Phenotypic immune characterization of gastric and esophageal adenocarcinomas reveals profound immune suppression in esophageal tumor locations

Background

Tumors in the distal esophagus (EAC), gastro-esophageal junction including cardia (GEJAC), and stomach (GAC) develop in close proximity and show strong similarities on a molecular and cellular level. However, recent clinical data showed that the effectiveness of chemo-immunotherapy is limited to a subset of GEAC patients and that EACs and GEJACs generally benefit less from checkpoint inhibition compared to GACs. As the composition of the tumor immune microenvironment drives response to (immuno)therapy we here performed a detailed immune analysis of a large series of GEACs to facilitate the development of a more individualized immunomodulatory strategy.

Methods

Extensive immunophenotyping was performed by 14-color flow cytometry in a prospective study to detail the immune composition of untreated gastro-esophageal cancers (n=104) using fresh tumor biopsies of 35 EACs, 38 GEJACs and 31 GACs. The immune cell composition of GEACs was characterized and correlated with clinicopathologic features such as tumor location, MSI and HER2 status. The spatial immune architecture of a subset of tumors (n=30) was evaluated using multiplex immunohistochemistry (mIHC) which allowed us to determine the tumor infiltration status of CD3+, CD8+, FoxP3+, CD163+ and Ki67+ cells.

Results

Immunophenotyping revealed that the tumor immune microenvironment of GEACs is heterogeneous and that immune suppressive cell populations such as monocytic myeloid-derived suppressor cells (mMDSC) are more abundant in EACs compared to GACs (p<0.001). In contrast, GACs indicated a proinflammatory microenvironment with elevated frequencies of proliferating (Ki67+) CD4 Th cells (p<0.001), Ki67+ CD8 T cells (p=0.002), and CD8 effector memory-T cells (p=0.024). Differences between EACs and GACs were confirmed by mIHC analyses showing lower densities of tumor- and stroma-infiltrating Ki67+ CD8 T cells in EAC compared to GAC (both p=0.021).

Discussions

This comprehensive immune phenotype study of a large series of untreated GEACs, identified that tumors with an esophageal tumor location have more immune suppressive features compared to tumors in the gastro-esophageal junction or stomach which might explain the location-specific responses to checkpoint inhibitors in this disease. These findings provide an important rationale for stratification according to tumor location in clinical studies and the development of location-dependent immunomodulatory treatment approaches.

Impact of 18FFDG-PET/CT and Laparoscopy in Staging of Locally Advanced Gastric Cancer: A Cost Analysis in the Prospective Multicenter PLASTIC-Study

BACKGROUND

Unnecessary D2-gastrectomy and associated costs can be prevented after detecting non-curable gastric cancer, but impact of staging on treatment costs is unclear. This study determined the cost impact of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18FFDG-PET/CT) and staging laparoscopy (SL) in gastric cancer staging.

MATERIALS AND METHODS

In this cost analysis, four staging strategies were modeled in a decision tree: (1) 18FFDG-PET/CT first, then SL, (2) SL only, (3) 18FFDG-PET/CT only, and (4) neither SL nor 18FFDG-PET/CT. Costs were assessed on the basis of the prospective PLASTIC-study, which evaluated adding 18FFDG-PET/CT and SL to staging advanced gastric cancer (cT3-4 and/or cN+) in 18 Dutch hospitals. The Dutch Healthcare Authority provided 18FFDG-PET/CT unit costs. SL unit costs were calculated bottom-up. Gastrectomy-associated costs were collected with hospital claim data until 30 days postoperatively. Uncertainty was assessed in a probabilistic sensitivity analysis (1000 iterations).

RESULTS

18FFDG-PET/CT costs were €1104 including biopsy/cytology. Bottom-up calculations totaled €1537 per SL. D2-gastrectomy costs were €19,308. Total costs per patient were €18,137 for strategy 1, €17,079 for strategy 2, and €19,805 for strategy 3. If all patients undergo gastrectomy, total costs were €18,959 per patient (strategy 4). Performing SL only reduced costs by €1880 per patient. Adding 18FFDG-PET/CT to SL increased costs by €1058 per patient; IQR €870-1253 in the sensitivity analysis.

CONCLUSIONS

For advanced gastric cancer, performing SL resulted in substantial cost savings by reducing unnecessary gastrectomies. In contrast, routine 18FFDG-PET/CT increased costs without substantially reducing unnecessary gastrectomies, and is not recommended due to limited impact with major costs.

TRIAL REGISTRATION

NCT03208621. This trial was registered prospectively on 30-06-2017.

The impact of sex on treatment and outcome in relation to histological subtype in patients with resectable gastric cancer: Results from the randomized CRITICS trial

BACKGROUND AND OBJECTIVE

This study aims to investigate the impact of sex on outcome measures stratified by histological subtype in patients with resectable gastric cancer (GC).

METHODS

A post-hoc analysis of the CRITICS-trial, in which patients with resectable GC were treated with perioperative therapy, was performed. Histopathological characteristics and survival were evaluated for males and females stratified for histological subtype (intestinal/diffuse). Additionally, therapy-related toxicity and compliance were compared.

RESULTS

Data from 781 patients (523 males) were available for analyses. Female sex was associated with a distal tumor localization in intestinal (p = 0.014) and diffuse tumors (p < 0.001), and younger age in diffuse GC (p = 0.035). In diffuse GC, tumor-positive resection margins were also more common in females than males (21% vs. 10%; p = 0.020), specifically at the duodenal margin. During preoperative chemotherapy, severe toxicity occurred in 327 (63%) males and 184 (71%) females (p = 0.015). Notwithstanding this, relative dose intensities were not significantly different between sexes.

CONCLUSIONS

Positive distal margin rates were higher in females with diffuse GC, predominantly at the duodenal site. Females also experience more toxicity, but this neither impacts dose intensities nor surgical resection rates. Clinicians should be aware of these different surgical outcomes when treating males and females with GC.

Patients' perspectives and the perceptions of healthcare providers in the treatment of early rectal cancer; a qualitative study

BACKGROUND

Shared decision-making has become of increased importance in choosing the most suitable treatment strategy for early rectal cancer, however, clinical decision-making is still primarily based on physicians' perspectives. Balancing quality of life and oncological outcomes is difficult, and guidance on patients' involvement in this subject in early rectal cancer is limited. Therefore, this study aimed to explore preferences and priorities of patients as well as physicians' perspectives in treatment for early rectal cancer.

METHODS

In this qualitative study, semi-structured interviews were performed with early rectal cancer patients (n = 10) and healthcare providers (n = 10). Participants were asked which factors influenced their preferences and how important these factors were. Thematic analyses were performed. In addition, participants were asked to rank the discussed factors according to importance to gain additional insights.

RESULTS

Patients addressed the following relevant factors: the risk of an ostomy, risk of poor bowel function and treatment related complications. Healthcare providers emphasized oncological outcomes as tumour recurrence, risk of an ostomy and poor bowel function. Patients perceived absolute risks of adverse outcome to be lower than healthcare providers and were quite willing undergo organ preservation to achieve a better prospect of quality of life.

CONCLUSION

Patients' preferences in treatment of early rectal cancer vary between patients and frequently differ from assumptions of preferences by healthcare providers. To optimize future shared decision-making, healthcare providers should be aware of these differences and should invite patients to explore and address their priorities more explicitly during consultation. Factors deemed important by both physicians and patients should be expressed during consultation to decide on a tailored treatment strategy.

Spatial immune composition of tumor microenvironment in patients with pancreatic cancer

This study examined the composition of the immune microenvironment at different sites within resected pancreas specimens from patients with pancreatic ductal adenocarcinoma (PDAC). Therefore, single-cell suspensions were made from fresh tumor and non-tumorous tissue. Fourteen patients were included from whom twelve PDAC and five non-tumorous samples were obtained. These samples were analyzed with a nineteen marker panel on the Aurora spectral flow cytometer. Furthermore, slides from formalin-fixed paraffine PDACs of eight additional patients were stained with eight markers and analyzed by multispectral imaging. These corresponded to central tumor, periphery of the tumor, i.e., invasive front and resected lymph node and were divided into tumor and adjacent tissue. In the single-cell suspension, a decreased ratio between lymphoid and myeloid cells and between M1 and M2 macrophages was observed in the tumor tissue compared to non-tumorous tissue. Furthermore, an increase in CD169 + macrophages in patients undergoing neoadjuvant therapy was found. Using immunofluorescence, more macrophages compared to T cells were observed, as well as a lower ratio of CD8 to M2 macrophage, a higher ratio of CD4-CD8 T cells and a higher ratio of immune-suppressive cells to pro-inflammatory cells in the PDAC area compared to the adjacent non-tumorous tissue. Finally, there were more immune-suppressive cells in the central tumor area compared to the invasive front. In conclusion, we show a gradient in the immune-suppressive environment in PDAC from most suppressive in the central tumor to least suppressive in distant non-tumorous tissue.

The impact of the COVID-19 pandemic on the diagnosis, stage, and treatment of esophagogastric cancer

BACKGROUND

The COVID-19 pandemic has affected the entire global healthcare system, including oncological care. This study investigated the effects of the COVID-19 pandemic on the diagnosis, stage, and treatment of esophagogastric cancer in the Netherlands.

METHODS

Patients diagnosed in 2020 were divided into 5 periods, based on the severity of the COVID-19 pandemic in the Netherlands, and compared to patients diagnosed in the same period in the years 2017-2019. Patient characteristics and treatments were evaluated for esophageal cancer (EC) and gastric cancer (GC) separately.

RESULTS

The number of esophagogastric cancer diagnoses decreased prominently during the first 2 months of the COVID-19 pandemic. During this period, a significantly higher percentage of GC patients was diagnosed with incurable disease (52.5% in 2017-2019 and 67.7% in 2020, p = 0.011). We observed a significant reduction in the percentage of patients with potentially curable EC treated with resection and neoadjuvant chemoradiotherapy (from 35.0% in 2017-2019 to 27.3% in 2020, p < 0.001). Also, patients diagnosed with incurable GC were treated less frequently with a resection (from 4.6% in 2017-2019 to 1.5% in 2020, p = 0.009) in the second half of 2020.

CONCLUSIONS

Compared to previous years, the number of esophagogastric cancer diagnoses decreased in the first 2 months of the COVID-19 pandemic, while an increased percentage of patients was diagnosed with incurable disease. Both in the curative and palliative setting, patients were less likely to be treated with a surgical resection.

Prognostic Value of T-Cell Density in the Tumor Center and Outer Margins in Gastric Cancer

Tumor-infiltrating lymphocytes are associated with the survival of gastric cancer patients. T-cell densities in the tumor and its periphery were previously identified as prognostic T-cell markers for resectable gastric cancer. Immunohistochemistry for 5 T-cell markers, CD3, CD45RO, CD8, FOXP3, and granzyme B was performed on serial sections of N = 251 surgical resection specimens of patients treated with surgery only in the D1/D2 trial. Positive T cells were digitally quantified into tiles of 0.25 mm2 across 3 regions: the tumor center (TC), the inner invasive margin, and the outer invasive margin (OIM). A classification and regression tree model was employed to identify the optimal combination of median T-cell densities per region with cancer-specific survival (CSS) as the outcome. All statistical tests were 2-sided. CD8OIM was identified as the most dominant prognostic factor, followed by FOXP3TC, resulting in a decision tree containing 3 prognostically distinct subgroups with high (Hi) or low (Lo) density of the markers: CD8OIMHi, CD8OIMLo/FOXP3TCHi, and CD8OIMLo/FOXP3TCLo. In a multivariable Cox regression analysis, which included pathological T and N stages, Lauren histologic types, EBV status, microsatellite instability, and type of surgery, the immune subgroups were independent predictors for CSS. CSS was lower for CD8OIMLo/FOXP3TCHi (HR: 5.02; 95% CI: 2.03-12.42) and for CD8OIMLo/FOXP3TCLo (HR: 7.99; 95% CI: 3.22-19.86), compared with CD8OIMHi (P < .0001). The location and density of both CD8+ and FOXP3+ T cells in resectable gastric cancer are independently associated with survival. The combination of CD8OIM and FOXP3TC T-cell densities is a promising stratification factor that should be validated in independent studies.

Clinical consequences of diagnostic variability in the histopathological evaluation of early rectal cancer

INTRODUCTION

In early rectal cancer, organ sparing treatment strategies such as local excision have gained popularity. The necessity of radical surgery is based on the histopathological evaluation of the local excision specimen. This study aimed to describe diagnostic variability between pathologists, and its impact on treatment allocation in patients with locally excised early rectal cancer.

MATERIALS AND METHODS

Patients with locally excised pT1-2 rectal cancer were included in this prospective cohort study. Both quantitative measures and histopathological risk factors (i.e. poor differentiation, deep submucosal invasion, and lymphatic- or venous invasion) were evaluated. Interobserver variability was reported by both percentages and Fleiss' Kappa- (ĸ) or intra-class correlation coefficients.

RESULTS

A total of 126 patients were included. Ninety-four percent of the original histopathological reports contained all required parameters. In 73 of the 126 (57.9%) patients, at least one discordant parameter was observed, which regarded histopathological risk factors for lymph node metastases in 36 patients (28.6%). Interobserver agreement among different variables varied between 74% and 95% or ĸ 0.530-0.962. The assessment of lymphovascular invasion showed discordances in 26% (ĸ = 0.530, 95% CI 0.375-0.684) of the cases. In fourteen (11%) patients, discordances led to a change in treatment strategy.

CONCLUSION

This study demonstrated that there is substantial interobserver variability between pathologists, especially in the assessment of lymphovascular invasion. Pathologists play a key role in treatment allocation after local excision of early rectal cancer, therefore interobserver variability needs to be reduced to decrease the number of patients that are over- or undertreated.

Molecular characterization of gastric adenocarcinoma diagnosed in patients previously treated for Hodgkin lymphoma or testicular cancer

Introduction

The risk of developing gastric cancer is increased in patients treated with radiotherapy for Hodgkin lymphoma (HL) or testicular cancer (TC). This study aims to assess if gastric adenocarcinoma after treatment for HL/TC (t-GC) is molecularly different from gastric adenocarcinoma in the general population.

Methods

Patients were diagnosed with t-GC ≥5 years after treatment for HL/TC. Four molecular subtypes were identified using immunohistochemical and molecular analyses: Epstein-Barr virus (EBV), mismatch repair (MMR) deficiency or microsatellite instability (MSI), aberrant p53 staining as surrogate for chromosomal instability (sCIN), and a surrogate for genomic stability (sGS) without these aberrations. Results were compared with gastric cancer in the general population (p-GC) described in literature.

Results

Molecular subtyping of 90 t-GCs resulted in 3% EBV, 8% MSI, 36% sCIN and 53% sGS. 3/6 of MSI t-GCs had MLH1 promoter methylation and 2/6 were explained by double somatic mutations in MMR genes. T-GCs were more frequently sGS than p-GCs (53% vs. 38%, p = 0.04). T-GC was more frequently sGS in HL/TC patients diagnosed before 1990, than after 1990 (63% vs. 38%, p = 0.03). T-GCs located in the antrum, an area that receives high irradiation doses, were more frequently sGS (61% vs. 28% in p-GCs, p = 0.02).

Conclusion

Our results demonstrate that t-GCs are more frequently of the sGS subtype than p-GCs. An association of t-GC of the sGS subtype with prior anticancer treatment is suggested by the high frequency in HL/TC patients who were treated before 1990, a time period in which HL/TC treatments were more extensive.

Triplet Chemotherapy with Cisplatin versus Oxaliplatin in the CRITICS Trial: Treatment Compliance, Toxicity, Outcomes and Quality of Life in Patients with Resectable Gastric Cancer

(1) Background: Perioperative chemotherapy is the current standard treatment for patients with resectable gastric cancer. Based on studies in patients with metastatic gastric cancer, oxaliplatin has replaced cisplatin in the curative setting as well. However, evidence to prefer oxaliplatin over cisplatin in the curative setting is limited. (2) Methods: We compared patient-related and tumor-related outcomes for cisplatin versus oxaliplatin in patients with resectable gastric cancer treated with perioperative chemotherapy in the CRITICS trial. (3) Results: Preoperatively, 632 patients received cisplatin and 149 patients received oxaliplatin. Preoperative severe toxicity was encountered in 422 (67%) patients who received cisplatin versus 89 (60%) patients who received oxaliplatin (p = 0.105). Severe neuropathy was observed in 5 (1%) versus 6 (4%; p = 0.009) patients, respectively. Postoperative severe toxicity occurred in 109 (60%) versus 26 (51%) (p = 0.266) patients; severe neuropathy in 2 (1%) versus 2 (4%; p = 0.209) for patients who received cisplatin or oxaliplatin, respectively. Diarrhea impacted the quality of life more frequently in patients who received oxaliplatin compared to cisplatin. Complete or near-complete pathological response was achieved in 94 (21%) versus 16 (15%; p = 0.126) patients who received cisplatin or oxaliplatin, respectively. Overall survival was not significantly different in both groups (p = 0.300). (4) Conclusions: Both cisplatin and oxaliplatin are legitimate options as part of systemic treatment in patients with resectable gastric cancer.

Predictive value of chromosome 18q11.2-q12.1 loss for benefit from bevacizumab in metastatic colorectal cancer; a post-hoc analysis of the randomized phase III-trial AGITG-MAX

The VEGF‐A monoclonal antibody bevacizumab is currently recommended for first‐line treatment of all metastatic colorectal cancer (mCRC) patients. Cost‐benefit ratio and side‐effects however necessitate patient selection. A large retrospective yet nonrandomized study showed that patients with loss of chromosome 18q11.2‐q12.1 in the tumor and treated with bevacizumab have 3 months improved median progression‐free (PFS) and overall survival (OS) benefit compared to patients without this loss and/or treatment modality. Implementation for loss of chromosome 18q11.2‐q12.1 as a marker in clinical practice mandates evidence in a randomized controlled trial for bevacizumab. Of the trials with randomization of chemotherapy vs chemotherapy with bevacizumab, the AGITG‐MAX trial was the only one with tumor materials available. Chromosome 18q11.2‐q12.1 copy number status was measured for 256 AGITG‐MAX trial patients and correlated with PFS according to a predefined analysis plan with marker‐treatment interaction as the primary end‐point. Chromosome 18q11.2‐q12.1 losses were detected in 71% of patients (181/256) characteristic for mCRC. Consistent with the nonrandomized study, significant PFS benefit of bevacizumab was observed in patients with chromosome 18q11.2‐q12.1 loss (P = .009), and not in patients without 18q loss (P = .67). Although significance for marker‐treatment interaction was not reached (P_interaction = .28), hazard ratio and 95% confidence interval of this randomized cohort (HR_interaction = 0.72; 95% CI = 0.39‐1.32) shows striking overlap with the nonrandomized study cohorts (HR_interaction = 0.41; 95% CI = 0.32‐0.8) supported by a nonsignificant Cochrane χ² test (P = .11) for heterogeneity. We conclude that post hoc analysis of the AGITG‐MAX RCT provides supportive evidence for chromosome 18q11.2‐q12.1 as a predictive marker for bevacizumab in mCRC patients.

Quality of Life Is Associated With Survival in Patients With Gastric Cancer: Results From the Randomized CRITICS Trial

BACKGROUND

The evaluation of health-related quality of life (HRQoL) in clinical trials has become increasingly important because it addresses the impact of treatment from the patient's perspective. The primary aim of this study was to investigate the effect of postoperative chemotherapy and chemoradiotherapy (CRT) after neoadjuvant chemotherapy and surgery with extended (D2) lymphadenectomy on HRQoL in the CRITICS trial. Second, we investigated the potential prognostic value of pretreatment HRQoL on event-free survival (EFS) and overall survival (OS).

PATIENTS AND METHODS

Patients in the CRITICS trial were asked to complete HRQoL questionnaires (EORTC Quality-of-Life Questionnaire-Core 30 and Quality-of-Life Questionnaire gastric cancer-specific module) at baseline, after preoperative chemotherapy, after surgery, after postoperative chemotherapy or CRT, and at 12 months follow-up. Patients with at least 1 evaluable questionnaire (645 of 788 randomized patients) were included in the HRQoL analyses. The predefined endpoints included dysphagia, pain, physical functioning, fatigue, and Quality-of-Life Questionnaire-Core 30 summary score. Linear mixed modeling was used to assess differences over time and at each time point. Associations of baseline HRQoL with EFS and OS were investigated using multivariate Cox proportional hazards analyses.

RESULTS

At completion of postoperative chemo(radio)therapy, the chemotherapy group had significantly better physical functioning (P=.02; Cohen's effect size = 0.42) and less dysphagia (P=.01; Cohen's effect size = 0.38) compared with the CRT group. At baseline, worse social functioning (hazard ratio [HR], 2.20; 95% CI, 1.36-3.55; P=.001), nausea (HR, 1.89; 95% CI, 1.39-2.56; P<.001), worse WHO performance status (HR, 1.55; 95% CI, 1.13-2.13; P=.007), and histologic subtype (diffuse vs intestinal: HR, 1.94; 95% CI, 1.42-2.67; P<.001; mixed vs intestinal: HR, 2.35; 95% CI, 1.35-4.12; P=.003) were significantly associated with worse EFS and OS.

CONCLUSIONS

In the CRITICS trial, the chemotherapy group had significantly better physical functioning and less dysphagia after postoperative treatment. HRQoL scales at baseline were significantly associated with EFS and OS.

Response to neoadjuvant chemotherapy and survival in molecular subtypes of resectable gastric cancer: a post hoc analysis of the D1/D2 and CRITICS trials

BACKGROUND

Epstein-Barr virus positivity (EBV+) and microsatellite instability (MSI-high) are positive prognostic factors for survival in resectable gastric cancer (GC). However, benefit of perioperative treatment in patients with MSI-high tumors remains topic of discussion. Here, we present the clinicopathological outcomes of patients with EBV+, MSI-high, and EBV-/MSS GCs who received either surgery only or perioperative treatment.

METHODS

EBV and MSI status were determined on tumor samples collected from 447 patients treated with surgery only in the D1/D2 trial, and from 451 patients treated perioperatively in the CRITICS trial. Results were correlated to histopathological response, morphological tumor characteristics, and survival.

RESULTS

In the D1/D2 trial, 5-year cancer-related survival was 65.2% in 47 patients with EBV+, 56.7% in 47 patients with MSI-high, and 47.6% in 353 patients with EBV-/MSS tumors. In the CRITICS trial, 5-year cancer-related survival was 69.8% in 25 patients with EBV+, 51.7% in 27 patients with MSI-high, and 38.6% in 402 patients with EBV-/MSS tumors. Interestingly, all three MSI-high tumors with moderate to complete histopathological response (3/27, 11.1%) had substantial mucinous differentiation. No EBV+ tumors had a mucinous phenotype. 115/402 (28.6%) of EBV-/MSS tumors had moderate to complete histopathological response, of which 23/115 (20.0%) had a mucinous phenotype.

CONCLUSIONS

In resectable GC, MSI-high had favorable outcome compared to EBV-/MSS, both in patients treated with surgery only, and in those treated with perioperative chemo(radio)therapy. Substantial histopathological response was restricted to mucinous MSI-high tumors. The mucinous phenotype might be a relevant parameter in future clinical trials for MSI-high patients.

Prognostic value of tumor markers and ctDNA in patients with resectable gastric cancer receiving perioperative treatment: results from the CRITICS trial

AIM

To evaluate the prognostic value of tumor markers in a European cohort of patients with resectable gastric cancer.

METHODS

We performed a post hoc analysis of the CRITICS trial, in which 788 patients received perioperative therapy. Association between survival and pretreatment CEA, CA 19-9, alkaline phosphatase, neutrophils, hemoglobin and lactate dehydrogenase were explored in uni- and multivariable Cox regression analyses. Likelihoods to receive potentially curative surgery were investigated for patients without elevated tumor markers versus one of the tumor markers elevated versus both tumor markers elevated. The association between tumor markers and the presence of circulating tumor DNA (ctDNA) was explored in 50 patients with available ctDNA data.

RESULTS

In multivariable analysis, in which we corrected for allocated treatment and other baseline characteristics, elevated pretreatment CEA (HR 1.43; 95% CI 1.11-1.85, p < 0.001) and CA 19-9 (HR 1.79; 95% CI 1.42-2.25, p < 0.001) were associated with worse OS. Likelihoods to receive potentially curative surgery were 86%, 77% and 60% for patients without elevated tumor marker versus either elevated CEA or CA 19-9 versus both elevated, respectively (p < 0.001). Although both preoperative presence of ctDNA and tumor markers were prognostic for survival, no association was found between these two parameters.

CONCLUSION

CEA and CA 19-9 were independent prognostic factors for survival in a large cohort of European patients with resectable gastric cancer. No relationship was found between tumor markers and ctDNA. These factors could potentially guide treatment choices and should be included in future trials to determine their definitive position.

TRIAL REGISTRATION

ClinicalTrial.gov identifier: NCT00407186. EudraCT number: 2006-00413032.

Molecular pathways in post-colonoscopy versus detected colorectal cancers: results from a nested case-control study

BACKGROUND

Post-colonoscopy colorectal cancers (PCCRCs) pose challenges in clinical practice. PCCRCs occur due to a combination of procedural and biological causes. In a nested case-control study, we compared clinical and molecular features of PCCRCs and detected CRCs (DCRCs).

METHODS

Whole-genome chromosomal copy number changes and mutation status of genes commonly affected in CRC were examined by low-coverage WGS and targeted sequencing, respectively. MSI and CIMP status was also determined.

RESULTS

In total, 122 PCCRCs and 98 DCRCs with high-quality DNA were examined. PCCRCs were more often located proximally (P < 0.001), non-polypoid appearing (P = 0.004), early stage (P = 0.009) and poorly differentiated (P = 0.006). PCCRCs showed significantly less 18q loss (FDR < 0.2), compared to DCRCs. No significant differences in mutations were observed. PCCRCs were more commonly CIMP high (P = 0.014) and MSI (P = 0.029). After correction for tumour location, only less 18q loss remained significant (P = 0.005).

CONCLUSION

Molecular features associated with the sessile serrated lesions (SSLs) and non-polypoid colorectal neoplasms (CRNs) are more commonly seen in PCCRCs than in DCRCs. These together with the clinical features observed support the hypothesis that SSLs and non-polypoid CRNs are contributors to the development of PCCRCs. The future focus should be directed at improving the detection and endoscopic removal of these non-polypoid CRN and SSLs.

CLINICAL TRIAL REGISTRATION

NTR3093 in the Dutch trial register ( www.trialregister.nl ).

Diagnostic variability in the histopathological assessment of advanced colorectal adenomas and early colorectal cancer in a screening population

Aim

The aim of this study was to evaluate interobserver variability between individual pathologists and a panel of pathologists in the histopathological assessment of advanced colorectal neoplasms in the Dutch bowel cancer screening population.

Methods and results

Histological slides of adenomas with high‐grade dysplasia and early colorectal carcinomas (CRC) from 20 different laboratories were reviewed by the pathology panel of the Dutch bowel screening programme. Interobserver variability was reported by descriptive statistics. In addition, potential clinical consequences of discrepancies were evaluated. A total of 104 cases of adenomas with high‐grade dysplasia and 83 early CRCs were reviewed. Discrepancies were observed in 41 of 104 (39.4%) adenoma cases, which potentially had clinical consequences in 16 (15.4%) cases. For CRC, discrepancies were shown in 44 of 83 cases (53.0%) and would have potentially led to alternative treatment strategies in 25 (30.1%) cases. Most frequently, discrepancies were observed in the assessment of lymphovascular invasion (23 of 73 cases, 31.5%).

Conclusion

This study showed that considerable interobserver variability is present in the histopathological assessment of advanced colorectal neoplasia, which may impact upon treatment choices. Additional stains and education, as well as intercollegial consultation, might decrease this variability.

Tumor-immune landscape patterns before and after chemoradiation in resectable esophageal adenocarcinomas

Immunotherapy is a new anti‐cancer treatment option, showing promising results in clinical trials. To investigate potential immune biomarkers in esophageal adenocarcinoma (EAC), we explored immune landscape patterns in the tumor microenvironment before and after neoadjuvant chemoradiation (nCRT). Sections from matched pretreatment biopsies and post‐nCRT resection specimens (n = 188) were stained for (1) programmed death‐ligand 1 (PD‐L1, CD274); (2) programmed cell death protein 1 (PD‐1, CD279), forkhead box P3 (FOXP3), CD8, pan‐cytokeratin multiplex; and (3) an MHC class I, II duplex. The densities of tumor‐associated immune cells (TAICs) were calculated using digital image analyses and correlated to histopathological nCRT response [tumor regression grade (TRG)], survival, and post‐nCRT immune patterns. PD‐L1 positivity defined by a combined positive score of >1 was associated with a better response post‐nCRT (TRG 1–3 versus 4, 5, p = 0.010). In addition, high combined mean densities of CD8⁺, FOXP3⁺, and PD‐1⁺ TAICs in the tumor epithelium and stroma of biopsies were associated with a better response (TRG 1–3 versus 4, 5, p = 0.025 and p = 0.044, respectively). Heterogeneous TAIC density patterns were observed post‐nCRT, with significantly higher CD8⁺ and PD‐1⁺ TAIC mean densities compared with biopsies (both p = 0.000). Three immune landscape patterns were defined post‐nCRT: ‘inflamed’, ‘invasive margin’, and ‘desert’, of which ‘inflamed’ was the most frequent (57%). Compared with matched biopsies, resection specimens with ‘inflamed’ tumors showed a significantly higher increase in CD8⁺ density compared with non‐inflamed tumors post‐nCRT (p = 0.000). In this cohort of EAC patients, higher TAIC densities in pretreatment biopsies were associated with response to nCRT. This warrants future research into the potential of the tumor‐immune landscape for patient stratification and novel (immune) therapeutic strategies. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd on behalf of The Pathological Society of Great Britain and Ireland.

18F-Fludeoxyglucose-Positron Emission Tomography/Computed Tomography and Laparoscopy for Staging of Locally Advanced Gastric Cancer: A Multicenter Prospective Dutch Cohort Study (PLASTIC)

Importance

The optimal staging for gastric cancer remains a matter of debate.

Objective

To evaluate the value of 18F-fludeoxyglucose-positron emission tomography with computed tomography (FDG-PET/CT) and staging laparoscopy (SL) in addition to initial staging by means of gastroscopy and CT in patients with locally advanced gastric cancer.

Design, Setting, and Participants

This multicenter prospective, observational cohort study included 394 patients with locally advanced, clinically curable gastric adenocarcinoma (≥cT3 and/or N+, M0 category based on CT) between August 1, 2017, and February 1, 2020.

Exposures

All patients underwent an FDG-PET/CT and/or SL in addition to initial staging.

Main Outcomes and Measures

The primary outcome was the number of patients in whom the intent of treatment changed based on the results of these 2 investigations. Secondary outcomes included diagnostic performance, number of incidental findings on FDG-PET/CT, morbidity and mortality after SL, and diagnostic delay.

Results

Of the 394 patients included, 256 (65%) were men and mean (SD) age was 67.6 (10.7) years. A total of 382 patients underwent FDG-PET/CT and 357 underwent SL. Treatment intent changed from curative to palliative in 65 patients (16%) based on the additional FDG-PET/CT and SL findings. FDG-PET/CT detected distant metastases in 12 patients (3%), and SL detected peritoneal or locally nonresectable disease in 73 patients (19%), with an overlap of 7 patients (2%). FDG-PET/CT had a sensitivity of 33% (95% CI, 17%-53%) and specificity of 97% (95% CI, 94%-99%) in detecting distant metastases. Secondary findings on FDG/PET were found in 83 of 382 patients (22%), which led to additional examinations in 65 of 394 patients (16%). Staging laparoscopy resulted in a complication requiring reintervention in 3 patients (0.8%) without postoperative mortality. The mean (SD) diagnostic delay was 19 (14) days.

Conclusions and Relevance

This study's findings suggest an apparently limited additional value of FDG-PET/CT; however, SL added considerably to the staging process of locally advanced gastric cancer by detection of peritoneal and nonresectable disease. Therefore, it may be useful to include SL in guidelines for staging advanced gastric cancer, but not FDG-PET/CT.

Risk Factors for Metachronous Isolated Peritoneal Metastasis after Preoperative Chemotherapy and Potentially Curative Gastric Cancer Resection: Results from the CRITICS Trial

Simple Summary

Around 20% of gastric cancer patients develop peritoneal metastasis after preoperative chemotherapy and curative surgery. Patients with peritoneal metastasis as a single site of metastasis may potentially benefit from prophylactic strategies. In this post-hoc analysis of the international phase III CRITICS trial, we aim to identify factors that can distinguish patients at high risk for developing peritoneal metastasis as a single site. Diffuse or mixed histological subtype, tumors with serosal involvement (ypT4) and advanced lymph node stage (ypN3 or a tumor positive lymph node ratio >20%) were independent risk factors for isolated peritoneal metastasis after preoperative chemotherapy and curative surgery. The combination of these risk factors identifies a subgroup that may benefit from treatment strategies that aim to prevent peritoneal metastasis.

Abstract

Gastric cancer (GC) patients at high risk of developing peritoneal metastasis (PM) as a single site of metastasis after curative treatment may be candidates for adjuvant prophylactic strategies. Here we investigated risk factors for metachronous isolated PM in patients who were treated in the CRITICS trial (NCT00407186). Univariable and multivariable analyses on both metachronous isolated PM and ‘other events’, i.e., (concurrent) distant metastasis, locoregional recurrence or death, were performed using a competing risk model and summarized by cumulative incidences. Isolated PM occurred in 64 of the 606 (11%) included patients. Diffuse or mixed histological subtype, ypT4 tumor stage and LN^high (ypN3 lymph node stage or a lymph node ratio >20%) were independent risk factors for isolated PM in both univariable and multivariable analyses. Likewise, LN^high was an independent risk factor for ‘other events’. Patients with tumors who were positive for all three independent risk factors had the highest two-year cumulative incidence of 43% for isolated PM development. In conclusion, diffuse or mixed histological subtype, ypT4 and LN^high were identified as independent risk factors for isolated PM in patients treated with preoperative chemotherapy followed by surgical resection. The combination of these factors may identify a subgroup that may benefit from PM-preventing treatment strategies.

Interferon- and STING-independent induction of type I interferon stimulated genes during fractionated irradiation

BACKGROUND

Improvement of radiotherapy efficacy requires better insight in the dynamic responses that occur during irradiation. Here, we aimed to identify the molecular responses that are triggered during clinically applied fractionated irradiation.

METHODS

Gene expression analysis was performed by RNAseq or microarray analysis of cancer cells or xenograft tumors, respectively, subjected to 3-5 weeks of 5 × 2 Gy/week. Validation of altered gene expression was performed by qPCR and/or ELISA in multiple cancer cell lines as well as in pre- and on-treatment biopsies from esophageal cancer patients ( NCT02072720 ). Targeted protein inhibition and CRISPR/Cas-induced gene knockout was used to analyze the role of type I interferons and cGAS/STING signaling pathway in the molecular and cellular response to fractionated irradiation.

RESULTS

Gene expression analysis identified type I interferon signaling as the most significantly enriched biological process induced during fractionated irradiation. The commonality of this response was confirmed in all irradiated cell lines, the xenograft tumors and in biopsies from esophageal cancer patients. Time-course analyses demonstrated a peak in interferon-stimulated gene (ISG) expression within 2-3 weeks of treatment. The response was accompanied by a variable induction of predominantly interferon-beta and/or -lambda, but blocking these interferons did not affect ISG expression induction. The same was true for targeted inhibition of the upstream regulatory STING protein while knockout of STING expression only delayed the ISG expression induction.

CONCLUSIONS

Collectively, the presented data show that clinically applied fractionated low-dose irradiation can induce a delayed type I interferon response that occurs independently of interferon expression or STING signaling. These findings have implications for current efforts that aim to target the type I interferon response for cancer treatment.

Sialic acids in pancreatic cancer cells drive tumour-associated macrophage differentiation via the Siglec receptors Siglec-7 and Siglec-9

Changes in glycosylation during tumour progression are a key hallmark of cancer. One of the glycan moieties generally overexpressed in cancer are sialic acids, which can induce immunomodulatory properties via binding to Siglec receptors. We here show that Pancreatic Ductal Adenocarcinoma (PDAC) tumour cells present an increased sialylation that can be recognized by Siglec-7 and Siglec-9 on myeloid cells. We identified the expression of the α2,3 sialyltransferases ST3GAL1 and ST3GAL4 as main contributor to the synthesis of ligands for Siglec-7 and Siglec-9 in tumour cells. Analysing the myeloid composition in PDAC, using single cell and bulk transcriptomics data, we identified monocyte-derived macrophages as contributors to the poor clinical outcome. Tumour-derived sialic acids dictate monocyte to macrophage differentiation via signalling through Siglec-7 and Siglec-9. Moreover, triggering of Siglec-9 in macrophages reduce inflammatory programmes, while increasing PD-L1 and IL-10 expression, illustrating that sialic acids modulate different myeloid cells. This work highlights a critical role for sialylated glycans in controlling immune suppression and provides new potential targets for cancer immunotherapy in PDAC.

Molecular profiles of response to neoadjuvant chemoradiotherapy in oesophageal cancers to develop personalized treatment strategies

Identification of molecular predictive markers of response to neoadjuvant chemoradiation could aid clinical decision‐making in patients with localized oesophageal cancer. Therefore, we subjected pretreatment biopsies of 75 adenocarcinoma (OAC) and 16 squamous cell carcinoma (OSCC) patients to targeted next‐generation DNA sequencing, as well as biopsies of 85 OAC and 20 OSCC patients to promoter methylation analysis of eight GI‐specific genes, and subsequently searched for associations with histopathological response and disease‐free (DFS) and overall survival (OS). Thereby, we found that in OAC, CSMD1 deletion (8%) and ETV4 amplification (5%) were associated with a favourable histopathological response, whereas SMURF1 amplification (5%) and SMARCA4 mutation (7%) were associated with an unfavourable histopathological response. KRAS (15%) and GATA4 (7%) amplification were associated with shorter OS. In OSCC, TP63 amplification (25%) and TFPI2 (10%) gene promoter methylation were associated with an unfavourable histopathological response and shorter DFS (TP63) and OS (TFPI2), whereas CDKN2A deletion (38%) was associated with prolonged OS. In conclusion, this study identified candidate genetic biomarkers associated with response to neoadjuvant chemoradiotherapy in patients with localized oesophageal cancer.

Neoadjuvant Chemoradiotherapy Combined with Atezolizumab for Resectable Esophageal Adenocarcinoma: A Single-arm Phase II Feasibility Trial (PERFECT)

PURPOSE

The CROSS trial established neoadjuvant chemoradiotherapy (nCRT) for patients with resectable esophageal adenocarcinoma (rEAC). In the PERFECT trial, we investigated the feasibility and efficacy of nCRT combined with programmed-death ligand-1 (PD-L1) inhibition for rEAC.

PATIENTS AND METHODS

Patients with rEAC received nCRT according to the CROSS regimen combined with five cycles of atezolizumab (1,200 mg). The primary endpoint was the feasibility of administering five cycles of atezolizumab in ≥75% patients. A propensity score-matched nCRT cohort was used to compare pathologic response, overall survival, and progression-free survival. Exploratory biomarker analysis was performed on repeated tumor biopsies.

RESULTS

We enrolled 40 patients of whom 85% received all cycles of atezolizumab. Immune-related adverse events of any grade were observed in 6 patients. In total, 83% proceeded to surgery. Reasons for not undergoing surgery were progression (n = 4), patient choice (n = 2), and death (n = 1). The pathologic complete response rate was 25% (10/40). No statistically significant difference in response or survival was found between the PERFECT and the nCRT cohort. Baseline expression of an established IFNγ signature was higher in responders compared with nonresponders (P = 0.043). On-treatment nonresponders showed either a high number of cytotoxic lymphocytes (CTL) with a transcriptional signature consistent with expression of immune checkpoints, or a low number of CTLs.

CONCLUSIONS

Combining nCRT with atezolizumab is feasible in patients with rEAC. On the basis of our exploratory biomarker study, future studies are necessary to elucidate the potential of neoadjuvant immunotherapy in patient subgroups.See related commentary by Catenacci, p. 3269.

Towards Personalization in the Curative Treatment of Gastric Cancer

Gastric cancer is the fifth most common cancer worldwide and has a high mortality rate. In the last decades, treatment strategy has shifted from an exclusive surgical approach to a multidisciplinary strategy. Treatment options for patients with resectable gastric cancer as recommended by different worldwide guidelines, include perioperative chemotherapy, pre- or postoperative chemoradiotherapy and postoperative chemotherapy. Although gastric cancer is a heterogeneous disease with respect to patient-, tumor-, and molecular characteristics, the current standard of care is still according to a one-size-fits-all approach. In this review, we discuss the background of the different treatment strategies in resectable gastric cancer including the current standard, the specific role of radiotherapy, and describe the current areas of research and potential strategies for personalization of therapy.

A specific microRNA profile as predictive biomarker for systemic treatment in patients with metastatic colorectal cancer

Background

Palliative systemic therapy is currently standard of care for patients with extensive metastatic colorectal cancer (mCRC). A biomarker predicting chemotherapy benefit which prevents toxicity from ineffective treatment is urgently needed. Therefore, a previously developed tissue‐derived microRNA profile to predict clinical benefit from chemotherapy was evaluated in tissue biopsies and serum from patients with mCRC.

Methods

Samples were prospectively collected from patients (N = 132) who were treated with capecitabine or 5‐FU/LV with oxaliplatin ± bevacizumab. Response evaluation was performed according to RECIST 1.1 after three or four cycles, respectively. Baseline tissue and serum miRNAs expression levels of miR‐17‐5p, miR‐20a‐5p, miR‐30a‐5p, miR‐92a‐3p, miR‐92b‐3p, and miR‐98‐5p were quantified with RT‐qPCR and droplet digital PCR, respectively. Combined predictive performance of selected variables was tested using logistic regression analysis.

Results

From 132 patients, 81 fresh frozen tissue biopsies from metastases and 93 serum samples were available. Based on expression levels of miRNAs in tissue, progressive disease could be predicted with an AUC of 0.85 (95% CI:0.72‐0.91) and response could be predicted with an AUC of 0.70 (95% CI:0.56‐0.80). This did not outperform clinical parameters alone (respectively P = .14 and P = .27). Expression levels of miR‐92a‐3p and miR‐98‐5p in serum significantly improved the predictive value of clinical parameters for response to chemotherapy (AUC 0.74, 95% CI:0.64‐0.84, P = .003) in this cohort.

Conclusions

The additive predictive value to clinical parameters of the tissue‐derived six miRNA profile for clinical benefit could not be validated in patients with mCRC treated with first‐line systemic therapy. Although miR‐92a‐3p and miR‐98‐5p serum levels improved the predictive value of clinical parameters, it remained insufficient for clinical decision‐making.

Venous thromboembolism during preoperative chemotherapy in the CRITICS gastric cancer trial

BACKGROUND

The occurrence of a venous thromboembolism (VTE) is common in patients with cancer. Gastric cancer has been associated with one of the highest risks for VTE. Chemotherapy, especially cisplatin has been associated with a high VTE risk. In this study, risk factors for VTE occurrence and their potential impact on subsequent therapeutic interventions were investigated in patients who underwent preoperative chemotherapy, in the CRITICS gastric cancer trial.

PATIENTS AND METHODS

Patients with resectable gastric cancer were preoperatively treated with three cycles of 3-weekly epirubicin, cisplatin or oxaliplatin, and capecitabine (ECC/EOC). VTE was defined as any thrombus in the venous system, excluding superficial and/or device related VTEs. Potential risk factors were analyzed in a multivariable regression model with age, gender, Body Mass Index (BMI), tumor localization, Lauren classification, type of chemotherapy (ECC/EOC), (cardiovascular) comorbidity, and previous VTE as independent risk factors. The impact of VTE on completion rate of preoperative chemotherapy, surgical resection rate, postoperative complications, and start of postoperative therapy were investigated.

RESULTS

Of 781 patients, 78 (10%) of 781 patients developed a VTE during preoperative chemotherapy. On multivariable analysis, BMI ≥ 30 kg/m² and previous VTE were associated with VTE occurrence (reference BMI < 25 kg/m² ; OR 2.190; 95% CI 1.152-4.164; P = .017/previous VTE; OR 3.617; 95% CI 1.201-10.890; P = .022). Treatment with cisplatin was, compared to oxaliplatin, not significantly associated with VTE occurrence (OR 1.535; 95% CI 0.761-3.094; P = .231). VTE occurrence did not affect completion of preoperative chemotherapy, surgical resection rate, postoperative complications, or start of postoperative therapy.

CONCLUSION

High BMI and previous VTE were independent risk factors for VTE occurrence during preoperative chemotherapy in patients with resectable gastric cancer. VTE occurrence in the preoperative setting did not affect receipt of further treatment.

Circulating Tumor DNA as a Preoperative Marker of Recurrence in Patients with Peritoneal Metastases of Colorectal Cancer: A Clinical Feasibility Study

Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy (CRS-HIPEC) may be curative for colorectal cancer patients with peritoneal metastases (PMs) but it has a high rate of morbidity. Accurate preoperative patient selection is therefore imperative, but is constrained by the limitations of current imaging techniques. In this pilot study, we explored the feasibility of circulating tumor (ct) DNA analysis to select patients for CRS-HIPEC. Thirty patients eligible for CRS-HIPEC provided blood samples preoperatively and during follow-up if the procedure was completed. Targeted Next-Generation Sequencing (NGS) of DNA from PMs was used to identify bespoke mutations that were subsequently tested in corresponding plasma cell-free (cf) DNA samples using droplet digital (dd) PCR. CtDNA was detected preoperatively in cfDNA samples from 33% of patients and was associated with a reduced disease-free survival (DFS) after CRS-HIPEC (median 6.0 months vs median not reached, p = 0.016). This association could indicate the presence of undiagnosed systemic metastases or an increased metastatic potential of the tumors. We demonstrate the feasibility of ctDNA to serve as a preoperative marker of recurrence in patients with PMs of colorectal cancer using a highly sensitive technique. A more appropriate treatment for patients with preoperative ctDNA detection may be systemic chemotherapy in addition to, or instead of, CRS-HIPEC.

Older versus younger adults with gastric cancer receiving perioperative treatment: Results from the CRITICS trial

AIM

To evaluate treatment-related toxicity, treatment compliance, surgical complications and event-free survival (EFS) in older (≥70 years) versus younger (<70 years) adults who underwent perioperative treatment for gastric cancer.

METHODS

In the CRITICS trial, 788 patients with resectable gastric cancer were randomised before start of any treatment and received preoperative chemotherapy (3 cycles of epirubicin, cisplatin or oxaliplatin and capecitabine), followed by surgery, followed by either postoperative chemotherapy or chemoradiotherapy (45Gy + cisplatin + capecitabine).

RESULTS

172 (22%) patients were older adults. During preoperative chemotherapy, 131 (77%) older adults versus 380 (62%) younger adults experienced severe toxicity (p < 0.001); older adults received significantly lower relative dose intensities (RDIs) for all chemotherapeutic drugs. Equal proportions of older versus younger adults underwent curative surgery: 137 (80%) versus 499 (81%), with comparable postoperative complications and postoperative mortality. Postoperative therapy after curative surgery started in 87 (64%) older adults versus 391 (78%) younger adults (p < 0.001). Incidence of severe toxicity during postoperative chemotherapy was 22 (54%) in older adults versus 113 (59%) in younger adults (p = 0.541); older adults received significantly lower RDIs for all chemotherapeutic drugs. Severe toxicity rates for postoperative chemoradiotherapy were 22 (48%) older adults versus 89 (45%) for younger adults (p = 0.703), with comparable chemotherapy RDIs and radiotherapy dose. Two-year EFS was 53% for older adults versus 51% for younger adults.

CONCLUSION

Perioperative treatment compliance, especially in the postoperative phase, was poorer in older adults compared with younger adults. As comparable proportions of patients underwent curative surgery, future studies should focus on neo-adjuvant treatment.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00407186. EudraCT number: 2006-00413032.

Interobserver, intraobserver, and interlaboratory variability in reporting pT4a colon cancer

Clinical significance of the pT4 category in colon cancer is increasing with several therapeutic implications. The aim of this study was to evaluate variability in diagnosing pT4a colon cancer. Twelve pathologists classified 66 preselected scanned Hematoxylin/Eosin-stained slides with tumor cells at a distance of 25-1500 μm (n = 22), 0-25 μm (n = 22), or on (n = 22) the peritoneal surface. Inter- and intraobserver variability were calculated using Kappa statistics. For interlaboratory variability, pathology reports of pT3 and pT4a colon cancer were extracted from the Dutch Pathology Registry between 2012 and 2015. The proportion of pT4a (pT4a/(pT3+pT4a)) was compared between 33 laboratories. Potential risk of understaging was assessed by determining the average number of blocks taken from pT3 and pT4a N0-2M0 tumors with metachronous peritoneal metastasis. Interobserver variability among 12 pathologists was 0.50 (95%CI 0.41-0.60; moderate agreement). Intraobserver variability (8 pathologists) was 0.71 (substantial agreement). A total of 7745 reports with pT3 or pT4aN0-2M0 colon cancer from 33 laboratories were included for interlaboratory analysis. Median percentage of pT4a was 15.5% (range 3.2-24.6%). After adjustment for case mix, 8 labs diagnosed pT4a significantly less or more frequently than the median lab. Metachronous peritoneal metastases were histologically verified in 170 of 6629 pT3 and in 129 of 1116 pT4a tumors, with a mean number of blocks of 4.03(SD 1.51) and 4.78 (SD 1.76) taken from the primary tumors, respectively (p < 0.001). A substantial variability in diagnosing pT4a colon cancer exists, both at pathologist and laboratory level. Diagnosis of pT4a stage appears to be challenging and there is a need for standardizing assessment of this pathological entity.

IBD-Associated Dysplastic Lesions Show More Chromosomal Instability Than Sporadic Adenomas

BACKGROUND

Patients with longstanding inflammatory bowel disease (IBD; ie, ulcerative colitis and Crohn's disease) have an increased risk of colorectal cancer (CRC). Due to ongoing inflammation, IBD-associated dysplastic lesions can develop. These lesions have an increased risk to progress to cancer compared with sporadic adenomas, which are also found in these patients. Differentiating between these 2 types of dysplasia remains challenging, both clinically and histologically, while treatment strategies may differ. Therefore, the aim of this study was to investigate molecular alterations associated with colorectal dysplasia to cancer progression in IBD and evaluate to what extent these alterations differ from sporadic adenomas.

METHODS

DNA copy number aberrations and mutation analyses of 48 genes were performed by next-generation sequencing in 43 IBD-associated dysplastic lesions, 30 of which were dysplastic and 13 of which were cancers. Results were compared with existing DNA copy number and mutation data from 118 sporadic adenomas and 24 sporadic cancers.

RESULTS

Inflammatory bowel disease-associated dysplastic lesions harbor patterns of DNA copy number aberrations comparable to carcinomas, which are rare in sporadic adenomas. TP53 mutation was the most frequent mutation observed in IBD-associated dysplastic lesions and in cancers. FBXW7 was mutated significantly more often in IBD-associated dysplastic lesions than in sporadic adenomas.

CONCLUSIONS

Inflammatory bowel disease-associated dysplastic lesions show more DNA copy number aberrations than sporadic adenomas. TP53 and FBXW7 mutations appear to be involved in the development of IBD-associated dysplastic lesions and cancer. These findings indicate that IBD-associated dysplastic lesions are more genomically unstable, possibly reflecting a faster progression toward cancer.

Circulating Tumor DNA Analysis: Clinical Implications for Colorectal Cancer Patients. A Systematic Review

Background

Liquid biopsies could improve diagnosis, prognostication, and monitoring of colorectal cancer (CRC). Mutation, chromosomal copy number alteration, and methylation analysis in circulating tumor DNA (ctDNA) from plasma or serum has gained great interest. However, the literature is inconsistent on preferred candidate markers, hampering a clear direction for further studies and clinical translation. This review assessed the potential of ctDNA analysis for clinical utility.

Methods

A systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines was conducted up to December 3, 2018, followed by methodological quality assessment. Primary endpoints were accuracy for detection, prognostication, and monitoring.

Results

Eighty-four studies were included. For CRC detection, sensitivity was 75% using ctDNA mutation analysis and up to 96% using copy number analysis. Septin 9 (SEPT9) hypermethylation analysis showed sensitivities of 100% and specificities of 97%. Regarding prognostication, ctDNA KRAS mutations were associated with oncological outcome and could predict response to anti-epidermal growth factor receptor therapy. For monitoring, sequential ctDNA KRAS mutation analysis showed promise for detection of relapses or therapy resistance.

Conclusions

This comprehensive overview of ctDNA candidate markers demonstrates SEPT9 methylation analysis to be promising for CRC detection, and KRAS mutation analysis could assist in prognostication and monitoring. Prospective evaluation of marker panels in clinical decision making should bring ctDNA analysis into practice.

Copy number load predicts outcome of metastatic colorectal cancer patients receiving bevacizumab combination therapy

Increased copy number alterations (CNAs) indicative of chromosomal instability (CIN) have been associated with poor cancer outcome. Here, we study CNAs as potential biomarkers of bevacizumab (BVZ) response in metastatic colorectal cancer (mCRC). We cluster 409 mCRCs in three subclusters characterized by different degrees of CIN. Tumors belonging to intermediate-to-high instability clusters have improved outcome following chemotherapy plus BVZ versus chemotherapy alone. In contrast, low instability tumors, which amongst others consist of POLE-mutated and microsatellite-instable tumors, derive no further benefit from BVZ. This is confirmed in 81 mCRC tumors from the phase 2 MoMa study involving BVZ. CNA clusters overlap with CRC consensus molecular subtypes (CMS); CMS2/4 xenografts correspond to intermediate-to-high instability clusters and respond to FOLFOX chemotherapy plus mouse avastin (B20), while CMS1/3 xenografts match with low instability clusters and fail to respond. Overall, we identify copy number load as a novel potential predictive biomarker of BVZ combination therapy.

Increased copy number alterations, indicative of chromosomal instability, is associated with poor cancer outcome. Here, metastatic colorectal cancer patients displaying intermediate-high CIN associate with improved outcome following chemotherapy and bevacizumab treatment, suggesting CIN as a predictive biomarker.

CRITICS-II: a multicentre randomised phase II trial of neo-adjuvant chemotherapy followed by surgery versus neo-adjuvant chemotherapy and subsequent chemoradiotherapy followed by surgery versus neo-adjuvant chemoradiotherapy followed by surgery in resectable gastric cancer

Background

Although radical surgery remains the cornerstone of cure in resectable gastric cancer, survival remains poor. Current evidence-based (neo)adjuvant strategies have shown to improve outcome, including perioperative chemotherapy, postoperative chemoradiotherapy and postoperative chemotherapy. However, these regimens suffer from poor patient compliance, particularly in the postoperative phase of treatment. The CRITICS-II trial aims to optimize preoperative treatment by comparing three treatment regimens: (1) chemotherapy, (2) chemotherapy followed by chemoradiotherapy and (3) chemoradiotherapy.

Methods

In this multicentre phase II non-comparative study, patients with clinical stage IB-IIIC (TNM 8th edition) resectable gastric adenocarcinoma are randomised between: (1) 4 cycles of docetaxel+oxaliplatin+capecitabine (DOC), (2) 2 cycles of DOC followed by chemoradiotherapy (45Gy in combination with weekly paclitaxel and carboplatin) or (3) chemoradiotherapy. Primary endpoint is event-free survival, 1 year after randomisation (events are local and/or regional recurrence or progression, distant recurrence, or death from any cause). Secondary endpoints include: toxicity, surgical outcomes, percentage radical (R0) resections, pathological tumour response, disease recurrence, overall survival, and health related quality of life. Exploratory endpoints include translational studies on predictive and prognostic biomarkers.

Discussion

The aim of this study is to select the most promising among three preoperative treatment arms in patients with resectable gastric adenocarcinoma. This treatment regimen will subsequently be compared with the standard therapy in a phase III trial.

Trial registration

clinicaltrials.gov NCT02931890; registered 13 October 2016. Date of first enrolment: 21 December 2017.

Combination of a six microRNA expression profile with four clinicopathological factors for response prediction of systemic treatment in patients with advanced colorectal cancer

Background

First line chemotherapy is effective in 75 to 80% of patients with metastatic colorectal cancer (mCRC). We studied whether microRNA (miR) expression profiles can predict treatment outcome for first line fluoropyrimidine containing systemic therapy in patients with mCRC.

Methods

MiR expression levels were determined by next generation sequencing from snap frozen tumor samples of 88 patients with mCRC. Predictive miRs were selected with penalized logistic regression and posterior forward selection. The prediction co-efficients of the miRs were re-estimated and validated by real-time quantitative PCR in an independent cohort of 81 patients with mCRC.

Results

Expression levels of miR-17-5p, miR-20a-5p, miR-30a-5p, miR-92a-3p, miR-92b-3p and miR-98-5p in combination with age, tumor differentiation, adjuvant therapy and type of systemic treatment, were predictive for clinical benefit in the training cohort with an AUC of 0.78. In the validation cohort the addition of the six miR signature to the four clinicopathological factors demonstrated a significant increased AUC for predicting treatment response versus those with stable disease (SD) from 0.79 to 0.90. The increase for predicting treatment response versus progressive disease (PD) and for patients with SD versus those with PD was not significant. in the validation cohort. MiR-17-5p, miR-20a-5p and miR-92a-3p were significantly upregulated in patients with treatment response in both the training and validation cohorts.

Conclusion

A six miR expression signature was identified that predicted treatment response to fluoropyrimidine containing first line systemic treatment in patients with mCRC when combined with four clinicopathological factors. Independent validation demonstrated added predictive value of this miR-signature for predicting treatment response versus SD. However, added predicted value for separating patients with PD could not be validated. The clinical relevance of the identified miRs for predicting treatment response has to be further explored.

MACROD2 expression predicts response to 5-FU-based chemotherapy in stage III colon cancer

Background

Colorectal cancer (CRC) is caused by genetic aberrations. MACROD2 is commonly involved in somatic focal DNA copy number losses, in more than one-third of CRCs. In this study, we aimed to investigate the association of MACROD2 protein expression with clinical outcome in stage II and stage III colon cancer.

Methods

Tissue microarrays (TMA) containing formalin-fixed paraffin-embedded tissue cores from 386 clinically well-annotated primary stage II and III colon cancers were stained by immunohistochemistry and evaluated for MACROD2 protein expression. Disease-free survival (DFS) analysis was performed to estimate association with clinical outcome.

Results

Loss of nuclear MACROD2 protein expression in epithelial neoplastic cells of stage III microsatellite stable (MSS) colon cancers was associated with poor DFS within the subgroup of 59 patients who received 5-fluorouracil (5-FU)-based adjuvant chemotherapy (p=0.005; HR=3.8, 95% CI 1.4-10.0).

Conclusion

These data indicate that low nuclear expression of MACROD2 is associated with poor prognosis of patients with stage III MSS primary colon cancer who were treated with 5-FU-based adjuvant chemotherapy.

Outcomes and Treatment Options for Duodenal Adenocarcinoma: A Systematic Review and Meta-Analysis

Background

Duodenal adenocarcinoma (DA) is a rare tumor for which survival data per treatment modality and disease stage are unclear. This systematic review and meta-analysis aims to summarize the current literature on patient outcome after surgical, (neo)adjuvant, and palliative treatment in patients with DA.

Methods

A systematic search was performed according to the preferred reporting items for systematic reviews and meta-analyses guidelines, to 25 April 2017. Primary outcome was overall survival (OS), specified for treatment strategy or disease stage. Random-effects models were used for the calculation of pooled odds ratios per treatment modality. Included papers were also screened for prognostic factors.

Results

A total of 26 observational studies, comprising 6438 patients with DA, were included. Of these, resection with curative intent was performed in 71% (range 53–100%) of patients, and 29% received palliative treatment (range 0–61%). The pooled 5-year OS rate was 46% after curative resection, compared with 1% in palliative-treated patients (OR 0.04, 95% confidence interval [CI] 0.02–0.09, p < 0.0001). Both segmental resection and pancreaticoduodenectomy allowed adequate assessment of lymph node involvement and resulted in similar OS. Lymph node involvement correlated with worse OS (pooled 5-year survival rate 21% for nodal metastases vs. 65% for node-negative disease; OR 0.17, 95% CI 0.11–0.27, p < 0.0001). In the current literature, no survival benefit for adjuvant therapy after curative resection was found.

Conclusion

Resection with curative intent, either pancreaticoduodenectomy or segmental resection, and lack of nodal metastases, favors survival for DA. Further studies exploring multimodality (neo)adjuvant therapy are warranted to investigate their benefit.

Electronic supplementary material

The online version of this article (10.1245/s10434-018-6567-6) contains supplementary material, which is available to authorized users.

Loss of Chromosome 18q11.2-q12.1 Is Predictive for Survival in Patients With Metastatic Colorectal Cancer Treated With Bevacizumab

Purpose Patients with metastatic colorectal cancer (mCRC) have limited benefit from the addition of bevacizumab to standard chemotherapy. However, a subset probably benefits substantially, highlighting an unmet clinical need for a biomarker of response to bevacizumab. Previously, we demonstrated that losses of chromosomes 5q34, 17q12, and 18q11.2-q12.1 had a significant correlation with progression-free survival (PFS) in patients with mCRC treated with bevacizumab in the CAIRO2 clinical trial but not in patients who did not receive bevacizumab in the CAIRO trial. This study was designed to validate these findings. Materials and Methods Primary mCRC samples were analyzed from two cohorts of patients who received bevacizumab as first-line treatment; 96 samples from the European multicenter study Angiopredict (APD) and 81 samples from the Italian multicenter study, MOMA. A third cohort of 90 samples from patients with mCRC who did not receive bevacizumab was analyzed. Copy number aberrations of tumor biopsy specimens were measured by shallow whole-genome sequencing and were correlated with PFS, overall survival (OS), and response. Results Loss of chromosome 18q11.2-q12.1 was associated with prolonged PFS most significantly in both the cohorts that received bevacizumab (APD: hazard ratio, 0.54; P = .01; PFS difference, 65 days; MOMA: hazard ratio, 0.55; P = .019; PFS difference, 49 days). A similar association was found for OS and overall response rate in these two cohorts, which became significant when combined with the CAIRO2 cohort. Median PFS in the cohort of patients with mCRC who did not receive bevacizumab and in the CAIRO cohort was similar to that of the APD, MOMA, and CAIRO2 patients without an 18q11.2-q12.1 loss. Conclusion We conclude that the loss of chromosome 18q11.2-q12.1 is consistently predictive for prolonged PFS in patients receiving bevacizumab. The predictive value of this loss is substantiated by a significant gain in OS and overall response rate.

Non responders to neoadjuvant chemoradiation for esophageal cancer: why better prediction is necessary

BACKGROUND

Patients with pathologic limited or no response (pNR) to neoadjuvant chemoradiation (nCRT) are subjected to curative intended esophagectomy with subsequent perioperative morbidity and mortality, but potentially only harm from nCRT. The primary aim of this study was to compare the overall survival (OS) of patients with pNR and patients who underwent primary esophagectomy to evaluate potentially benefits of nCRT in these patients. The secondary aim was to identify predictive clinicopathologic factors for pNR and pathologic complete response (pCR) to nCRT with the goal to preselect these patients before the start of treatment.

METHODS

From the period 2005 to 2016, 206 esophageal cancer (EC) patients treated with Carboplatin/Paclitaxel and radiotherapy with complementary esophagectomy were included in this cohort. OS of patients with pNR was compared with a historical cohort of primary surgically treated patients (n=218) after a propensity score matching resulting in a group of 68 patients with pNR after nCRT versus a group of 68 primary esophagectomy patients.

RESULTS

The OS in the pNR group and the primary esophagectomy group was comparable (P=0.986). No predictive factors were found in this cohort for pNR. Female gender (OR 2.5, 95% CI 1.2-5.3) and squamous cell carcinoma (SCC) (OR 2.6, 95% CI 1.3-5.3) were identified as independent predictive factors for pCR.

CONCLUSIONS

Patients with a pNR do not benefit from nCRT followed by resection. These patients had a similar OS as those who had a primary esophagectomy alone. Although this indicates that nCRT does not negatively impact the OS of patients with pNR, patients still have an increased morbidity because of nCRT. Hence, it is important to identify factors that predict pNR. The ability to predict pNR (and pCR) will enable tailored and personalized care preventing unnecessary nCRT with increased morbidity.

Decoy receptor 1 (DCR1) promoter hypermethylation and response to irinotecan in metastatic colorectal cancer

Diversity in colorectal cancer biology is associated with variable responses to standard chemotherapy. We aimed to identify and validate DNA hypermethylated genes as predictive biomarkers for irinotecan treatment of metastatic CRC patients.

Candidate genes were selected from 389 genes involved in DNA Damage Repair by correlation analyses between gene methylation status and drug response in 32 cell lines. A large series of samples (n=818) from two phase III clinical trials was used to evaluate these candidate genes by correlating methylation status to progression-free survival after treatment with first-line single-agent fluorouracil (Capecitabine or 5-fluorouracil) or combination chemotherapy (Capecitabine or 5-fluorouracil plus irinotecan (CAPIRI/FOLFIRI)).

In the discovery (n=185) and initial validation set (n=166), patients with methylated Decoy Receptor 1 (DCR1) did not benefit from CAPIRI over Capecitabine treatment (discovery set: HR=1.2 (95%CI 0.7-1.9, p=0.6), validation set: HR=0.9 (95%CI 0.6-1.4, p=0.5)), whereas patients with unmethylated DCR1 did (discovery set: HR=0.4 (95%CI 0.3-0.6, p=0.00001), validation set: HR=0.5 (95%CI 0.3-0.7, p=0.0008)). These results could not be replicated in the external data set (n=467), where a similar effect size was found in patients with methylated and unmethylated DCR1 for FOLFIRI over 5FU treatment (methylated DCR1: HR=0.7 (95%CI 0.5-0.9, p=0.01), unmethylated DCR1: HR=0.8 (95%CI 0.6-1.2, p=0.4)).

In conclusion, DCR1 promoter hypermethylation status is a potential predictive biomarker for response to treatment with irinotecan, when combined with capecitabine. This finding could not be replicated in an external validation set, in which irinotecan was combined with 5FU. These results underline the challenge and importance of extensive clinical evaluation of candidate biomarkers in multiple trials.

Why is colon cancer survival improving by time? A nationwide survival analysis spanning 35 years

There is limited information present to explain temporal improvements in colon cancer survival. This nationwide study investigates the temporal changes in survival over a 35-year period (1970-2004) in Iceland and uses incidence, mortality, surgery rate, stage distribution, lymph node yield, tumor location and histological type to find explanations for these changes. Patients diagnosed with colon cancer in Iceland 1970-2004 were identified (n = 1962). All histopathology was reassessed. Proportions, age-standardized incidence and mortality, relative, cancer-specific and overall survival and conditional survival were calculated. When comparing first and last diagnostic periods (1970-1978 and 1997-2004), 5-year relative survival improved by 12% for men and 9% for women. At the same time surgery rate increased by 12% and the proportion of stage I increased by 9%. Stage-stratified, improved 5-year relative survival was mainly observed in stages II and III and coincided with higher lymph node yields, proportional reduction of stage II cancers and proportional increase of stage III cancers, indicating stage migration between these stages. Improvement in 1-year survival was mainly observed in stages III and IV. Five-year survival improvement for patients living beyond 1 year was minimum to none. There were no changes in histology that coincided with neither increased incidence nor possibly influencing improved survival. Concluding, as a novel finding, 1-year mortality, which previously has been identified as an important variable in explaining international survival differences, is in this study identified as also being important in explaining temporal improvements in colon cancer survival in Iceland.

Loss of KCNQ1 expression in stage II and stage III colon cancer is a strong prognostic factor for disease recurrence

Background:

Colorectal cancer (CRC) is the third most common cancer worldwide. Accurately identifying stage II CRC patients at risk for recurrence is an unmet clinical need. KCNQ1 was previously identified as a tumour suppressor gene and loss of expression was associated with poor survival in patients with CRC liver metastases. In this study the prognostic value of KCNQ1 in stage II and stage III colon cancer patients was examined.

Methods:

KCNQ1 mRNA expression was assessed in 90 stage II colon cancer patients (AMC-AJCCII-90) using microarray gene expression data. Subsequently, KCNQ1 protein expression was evaluated in an independent cohort of 386 stage II and stage III colon cancer patients by immunohistochemistry of tissue microarrays.

Results:

Low KCNQ1 mRNA expression in stage II microsatellite stable (MSS) colon cancers was associated with poor disease-free survival (DFS) (P=0.025). Loss of KCNQ1 protein expression from epithelial cells was strongly associated with poor DFS in stage II MSS (P<0.0001), stage III MSS (P=0.0001) and stage III microsatellite instable colon cancers (P=0.041). KCNQ1 seemed an independent prognostic value in addition to other high-risk parameters like angio-invasion, nodal stage and microsatellite instability-status.

Conclusions:

We conclude that KCNQ1 is a promising biomarker for prediction of disease recurrence and may aid stratification of patients with stage II MSS colon cancer for adjuvant chemotherapy.

Clinical picture: multiple sites of ectopic pancreatic tissue

A case is presented with multiple sites of ectopic pancreatic tissue in the gastro-intestinal tract. The sites were found in the stomach and duodenum, one site of ectopic pancreatic tissue presented with necrotizing pancreatitis. Ectopic pancreatic tissue can be defined as all pancreatic tissue, with no anatomical or vascular continuity with the orthotopic pancreas. The ectopic tissue most likely originates from the spreading of cells, during the allocation of structures derived from the foregut in the embryonic phase. Over ninety percent of ectopic tissue presents in the upper gastrointestinal tract, although other locations have been described. To date this is the first case-report about a patient with multiple localizations of ectopic pancreatic tissue.

Hereditary diffuse gastric cancer: updated clinical guidelines with an emphasis on germline CDH1 mutation carriers

Germline CDH1 mutations confer a high lifetime risk of developing diffuse gastric (DGC) and lobular breast cancer (LBC). A multidisciplinary workshop was organised to discuss genetic testing, surgery, surveillance strategies, pathology reporting and the patient's perspective on multiple aspects, including diet post gastrectomy. The updated guidelines include revised CDH1 testing criteria (taking into account first-degree and second-degree relatives): (1) families with two or more patients with gastric cancer at any age, one confirmed DGC; (2) individuals with DGC before the age of 40 and (3) families with diagnoses of both DGC and LBC (one diagnosis before the age of 50). Additionally, CDH1 testing could be considered in patients with bilateral or familial LBC before the age of 50, patients with DGC and cleft lip/palate, and those with precursor lesions for signet ring cell carcinoma. Given the high mortality associated with invasive disease, prophylactic total gastrectomy at a centre of expertise is advised for individuals with pathogenic CDH1 mutations. Breast cancer surveillance with annual breast MRI starting at age 30 for women with a CDH1 mutation is recommended. Standardised endoscopic surveillance in experienced centres is recommended for those opting not to have gastrectomy at the current time, those with CDH1 variants of uncertain significance and those that fulfil hereditary DGC criteria without germline CDH1 mutations. Expert histopathological confirmation of (early) signet ring cell carcinoma is recommended. The impact of gastrectomy and mastectomy should not be underestimated; these can have severe consequences on a psychological, physiological and metabolic level. Nutritional problems should be carefully monitored.

Treatment strategies in colorectal cancer patients with initially unresectable liver-only metastases, a study protocol of the randomised phase 3 CAIRO5 study of the Dutch Colorectal Cancer Group (DCCG)

Background

Colorectal cancer patients with unresectable liver-only metastases may be cured after downsizing of metastases by neoadjuvant systemic therapy. However, the optimal neoadjuvant induction regimen has not been defined, and the lack of consensus on criteria for (un)resectability complicates the interpretation of published results.

Methods/design

CAIRO5 is a multicentre, randomised, phase 3 clinical study. Colorectal cancer patients with initially unresectable liver-only metastases are eligible, and will not be selected for potential resectability. The (un)resectability status is prospectively assessed by a central panel consisting of at least one radiologist and three liver surgeons, according to predefined criteria. Tumours of included patients will be tested for RAS mutation status. Patients with RAS wild type tumours will be treated with doublet chemotherapy (FOLFOX or FOLFIRI) and randomised between the addition of either bevacizumab or panitumumab, and patients with RAS mutant tumours will be randomised between doublet chemotherapy (FOLFOX or FOLFIRI) plus bevacizumab or triple chemotherapy (FOLFOXIRI) plus bevacizumab. Radiological evaluation to assess conversion to resectability will be performed by the central panel, at an interval of two months.

The primary study endpoint is median progression-free survival. Secondary endpoints are the R0/1 resection rate, median overall survival, response rate, toxicity, pathological response of resected lesions, postoperative morbidity, and correlation of baseline and follow-up evaluation with respect to outcomes by the central panel.

Discussion

CAIRO5 is a prospective multicentre trial that investigates the optimal systemic induction therapy for patients with initially unresectable, liver-only colorectal cancer metastases.

Trial registration

CAIRO 5 is registered at European Clinical Trials Database (EudraCT) (2013-005435-24).

CAIRO 5 is registered at ClinicalTrials.gov: NCT02162563, June 10, 2014.

Genomic landscape of metastatic colorectal cancer

Response to drug therapy in individual colorectal cancer (CRC) patients is associated with tumour biology. Here we describe the genomic landscape of tumour samples of a homogeneous well-annotated series of patients with metastatic CRC (mCRC) of two phase III clinical trials, CAIRO and CAIRO2. DNA copy number aberrations of 349 patients are determined. Within three treatment arms, 194 chromosomal subregions are associated with progression-free survival (PFS; uncorrected single-test P-values <0.005). These subregions are filtered for effect on messenger RNA expression, using an independent data set from The Cancer Genome Atlas which returned 171 genes. Three chromosomal regions are associated with a significant difference in PFS between treatment arms with or without irinotecan. One of these regions, 6q16.1–q21, correlates in vitro with sensitivity to SN-38, the active metabolite of irinotecan. This genomic landscape of mCRC reveals a number of DNA copy number aberrations associated with response to drug therapy.

Response to drug therapy in colorectal cancer (CRC) patients has been associated with tumour heterogeneity. Here the authors analyse DNA copy number aberrations in primary tumours from CRC patients and identify genetic variants that influence drug response.

Performance of amplicon-based next generation DNA sequencing for diagnostic gene mutation profiling in oncopathology

PURPOSE

Next generation DNA sequencing (NGS) holds promise for diagnostic applications, yet implementation in routine molecular pathology practice requires performance evaluation on DNA derived from routine formalin-fixed paraffin-embedded (FFPE) tissue specimens. The current study presents a comprehensive analysis of TruSeq Amplicon Cancer Panel-based NGS using a MiSeq Personal sequencer (TSACP-MiSeq-NGS) for somatic mutation profiling.

METHODS

TSACP-MiSeq-NGS (testing 212 hotspot mutation amplicons of 48 genes) and a data analysis pipeline were evaluated in a retrospective learning/test set approach (n = 58/n = 45 FFPE-tumor DNA samples) against 'gold standard' high-resolution-melting (HRM)-sequencing for the genes KRAS, EGFR, BRAF and PIK3CA. Next, the performance of the validated test algorithm was assessed in an independent, prospective cohort of FFPE-tumor DNA samples (n = 75).

RESULTS

In the learning set, a number of minimum parameter settings was defined to decide whether a FFPE-DNA sample is qualified for TSACP-MiSeq-NGS and for calling mutations. The resulting test algorithm revealed 82% (37/45) compliance to the quality criteria and 95% (35/37) concordant assay findings for KRAS, EGFR, BRAF and PIK3CA with HRM-sequencing (kappa = 0.92; 95% CI = 0.81-1.03) in the test set. Subsequent application of the validated test algorithm to the prospective cohort yielded a success rate of 84% (63/75), and a high concordance with HRM-sequencing (95% (60/63); kappa = 0.92; 95% CI = 0.84-1.01). TSACP-MiSeq-NGS detected 77 mutations in 29 additional genes.

CONCLUSION

TSACP-MiSeq-NGS is suitable for diagnostic gene mutation profiling in oncopathology.

High-level copy number gains of established and potential drug target genes in gastric cancer as a lead for treatment development and selection

PURPOSE

The overall survival rate of patients with advanced gastric cancer is poor. Therefore, there is an urgent need for new treatment options for these patients. The identification of drug target genes located on DNA regions exhibiting high-level copy number gains (CNG) may be an effective approach, as has e.g. previously been shown for HER2. The aim of the present study was to identify putative drug targets in patients with gastric cancer by applying this strategy.

METHODS

Genome-wide array comparative genomic hybridization (array CGH) data available from 183 primary gastric cancer samples were analyzed through Ingenuity Pathway Analysis (IPA) to assess whether any established or potential anticancer drug target genes showed high-level CNG, including focal amplifications.

RESULTS

A total of 147 high-level gained regions were identified in the gastric cancer samples, harboring 167 genes that had previously been annotated as drug target genes. Thirty (18 %) of these genes showed high-level gains in at least 2 % of the tumors. The identified drug target genes included those for drugs known to be active in advanced (gastric) cancer, targets for targeted therapies in clinical development, as well as targets for drugs currently used for other indications but of potential interest for anticancer treatment. In addition, 12 potential drug target genes were identified, including genes involved in growth factor signaling and cell cycle regulation.

CONCLUSION

The majority of gastric cancers carried one or more high-level CNGs or focal amplifications encompassing putative drug target genes. A number of the associated drugs are currently not being considered for treatment of gastric cancer. Based on these results we hypothesize that DNA copy number profiling may be a useful tool to identify new drug targets and to guide individualized treatment strategies in patients with gastric cancer.

Promoter methylation of Wnt-antagonists in polypoid and nonpolypoid colorectal adenomas

BACKGROUND

Nonpolypoid adenomas are a subgroup of colorectal adenomas that have been associated with a more aggressive clinical behaviour compared to their polypoid counterparts. A substantial proportion of nonpolypoid and polypoid adenomas lack APC mutations, APC methylation or chromosomal loss of the APC locus on chromosome 5q, suggesting the involvement of other Wnt-pathway genes. The present study investigated promoter methylation of several Wnt-pathway antagonists in both nonpolypoid and polypoid adenomas.

METHODS

Quantitative methylation-specific PCR (qMSP) was used to evaluate methylation of four Wnt-antagonists, SFRP2, WIF-1, DKK3 and SOX17 in 18 normal colorectal mucosa samples, 9 colorectal cancer cell lines, 18 carcinomas, 44 nonpolypoid and 44 polypoid adenomas. Results were integrated with previously obtained data on APC mutation, methylation and chromosome 5q status from the same samples.

RESULTS

Increased methylation of all genes was found in the majority of cell lines, adenomas and carcinomas compared to normal controls. WIF-1 and DKK3 showed a significantly lower level of methylation in nonpolypoid compared to polypoid adenomas (p < 0.01). Combining both adenoma types, a positive trend between APC mutation and both WIF-1 and DKK3 methylation was observed (p < 0.05).

CONCLUSIONS

Methylation of Wnt-pathway antagonists represents an additional mechanism of constitutive Wnt-pathway activation in colorectal adenomas. Current results further substantiate the existence of partially alternative Wnt-pathway disruption mechanisms in nonpolypoid compared to polypoid adenomas, in line with previous observations.

Laparoscopic sentinel lymph node identification in patients with colon carcinoma using a near-infrared dye: description of a new technique and feasibility study

BACKGROUND

After promising results were obtained from studies in large animals, a technique using indocyanine green (ICG) is being introduced for sentinel lymph node (SLN) biopsy in colon cancer patients.

SUBJECTS AND METHODS

Colon cancer patients without clinical signs of metastatic disease, presenting at the VU University Medical Center (Amsterdam, The Netherlands) or Kennemer Gasthuis (Haarlem, The Netherlands), were asked to participate in the study. During laparoscopy, a subserosal injection of 2.5 mg of ICG diluted in 1 mL of 0.9% NaCl plus 2% human albumin was performed using a percutaneously inserted long rigid or flexible needle. After injection, a near-infrared laparoscope (Olympus Corp., Tokyo, Japan) was used for lymph flow and SLN visualization. The SLNs were laparoscopically harvested and analyzed by a senior pathologist using multisectioning and immunohistochemistry.

RESULTS

Fourteen patients were included (six women, eight men), with a median age of 75.5 (interquartile range [IQR], 67.8-81.0) years and a median body mass index of 25.1 (IQR, 22.7-26.0) kg/m(2). Median tumor diameter was 4.5 (IQR, 3.4-7.0) cm. At least one SLN was identified in all patients, with a median number of 2.0 (IQR, 2.0-3.3) SLNs. The median time between injection and identification of the SLN was 15.0 (IQR, 13.3-29.3) minutes. Positioning of the needle tip into the subserosal layer was found to be more effective using the flexible needle. When this flexible needle was used, less spill of dye was observed. All SLNs were negative. We observed four false-negative nodes, all after using a rigid needle. None of the patients showed an adverse reaction to the ICG injection.

CONCLUSIONS

Preliminary results of laparoscopic sentinel node identification using a near-infrared dye show this procedure is safe and feasible. It was possible to detect lymph nodes in all patients. Large tumor size, drainage to adjacent lymphatic vessels, and the use of a rigid needle might contribute to false-negative nodes.