Long-term outcomes after non-curative endoscopic resection for esophageal squamous cell carcinoma followed by additional chemoradiotherapy

Endoscopic resection (ER) of esophageal squamous cell carcinoma (ESCC) is evaluated pathologically, and additional treatment is recommended for cases resulting in non-curative resection, defined as pMM with lymphovascular invasion (LVI), pSM, or positive vertical margin. This study aimed to assess long-term outcomes and risk factors for recurrence in patients with ESCC treated with non-curative ER followed by additional chemoradiotherapy (CRT). We retrospectively reviewed the clinical courses of patients who underwent non-curative ER followed by additional CRT for ESCCs between August 2007 and December 2017. Recurrence rates and risk factors for recurrence were analyzed. Among 97 patients with non-curative ER, 73 underwent additional CRT. With a median follow-up period of 71 months, recurrences were observed in 10 (14%) of 73 patients, with a median interval of 24.5 (1-59 months). The 3- and 5-year recurrence-free survival were 89 and 85%, respectively, and the 3- and 5-year overall survival rates were 96 and 91%, respectively. Multivariate analysis showed that lymphatic invasion was an independent risk factor for recurrence in patients with non-curative ESCC receiving additional CRT. Among the 10 patients with recurrence, 4, 3, 2, and 1 underwent surgery, chemotherapy, supportive care, and CRT, respectively. Notably, all four patients who underwent surgery survived, regardless of regional and/or distant lymph node metastasis. Lymphatic invasion is an independent risk factor for the recurrence of non-curative ESCCs. Careful follow-up is required for at least 5 years after ER with additional CRT.

Sleeping Beauty transposon mutagenesis in mouse intestinal organoids identifies genes involved in tumor progression and metastasis

To identify genes important for colorectal cancer (CRC) development and metastasis, we established a new metastatic mouse organoid model using Sleeping Beauty (SB) transposon mutagenesis. Intestinal organoids derived from mice carrying actively mobilizing SB transposons, an activating KrasG12D, and an inactivating ApcΔ716 allele, were transplanted to immunodeficient mice. While 66.7% of mice developed primary tumors, 7.6% also developed metastatic tumors. Analysis of SB insertion sites in tumors identified numerous candidate cancer genes (CCGs) identified previously in intestinal SB screens performed in vivo, in addition to new CCGs, such as Slit2 and Atxn1. Metastatic tumors from the same mouse were clonally related to each other and to primary tumors, as evidenced by the transposon insertion site. To provide functional validation, we knocked out Slit2, Atxn1, and Cdkn2a in mouse tumor organoids and transplanted to mice. Tumor development was promoted when these gene were knocked out, demonstrating that these are potent tumor suppressors. Cdkn2a knockout cells also metastasized to the liver in 100% of the mice, demonstrating that Cdkn2a loss confers metastatic ability. Our organoid model thus provides a new approach that can be used to understand the evolutionary forces driving CRC metastasis and a rich resource to uncover CCGs promoting CRC.

Assessing the efficacy of target adaptive sampling long-read sequencing through hereditary cancer patient genomes

Innovations in sequencing technology have led to the discovery of novel mutations that cause inherited diseases. However, many patients with suspected genetic diseases remain undiagnosed. Long-read sequencing technologies are expected to significantly improve the diagnostic rate by overcoming the limitations of short-read sequencing. In addition, Oxford Nanopore Technologies (ONT) offers adaptive sampling and computationally driven target enrichment technology. This enables more affordable intensive analysis of target gene regions compared to standard non-selective long-read sequencing. In this study, we developed an efficient computational workflow for target adaptive sampling long-read sequencing (TAS-LRS) and evaluated it through application to 33 genomes collected from suspected hereditary cancer patients. Our workflow can identify single nucleotide variants with nearly the same accuracy as the short-read platform and elucidate complex forms of structural variations. We also newly identified several SINE-R/VNTR/Alu (SVA) elements affecting the APC gene in two patients with familial adenomatous polyposis, as well as their sites of origin. In addition, we demonstrated that off-target reads from adaptive sampling, which is typically discarded, can be effectively used to accurately genotype common single-nucleotide polymorphisms (SNPs) across the entire genome, enabling the calculation of a polygenic risk score. Furthermore, we identified allele-specific MLH1 promoter hypermethylation in a Lynch syndrome patient. In summary, our workflow with TAS-LRS can simultaneously capture monogenic risk variants including complex structural variations, polygenic background as well as epigenetic alterations, and will be an efficient platform for genetic disease research and diagnosis.

Decoding the basis of histological variation in human cancer

Molecular abnormalities that shape human neoplasms dissociate their phenotypic landscape from that of the healthy counterpart. Through the lens of a microscope, tumour pathology optically captures such aberrations projected onto a tissue slide and has categorized human epithelial neoplasms into distinct histological subtypes based on the diverse morphogenetic and molecular programmes that they manifest. Tumour histology often reflects tumour aggressiveness, patient prognosis and therapeutic vulnerability, and thus has been used as a de facto diagnostic tool and for making clinical decisions. However, it remains elusive how the diverse histological subtypes arise and translate into pleiotropic biological phenotypes. Molecular analysis of clinical tumour tissues and their culture, including patient-derived organoids, and add-back genetic reconstruction of tumorigenic pathways using gene engineering in culture models and rodents further elucidated molecular mechanisms that underlie morphological variations. Such mechanisms include genetic mutations and epigenetic alterations in cellular identity codes that erode hard-wired morphological programmes and histologically digress tumours from the native tissues. Interestingly, tumours acquire the ability to grow independently of the niche-driven stem cell ecosystem along with these morphological alterations, providing a biological rationale for histological diversification during tumorigenesis. This Review comprehensively summarizes our current understanding of such plasticity in the histological and lineage commitment fostered cooperatively by molecular alterations and the tumour environment, and describes basic and clinical implications for future cancer therapy.

Precancerous nature of intestinal metaplasia with increased chance of conversion and accelerated DNA methylation

OBJECTIVE

The presence of intestinal metaplasia (IM) is a risk factor for gastric cancer. However, it is still controversial whether IM itself is precancerous or paracancerous. Here, we aimed to explore the precancerous nature of IM by analysing epigenetic alterations.

DESIGN

Genome-wide DNA methylation analysis was conducted by EPIC BeadArray using IM crypts isolated by Alcian blue staining. Chromatin immunoprecipitation sequencing for H3K27ac and single-cell assay for transposase-accessible chromatin by sequencing were conducted using IM mucosa. NOS2 was induced using Tet-on gene expression system in normal cells.

RESULTS

IM crypts had a methylation profile unique from non-IM crypts, showing extensive DNA hypermethylation in promoter CpG islands, including those of tumour-suppressor genes. Also, the IM-specific methylation profile, namely epigenetic footprint, was present in a fraction of gastric cancers with a higher frequency than expected, and suggested to be associated with good overall survival. IM organoids had remarkably high NOS2 expression, and NOS2 induction in normal cells led to accelerated induction of aberrant DNA methylation, namely epigenetic instability, by increasing DNA methyltransferase activity. IM mucosa showed dynamic enhancer reprogramming, including the regions involved in higher NOS2 expression. NOS2 had open chromatin in IM cells but not in gastric cells, and IM cells had frequent closed chromatin of tumour-suppressor genes, indicating their methylation-silencing. NOS2 expression in IM-derived organoids was upregulated by interleukin-17A, a cytokine secreted by extracellular bacterial infection.

CONCLUSIONS

IM cells were considered to have a precancerous nature potentially with an increased chance of converting into cancer cells, and an accelerated DNA methylation induction due to abnormal NOS2 expression.

Phase II Trial of Nivolumab in Metastatic Rare Cancer with dMMR or MSI-H and Relation with Immune Phenotypic Analysis (the ROCK Trial)

PURPOSE

Mismatch repair deficiency (dMMR)/microsatellite instability-high (MSI-H) are positive predictive markers for immune checkpoint inhibitors. However, data on the activity of nivolumab in advanced dMMR/MSI-H rare cancers and more accurate biomarkers are worth exploring.

PATIENTS AND METHODS

We conducted a multicenter phase II, open-label, single-arm clinical trial to explore the effectiveness and safety of nivolumab monotherapy in patients with advanced rare cancers with dMMR/MSI-H, in parallel with immune phenotype analysis, to explore new biomarkers. A Bayesian adaptive design was applied. Characterization of peripheral blood mononuclear cells (PBMC) was characterized by multicolor flow cytometric analysis and CyTOF using samples collected before and after the intervention. The dMMR was identified by the complete loss of MLH1/MSH2/MSH6/PMS2.

RESULTS

From May 2018 to March 2021, 242 patients were screened, and 11 patients were enrolled, of whom 10 were included in the full analysis. Median follow-up was 24.7 months (interquartile range, 12.4-31.5). Objective response rate was 60% [95% confidence interval (CI), 26.2-87.8] by central assessment and 70% (95% CI, 34.8-93.3) by local investigators. Median progression-free survival was 10.1 months (95% CI, 0.9-11.1). No treatment-related adverse events of grade 3 or higher were observed. Patients with a tumor mutation burden of ≥10/Mb showed a 100% response rate (95% CI, 47.8-100). Responders had increased T-bet+ PD-1+ CD4+ T cells in PBMC compared with nonresponders (P < 0.05).

CONCLUSIONS

The trial met its primary endpoint with nivolumab, demonstrating clinical benefit in advanced dMMR/MSI-H rare solid cancers. Besides, the proportion of T-bet+ PD-1+ CD4+ T-cells may serve as a novel predictive biomarker.

Fucoxanthin Inhibits Development of Sigmoid Colorectal Cancer in a PDX Model With Alterations of Growth, Adhesion, and Cell Cycle Signals

BACKGROUND/AIM

Fucoxanthin (Fx), a dietary marine xanthophyll, exerts potent anticancer effects in various colorectal cancer (CRC) animal models. However, therapeutic effects of Fx in human cancer tissues remain unclear. A patient-derived xenograft (PDX) mouse model transplanted with cancer tissues from patients is widely accepted as the best preclinical model for evaluating the anticancer potential of drug candidates.

MATERIALS AND METHODS

Herein, we investigated the anticancer effects of Fx in PDX mice transplanted with cancer tissues derived from a patient with CRC (CRC-PDX) using LC-MS/MS- and western blot-based proteome analysis.

RESULTS

The tumor in the patient with CRC was a primary adenocarcinoma (T3N0M0, stage II) showing mutations of certain genes that were tumor protein p53 (TP53), AT-rich interaction domain 1A (ARID1A), neuroblastoma RAS viral oncogene homolog (NRAS), and PMS1 homolog 2 (PMS2). Administration of Fx significantly suppressed the tumor growth (0.6-fold) and tended to induce differentiation in CRC-PDX mice. Fx up-regulated glycanated-decorin (Gc-DCN) expression, and down-regulated Kinetochore-associated protein DSN1 homolog (DSN1), phospho(p) focal adhesion kinase (pFAK)(Tyr397), pPaxillin(Tyr31), and c-MYC involved in growth, adhesion, and/or cell cycle, in the tumors of CRC-PDX mice than in control mice. Alterations in the five proteins were consistent with those in human CRC HT-29 and HCT116 cells treated with fucoxanthinol (FxOH, a major metabolite of Fx).

CONCLUSION

Fx suppresses development of human-like CRC tissues, especially through growth, adhesion, and cell cycle signals.

A discrimination model by machine learning to avoid gastrectomy for early gastric cancer

Aim

Gastrectomy is recommended for patients with early gastric cancer (EGC) because the possibility of lymph node metastasis (LNM) cannot be completely denied. The aim of this study was to develop a discrimination model to select patients who do not require surgery using machine learning.

Methods

Data from 382 patients who received gastrectomy for gastric cancer and who were diagnosed with pT1b were extracted for developing a discrimination model. For the validation of this discrimination model, data from 140 consecutive patients who underwent endoscopic resection followed by gastrectomy, with a diagnosis of pT1b EGC, were extracted. We applied XGBoost to develop a discrimination model for clinical and pathological variables. The performance of the discrimination model was evaluated based on the number of cases classified as true negatives for LNM, with no false negatives for LNM allowed.

Results

Lymph node metastasis was observed in 95 patients (25%) in the development cohort and 11 patients (8%) in the validation cohort. The discrimination model was developed to identify 27 (7%) patients with no indications for additional surgery due to the prediction of an LNM-negative status with no false negatives. In the validation cohort, 13 (9%) patients were identified as having no indications for additional surgery and no patients with LNM were classified into this group.

Conclusion

The discrimination model using XGBoost algorithms could select patients with no risk of LNM from patients with pT1b EGC. This discrimination model was considered promising for clinical decision-making in relation to patients with EGC.

A comprehensive appraisal of HER2 heterogeneity in HER2-amplified and HER2-low colorectal cancer

BACKGROUND

This study aimed to elucidate the clinicopathological and molecular features of HER2-amplified and HER2-low colorectal cancers (CRCs). We also characterised HER2 expression statuses in CRCs focusing on their intratumoral heterogeneity and alterations in metastatic lesions to establish practical HER2 status assessment.

METHODS

We evaluated 1009 CRCs for HER2 expression and HER2 amplification by immunohistochemistry and FISH, respectively, and correlated the results to clinicopathological and molecular data. For HER2-positive tumours, HER2 expression in metastatic lesions was also assessed.

RESULTS

Twenty-five HER2-amplified (2.5%) and 46 HER2-low tumours (4.6%) were identified. HER2-amplified tumours consistently lacked a mucinous component and HER2-low tumours tended to be in the right colon, but no other clinicopathological features were noted. KRAS, NRAS or BRAF mutations were detected in only two HER2-amplified tumours (8%), whereas 23 HER2-low tumours (50%) had one of these mutations. Most HER2-amplified and HER2-low tumours showed a homogeneous or mosaic HER2 expression pattern and a clustered heterogeneous expression pattern was rather rare. HER2 expression was maintained in most metastatic lesions in both HER2-amplified (93%) and HER2-low tumours (81%).

CONCLUSIONS

These results suggest that biopsy-based assessment of primary lesions is appropriate for the identification of CRC patients eligible for systemic HER2-targeted therapy.

Assessment of Elastic Laminal Invasion Contributes to an Objective pT3 Subclassification in Colon Cancer

The extent of tumor spread influences on the clinical outcome, and which determine T stage of colorectal cancer. However, pathologic discrimination between pT3 and pT4a in the eighth edition of the American Joint Committee on Cancer (AJCC)-TNM stage is subjective, and more objective discrimination method for deeply invasive advanced colon cancer is mandatory for standardized patient management. Peritoneal elastic laminal invasion (ELI) detected using elastic staining may increase the objective discrimination of deeply invasive advanced colon cancer. In this study, we constructed ELI study group to investigate feasibility, objectivity, and prognostic utility of ELI. Furthermore, pT classification using ELI was investigated based on these data. At first, concordance study investigated objectivity using 60 pT3 and pT4a colon cancers. Simultaneously, a multi-institutional retrospective study was performed to assess ELI's prognostic utility in 1202 colon cancer cases from 6 institutions. In the concordance study, objectivity, represented by κ, was higher in the ELI assessment than in pT classification. In the multi-institutional retrospective study, elastic staining revealed that ELI was a strong prognostic factor. The clinical outcome of pT3 cases with ELI was significantly and consistently worse than that of those without ELI. pT classification into pT3 without ELI, pT3 with ELI, and pT4a was an independent prognostic factor. In this study, we revealed that ELI is an objective method for discriminating deeply invasive advanced colon cancer. Based on its feasibility, objectivity, and prognostic utility, ELI can subdivide pT3 lesions into pT3a (without ELI) and pT3b (with ELI).

Multiancestry genomic and transcriptomic analysis of gastric cancer

Gastric cancer is among the most common malignancies worldwide, characterized by geographical, epidemiological and histological heterogeneity. Here, we report an extensive, multiancestral landscape of driver events in gastric cancer, involving 1,335 cases. Seventy-seven significantly mutated genes (SMGs) were identified, including ARHGAP5 and TRIM49C. We also identified subtype-specific drivers, including PIGR and SOX9, which were enriched in the diffuse subtype of the disease. SMGs also varied according to Epstein-Barr virus infection status and ancestry. Non-protein-truncating CDH1 mutations, which are characterized by in-frame splicing alterations, targeted localized extracellular domains and uniquely occurred in sporadic diffuse-type cases. In patients with gastric cancer with East Asian ancestry, our data suggested a link between alcohol consumption or metabolism and the development of RHOA mutations. Moreover, mutations with potential roles in immune evasion were identified. Overall, these data provide comprehensive insights into the molecular landscape of gastric cancer across various subtypes and ancestries.

Comparison of clinicopathological and genomic profiles in anal squamous cell carcinoma between Japanese and Caucasian cohorts

Anal squamous cell carcinoma (ASCC) is a rare tumor of the gastrointestinal tract. We aimed to compare the genetic backgrounds and their effect on clinical outcomes between Japanese and Caucasian patients with ASCC. Forty-one patients diagnosed with ASCC at the National Cancer Center Hospital were enrolled and evaluated for clinicopathological features, human papillomavirus (HPV) infection, HPV genotypes, p16 expression, PD-L1, and association of p16 status with the efficacy of concurrent chemoradiotherapy (CCRT). Target sequencing for hotspot mutations in 50 cancer-related genes was performed using genomic DNA from 30 available samples. Of 41 patients, 34 were HPV-positive (among them, HPV 16 was predominant; 73.2%); 38 patients were p16-positive (92.7%); and 39 patients received CCRT, of whom 36 were p16-positive and three p16-negative. p16-positive patients showed better complete response than p16-negative patients. Among 28 samples, 15 showed mutations in PIK3CA, FBXW7, ABL1, TP53, and PTEN; no difference in mutation profiles between the Japanese and Caucasian cohorts was observed. Actionable mutations were detected in both Japanese and Caucasian patients with ASCC. Genetic backgrounds, such as the HPV 16 genotype and PIK3CA mutations, were common regardless of ethnicity. p16 status may be a prognostic biomarker for CCRT in Japanese patients with ASCC.

Nomogram as a novel predictive tool for lymph node metastasis in T1 colorectal cancer treated with endoscopic resection: A nationwide, multicenter study

BACKGROUND AND AIMS

Since 2009, the Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines have been recommending tumor budding and submucosal invasion depth, in addition to lymphovascular invasion and tumor grade, to be included as risk factors for lymph node metastasis (LNM) in T1 colorectal carcinoma (CRC) patients. In this study, a novel nomogram was developed and validated using large-scale real-world data, including the JSCCR risk factors, to accurately evaluate the risk of LNM in T1 CRC.

METHODS

Data from 4,673 T1 CRC patients treated at 27 high-volume institutions between 2009 and 2016 were analyzed for LNM risk. To prepare a nonrandom split sample, the total cohort was divided into development and validation cohorts. Pathological findings were extracted from the medical records of each participating institution. The discrimination ability was measured using the concordance index, and the variability in each prediction was evaluated using calibration curves.

RESULTS

Six independent risk factors for LNM, including submucosal invasion depth and tumor budding, were identified in the development cohort and entered into a nomogram. The concordance index was 0.784 for the clinical calculator in the development cohort and 0.790 in the validation cohort. The calibration curve approached the 45-degree diagonal in the validation cohort.

CONCLUSIONS

This is the first nomogram to include submucosal invasion depth and tumor budding for use in routine pathological diagnosis based on data from a nationwide multi-institutional study. With this nomogram developed with real-world data decision-making for an appropriate treatment strategy for T1 CRC should improve.

Clinical Guidelines for Diagnosis and Management of Juvenile Polyposis Syndrome in Children and Adults-Secondary Publication

Juvenile polyposis syndrome (JPS) is a rare disease characterized by multiple hamartomatous polyps within the gastrointestinal tract. SMAD4 or BMPR1A is known as a causative gene of JPS. Approximately 75% of newly diagnosed cases have an autosomal-dominantly inherited condition, whereas 25% are sporadic without previous history of polyposis in the family pedigree. Some patients with JPS develop gastrointestinal lesions in childhood and require continuous medical care until adulthood. JPS is classified into three categories according to phenotypic features of polyp distributions, including generalized juvenile polyposis, juvenile polyposis coli, and juvenile polyposis of the stomach. Juvenile polyposis of the stomach is caused by germline pathogenic variants of SMAD4 with a high risk leading to gastric cancer. Pathogenic variants of SMAD4 are also associated with hereditary hemorrhagic telangiectasia-JPS complex, inducing regular cardiovascular survey. Despite growing concerns regarding the managing JPS in Japan, there are no practical guidelines. To address this situation, the guideline committee was organized by the Research Group on Rare and Intractable Diseases granted by the Ministry of Health, Labor and Welfare involving specialists from multiple academic societies. The present clinical guidelines explain the principles in the diagnosis and management of JPS with three clinical questions and corresponding recommendations based on a careful review of the evidence and involve incorporating the concept of the Grading of Recommendations, Assessment, Development, and Evaluation system. Herein, we present the clinical practice guidelines of JPS to promote seamless implementation of accurate diagnosis and appropriate management of pediatric, adolescent, and adult patients with JPS.

Clinicopathological Features of Early-Stage Esophageal Carcinosarcoma

Esophageal carcinosarcoma (EC) is a rare malignant tumor, accounting for 0.5–2.8% of esophageal cancers. Most are advanced cancers that are detected as polypoid lesions and are treated with multidisciplinary therapy with a focus on surgery. However, endoscopic findings, pathological findings, and long-term outcomes of early-stage EC are often unclear because there are very few reported cases. This paper reports three cases of EC confined to the mucosal layer. The macroscopic type of all tumors was polypoid lesion with a slightly depressed lesion. All cases were clinically diagnosed as invasive cancer before treatment. Pathological diagnosis of tumor depth showed that one case had invaded the lamina propria mucosae, and two cases had invaded the muscularis mucosae (MM). One case of diagnosed MM had lymphoid invasion and lymph node metastasis to the upper mediastinum. After 1 year, although adjuvant treatment had been administered, there was lymph node recurrence in the left upper clavicle, and thus chemoradiation therapy was performed. Two other cases survived without recurrence. Early-stage EC is characterized by polypoid lesions with a slightly depressed lesion, and it is challenging to predict the histology on biopsy. Furthermore, it is difficult to determine the depth of invasion in the MM and submucosal layer in squamous cell carcinoma by endoscopy alone, and hence depth diagnosis by multiple modalities should be considered.

Clinicopathological and molecular characteristics of RSPO fusion-positive colorectal cancer

BACKGROUND

RSPO fusions that lead to WNT pathway activation are potential therapeutic targets in colorectal cancer (CRC), but their clinicopathological significance remains unclear.

METHODS

We screened 1019 CRCs for RSPO fusions using multiplex reverse transcription-PCR. The RSPO fusion-positive tumours were subjected to whole-exome sequencing (WES).

RESULTS

Our analysis identified 29 CRCs with RSPO fusions (2.8%), consisting of five with an EIF3E-RSPO2 fusion and 24 with PTPRK-RSPO3 fusions. The patients were 17 women and 12 men. Thirteen tumours (45%) were right-sided. Histologically, approximately half of the tumours (13/29, 45%) had a focal or extensive mucinous component that was significantly more frequent than the RSPO fusion-negative tumours (13%; P = 8.1 × 10^-7). Four tumours (14%) were mismatch repair-deficient. WES identified KRAS, BRAF, and NRAS mutations in a total of 27 tumours (93%). In contrast, pathogenic mutations in major WNT pathway genes, such as APC, CTNNB1 and RNF43, were absent. RSPO fusion status did not have a statistically significant influence on the overall or recurrence-free survival. These clinicopathological and genetic features were also confirmed in a pooled analysis of previous studies.

CONCLUSION

RSPO fusion-positive CRCs constitute a rare subgroup of CRCs with several characteristic clinicopathological and genetic features.

Effectiveness of Etoposide and Cisplatin vs Irinotecan and Cisplatin Therapy for Patients With Advanced Neuroendocrine Carcinoma of the Digestive System: The TOPIC-NEC Phase 3 Randomized Clinical Trial

Question

For patients with advanced neuroendocrine carcinoma of the digestive system, which of the 2 community standard regimens is more effective: etoposide plus cisplatin (EP) or irinotecan plus cisplatin (IP)?

Findings

In this randomized clinical trial of 170 patients who were chemotherapy naive and had recurrent or unresectable neuroendocrine carcinoma of the digestive system, median overall survival was 12.5 months in the EP arm and 10.9 months in the IP arm.

Meaning

Both EP and IP therapy remain standard first-line chemotherapy options.

Importance

Etoposide plus cisplatin (EP) and irinotecan plus cisplatin (IP) are commonly used as community standard regimens for advanced neuroendocrine carcinoma (NEC).

Objective

To identify whether EP or IP is a more effective regimen in terms of overall survival (OS) in patients with advanced NEC of the digestive system.

Design, Setting, and Participants

This open-label phase 3 randomized clinical trial enrolled chemotherapy-naive patients aged 20 to 75 years who had recurrent or unresectable NEC (according to the 2010 World Health Organization classification system) arising from the gastrointestinal tract, hepatobiliary system, or pancreas. Participants were enrolled across 50 institutions in Japan between August 8, 2014, and March 6, 2020.

Interventions

In the EP arm, etoposide (100 mg/m²/d on days 1, 2, and 3) and cisplatin (80 mg/m²/d on day 1) were administered every 3 weeks. In the IP arm, irinotecan (60 mg/m²/d on days 1, 8, and 15) and cisplatin (60 mg/m²/d on day 1) were administered every 4 weeks.

Main Outcomes and Measures

The primary end point was OS. In total, data from 170 patients were analyzed to detect a hazard ratio (HR) of 0.67 (median OS of 8 and 12 months in inferior and superior arms, respectively) with a 2-sided α of 10% and power of 80%. The pathologic findings were centrally reviewed following treatment initiation.

Results

Among the 170 patients included (median [range] age, 64 [29-75] years; 117 [68.8%] male), median OS was 12.5 months in the EP arm and 10.9 months in the IP arm (HR, 1.04; 90% CI, 0.79-1.37; P = .80). The median progression-free survival was 5.6 (95% CI, 4.1-6.9) months in the EP arm and 5.1 (95% CI, 3.3-5.7) months in the IP arm (HR, 1.06; 95% CI, 0.78-1.45). A subgroup analysis of OS demonstrated that EP produced more favorable OS in patients with poorly differentiated NEC of pancreatic origin (HR, 4.10; 95% CI, 1.26-13.31). The common grade 3 and 4 adverse events in the EP vs IP arms were neutropenia (75 of 82 [91.5%] patients vs 44 of 82 [53.7%] patients), leukocytopenia (50 of 82 [61.0%] patients vs 25 of 82 [30.5%] patients), and febrile neutropenia (FN) (22 of 82 [26.8%] patients vs 10 of 82 [12.2%] patients). While incidence of FN was initially high in the EP arm, primary prophylactic use of granulocyte colony-stimulating factor effectively reduced the incidence of FN.

Conclusions and Relevance

Results of this randomized clinical trial demonstrate that both EP and IP remain the standard first-line chemotherapy options. Although AEs were generally manageable, grade 3 and 4 AEs were more common in the EP arm.

Trial Registration

Japan Registry of Clinical Trials: jRCTs031180005; UMIN Clinical Trials Registry: UMIN000014795

Characteristics of colorectal neuroendocrine tumors in patients prospectively enrolled in a Japanese multicenter study: a first report from the C-NET STUDY

BACKGROUND

This is the first report from a multicenter prospective cohort study of colorectal neuroendocrine tumor (NET), the C-NET STUDY, conducted to assess the long-term outcomes of the enrolled patients. This report aimed to elucidate the clinicopathological features of the enrolled patients and lesions.

METHODS

Colorectal NET patients aged 20-74 years were consecutively enrolled and followed up at 50 institutions. The baseline characteristics and clinicopathological findings at enrollment and treatment were assessed.

RESULTS

A total of 495 patients with 500 colorectal NETs were included. The median patient age was 54 years, and 85.3% were asymptomatic. The most frequent lesion location was the lower rectum (88.0%); 99.4% of the lesions were clinically diagnosed to be devoid of metastatic findings, and 95.4% were treated with endoscopic resection. Lesions < 10 mm comprised 87.0% of the total, 96.6% had not invaded the muscularis propria, and 92.6% were classified as WHO NET grade 1. Positive lymphovascular involvement was found in 29.2% of the lesions. Its prevalence was high even in small NETs with immunohistochemical/special staining for pathological assessment (26.4% and 40.9% in lesions sized < 5 mm and 5-9 mm, respectively). Among 70 patients who underwent radical surgery primarily or secondarily, 18 showed positive lymph node metastasis.

CONCLUSIONS

The characteristics of real-world colorectal NET patients and lesions are elucidated. The high positivity of lymphovascular involvement in small NETs highlights the necessity of assessing the clinical significance of positive lymphovascular involvement based on long-term outcomes, which will be examined in later stages of the C-NET STUDY.

TRIAL REGISTRATION NUMBER

UMIN000025215.

Anal Intraepithelial Neoplasia: Precursor of Anal Squamous Cell Carcinoma

Anal squamous cell carcinoma (SCC) is rare, but it has been commonly detected as an invasive cancer. The standard treatment for anal SCC was surgical resection. However, recent medical advances have enabled the standard treatment to be chemoradiotherapy. Anal intraepithelial neoplasia (AIN) is a premalignant lesion of SCC. The screening test for AIN and human papilloma virus vaccine are important for the following high-risk patients: patients positive for human immunodeficiency virus and men who have sexual intercourse with men. Although cytology can be easily applied for a screening test, the false-negative rate for AIN is high. Instead, high-resolution anoscopy (HRA) has been gaining attention as a promising screening method for high-risk patients. Investigations comparing characteristic findings of HRA with the histology of AIN have demonstrated that HRA is a highly specific test for AIN.

Magnifying or image-enhanced endoscopies are also routinely used for colonoscopy, as they allow detailed observations at higher magnifications than those of HRA. Hence, these endoscopic modalities can be applied for assessing AIN. Ablation therapies or topical medications are available as the local treatment for AIN. Although endoscopic submucosal dissection is considered to be feasible to remove AIN, it has a technical difficulty to approach endoscopically invisible areas. Hence, this technique may be useful to resect AIN localized in the endoscopically visible areas, when the localization is confirmed via targeted biopsy.

Diagnosis and treatment of colorectal tumors: Differences between Japan and the West and future prospects

Dye‐based chromoendoscopy has long been used routinely for endoscopic diagnosis of gastrointestinal tumors including colorectal tumors in Japan. In the West, on the other hand, dye‐based chromoendoscopy was not so commonly used. However, with the development of narrow band imaging (NBI), image‐enhanced endoscopy diagnosis has rapidly increased in the West.

The most critical difference between Japan and the West is the histopathological evaluation of the lesions, which determines a major cause of differences in diagnostic and treatment strategies. In the West, intramucosal adenocarcinoma is not diagnosed until the cancer has invaded submucosal layer. In Japan, on the other hand, cancer is mainly diagnosed based on nuclear and structural atypia, and thus intramucosal adenocarcinoma is diagnosed in lesions that correspond to high‐grade adenoma in the West.

In the West, since intramucosal carcinoma is not diagnosed by pathology, all benign adenomas are treated by piecemeal endoscopic resection, and only cancer invading the superficial submucosal layer is indicated for endoscopic submucosal dissection (ESD). Because of the risk of lymph node metastasis in the deep submucosal invasion, the European Society of Gastrointestinal Endoscopy and American Society for Gastrointestinal Endoscopy guidelines state that only superficial submucosal cancer is an indication for ESD. Unfortunately, it is impossible to selectively extract only superficial submucosal invasive cancer even with the use of magnified NBI and pit pattern observation. Therefore, we think that pathologists need to diagnose intramucosal adenocarcinoma with the potential to invade the submucosal layer based on the nuclear and structural atypia. Consequently, intramucosal adenocarcinoma and superficial submucosal cancers should be considered for en‐bloc ESD.

Prediction of tissue origin of adenocarcinomas in the esophagogastric junction by DNA methylation

BACKGROUND

Prediction of tissue origin of esophagogastric junction (EGJ) adenocarcinomas can be important for therapeutic decision, but no molecular marker is available. Here, we aimed to develop such a marker taking advantage of tissue-specific profiles of DNA methylation.

METHODS

DNA methylation profiles of gastric adenocarcinomas (GACs) were obtained by an Infinium HumanMethylation450 BeadChip array, and those of esophageal adenocarcinoma (EACs) were obtained from the TCGA database. DNA from formalin-fixed paraffin-embedded (FFPE) samples was analyzed by bisulfite pyrosequencing.

RESULTS

In the screening set, 51 of 145,841 CpG sites in CpG islands were methylated at significantly higher levels in 30 GACs compared to those in 30 EACs. Among them, SLC46A3 and cg09177106 were unmethylated in all the 30 EACs. Predictive powers of these two markers were successfully confirmed in an independent validation set (18 GACs and 18 EACs) (SLC46A3, sensitivity = 77.8%, specificity = 100%; cg09177106, sensitivity = 83.3%, specificity = 94.4%), and could be applied to FFPE samples (37 GACs and 18 EACs) (SLC46A3, P = 0.0001; cg09177106, P = 0.0028). On the other hand, EAC-specific markers informative in the FFPE samples could not be isolated. Using these GAC-specific markers, nine of 46 (19.6%) TCGA EGJ adenocarcinomas were predicted to be GACs.

CONCLUSIONS

Two GAC-specific markers, SLC46A3 and cg09177106, had a high specificity for identifying the tissue origin of EGJ adenocarcinoma.

Randomized phase III study of etoposide plus cisplatin versus irinotecan plus cisplatin in advanced neuroendocrine carcinoma of the digestive system: A Japan Clinical Oncology Group study (JCOG1213)

501

Background: Neuroendocrine carcinoma (NEC) arising in the digestive system is a rare and high-grade malignant tumor. Treatment guidelines for advanced NEC recommend platinum-based chemotherapy regimens. Etoposide plus cisplatin (EP) and irinotecan plus cisplatin (IP) are commonly used as community standard regimens for NEC. However, it is unknown which is more effective. This phase III study aimed to identify more effective regimen between EP and IP in terms of overall survival (OS) for patients with advanced NEC. Methods: Eligibility criteria included chemotherapy-naïve patients with recurrent or unresectable, histologically confirmed NEC (WHO2010) arising from the gastrointestinal tract (GI), hepatobiliary and pancreas (HBP), ECOG PS of 0-1, age of 20–75 years. In the EP arm, etoposide (100 mg/m2 on days 1, 2 and 3) and cisplatin (80 mg/m2 on day 1) were administered every 3 weeks. In the IP arm, irinotecan (60 mg/m2 on days 1, 8 and 15) and cisplatin (60 mg/m2 on day 1) were repeated every 4 weeks. The primary endpoint was OS. Total of 140 patients (114 events) were required to detect a hazard ratio (HR) of 0.67 (median OS; 8/12 months in inferior/superior arms) with a two-sided alpha of 10% and power of 70%. Due to a rapid accrual, the sample size was increased to 170 (power of 80%). Pathology was centrally reviewed after the start of treatment. Results: Of all enrolled 170 patients (GI: 100, HBP: 70) from Aug 2014 to March 2020, median OS was 12.5 months in EP and 10.9 months in IP (HR 1.043 [a ratio of EP to IP], 90% CI, 0.794-1.370, p= 0.797). Median progression-free survival (PFS) was 5.6 months in EP and 5.1 months in IP (HR 1.060, 95% CI, 0.777-1.445). Response rate (RR) was 54.5% (42/77) in EP and 52.5% (42/80) in IP among patients with target lesions. No interactions with OS, PFS, or RR were seen in pre-planned subgroup analyses including primary organs or pathological findings. The common Grade 3-4 AEs (EP/IP) was neutropenia (91.5%/53.7%), leukocytopenia (61.0%/30.5%), and febrile neutropenia (26.8%/12.2%). Conclusions: A superiority was not demonstrated, which indicates that both EP and IP remain standard first-line chemotherapy. Clinical trial information: UMIN000014795.

Correlation of combined positive score of PD-L1 expression and clinical efficacy for advanced esophageal squamous cell carcinoma treated with nivolumab monotherapy

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Background: Based on the results of the ATTRACTION-3 trial, nivolumab has shown superiority compared to taxane monotherapy as second-line treatment for advanced esophageal squamous cell carcinoma (ESCC) patients (pts). However, the PD-L1 expression by tumor proportion score (TPS) did not obviously correlate to the efficacy. In contrast, PD-L1 expression by combined positive score (CPS) was used as a companion diagnosis for pembrolizumab in ESCC. There are little data on CPS with nivolumab in ESCC. Methods: We retrospectively reviewed the medical records of the pts with ESCC who received nivolumab monotherapy in our hospital. The CPS before nivolumab was evaluated by 22C3 antibody. We evaluated the correlation of CPS and clinical efficacy of progression-free survival (PFS), overall response rate (ORR), disease control rate (DCR) by using Cox proportional regression model and Fisher’s exact test. Results: Eighty-seven pts were selected for this analysis with a median follow-up time of 7.9 (1.2-84.1) months. Thirty pts (34.5%) had CPS < 10, and 57 patients (65.5%) had CPS≥10. Between two groups, the characteristics were as follows; median age (range): 62 (35-85) and 66 (46-85) years, PS 0: 20.0/36.8%, prior taxane: 50.0/40.4%, prior radiotherapy: 86.7/77.2%, respectively. The median PFS (95%CI) were 1.8 (1.2-2.8)/2.6 (1.8-33.8) months (HR: 0.85 [0.52-1.38], p = 0.50). The ORR/DCR were 21.1/31.6% in CPS < 10 group, and 22.2/57.8% in CPS≥10 group, and there was no statistical significance, respectively (p = 1.0/0.10). In multivariate analysis, only higher age was the favorite factor for PFS. From the result with another cut-off level of CPS, the proportion of CPS≥1/CPS≥20 was 90.8/36.8%. The HR of multivariate analysis with CPS≥1/CPS≥20 was 1.24/0.73, respectively. Conclusions: There was a trend toward better PFS with a higher cut-off point of CPS. CPS had the potential to be a biomarker even for nivolumab for advanced ESCC pts.

Endoscopic features of isolated and traditional serrated adenoma-associated superficially serrated adenomas of the colorectum

BACKGROUND AND AIM

Superficially serrated adenoma (SuSA) is a recently proposed subtype of colorectal serrated lesions. It is characterized by distinct clinicopathological and molecular features, including mixed serrated and adenomatous histology and frequent genetic alterations involving KRAS and RSPO. This study aimed to characterize the endoscopic features of isolated and traditional serrated adenoma (TSA)-associated SuSAs.

METHODS

We retrospectively evaluated the endoscopic findings of 25 isolated SuSAs and 21 TSA-associated SuSAs that were histologically and molecularly characterized.

RESULTS

SuSAs appeared as a sessile polyp or slightly elevated lesion located mostly in the sigmoid colon and rectum (88%). The size was between 3 and 20 mm (median, 6 mm). Most of them exhibited KRAS mutations (96%) and RSPO fusions/overexpression (92%). Endoscopically, many lesions had a whitish color (84%), a distinct border (96%), an irregular border (76%), and a lobulated surface (72%). However, diminutive lesions exhibited overlapping features with hyperplastic polyps. On narrow-band imaging, vessel patterns were invisible or appeared as lacy microvessels in most lesions (80%). Chromoendoscopy invariably showed stellar or elongated/branched stellar pits, indicating a serrated microarchitecture. Most TSA-associated SuSAs typically presented as polyps with a two-tier raised appearance, consisting of whitish lower and reddish higher components corresponding to a SuSA and a TSA, respectively.

CONCLUSIONS

SuSAs exhibit several characteristic endoscopic features on white-light and image-enhanced endoscopy. Diminutive lesions exhibit endoscopic features overlapping with hyperplastic polyps. Nonetheless, the endoscopic diagnosis of larger and TSA-associated SuSAs may be feasible.

Comparable genetic alteration profiles between gastric cancers with current and past Helicobacter pylori infection

Gastric cancers can develop even after Helicobacter pylori (H. pylori) eradication in 0.2-2.9% cases per year. Since H. pylori is reported to directly activate or inactivate cancer-related pathways, molecular profiles of gastric cancers with current and past H. pylori infection may be different. Here, we aimed to analyze whether profiles of point mutation and gene amplification are different between the two groups. Current or past infection by H. pylori was determined by positive or negative amplification of H. pylori jhpr3 gene by PCR, and past infection was established by the presence of endoscopic atrophy. Among the 90 gastric cancers analyzed, 55 were with current infection, and 35 were with past infection. Target sequencing of 46 cancer-related genes revealed that 47 gastric cancers had 68 point mutations of 15 different genes, such as TP53 (36%), KRAS (4%), and PIK3CA (4%) and that gene amplification was present for ERBB2, KRAS, PIK3CA, and MET among the 26 genes assessed for copy number alterations. Gastric cancers with current and past infection had similar frequencies of TP53 mutations (38% and 31%, respectively; p = 0.652) and oncogene activation (20% and 29%, respectively; p = 0.444). Gastric cancers with current and past infection had comparable profiles of genetic alterations.

APC mutations are common in adenomas but infrequent in adenocarcinomas of the non-ampullary duodenum

BACKGROUND

Recent studies highlighted the clinicopathological heterogeneity of non-ampullary duodenal adenomas and adenocarcinomas, but the detailed process of the malignant transformation remains unclear.

METHODS

We analyzed 144 adenomas and 54 adenocarcinomas of the non-ampullary duodenum for immunohistochemical phenotypes, genetic alterations, and mismatch repair (MMR) status to probe their histogenetic relationship.

RESULTS

The median ages of patients with adenoma and adenocarcinoma were the same (66 years). Adenomas were histologically classified as intestinal-type adenoma (n = 124), pyloric gland adenoma (PGA, n = 10), gastric-type adenoma, not otherwise specified (n = 9), and foveolar-type adenoma (n = 1). Protein-truncating APC mutations were highly frequent in adenomas (85%), with the highest prevalence in intestinal-type adenomas (89%), but rare in adenocarcinomas (9%; P = 2.1 × 10^-23). Close associations between phenotypic marker expression and genetic alterations were observed in adenomas, but not in adenocarcinomas, excluding the common association between GNAS mutations and MUC5AC expression. MMR deficiency was more frequent in adenocarcinomas (20%) than in adenomas (1%; P = 2.6 × 10^-6). One MMR-deficient adenoma and three MMR-deficient adenocarcinomas occurred in patients with Lynch syndrome. Additionally, three other patients with an MMR-deficient adenocarcinoma fulfilled the revised Bethesda criteria.

CONCLUSION

The discrepant APC mutation frequency between adenomas and adenocarcinomas suggests that APC-mutated adenomas, which constitute the large majority of non-ampullary duodenal adenomas, are less prone to malignant transformation. Non-ampullary duodenal adenocarcinomas frequently exhibit MMR deficiency and should be subject to MMR testing to determine appropriate clinical management, including the identification of patients with Lynch syndrome.

Spontaneous Regression of Mismatch Repair-Deficient Colon Cancer: A Case Series

Spontaneous regression of cancer is a rare phenomenon, with 33 colorectal cancer cases reported between 1900 and 2020.^1-4 Spontaneous regression is defined as the partial or complete disappearance of a tumor without treatment.^1,3 Several factors may be involved in this process, including biopsy, mechanical stress, humoral factors, and infection.^1,5 However, no concrete evidence for the mechanistic insights has been indicated.

Pathological complete response at the para-aortic nodes as a possible surrogate endpoint in gastric cancer surgery with para-aortic node dissection after neoadjuvant chemotherapy

PURPOSE

Gastric cancer with para-aortic node (PAN) metastasis has a chance to be cured with multidisciplinary treatment of D2 and PAN dissection (PAND) following neoadjuvant chemotherapy (NAC), but its prognosis remains unsatisfactory. To establish a better multidisciplinary treatment, a better surrogate endpoint is needed. The present study focused on a pathological complete response at the PANs alone as a new surrogate endpoint and evaluated its prognostic value.

METHODS

The study examined patients who received radical gastrectomy with D2 and PAND after NAC for gastric cancer with PAN metastasis from 2004 to 2015. The study compared five methods of evaluating the response to NAC: RECIST, clinical disappearance of PANs (cPAN), histological response of the primary tumor defined by Japanese Classification of Gastric Carcinoma (JCGC histological criteria) and Becker's criteria, and pathological disappearance of PANs (pPAN). The efficacy of these methods was compared using the hazard ratio (HR) for death between responders and non-responders.

RESULTS

Thirty-two patients were analyzed. The respective HR and 5-year overall survival rates of responders and non-responders were 1.316 and 49.1% vs. 60.0% by RECIST, 1.106 and 52.9% vs. 52.5% by cPAN, 0.246 and 71.3% vs. 28.6% by JCGC histological criteria, 0.239 and 76.2% vs. 36.8% by Becker's criteria, and 0.074 and 81.0% vs. 0.0% by pPAN.

CONCLUSIONS

A pathological complete response at the PANs had the lowest HR and clearly differentiated the survival, suggesting it might be a good surrogate endpoint for identifying future candidates for NAC in multidisciplinary treatment for gastric cancer with PAN metastasis.

Treatment outcomes of endoscopic submucosal dissection and surgery for colorectal neoplasms in patients with ulcerative colitis

Objectives

This study aimed to clarify the validity and long‐term outcomes of colorectal endoscopic submucosal dissection (ESD) of visible lesions (≥20 mm) in patients with ulcerative colitis (UC) and investigate the incidence of undetected lesions in surgical specimens.

Methods

This single‐center retrospective study included 11 lesions from nine patients with UC who underwent ESD and 19 lesions from nine patients with UC who underwent colectomy between March 2001 and January 2019. We evaluated the endoscopic findings of scarring, atrophy, and loss of haustra in the ESD group, and we determined the lesion visibility in the colectomy group. We investigated the clinicopathological features of all lesions and examined the follow‐up evaluations in the ESD group.

Results

The en bloc and curative resection rates of ESDs were 91% and 82%, respectively. Endoscopic findings of scarring, atrophic colitis, and loss of haustra were observed in two (18%), seven (64%), and one (9%) lesions, respectively. The two lesions with scarring showed severe submucosal fibrosis. Mortality and recurrence were not observed during the median follow‐up of 25 months. Metachronous lesions ≥20 mm were detected in two patients, which were successfully treated with ESDs. In the colectomy specimens, 21% of the lesions were undetected, 67% had multiple neoplasms, and 33% had multiple invasive cancers.

Conclusions

ESD is feasible and valid for large visible lesions in patients with UC; however, for lesions with endoscopic findings of scarring, technical difficulties in endoscopic resection must be considered. In addition, intensive surveillance colonoscopy is necessary to detect undetected lesions.

Summarise the estabished knowledge on this subject

The number of patients with ulcerative colitis (UC) has increased.

Clinical guidelines recommend that endoscopic resection for endoscopically visible dysplasia rather than colectomy in patients with UC.

Although some studies on the treatment outcomes of endoscopic submucosal dissection (ESD) for patients with UC have been conducted, the sample size was small and almost all reported lesions were relatively small (i.e., <20 mm); thus, the available data are limited.

What are the significance and/or new findins of this study?

Good outcomes of ESD for visible lesions (>20 mm) in patients with ulcerative colitis were demonstrated.

Technical difficulties are highly possible in lesions with endoscopic findings of scarring.

The prevalence of undetected lesions (approximately 20%) was the same between high (2‐3) and low (0‐1) Mayo endoscopic subscore groups based on the surgical specimens.

SAA1 is upregulated in gastric cancer-associated fibroblasts possibly by its enhancer activation

Cancer-associated fibroblasts (CAFs) tend to have tumor-promoting capacity, and can provide therapeutic targets. Even without cancer cells, CAF phenotypes are stably maintained, and DNA methylation and H3K27me3 changes have been shown to be involved. Here, we searched for a potential therapeutic target in primary CAFs from gastric cancer and a mechanism for its dysregulation. Expression microarray using eight CAFs and seven non-CAFs (NCAFs) revealed that serum amyloid A1 (SAA1), which encodes an acute phase secreted protein, was second most upregulated in CAFs, following IGF2. Conditioned medium (CM) derived from SAA1-overexpressing NCAFs was shown to increase migration of gastric cancer cells compared with that from control NCAFs, and its tumor-promoting effect was comparable to that of CM from CAFs. In addition, increased migration of cancer cells by CM from CAFs was mostly canceled with CM from CAFs with SAA1 knockdown. Chromatin immunoprecipitation (ChIP)-quantitative PCR showed that CAFs had higher levels of H3K27ac, an active enhancer mark, in the promoter and the two far upstream regions of SAA1 than NCAFs. Also, BET bromodomain inhibitors, JQ1 and mivebresib, decreased SAA1 expression and tumor-promoting effects in CAFs, suggesting SAA1 upregulation by enhancer activation in CAFs. Our present data showed that SAA1 is a candidate therapeutic target from gastric CAFs and indicated that increased enhancer acetylation is important for its overexpression.

Comparison of model fit and discriminatory ability of the 8th edition of the tumor-node-metastasis classification and the 9th edition of the Japanese classification to identify stage III colorectal cancer

BACKGROUND

The most widely accepted staging system for colorectal cancer (CRC) is the tumor-node-metastasis (TNM) classification. In Japan, the Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma (JCCRC) system is used. The two systems differ mainly in relation to tumor deposits (TD) and metastasis in the regional lymph nodes along the main feeding arteries and lateral pelvic lymph nodes (N3). Here, we investigated the prognostic ability of the two systems for stage III CRC.

METHODS

We reviewed 696 consecutive patients who underwent curative resection of stage III CRC at the National Cancer Center Hospital between May 2007 and April 2014. We examined the clinicopathological features of CRC and predicted overall survival (OS) and relapse-free survival (RFS) according to the 8th TNM and 9th JCCRC systems. The systems were compared using Akaike's information criterion (AIC), Harrell's concordance index (C-index), and time-dependent receiver-operating characteristic (ROC) curves.

RESULTS

The 9th JCCRC system was more clinically effective according to AIC (OS, 1199 vs. 1206; RFS, 2047 vs. 2057), showed better discriminatory ability according to the C-index (OS, 0.65 vs. 0.62; RFS, 0.62 vs. 0.58), and its time-dependent ROC curve was superior compared with the 8th TNM system.

CONCLUSION

These results suggest that the 9th JCCRC system has superior discriminative ability to the 8th TNM system, because the 9th JCCRC accounts for the presence of TD and N3 disease, which were both significant predictors of poor prognosis. Reconsidering the clinical value of these two factors in the TNM system could improve its clinical significance.

Histopathological atlas of desmoplastic reaction characterization in colorectal cancer

Emergent scientific evidence indicates the central role of cancer-associated fibroblasts in determining whether the microenvironment of cancer works as friend or foe of the host; however, there is no unified histological evaluation framework of fibrotic stroma in colorectal cancers. Myxoid stroma and keloid-like collagen are site-specific histopathological features generated by cancer-associated fibroblasts, which appear exclusively in the tumor front during desmoplastic reaction. On the basis of these two stromal components, desmoplastic reaction is categorized into three patterns-immature, intermediate and mature-using hematoxylin and eosin staining. In January 2020, a prospective randomized clinical trial, JCOG1805, to elucidate the value of adjuvant chemotherapy in stage II colorectal cancer patients with pathological risk factors of recurrence was launched in Japan, in which intermediate/immature desmoplastic reaction is one of the four risk factors selected as inclusion criteria. This paper covers the diagnostic criteria for the desmoplastic reaction classification being used in the JCOG1805 study.

Endoscopic Resection Before Surgery Does Not Affect the Recurrence Rate in Patients With High-Risk T1 Colorectal Cancer

INTRODUCTION

Patients with high-risk T1 colorectal cancer (CRC) after endoscopic resection (ER) should undergo surgery in view of the risk of lymph node metastasis. Although additional surgery can potentially prevent recurrence, there is a paucity of data and longitudinal studies exploring this potential. Hence, this study aimed to evaluate the prolonged influence of ER before additional surgery on recurrence in T1 CRC.

METHODS

Between January 2004 and October 2015, 162 patients who underwent secondary surgery (SS) after ER ([ER + SS] group) and 392 consecutive patients with T1 CRC who underwent primary surgery at our institution were retrospectively analyzed. Recurrence was analyzed in these 2 groups. High-risk CRC patients were histologically defined according to the Japanese Society for Cancer of the Colon and Rectum guidelines (2016) for the treatment of CRC. Data were analyzed based on clinical and histological features, including lymph node metastasis, and the number of lymph nodes evaluated.

RESULTS

The recurrence rate was comparable between the ER + SS and primary surgery groups, with no significant difference (P = 0.625, log-rank test). There was no significant difference in the recurrence in patients receiving adjuvant chemotherapy in both groups (7.4% vs 10.4%, P = 0.27). The difference in the mean number of lymph nodes dissected between both groups was also not significant (24.3 vs 25.3, P = 0.43).

DISCUSSION

There was no significant difference in recurrence rates between patients undergoing ER before surgery and those undergoing primary surgery for high-risk T1 CRC. Hence, ER may be acceptable for high-risk T1 CRC.

Influence of degree of DNA degradation in formalin-fixed and paraffin-embedded tissue samples on accuracy of genome-wide DNA methylation analysis

Aim: Depending upon the degree of DNA degradation of formalin-fixed and paraffin-embedded tissue samples, accuracy of measurement by Infinium MethylationEPIC BeadChip assay (Illumina, CA, USA) was assessed. Materials & methods: DNA quality of six formalin-fixed and paraffin-embedded lung tissue samples with different formalin fixation periods was assessed by Illumina quality control, DNA copy number and DNA integrity number value. Infinium data from restored bisulfite treated DNA were compared with datum from a fresh-frozen sample. Results: The correlation coefficient decreased from 0.993 to 0.970 depending upon DNA degradation, even if the Illumina quality control was met. Exclusion of specific probes improved the correlation regardless of tissue. Conclusion: Poor DNA quality can be assessed as an amplifiable DNA copy number and DNA integrity number value. Probe filtering has the potential to improve assay accuracy.

Risk of Lymph Node Metastasis in Patients with the Superficial Spreading Type of Esophageal Squamous Cell Carcinoma

BACKGROUND

Little is known about the clinicopathological characteristics of superficial spreading-type esophageal carcinoma extending ≥5 cm along the long axis of the esophagus. This study was aimed at investigating the frequency of lymph node metastasis (LNM) in patients with superficial spreading-type esophageal carcinoma.

METHODS

We reviewed the data of 320 patients with superficial esophageal squamous cell carcinoma who had undergone esophagectomy with lymph node dissection at our hospital between 1986 and 2010. The incidence of LNM was compared between the spreading (≥5 cm) and nonspreading (< 5 cm) types.

RESULTS

The multivariate analysis revealed significant differences in the likelihood of LNM depending on the lymphovascular invasion, the infiltrative growth pattern (INF)-c, and the depth. There was no difference in the LNM frequency between nonspreading and spreading type in the patients with epithelium (EP)-lamina propria, muscularis mucosa (MM)-submucosa (SM)1 and SM2/3 lesions. The frequencies of LNMs (nonspreading-type vs. spreading-type tumors) in the patients with MM-SM1 lesions were 7/47 (14.9%) versus 4/25 (16%) and those in the patients with SM2/3 lesions were 22/58 (37.9%) versus 4/14 (28.9%), when the lesions did not have lymphovascular invasion and INF-c.

CONCLUSIONS

Endoscopic resection can be selected for -EP-SM1 lesions, regardless of whether the lesions are of the spreading type or nonspreading type.

Gastric cancer is highly prevalent in Lynch syndrome patients with atrophic gastritis

BACKGROUND

Although gastric cancer is one of the Lynch syndrome (LS)-related tumors, the clinicopathological features of gastric cancer in patients with LS remain uncertain. To investigate the incidence risk and clinicopathological features of gastric neoplasms in LS, we conducted a retrospective cohort study in Japanese LS patients.

METHODS

LS patients with pathogenic mismatch repair (MMR) gene variants were extracted from the LS registry of the National Cancer Center Hospital, Japan. Cumulative risks of gastric neoplasm, including dysplasia and cancer, were estimated using the Kaplan-Meier method. Gastric atrophy was evaluated endoscopically and/or histologically. Immunohistochemical staining for MMR proteins was performed for all available specimens.

RESULTS

Of 118 eligible patients, 26 patients were diagnosed with 58 gastric neoplasms. The cumulative incidence of gastric neoplasm was 41.0% (95% confidence interval, 26.9-55.0) at the age of 70. Of these, 13 (50%) patients developed synchronous and/or metachronous multiple gastric neoplasms. Among the 49 gastric neoplasms available for detailed pathological evaluation, all were associated with intestinal metaplasia. Immunohistochemically, 42 (86%) were MMR-deficient. The individuals with gastric atrophy had a significantly higher risk of developing gastric neoplasms compared with those without gastric atrophy (26 cases/54 individuals vs. 0 cases/53 individuals) (P = 0.026).

CONCLUSION

LS patients, particularly those with atrophic gastritis, are at high risk of gastric neoplasm and often develop multiple tumors. Endoscopic surveillance for gastric cancer is recommended for LS patients, especially those with atrophic gastritis.

NTRK fusion-positive colorectal cancer in Japanese population

ALK, ROS1 and NTRK fusions are involved in the tumorigenesis of various organs, including colorectal cancer. This study aims to clarify the prevalence of these fusions in colorectal cancer in the Japanese population. Immunohistochemical analysis of 1012 specimens of colorectal cancer revealed two NTRK-positive cases (0.2%) whereas no ALK- or ROS1-positive cases were identified. Reverse transcription polymerase chain reaction (RT-PCR) detected an LMNA-NTRK1 fusion in a case of adenosquamous carcinoma and a TPM3-NTRK1 fusion in a case of tubular adenocarcinoma. Both NTRK1 fusion-positive cases lacked activating mutations in KRAS and BRAF and were mismatch repair-deficient with loss of MLH1 and PMS2 expression and MLH1 promoter methylation. Our results show that receptor tyrosine kinase fusions are rare but present in colorectal cancers in Japanese patients, with a prevalence similar to that reported in other countries.

Re-expression of REG family and DUOXs genes in CRC organoids by co-culturing with CAFs

Organoids derived from epithelial tumors have recently been utilized as a preclinical model in basic and translational studies. This model is considered to represent the original tumor in terms of 3D structure, genetic and cellular heterogeneity, but not tumor microenvironment. In this study, we established organoids and paired cancer-associated fibroblasts (CAFs) from surgical specimens of colorectal carcinomas (CRCs), and evaluated gene expression profiles in organoids with and without co-culture with CAFs to assess interactions between tumor cells and CAFs in tumor tissues. We found that the expression levels of several genes, which are highly expressed in original CRC tissues, were downregulated in organoids but re-expressed in organoids by co-culturing with CAFs. They comprised immune response- and external stimulus-related genes, e.g., REG family and dual oxidases (DUOXs), which are known to have malignant functions, leading tumor cells to proliferative and/or anti-apoptotic states and drug resistant phenotypes. In addition, the degree of differential induction of REG1 and DUOX2 in the co-culture system varied depending on CAFs from each CRC case. In conclusion, the co-culture system of CRC organoids with paired CAFs was able to partially reproduce the tumor microenvironment.

Recurrence after ESD curative resection for early gastric cancer

BACKGROUND

Endoscopic submucosal dissection (ESD) is gaining ground as a minimally invasive treatment for early gastric cancer (EGC) that has a negligible risk of lymph node metastasis. According to the 5th edition of Japanese gastric cancer treatment guidelines, annual or biannual follow-up with endoscopy is recommended, but follow-up with abdominal ultrasonography or computed tomography (CT) for surveillance of metastases is not recommended after the eCuraA resection. However, we experienced a case of lymph node recurrence following ESD resulting in eCuraA.

CASE PRESENTATION

A 76-year-old female received ESD for EGC in a previous hospital 4 years ago. Pathological findings were tub1, 30 mm, T1a (M), UL0, Ly0, V0, pHM-, pVM- (eCuraA) according to the 15th edition of Japanese Classification of Gastric Carcinoma. Follow-up esophagogastroduodenoscopy revealed submucosal tumor, which was suspected as a swollen lymph node by CT and endoscopic ultrasound fine-needle aspiration revealed the recurrence of gastric cancer. We performed total gastrectomy with D2 lymph node dissection. Postoperative pathological examination revealed no local recurrent tumor at the ESD site in the stomach. Swollen lymph node was diagnosed as metastasis and lymph node metastasis was limited near the cardia.

CONCLUSION

This case provides valuable information about tumor with a minimum poorly differentiated adenocarcinoma component may develop lymph node metastasis even satisfying the guidelines criteria for curative resection.

Impact of DNA integrity on the success rate of tissue-based next-generation sequencing: Lessons from nationwide cancer genome screening project SCRUM-Japan GI-SCREEN

In the nationwide cancer genome screening project SCRUM-Japan GI-SCREEN, 2590 archival formalin-fixed paraffin-embedded (FFPE) tumor tissues from 19 institutions were analyzed with two tissue-based next-generation sequencing (NGS) panels at the Clinical Laboratory Improvement Amendments (CLIA)-certified College of American Pathologists (CAP)-accredited central laboratory. The Oncomine Cancer Research Panel (OCP; 143 genes) succeeded in producing validated results for only 68.3% of the samples (%OCP-success). CE-IVD (25 genes) succeeded in 45.9% of the OCP-failed samples, leading to an overall NGS success (%combined-success) rate as high as 82.9%. Among 2573 samples, the DNA-integrity (ΔCt )-high (ΔCt  < 4.4, n = 1253) samples showed significantly higher %OCP- and %combined-success rates (90.2% and 97.4%, respectively) than the DNA-integrity-intermediate (4.4 < ΔCt  < 6.3, n = 911; 68.9% and 88.7%) and DNA-integrity-low ones (ΔCt  > 6.3 or polymerase chain reaction-failed, n = 409; 5.6% and 24.7%). Other factors associated with NGS success included the FFPE-sample storage period (<4 years), the specimen type (surgical) and the primary tumor site (colorectal). Multivariable analysis revealed DNA integrity as the factor with the strongest independent association with NGS success, although it was suggested that other institution-specific factors contribute to the discordance of inter-institutional NGS success rates. Our results emphasize the importance of DNA quality in FFPE samples for NGS tests and the impact of DNA integrity on quality monitoring of pathology specimens for achieving successful NGS.

Case report: potential treatment of metastatic amphicrine carcinoma of the rectum with FOLFOXIRI chemotherapy

Amphicrine carcinoma (AmC) is a unique epithelial tumor displaying exocrine and endocrine features in the same cell. It shows an adenocarcinoma-like cellular form and has endocrine granules. There are few reports describing chemotherapy for AmC. Here, we describe a case with metastatic AmC from the rectum that was treated with FOLFOXIRI chemotherapy.

A 64-year-old man was diagnosed with a submucosal lesion on the scar produced after an endoscopic mucosal resection, which had been performed for adenocarcinoma of the rectum 2 years before. The endoscopic submucosal dissection revealed AmC. The abdominoperineal resection including lymph nodes dissection was performed. Thereafter, computed tomography showed multiple liver metastases, and FOLFOXIRI was administered. The best overall response was partial response, and progression-free survival was 8.7 months. After 16.0 months since first-line chemotherapy the patient died. We can therefore conclude that FOLFOXIRI may be effective for AmC of the rectum.

An Organoid Biobank of Neuroendocrine Neoplasms Enables Genotype-Phenotype Mapping

Gastroenteropancreatic (GEP) neuroendocrine neoplasm (NEN) that consists of neuroendocrine tumor and neuroendocrine carcinoma (NEC) is a lethal but under-investigated disease owing to its rarity. To fill the scarcity of clinically relevant models of GEP-NEN, we here established 25 lines of NEN organoids and performed their comprehensive molecular characterization. GEP-NEN organoids recapitulated pathohistological and functional phenotypes of the original tumors. Whole-genome sequencing revealed frequent genetic alterations in TP53 and RB1 in GEP-NECs, and characteristic chromosome-wide loss of heterozygosity in GEP-NENs. Transcriptome analysis identified molecular subtypes that are distinguished by the expression of distinct transcription factors. GEP-NEN organoids gained independence from the stem cell niche irrespective of genetic mutations. Compound knockout of TP53 and RB1, together with overexpression of key transcription factors, conferred on the normal colonic epithelium phenotypes that are compatible with GEP-NEN biology. Altogether, our study not only provides genetic understanding of GEP-NEN, but also connects its genetics and biological phenotypes.