Computed tomography scan efficacy in staging gastric linitis plastica lesion: a retrospective multicentric French study

The Genomic Signatures of Linitis Plastica Signal the Entrance into a New Era: Novel Approaches for Diagnosis and Treatment

Linitis Plastica (LP) is a rare and aggressive tumor with a distinctive development pattern, leading to the infiltration of the gastric wall, the thickening of the gastric folds and a "leather bottle appearance". LP is an extremely heterogeneous tumor caused by mutations in oncogenic and tumor suppressive genes, as well as molecular pathways, along with mutations in stromal cells and proteins related to tight junctions. Elucidating the molecular background of tumorigenesis and clarifying the correlation between cancerous cells and stromal cells are crucial steps toward discovering novel diagnostic methods, biomarkers and therapeutic targets/agents. Surgery plays a pivotal role in LP management, serving both as a palliative and curative procedure. In this comprehensive review, we aim to present all recent data on the molecular background of LP and the novel approaches to its management.

Analysis of genomic and immune intratumor heterogeneity in linitis plastica via multiregional exome and T-cell receptor sequencing

The molecular landscape and the intratumor heterogeneity (ITH) architecture of gastric linitis plastica (LP) are poorly understood. We performed whole-exome sequencing (WES) and T-cell receptor (TCR) sequencing on 40 tumor regions from four LP patients. The landscape and ITH at the genomic and immunological levels in LP tumors were compared with multiple cancers that have previously been reported. The lymphocyte infiltration was further assessed by immunohistochemistry (IHC) in LP tumors. In total, we identified 6339 non-silent mutations from multi-samples, with a median tumor mutation burden (TMB) of 3.30 mutations per Mb, comparable to gastric adenocarcinoma from the Cancer Genome Atlas (TCGA) cohort (P = 0.53). An extremely high level of genomic ITH was observed, with only 12.42%, 5.37%, 5.35%, and 30.67% of mutations detectable across 10 regions within the same tumors of each patient, respectively. TCR sequencing revealed that TCR clonality was substantially lower in LP than in multi-cancers. IHC using antibodies against CD4, CD8, and PD-L1 demonstrated scant T-cell infiltration in the four LP tumors. Furthermore, profound TCR ITH was observed in all LP tumors, with no T-cell clones shared across tumor regions in any of the patients, while over 94% of T-cell clones were restricted to individual tumor regions. The Morisita overlap index (MOI) ranged from 0.21 to 0.66 among multi-regions within the same tumors, significantly lower than that of lung cancer (P = 0.002). Our results show that LP harbored extremely high genomic and TCR ITH and suppressed T-cell infiltration, suggesting a potential contribution to the frequent recurrence and poor therapeutic response of this adenocarcinoma.

Lymphangitic carcinomatosis as the initial manifestation of primary signet-ring cell adenocarcinoma of the lung: A case report

Signet-ring cell carcinomas are an aggressive, poorly differentiated, and highly invasive adenocarcinoma carrying a poor prognosis. Most of these tumors originate in gastrointestinal organs; however, primary lung signet-ring cell adenocarcinomas can rarely occur. Tumoral lymphatic infiltration is a complication of these tumors and can cause phenomena such as lymphangitic carcinomatosis, characterized by a nodular thickening of the pleura, pleural effusions, and mediastinal lymphadenopathies. We report a case of a 63-year-old ex-smoker with a 2-week clinical course of dyspnea and pleuritic chest pain in which a nodular thickening of the pleura and pleural effusion were documented and led to the diagnosis of a primary signet-ring cell adenocarcinoma of the lung with lymphangitic carcinomatosis. This complication has never been described in the context of a primary lung tumor of this subtype. Both entities carry a high mortality and have no therapeutical options. This report adds to the information available about them.

Development of a Quantitative Diagnostic Criterion for Gastric Linitis Plastica: Findings From a Large Single-Institutional Study

Gastric linitis plastica (GLP) is a descriptive term but lacks a quantitative definition. Several relatively quantitative criteria had been proposed, such as tumor involving a limit of one-third or two-thirds of the gastric surface. However, these criteria needed doctors to subjectively judge tumor infiltration area, which made diagnosis difficult to be objective and reproducible. This study aimed to propose a quantitative diagnostic criterion for distinguishing GLP. We performed a retrospective cohort study of 2,907 patients with Borrmann III and IV gastric cancer (GC) who underwent gastrectomy between 2011 and 2018 in our center. The Kaplan–Meier curves showed that patients with an observed tumor size more than 8 cm had obviously lower overall survival (OS) and disease-free survival (DFS) rates than those with a size less than 8 cm(p < 0.001; p < 0.001). However, there was no significantly different prognosis of patients with tumor sizes between more than 8 cm and more than 10 cm (p = 0.248; p = 0.534). Moreover, patients with tumor sizes greater than 8 cm more presented with advanced stage and had extremely poor 3-year OS and DFS (31.4%; 29.3%), with a stronger propensity toward peritoneal metastasis. Therefore, we considered patients’ observed tumor size more than 8 cm as a critical value for distinguishing the prognosis of Borrmann III and IV GC. Furthermore, we proposed an observed tumor size more than 8 cm as a quantitative diagnostic criterion for GLP on the premise of satisfying the originally descriptive and pathological definition regardless of Borrmann type.

Is there still a place for conventional histopathology in the age of molecular medicine? Laurén classification, inflammatory infiltration and other current topics in gastric cancer diagnosis and prognosis

Gastric cancer (GC) is the fifth most common cancer and the third cause of cancer-related deaths worldwide. In western countries, more than half of GC patients are diagnosed at advanced stages and 5-year survival rates range between 20-30%. The only curative treatment is surgery, and despite recent advances in oncological therapies, GC prognosis is still poor. The main prognostic tool for patient categorization and treatment selection is the TNM classification, but its limitations are being increasingly recognized. Early recurrences may occur in early-stage disease, and patients at the same stage show heterogeneous outcomes. Thus, there is a need to improve GC stratification and to identify new prognostic factors, which may allow us to select drug-susceptible populations, refine patient grouping for clinical trials and discover new therapeutic targets. Molecular classifications have been developed, but they have not been translated to the clinical practice. On the other hand, histological assessment is cheap and widely available, and it is still a mainstay in the era of molecular medicine. Furthermore, histological features are acquiring new roles as reflectors of the genotype-phenotype correlation, and their potential impact on patient management is currently being analyzed. The aim of this literature review is to provide a modern overview of the histological assessment of GC. In this study, we discuss recent topics on the histological diagnosis of GC, focusing on the current role of Laurén classification and the potential value of new histological features in GC, such as inflammatory infiltration and tumor budding.

Endoscopic ultrasound efficacy in staging gastric linitis plastica lesion: a retrospective multicentric French study

BACKGROUND

Endoscopic ultrasound (EUS) is a key imaging technique in gastric cancer (GC). The aim of this study was to evaluate the performance of EUS in the staging of parietal and lymph node involvement in linitis plastica (LP) compared to "classical" GC.

METHODS

A retrospective multicentric French study was conducted on patients with no metastatic LP and operated by gastrectomy. A 2/1 matching based on pTNM stage and center was performed with GC.

RESULTS

Forty-three patients were included, sixteen patients in the LP group and 27 in the control group. Sensitivity and specificity of EUS for diagnosis of T3-T4 parietal invasion were 77% and 100% respectively in the LP group and 89% and 56% respectively in the control group. Sensitivity and specificity of EUS for diagnosis of lymph node involvement were 73% and 80%, respectively in the LP group and 88% and 50%, respectively in the control group. Patients from LP group had significantly more advanced histological lesion, and frequent undiagnosed peritoneal carcinomatosis.

CONCLUSIONS

This study evaluated for the first time in a European population, the preoperative EUS performance in LP. Our study identified a similar sensitivity and specificity of the EUS in LP compared to "classical" GC paving for a broader use of EUS in preoperative settings.

Development and internal validation of a diagnostic score for gastric linitis plastica

BACKGROUND

There is no consensual definition for gastric linitis plastica (GLP). We aim to construct a diagnostic score to distinguish this rare tumor from usual gastric adenocarcinomas.

METHODS

In this retrospective study, all patients who had gastrectomy for cancer between 2007 and 2017 in French tertiary centers were included. The outcome was a diagnosis of GLP based on pathological review of the surgical specimen. The diagnostic score was created by using variables that were most frequently associated with GLP using penalized logistic regression on multiply imputed datasets. We used discrimination measures to assess the performances of the score. Internal validation was performed using bootstrapping methods to correct for over-optimism.

RESULTS

220 patients including 71 linitis plastica (female 49%, median age 57 years) were analyzed. The six parameters retained in the diagnosis score were the presence of large folds and/or parietal thickening on at least one segment, pangastric infiltration and presence of gastric stenosis on the upper endoscopy, circumferential thickening on at least one segment and thickening of the third hyperechogenic layer on endoscopic ultrasound and the presence of signet ring cells on endoscopic biopsies. The area under the ROC curve (AUC) was 0.967 with a sensitivity of 94% [89.9-97.3] and a specificity of 88.7% [81.7-95.8] for a threshold of 2.75. After internal validation, the corrected AUC was 0.959.

CONCLUSION

It is the first study validating a pre-therapeutic diagnostic score (Saint Louis linitis score) with an excellent ability to discriminate GLP from non-GLP adenocarcinomas. An external validation is necessary to confirm our data.