in 27 patients. A pCR was achieved in five patients (18.5 %) out of 27. After a median follow-up of 19 months, the median progression-free survival was 13.7 months, and the median overall survival was not reached.

Conclusions

Adding cetuximab to preoperative C-RT was toxic and did not achieve a pCR > 20 % as required. The recommended doses, determined during the phase I part, could explain these disappointing results due to a reduction in chemotherapy dose-intensity.

Trial registration

This trial was registered with EudraCT number 2006-004770-27.

Outcomes of locally advanced gastric and gastroesophageal adenocarcinoma cancers treated with neoadjuvant FLOT in a tertiary care hospital in Pakistan

Background and aim

Docetaxel, oxaliplatin, leucovorin and 5-fluorouracil (FLOT) may improve overall survival (OS) in patients with locally advanced gastric and gastroesophageal cancer. Our study aims to determine the pathological response in these patients with the FLOT chemotherapy in the Neoadjuvant setting. This is the first study conducted in our country.

Methods

We conducted a retrospective cross-sectional study from March 2018 to December 2020. After ethical review committee approval, all patients who fulfilled the inclusion criteria and received treatment at our tertiary care center were included in the study. SPSS version 22 was used for data analysis. Frequencies and percentages were calculated for categorical. Values were presented as mean ± standard deviation (SD) for continuous variables. The chi-square test was used to determine the difference between categorical variables. A p-value of ≤0.05 was considered the level of significance. Kaplan-Meier curves were used to calculate survival analysis.

Results

Out of 41, 35 patients with locally advanced resectable gastric or gastroesophageal adenocarcinoma were included in our study analysis. The entire cohort had a male predominance, with a mean age of 59. All patients received neoadjuvant FLOT. Pathological treatment response achieved was 77%, of which 66% had partial and 11% had complete response. There is a significant association of pathological response with age, gender, stage, grade, co-morbid and number of chemotherapy cycles received (p-value =<0.05). The OS was 80% with the mean OS was 2.6 years (31 months).

Conclusion

Our study shows comparable response rates to other studies conducted internationally. Our findings confirm that FLOT is an effective and well-tolerated perioperative regimen with reasonable response rates in the Pakistani population. A more extensive longitudinal study would ensure these preliminary results in the local patient population.

Neoadjuvant Nivolumab Therapy for Esophageal Squamous Cell Carcinoma: A Single-Arm, Phase II Study

PURPOSE

Programmed death-1/programmed death-ligand 1 (PD-L1) inhibitors have shown efficacy in metastatic esophageal squamous cell carcinoma (ESCC) therapy. However, data is still limited regarding neoadjuvant immunotherapy for operable ESCC.

MATERIALS AND METHODS

Patients with clinical stage T2 or T3 and N0 ESCC received three cycles of nivolumab therapy every two weeks before surgical resection. The primary endpoint is major pathologic responses (MPR) rate (≤ 10% of residual viable tumor [RVT]).

RESULTS

Total 20 patients completed the planned nivolumab therapy. Among them, 17 patients underwent surgery as protocol, showing MPR in two patients (MPR rate, 11.8%), including one pathologic complete response, on conventional pathologic response evaluation. Pathologic response was re-evaluated using the immune-related pathologic response criteria based on immune-related RVT (irRVT). Three patients were classified as immunologic major pathologic response (iMPR; ≤ 10% irRVT, iMPR rate: 17.6%), five as pathologic partial response (> 10% and < 90% irRVT), and nine as pathologic nonresponse (≥ 90% irRVT). The combined positive score (CPS) for PD-L1 in the baseline samples was predictable for iMPR, with the probability as 37.5% in CPS ≥ 10 (3/8) and 0% in CPS < 10 (0/9).

CONCLUSION

Although the efficacy of neoadjuvant nivolumab therapy was modest in unselected ESCC patients, further researches on neoadjuvant immunotherapy are necessary in patients with PD-L1 expressed ESCC.

Current trends and future prospects of drug repositioning in gastrointestinal oncology

Gastrointestinal (GI) cancers comprise a significant number of cancer cases worldwide and contribute to a high percentage of cancer-related deaths. To improve survival rates of GI cancer patients, it is important to find and implement more effective therapeutic strategies with better prognoses and fewer side effects. The development of new drugs can be a lengthy and expensive process, often involving clinical trials that may fail in the early stages. One strategy to address these challenges is drug repurposing (DR). Drug repurposing is a developmental strategy that involves using existing drugs approved for other diseases and leveraging their safety and pharmacological data to explore their potential use in treating different diseases. In this paper, we outline the existing therapeutic strategies and challenges associated with GI cancers and explore DR as a promising alternative approach. We have presented an extensive review of different DR methodologies, research efforts and examples of repurposed drugs within various GI cancer types, such as colorectal, pancreatic and liver cancers. Our aim is to provide a comprehensive overview of employing the DR approach in GI cancers to inform future research endeavors and clinical trials in this field.

Long-Term Postsurgical Outcomes of Neoadjuvant Chemoradiation (CROSS) Versus Chemotherapy (FLOT) for Multimodal Treatment of Adenocarcinoma of the Esophagus and the Esophagogastric Junction

BACKGROUND

The question of the ideal neoadjuvant therapy for locally advanced esophagogastric adenocarcinoma has not been answered to date. Multimodal treatment has become a standard treatment for these adenocarcinomas. Currently, perioperative chemotherapy (FLOT) or neoadjuvant chemoradiation (CROSS) is recommended.

METHODS

A monocentric retrospective analysis compared long-term survival after CROSS versus FLOT. The study enrolled patients with adenocarcinoma of the esophagus (EAC) or the esophagogastric junction type I or II undergoing oncologic Ivor-Lewis esophagectomy between January 2012 and December 2019. The primary objective was to determine the long-term outcome in terms of overall survival. The secondary objectives were to determine differences regarding the histopathologic categories after neoadjuvant treatment and the histomorphologic regression.

RESULTS

The findings showed no survival advantage for one or the other treatment in this highly standardized cohort. All the patients underwent open (CROSS: 9.4% vs. FLOT: 22%), hybrid (CROSS: 82% vs. FLOT: 72%), or minimally invasive (CROSS: 8.9% vs. FLOT: 5.6%) thoracoabdominal esophagectomy. The median post-surgical follow-up period was 57.6 months (95% confidence interval [CI] 23.2-109.7 months), and the median survival was longer for the CROSS patients (54 months) than for the FLOT patients (37.2 months) (p = 0.053). The overall 5-years survival was 47% for the entire cohort (48% for the CROSS and 43% for the FLOT patients). The CROSS patients showed a better pathologic response and fewer advanced tumor stages.

CONCLUSION

The improved pathologic response after CROSS cannot be translated into longer overall survival. To date, the choice of which neoadjuvant treatment to use can be made only on the basis of clinical parameters and the patient's performance status.

An artificial neural network-based radiomics model for predicting the radiotherapy response of advanced esophageal squamous cell carcinoma patients: a multicenter study

Radiotherapy benefits patients with advanced esophageal squamous cell carcinoma (ESCC) in terms of symptom relief and long-term survival. In contrast, a substantial proportion of ESCC patients have not benefited from radiotherapy. This study aimed to establish and validate an artificial neural network-based radiomics model for the pretreatment prediction of the radiotherapy response of advanced ESCC by using integrated data combined with feasible baseline characteristics of computed tomography. A total of 248 patients with advanced ESCC who underwent baseline CT and received radiotherapy were enrolled in this study and were analyzed by two types of radiomics models, machine learning and deep learning. As a result, the Att. Resnet50 pretrained network model indicated superior performance, with AUCs of 0.876, 0.802 and 0.732 in the training, internal validation, and external validation cohorts, respectively. Similarly, our Att. Resnet50 pretrained network model showed excellent calibration and significant clinical benefit according to the C index and decision curve analysis. Herein, a novel pretreatment radiomics model was established based on deep learning methods and could be used for radiotherapy response prediction in advanced ESCC patients, thus providing reliable evidence for therapeutic decision-making.

Investigating the susceptibility of treatment-resistant oesophageal tumours to natural killer cell-mediated responses

The majority of oesophageal adenocarcinoma (OAC) patients do not respond to multimodal treatment regimens and face dismal survival rates. Natural killer (NK) cells are crucial anti-tumour immune cells, and this study investigated the susceptibility of treatment-resistant OAC cells to these potent tumour killers. Natural killer receptor (NKR) ligand expression by OE33CisP (cisplatin-sensitive) and OE33CisR (cisplatin-resistant) cells was investigated. The immunomodulatory effects of OE33CisP and OE33CisR cells on NK cell phenotype and function were assessed. Finally, the impact of chemotherapy regimens on NKR ligand shedding was examined. Our data revealed significantly less surface expression of activating ligands B7-H6, MICA/B, ULBP-3 and activating/inhibitory ligands PVRL-1 and PVRL-4 by OE33CisR cells, compared to OE33CisP cells. Co-culture with OE33CisR cells reduced the frequencies of NKp30⁺ and NKp46⁺ NK cells and increased frequencies of TIGIT⁺, FasL⁺ and TRAIL⁺ NK cells. Frequencies of IFN-γ-producing NK cells increased while frequencies of TIM-3⁺ NK cells decreased after culture with OE33CisP and OE33CisR cells. Frequencies of circulating NKp30⁺ NK cells were significantly lower in OAC patients with the poorest treatment response and in patients who received FLOT chemotherapy, while B7-H6 shedding by OAC tumour cells was induced by FLOT. Overall, OE33CisR cells express less activating NKR ligands than OE33CisP cells and have differential effects on NKR expression by NK cells. However, neither cell line significantly dampened NK cell cytokine production, death receptor expression or degranulation. In addition, our data indicate that FLOT chemotherapy may promote B7-H6 shedding and immune evasion with detrimental consequences in OAC patients.

Clinical Significance of Endoscopic Response Evaluation to Predict the Distribution of Residual Tumor after Neoadjuvant Chemotherapy for Esophageal Squamous Cell Carcinoma

PURPOSE

To appropriately adopt the organ preservation approach, including subsequent chemoradiotherapy (CRT) in patients who respond to neoadjuvant chemotherapy (NAC), the distribution of residual disease, including pathological lymph nodes (LNs) and recurrence site, needs to be recognized preoperatively. This study was designed to evaluate whether endoscopic response evaluation can predict residual tumor distribution.

METHODS

Patients with esophageal squamous cell carcinoma who underwent transthoracic esophagectomy (TTE) were retrospectively reviewed. Endoscopic responder (ER) to NAC was defined according to primary tumor endoscopic findings. Recurrence-free survival (RFS), overall survival (OS), and residual tumor patterns were compared between groups.

RESULTS

Of 193 patients, 40 (20%) were classified as ER. ERs showed significantly better RFS and OS. The pN location was found within the primary tumor and cN field in 88% of ERs, which was significantly higher than non-ERs at 63% (p = 0.004). Furthermore, the postoperative recurrence incidence in the distant organ was significantly lower in the ERs than the non-ERs (8%, 32%, respectively, p = 0.002). Residual disease, including postoperative initial recurrence, existed within the same field as the primary tumor and cN in 88% of ERs, significantly higher than 42% in the non-ERs (p < 0.001).

CONCLUSIONS

Endoscopic response evaluation can preoperatively predict distribution of residual tumors after NAC, which could help radiation field selection in subsequent definitive CRT when patients prefer to omit TTE. Along with improvements in NAC response rate, this could facilitate organ preservation in patients who respond to NAC.

Current state of prognostication, therapy and prospective innovations for Barrett's-related esophageal adenocarcinoma: a literature review

Objective

Barrett's esophagus (BE) is the only known precursor to esophageal adenocarcinoma (EAC), which has one of the lowest 5-year survival rates in oncology. The reasons for poor survival are twofold: the large majority of diagnoses are in advanced stages (~80%) and limited treatment options, with a deficit of biology-guided therapies. As a rapidly growing public health concern with poor prognosis, research into the molecular progression for BE and novel therapeutics for EAC currently has high clinical utility. Review of the literature reveals that innovative analysis of metaplastic progression from BE to EAC at a molecular level can shed light on the underlying transformative probabilities of BE into malignant pathologies and may impact current of future therapeutic modalities for management of these diseases.

Background

EAC is the fastest increasing cancer in the United States with a 600% increase over the past 25 years. This cancer arises from dysplastic tissue of BE, a complication of gastroesophageal reflux disease (GERD). Chronic acid and bile reflux in the distal esophagus initiates a metaplastic conversion of normal squamous epithelium to premalignant intestinalized columnar epithelium. Patients with BE have a 125-fold higher risk of cancer compared to the general population.

Methods

We critically reviewed the current status of BE monitoring, and subsequent therapeutic strategies being used in patients who have progressed to cancer. Also, new diagnostic tools and therapeutic candidates for BE-related EAC are discussed. Highly-targeted searches of databases containing recent original peer-reviewed papers were utilized for this review.

Conclusions

Novel and well-described biomarkers analyzed in the patient's diseased tissue will provide for more powerful diagnostics, but also possess the potential to develop strategies for personalized management and identify targets for intervention to either cease disease progression or treat BE and/or EAC. Since millions of Americans develop BE without progressing to cancer, there is a critical need to identify the small percentage of Barrett's patients who possess hallmarks of disease progression or carcinogenesis with novel screening techniques. Incorporation of such tools into standard screening protocols for BE surveillance and/or therapy would be critical to detect malignant transformations before clinically obvious cancer ever develops.

Proteomic signatures of radioresistance: Alteration of inflammation, angiogenesis and metabolism-related factors in radioresistant oesophageal adenocarcinoma

The clinical management of locally advanced oesophageal adenocarcinoma (OAC) involves neoadjuvant chemoradiotherapy (CRT), but as radioresistance remains a major clinical challenge, complete pathological response to CRT only occurs in 20-30% of patients. In this study we used an established isogenic cell line model of radioresistant OAC to detect proteomic signatures of radioresistance to identify novel molecular and cellular targets of radioresistance in OAC. A total of 5785 proteins were identified of which 251 were significantly modulated in OE33R cells, when compared to OE33P. Gene ontology and pathway analysis of these significantly modulated proteins demonstrated altered metabolism in radioresistant cells accompanied by an inhibition of apoptosis. In addition, inflammatory and angiogenic pathways were positively regulated in radioresistant cells compared to the radiosensitive cells. In this study, we demonstrate, for the first time, a comprehensive proteomic profile of the established isogenic cell line model of radioresistant OAC. This analysis provides insights into the molecular and cellular pathways which regulate radioresistance in OAC. Furthermore, it identifies pathway specific signatures of radioresistance that will direct studies on the development of targeted therapies and personalised approaches to radiotherapy.

Review of MR-Guided Radiotherapy for Esophageal Cancer

In this review, we outline the potential benefits and the future role of MRI and MR-guided radiotherapy (MRgRT) in the management of esophageal cancer. Although not currently used in most clinical practice settings, MRI is a useful non-invasive imaging modality that provides excellent soft tissue contrast and the ability to visualize cancer physiology. Chemoradiation therapy with or without surgery is essential for the management of locally advanced esophageal cancer. MRI can help stage esophageal cancer, delineate the gross tumor volume (GTV), and assess the response to chemoradiotherapy. Integrated MRgRT systems can help overcome the challenge of esophageal motion due to respiratory motion by using real-time imaging and tumor tracking with respiratory gating. With daily on-table MRI, shifts in tumor position and tumor regression can be taken into account for online-adaptation. The combination of accurate GTV visualization, respiratory gating, and online adaptive planning, allows for tighter treatment volumes and improved sparing of the surrounding normal organs. This could lead to a reduction in radiotherapy induced cardiac toxicity, pneumonitis and post-operative complications. Tumor physiology as seen on diffusion weighted imaging or dynamic contrast enhancement can help individualize treatments based on the response to chemoradiotherapy. Patients with a complete response on MRI can be considered for organ preservation while patients with no response can be offered an earlier resection. In patients with a partial response to chemoradiotherapy, areas of residual cancer can be targeted for dose escalation. The tighter and more accurate targeting enabled with MRgRT may enable hypofractionated treatment schedules.

GATA binding protein 6 (GATA6) is co-amplified with PIK3CA in patients with esophageal adenocarcinoma and is linked to neoadjuvant therapy

Purpose

Driver mutations are typically absent in esophageal adenocarcinoma (EAC). Mostly, oncogenes are amplified as driving molecular events (including GATA6-amplification in 14% of cases). However, only little is known about its biological function and clinical relevance.

Methods

We examined a large number of EAC (n = 496) for their GATA6 amplification by fluorescence in situ hybridization (FISH) analyzing both primary resected (n = 219) and neoadjuvant treated EAC (n = 277). Results were correlated to clinicopathological data and known mutations/amplifications in our EAC-cohort.

Results

GATA6 amplification was detectable in 49 (9.9%) EACs of our cohort. We observed an enrichment of GATA6-positive tumors among patients after neoadjuvant treatment (12,3% amplified tumors versus 6,8% in the primary resected group; p = 0.044). Additionally, there was a simultaneous amplification of PIK3CA and GATA6 (p < 0.001) not detectable when analyzing other genes such as EGFR, ERBB2, KRAS or MDM2. Although we did not identify a survival difference depending on GATA6 in the entire cohort (p = 0.212), GATA6 amplification was associated with prolonged overall survival among patients with primary surgery (median overall-survival 121.1 vs. 41.4 months, p = 0.032). Multivariate cox-regression analysis did not confirm GATA6 as an independent prognostic marker, neither in the entire cohort (p = 0.210), nor in the subgroup with (p = 0.655) or without pretreatment (p = 0.961).

Conclusions

Our study investigates the relevance of GATA6 amplification on a large tumor collective, which includes primary resected tumors and the clinically relevant group of neoadjuvant treated EACs. Especially in the pretreated group, we found an accumulation of GATA6-amplified tumors (12.3%) and a frequent co-amplification of PIK3CA. Our data suggest an increased resistance to radio-chemotherapy in GATA6-amplified tumors.

Should adenosquamous esophageal cancer be treated like adenocarcinoma or squamous cell carcinoma?

BACKGROUND

Esophageal adenocarcinoma (AC) and squamous cell carcinoma (SCC) have distinct outcomes, treatment strategies, and response profiles to therapy. Adenosquamous carcinoma (ASC) is thought to behave more aggressively than each of its counterparts. The aim of this study is to determine ifASC is best managed as AC or SCC.

METHODS

National Cancer Database (2004-2015) was queried for patients with nonmetastatic esophageal ASC. The analysis was stratified by clinical node-negative (cN0) or clinical node-positive (cN1-3). Treatment was categorized into chemoradiation alone, surgery alone, or preoperative chemoradiation followed by surgery. The primary outcome was 5-year overall survival (OS).

RESULTS

Among 352 patients, 43% were cN0 (n = 151), 57% were cN1-3 (n = 201) and 55% had chemoradiation alone (n = 194), 15% surgery alone (n = 53), and 30% preoperative chemoradiation (n = 105). Among patients who had preoperative chemoradiation, 20% had pathologic complete response (n = 17). For either cN0 or cN1-3, Charlson-Deyo Comorbidity Index did not differ among the treatment groups(all p > 0.05). On Kaplan-Meier analysis for cN0, treatment with surgery alone had comparable OS to preoperative chemoradiation (47% vs 34%; P = .5) and each had improved OS compared to chemoradiation alone (30%; P = .02; P = .06). On univariate analysis for cN0, clinical T category was not associated with OS. For cN1-3, however, preoperative chemoradiation was associated with improved OS when compared to chemoradiation alone or surgery alone (27% vs 19% vs 0%; P < .001). This persisted when accounting for age and clinical T category (hazard ratio: 0.45; P < .001).

CONCLUSION

Esophageal ASC behaves more like AC in response to chemoradiation and survival based on treatment modality. A complete response to chemoradiation is only 20% unlike what has been shown for SCC, where chemoradiation is an acceptable definitive therapy. Esophageal ASC should be managed more like AC.

The Utility of Liquid Biopsies in Radiation Oncology

The use of therapeutic radiation is primarily guided by clinicopathologic factors and medical imaging, whereas molecular biomarkers currently play a comparatively minor role in most settings. Liquid biopsies provide a rich source of noninvasive tumor-specific biomarkers and are amenable to repeated and noninvasive assessment. Here, we review the current status of liquid biopsies and their potential impact on the field of radiation oncology. We focus on established and emerging approaches to analyze circulating tumor DNA and circulating tumor cells from peripheral blood. These promising classes of biomarkers could have an outsized impact on cancer management by meaningfully stratifying patients into risk groups, tracking radiation therapy efficacy during and after treatment, and identifying patients with radiosensitive or radioresistant disease. Finally, we highlight opportunities for future investigation including the need for prospective interventional studies employing liquid biopsies to guide the management of radiation therapy-treated patients.

Targeting hallmarks of cancer to enhance radiosensitivity in gastrointestinal cancers

Radiotherapy is used in the treatment of approximately 50% of all malignancies including gastrointestinal cancers. Radiation can be given prior to surgery (neoadjuvant radiotherapy) to shrink the tumour or after surgery to kill any remaining cancer cells. Radiotherapy aims to maximize damage to cancer cells, while minimizing damage to healthy cells. However, only 10-30% of patients with rectal cancer or oesophageal cancer have a pathological complete response to neoadjuvant chemoradiation therapy, with the rest suffering the negative consequences of toxicities and delays to surgery with no clinical benefit. Furthermore, in pancreatic cancer, neoadjuvant chemoradiation therapy results in a pathological complete response in only 4% of patients and a partial pathological response in only 31%. Resistance to radiation therapy is polymodal and associated with a number of biological alterations both within the tumour itself and in the surrounding microenvironment including the following: altered cell cycle; repopulation by cancer stem cells; hypoxia; altered management of oxidative stress; evasion of apoptosis; altered DNA damage response and enhanced DNA repair; inflammation; and altered mitochondrial function and cellular energetics. Radiosensitizers are needed to improve treatment response to radiation, which will directly influence patient outcomes in gastrointestinal cancers. This article reviews the literature to identify strategies - including DNA-targeting agents, antimetabolic agents, antiangiogenics and novel immunotherapies - being used to enhance radiosensitivity in gastrointestinal cancers according to the hallmarks of cancer. Evidence from radiosensitizers from in vitro and in vivo models is documented and the action of radiosensitizers through clinical trial data is assessed.

Relevant issues in tumor regression grading of histopathological response to neoadjuvant treatment in adenocarcinomas of the esophagus and gastroesophageal junction

Multimodality treatment combining surgery and oncologic treatment has become widely applied in curative treatment of esophageal and gastroesophageal junction adenocarcinoma. There is a need for a standardized tumor regression grade scoring system for clinically relevant effects of neoadjuvant treatment effects. There are numerous tumor regression grading systems in use and there is no international standardization. This review has found nine different international systems currently in use. These systems all differ in detail, which inhibits valid comparisons of results between studies. Tumor regression grading in esophageal and gastroesophageal junction adenocarcinoma needs to be improved and standardized. To achieve this goal, we have invited a significant group of international esophageal and gastroesophageal junction adenocarcinoma pathology experts to perform a structured review in the form of a Delphi process. The aims of the Delphi include specifying the details for the disposal of the surgical specimen and defining the details of, and the reporting from, the agreed histological tumor regression grade system including resected lymph nodes. The second step will be to perform a validation study of the agreed tumor regression grading system to ensure a scientifically robust inter- and intra-observer variability and to incorporate the consented tumor regression grading system in clinical studies to assess its predictive and prognostic role in treatment of esophageal and gastroesophageal junction adenocarcinomas. The ultimate aim of the project is to improve survival in esophageal and gastroesophageal adenocarcinoma by increasing the quality of tumor regression grading, which is a key component in treatment evaluation and future studies of individualized treatment of esophageal cancer.

Pretreatment Esophageal Wall Thickness Associated with Response to Chemoradiotherapy in Locally Advanced Esophageal Cancer

PURPOSE

A multimodality approach using concurrent chemoradiotherapy (CRT) followed by esophagectomy has been the standard treatment in patients with locally advanced esophageal squamous cell carcinoma (ESCC). Computed tomography (CT) is widely utilized to evaluate esophageal cancer before and after CRT. This study evaluated the utility of pretreatment maximal esophageal wall thickness on CT scans to predict treatment outcomes after CRT in patients with locally advanced ESCC.

METHODS

Eighty-one patients with T3 locally advanced ESCC, whom were treated completely with CRT with and without surgery, and had available CT scans before and after CRT at a university hospital between 2005 and 2015, were retrospectively reviewed.

RESULT

Twenty patients (24.7%) had esophagectomy after neoadjuvant CRT and sixty-one patients (75.3%) had definitive CRT. The maximal esophageal wall thicknesses were measured retrospectively and correlated with the response and survival after treatment. A total of 40% of neoadjuvant CRT patients achieved a pCR. There was a significant difference in pretreatment maximal esophageal wall thickness between the pCR and non-pCR groups (mean 11.9 ± 5.3 mm versus 16.9 ± 3 mm; p = 0.01). Pretreatment maximal esophageal wall thickness < 10 mm was significantly related to better overall survival than ≥ 10 mm (median survival 79 months versus 15 months; HR 3.21, 95%CI 1.14-9; p = 0.02). The neoadjuvant CRT group had significantly better survival than the definitive CRT group (median survival 51 months versus 14.5 months; HR 0.46; 95%CI 0.25-0.85; p = 0.01).

CONCLUSION

In our study, pretreatment esophageal wall thickness of T3 locally advanced ESCC is a useful indicator for predicting survival and pCR after treatment.

Targeting cyclin-dependent kinase 9 by a novel inhibitor enhances radiosensitization and identifies Axl as a novel downstream target in esophageal adenocarcinoma

Cyclin-dependent kinase 9 (CDK9) transcriptionally regulates several proteins and cellular pathways central to radiation induced tissue injury. We investigated a role of BAY1143572, a new highly specific CDK9 inhibitor, as a sensitizer to radiation in esophageal adenocarcinoma. In vitro synergy between the CDK9 inhibitor and radiation was evaluated by clonogenic assay. In vivo synergy between the CDK9 inhibitor and radiation was assessed in multiple xenograft models including a patient’s tumor derived xenograft (PDX). Reverse phase protein array (RPPA), western blotting, immunohistochemistry, and qPCR were utilized to identify and validate targets of the CDK9 inhibitor. The CDK9 inhibitor plus radiation significantly reduced growth of FLO-1, SKGT4, OE33, and radiation resistant OE33R xenografts and PDXs as compared to the cohorts treated with either single agent CDK9 inhibitor or radiation alone. RPPA identified Axl as a candidate target of CDK9 inhibition. Western blot and qPCR demonstrated reduced Axl mRNA (p = 0.02) and protein levels after treatment with CDK9 inhibitor with or without radiation in FLO-1 and SKGT4 cells. Axl protein expression in FLO-1 xenografts treated with combination of CDK9 inhibitor and radiation was significantly lower than the xenografts treated with radiation alone (p = 0.003). Clonogenic assay performed after overexpression of Axl in FLO-1 and SKGT4 cells enhanced radiosensitization by the CDK9 inhibitor, suggesting dependency of radiosensitization effects of the CDK9 inhibitor on Axl. In conclusion, these findings indicate that targeting CDK9 by BAY1143572 significantly enhances the effects of radiation and Axl is a novel downstream target of CDK9 in esophageal adenocarcinoma.

Genetic Variants in EGFR/PLCE1 Pathway Are Associated with Prognosis of Esophageal Squamous Cell Carcinoma after Radical Resection

Esophageal cancer (EC) is one of the most deadly malignant diseases. Several studies revealed that variations of the phospholipase C epsilon 1 (PLCE1) gene were associated with EC susceptibility. PLCE1 is located downstream of the epidermal growth factor receptor (EGFR) pathway. Presently, the single nucleotide polymorphisms (SNPs) of EGFR/PLCE1 genes and their associations with EC survival remain unclear. In this study, the associations between genetic variants in the EGFR/PLCE1 pathway and prognosis in 124 esophageal squamous cell carcinoma (ESCC) patients with radical resection were explored. The results showed that CC genotype of both PLCE1 rs17109671 and EGFR rs2072454 was associated with ESCC prognosis. Multivariate analysis revealed that patients with the two unfavorable genotypes had the worst overall survival (OS) or disease-free survival (DFS) (HR=6.099, 95%CI=1.903-19.552; HR=3.994, 95%CI=1.49-10.702, respectively). Additionally, combination of SNPs and tumor stage could better predict OS (for AUC, 0.774 vs. 0.709) and PFS (for AUC, 0.773 vs. 0.704) than tumor stage alone. In conclusion, genetic variants of the EGFR/PLCE1 may be predictors of the prognosis of ESCC after surgery. The individuals with the CC genotype of PLCE1 rs17109671 and EGFR rs2072454 should receive more aggressive treatments.

18F FDG-PET/CT evaluation of histological response after neoadjuvant treatment in patients with cancer of the esophagus or gastroesophageal junction

BACKGROUND

In most parts of the world, curatively intended treatment for esophageal cancer includes neoadjuvant therapy, either with chemoradiotherapy or chemotherapy alone, followed by esophagectomy. Currently 18F-FDG positron emission tomography/computed tomography (PET/CT) is used for preoperative disease staging, but is not well established in the evaluation of neoadjuvant treatment.

PURPOSE

To evaluate changes in PET parameters in relation to the histological primary tumor response in the surgical specimen in patients randomized to neoadjuvant chemoradiotherapy or chemotherapy.

MATERIAL AND METHODS

Patients were randomized between either neoadjuvant chemotherapy or chemoradiotherapy followed by esophagectomy.18F-FDG PET/CT exams were conducted at baseline and following neoadjuvant treatment. Standardized uptake ratio (SUR) values were measured in the primary tumor and compared as regards histological responders and non-responders as well as different treatment arms.

RESULTS

Seventy-nine patients were enrolled and 51 were available for analysis. A significant rate of SUR reduction was observed ( P = 0.02) in the primary tumor in histological responders compared to non-responders. Changes in SUR were significantly greater in responders following chemoradiotherapy ( P = 0.02), but not following chemotherapy alone ( P = 0.49). There was no statistically significant difference in SUR in patients with a complete histological response compared to those with a subtotal response.

CONCLUSION

Our results are similar to those of previous studies and show that changes in the rate of SUR can be used reliably to differentiate histological responders from non-responders after neoadjuvant treatment with either chemoradiotherapy or chemotherapy. Limitations of current PET technology are likely to restrict the possibility of accurately ruling out limited residual disease.

Characterisation of an Isogenic Model of Cisplatin Resistance in Oesophageal Adenocarcinoma Cells

Cisplatin (cis-diamminedichloroplatinum) is widely used for the treatment of solid malignancies; however, the development of chemoresistance hinders the success of this chemotherapeutic in the clinic. This study provides novel insights into the molecular and phenotypic changes in an isogenic oesophageal adenocarcinoma (OAC) model of acquired cisplatin resistance. Key differences that could be targeted to overcome cisplatin resistance are highlighted. We characterise the differences in treatment sensitivity, gene expression, inflammatory protein secretions, and metabolic rate in an isogenic cell culture model of acquired cisplatin resistance in OAC. Cisplatin-resistant cells (OE33 Cis R) were significantly more sensitive to other cytotoxic modalities, such as 2 Gy radiation (p = 0.0055) and 5-fluorouracil (5-FU) (p = 0.0032) treatment than parental cisplatin-sensitive cells (OE33 Cis P). Gene expression profiling identified differences at the gene level between cisplatin-sensitive and cisplatin-resistant cells, uncovering 692 genes that were significantly altered between OE33 Cis R cells and OE33 Cis P cells. OAC is an inflammatory-driven cancer, and inflammatory secretome profiling identified 18 proteins secreted at significantly altered levels in OE33 Cis R cells compared to OE33 Cis P cells. IL-7 was the only cytokine to be secreted at a significantly higher levels from OE33 Cis R cells compared to OE33 Cis P cells. Additionally, we profiled the metabolic phenotype of OE33 Cis P and OE33 Cis R cells under normoxic and hypoxic conditions. The oxygen consumption rate, as a measure of oxidative phosphorylation, is significantly higher in OE33 Cis R cells under normoxic conditions. In contrast, under hypoxic conditions of 0.5% O₂, the oxygen consumption rate is significantly lower in OE33 Cis R cells than OE33 Cis P cells. This study provides novel insights into the molecular and phenotypic changes in an isogenic OAC model of acquired cisplatin resistance, and highlights therapeutic targets to overcome cisplatin resistance in OAC.

Leukaemia inhibitory factor is associated with treatment resistance in oesophageal adenocarcinoma

Oesophageal cancer is an aggressive disease with a poor 5 year survival rate of <20% of diagnosed patients. Unfortunately, only 20-30% Oesophageal Adenocarinoma (OAC) patients show a beneficial response to neoadjuvant therapy (neoCT). Inflammation influences OAC given the increased risk of cancer development and poor outcome for obese patients where altered secretion of adipokines and cytokines from adipose tissue contributes a pro-tumourigenic environment. We carried out a large proteomics screen of 184 proteins to compare the inflammatory and oncogenic profiles of an isogenic radioresistant in-vitro model of OAC. We found that leukaemia inhibitory factor (LIF), an IL-6 type cytokine, was significantly elevated in radioresistant OAC cells (p=0.007). Furthermore, significantly higher circulating levels of LIF were present in the serum from treatment-naive OAC patients who had a subsequent poor pathological response to neo-adjuvant therapy, (p=0.037). Quantitative PCR analysis revealed expression of LIF receptor (LIFR) may function as a predictive indicator of response to neo-adjuvant chemoradiation therapy in OAC. LIF was demonstrated to be actively secreted from human OAC treatment-naïve biopsies and significantly correlated with the secretion of bFGF, VEGF-A and IL-8 (p<0.05, R=1), (p<0.05, R=0.9429), and (p<0.05, R=1) respectively. Importantly, LIF secretion negatively correlated with tumour infiltrating lymphocytes in pre-treatment OAC patient biopsies, (r=-0.8783, p=0.033). Elevated circulating LIF is a marker of poor response to neo-adjuvant treatment in OAC and secretion of this chemokine from the tumour is tightly linked with pro-tumourigenic mediators including bFGF, VEGF-A and IL-8. Targeting this pathway may be a novel mechanism enhance neoadjuvant treatment responses in OAC.

Patients' preferences for treatment after neoadjuvant chemoradiotherapy for oesophageal cancer

Background

After neoadjuvant chemoradiotherapy (nCRT) plus surgery for oesophageal cancer, 29 per cent of patients have a pathologically complete response in the resection specimen. Active surveillance after nCRT (instead of standard oesophagectomy) may improve health-related quality of life (HRQoL), but patients need to undergo frequent diagnostic tests and it is unknown whether survival is worse than that after standard oesophagectomy. Factors that influence patients' preferences, and trade-offs that patients are willing to make in their choice between surgery and active surveillance were investigated here.

Methods

A prospective discrete-choice experiment was conducted. Patients with oesophageal cancer completed questionnaires 4–6 weeks after nCRT, before surgery. Patients' preferences were quantified using scenarios based on five aspects: 5-year overall survival, short-term HRQoL, long-term HRQoL, the risk that oesophagectomy is still necessary, and the frequency of clinical examinations using endoscopy and PET–CT. Panel latent class analysis was used.

Results

Some 100 of 104 patients (96·2 per cent) responded. All aspects, except the frequency of clinical examinations, influenced patients' preferences. Five-year overall survival, the chance that oesophagectomy is still necessary and long-term HRQoL were the most important attributes. On average, based on calculation of the indifference point between standard surgery and active surveillance, patients were willing to trade off 16 per cent 5-year overall survival to reduce the risk that oesophagectomy is necessary from 100 per cent (standard surgery) to 35 per cent (active surveillance).

Conclusion

Patients are willing to trade off substantial 5-year survival to achieve a reduction in the risk that oesophagectomy is necessary.