Significance of background coloration in endoscopic detection of early esophageal squamous cell carcinoma

Endoscopic detection of esophageal low-grade squamous dysplasia: How to predict pathologic upgrades before treatment?

OBJECTIVE

In this study we aimed to predict the risk factors related to histopathologic upgrade after endoscopic submucosal dissection (ESD) in patients with pre-ESD esophageal squamous low-grade intraepithelial neoplasm (LGIN).

METHODS

A training cohort of 201 patients with biopsy-confirmed esophageal squamous LGIN and underwent ESD at a tertiary medical center between January 2017 and July 2019 were included. Risk factors for histological upgrade were identified using the least absolute shrinkage and selection operator (LASSO) regression. A nomogram was then established. Internal validation was evaluated by discrimination, calibration plot, and decision-curve analysis. Another cohort of 48 patients were prospectively collected from July 2019 to June 2021 for external validation of the nomogram.

RESULTS

The rate of histological upgrade was 34.8% (70/201) and 27.1% (13/48) in the training and validation sets, respectively. LASSO regression identified that tumor area (mm² ) per biopsy, Lugol's staining pattern, background coloration, and the circumferential range of the lesion were significantly associated with histological upgrade. The final nomogram attained favorable prediction efficacy in the training cohort (area under the receiver operating curve [AUROC] 0.96, 95% confidence interval [CI] 0.94-0.98) and validation cohort (AUROC 0.92, 95% CI 0.79 -0.99). This model generated well-fitted calibration and clinical-decision curves in both cohorts.

CONCLUSIONS

The nomogram may better guide clinical decision on whether performing EDS or follow-up for suspicious lesions in patients with biopsy-confirmed esophageal squamous LGIN.

Artificial intelligence and early esophageal cancer

The development of esophageal cancer (EC) from early to advanced stage results in a high mortality rate and poor prognosis. Advanced EC not only poses a serious threat to the life and health of patients but also places a heavy economic burden on their families and society. Endoscopy is of great value for the diagnosis of EC, especially in the screening of Barrett’s esophagus and early EC. However, at present, endoscopy has a low diagnostic rate for early tumors. In recent years, artificial intelligence (AI) has made remarkable progress in the diagnosis of digestive system tumors, providing a new model for clinicians to diagnose and treat these tumors. In this review, we aim to provide a comprehensive overview of how AI can help doctors diagnose early EC and precancerous lesions and make clinical decisions based on the predicted results. We analyze and summarize the recent research on AI and early EC. We find that based on deep learning (DL) and convolutional neural network methods, the current computer-aided diagnosis system has gradually developed from in vitro image analysis to real-time detection and diagnosis. Based on powerful computing and DL capabilities, the diagnostic accuracy of AI is close to or better than that of endoscopy specialists. We also analyze the shortcomings in the current AI research and corresponding improvement strategies. We believe that the application of AI-assisted endoscopy in the diagnosis of early EC and precancerous lesions will become possible after the further advancement of AI-related research.

Endoscopic resections for superficial esophageal squamous cell epithelial neoplasia: focus on histological discrepancies between biopsy and resected specimens

BACKGROUND

Endoscopic resection has been used for high-grade intraepithelial neoplasia (HGIN) and superficial esophageal squamous cell carcinoma (ESCC) with limited risk of lymph node metastasis. However, some of these lesions cannot be accurately diagnosed based on forceps biopsy prior to treatment. In this study we aimed to investigate how to solve this histological discrepancy and avoid over- and under-treatment.

METHODS

The medical records of patients with superficial esophageal squamous cell neoplasia who underwent endoscopic resection at our hospital from January 2012 to December 2019 were reviewed retrospectively. The histological discrepancy between the biopsy and resected specimens was calculated and its association with clinicopathological parameters was analyzed.

RESULTS

A total of 137 lesions from 129 patients were included. The discrepancy rate between forceps biopsy and resected specimens was 45.3% (62/137). Histological discrepancy was associated with the histological category of the biopsy (p < 0.001). In addition, 17 of the 30 (56.7%) biopsies that was diagnosed as indefinite/negative for neoplasia or low-grade intraepithelial neoplasia were upgraded to HGIN or ESCC after resection. The upgrade was due to lesion size ≥ 10 mm (p = 0.002) and type B intrapapillary capillary loops (p < 0.001). Moreover, 34 of the 83 biopsies that were diagnosed with HGIN were upgraded to ESCC after resection, which was related to lesion size (p = 0.001), location (p = 0.018), and pink color sign (p = 0.002).

CONCLUSIONS

Histological discrepancy between forceps biopsy and resected specimens is common in clinical practice. Recognizing the risk factors for each histological category of biopsy may reduce these discrepancies and improve clinical management.

Narrow band imaging under less-air condition improves the visibility of superficial esophageal squamous cell carcinoma

Background

The current virtual chromoendoscopy equipment cannot completely detect superficial squamous cell carcinoma (SCC) in the esophagus, despite its development in the recent years. Thus, in this study, we aimed to elucidate the appropriate air volume during endoscopic observation to improve the visibility of esophageal SCC.

Methods

This retrospective study included a total of 101 flat type esophageal SCCs identified between April 2017 and January 2019 at the Department of Gastrointestinal Oncology, Osaka International Cancer Institute. Video images of narrow band imaging (NBI) under both less-air and standard-air conditions were recorded digitally. Videos were evaluated by five endoscopists. Relative visibility between less-air and standard-air conditions of the brownish area, brownish color change of the epithelium, and dilated intrapapillary capillary loop (IPCL) were graded as 5 (definitely better under less-air condition) to 1 (definitely worse under less-air condition), with 3 indicating average visibility (equivalent to standard-air observation).

Results

The mean (standard deviation) visibility score of the brownish area, brownish color change of the epithelium, and dilated IPCLs under less-air condition were 3.94 (0.58), 3.73 (0.57), and 4.13 (0.60), respectively, which were significantly better than that under standard-air condition (p < 0.0001). Esophageal SCC evaluated as ≥ 4 in the mean visibility score of the brownish area, brownish color change of the epithelium, and dilated IPCLs accounted for 50% (51/101 lesions), 34% (34/101 lesions), and 67% (68/101 lesions), respectively.

Conclusions

The present results suggested that NBI with less air might improve the visibility of flat type esophageal SCC compared with NBI with standard air. Less-air NBI observation may facilitate the detection of flat type esophageal SCC.

Trial registration

The present study is a non-intervention trial.

Real-time automated diagnosis of precancerous lesions and early esophageal squamous cell carcinoma using a deep learning model (with videos)

BACKGROUND AND AIMS

We developed a system for computer-assisted diagnosis (CAD) for real-time automated diagnosis of precancerous lesions and early esophageal squamous cell carcinomas (ESCCs) to assist the diagnosis of esophageal cancer.

METHODS

A total of 6473 narrow-band imaging (NBI) images, including precancerous lesions, early ESCCs, and noncancerous lesions, were used to train the CAD system. We validated the CAD system using both endoscopic images and video datasets. The receiver operating characteristic curve of the CAD system was generated based on image datasets. An artificial intelligence probability heat map was generated for each input of endoscopic images. The yellow color indicated high possibility of cancerous lesion, and the blue color indicated noncancerous lesions on the probability heat map. When the CAD system detected any precancerous lesion or early ESCCs, the lesion of interest was masked with color.

RESULTS

The image datasets contained 1480 malignant NBI images from 59 consecutive cancerous cases (sensitivity, 98.04%) and 5191 noncancerous NBI images from 2004 cases (specificity, 95.03%). The area under curve was 0.989. The video datasets of precancerous lesions or early ESCCs included 27 nonmagnifying videos (per-frame sensitivity 60.8%, per-lesion sensitivity, 100%) and 20 magnifying videos (per-frame sensitivity 96.1%, per-lesion sensitivity, 100%). Unaltered full-range normal esophagus videos included 33 videos (per-frame specificity 99.9%, per-case specificity, 90.9%).

CONCLUSIONS

A deep learning model demonstrated high sensitivity and specificity for both endoscopic images and video datasets. The real-time CAD system has a promising potential in the near future to assist endoscopists in diagnosing precancerous lesions and ESCCs.

Discrepancy Between the Clinical and Final Pathological Findings of Lymph Node Metastasis in Superficial Esophageal Cancer

BACKGROUND

Recent advances in endoscopic examinations have resulted in the detection of a larger number of early esophageal cancers; however, there have been many cases with clinically negative but pathologically positive lymph node metastasis (LNM). In this study, we aimed to evaluate the discrepancy between the clinical and pathological diagnoses of LNM in patients with cT1a-MM/cT1b N0M0 esophageal cancer, and assess LNM size in these patients to clarify the presence of LNM that cannot be detected with current modalities.

METHODS

This study included 50 patients who underwent surgery for cT1a-MM/cT1b N0M0 thoracic esophageal squamous cell carcinoma between January 2012 and November 2016 at our institution. The maximum size of involved LNs and metastatic nests were measured, and the distribution of LNM was investigated.

RESULTS

Of the 50 patients, 13 (26%) had LNM on pathological examination. Lymphatic invasion was significantly more frequent in the LNM-positive group than in the LNM-negative group (p = 0.005). The median sizes of 28 involved LNs and metastatic nests were 3 and 1.6 mm, respectively. Of these LNs, 20 (71%) were classified as micrometastases (≤ 2 mm). The involved nodes were distributed across three fields.

CONCLUSIONS

There was a discrepancy between the clinical and final pathological findings of LNM in patients with cT1a-MM/cT1b N0M0 esophageal cancer. The detection of involved nodes with current modalities in these patients was difficult because of the small size of LNM. Therefore, continued strong consideration for extended LN dissection is necessary in these patients to ensure appropriate diagnosis and treatment.

A training program of a new simplified classification of magnified narrow band imaging for superficial esophageal squamous cell carcinoma

BACKGROUND AND AIM

Optimal staging of the invasion depth of superficial esophageal squamous cell carcinoma is vital before endoscopic treatment. A new simplified magnified narrow-band imaging (M-NBI) classification system based on vascular architecture has recently been developed by the Japan Esophageal Society; however, its validity remains uncertain.

METHODS

A total of 11 experienced and 11 inexperienced endoscopists were invited to join an endoscopic training program, which was composed of pretest, educational section, and post-test. The pretest and post-test sections included a set of endoscopic photos from 40 subjects with superficial esophageal squamous cell carcinoma with various invasion depths. Each subject appeared twice in the test, one with white-light imaging (WLI) only and the other with both WLI and M-NBI. The educational section included lectures and video demonstrations.

RESULTS

The accuracy of WLI alone and combined with M-NBI at baseline were 0.53, 0.57 and 0.43, 0.41 for the experienced and inexperienced endoscopists, respectively, which then improved to 0.57, 0.63 and 0.49, 0.52 after training. Inter-observer agreement (k-value) of WLI alone and combined WLI and M-NBI for the experienced and inexperienced endoscopists also improved from 0.61, 0.61, and 0.61, 0.53 to 0.68, 0.71, and 0.71, 0.59, respectively. Multivariate analysis revealed that the educational course but not experience in endoscopy, NBI, or magnification significantly improved the diagnostic accuracy. M-NBI had a significant additional benefit to WLI, with an improvement in accuracy from 36% to 56% for the cases with m3/sm1 cancers (P < 0.05).

CONCLUSIONS

A well-designed training program can improve the diagnostic accuracy in evaluating cancer invasion depth, with substantial agreement.

Efficacy of narrow-band imaging in detecting early esophageal cancer and risk factors for its occurrence

OBJECTIVE

The aim of this study is to evaluate the efficacy of narrow-band imaging (NBI) in the detecting early esophageal cancer and precancerous lesions and to investigate the risk factors for its occurrence.

METHODS

The esophagus was examined with ordinary endoscopy, NBI, and iodine staining. All the lesions were confirmed by histopathologically as the gold standard; NBI and intrapapillary capillary scale (IPCL) scale were compared with pathologic diagnosis. The accuracy, sensitivity, specificity, positive and negative predictive values (PPV, NPV) were calculated. Subgroup analysis was performed between the elderly vs. younger group, and head and neck squamous cell cancer (HNSCC) vs. non-HNSCC patients.

RESULTS

Ninety lesions were detected with ordinary endoscopy, 108 with NBI, and 120 with iodine staining. All esophageal cancers were detected both by NBI and by iodine staining. Accuracy, sensitivity, and specificity for esophageal cancer and precancerous lesion were 67.8%, 58.1%, and 76.6%; 92%, 89.7%, and 96%; 93.4%, 93.4%, and 93.2%, respectively. NBI endoscopy and iodine staining were superior to ordinary endoscopy for detecting esophageal cancer and precancerous lesions (p < 0.05). NBI showed better detection of esophageal neoplasms in the elderly patients (p < 0.001). The incidence of multiple squamous cell cancers (SCCs) was significantly higher in non-elderly group (p = 0.009). NBI can also detect more esophageal neoplastic lesions in patients with head and neck cancers (p = 0.003).

CONCLUSIONS

NBI endoscopy appears as effective as Lugol staining to detect and screen the early esophageal cancer. NBI shows better detection of esophageal neoplasms in the elderly patients. The incidence of multiple SCCs was much higher in non-elderly patients.

Vascular density of superficial esophageal squamous cell carcinoma determined by direct observation of resected specimen using narrow band imaging with magnifying endoscopy

Observation of the microvasculature using narrow band imaging (NBI) with magnifying endoscopy is useful for diagnosing superficial squamous cell carcinoma. Increased vascular density is indicative of cancer, but not many studies have reported differences between cancerous and noncancerous areas based on an objective comparison. We observed specimens of endoscopic submucosal dissection (ESD) using NBI magnification, and determined the vascular density of cancerous and noncancerous areas. A total of 25 lesions of esophageal squamous cell carcinoma that were dissected en bloc by ESD between July 2013 and December 2013 were subjected to NBI magnification. We constructed a device that holds an endoscope and precisely controls the movement along the vertical axis in order to observe submerged specimens by NBI magnification. NBI image files of both cancerous (pathologically determined invasion depth, m1/2) and surrounding noncancerous areas were created and subjected to vascular density assessment by two endoscopists who were blinded to clinical information. The invasion depth was m1/2 in 20, m3/sm1 in four and sm2 in one esophageal cancer lesion. Mean vascular density was significantly increased in cancerous areas (37.6 ± 16.3 vessels/mm2) compared with noncancerous areas (17.6 ± 10.0 vessels/mm2) (P < 0.05). The correlation coefficients between vascular density determined by two endoscopists were 0.86 and 0.81 in cancerous and noncancerous areas, respectively. Receiver operating curve (ROC) analysis revealed that the area under the curve (AUC) of vascular density was 0.895 (95% CI, 0.804-0.986). For this ROC curve, sensitivity was 78.3% and specificity was 87.0% when the cutoff value of vascular density was 26 vessels/mm2. NBI magnification confirmed significant increases in vascular density in cancerous areas compared with noncancerous areas in esophageal squamous cell carcinoma. The rates of agreement between vascular density values determined by two independent operators were high.

Diagnostic accuracy of probe-based confocal laser endomicroscopy in Lugol-unstained esophageal superficial lesions of patients with head and neck cancer

BACKGROUND AND AIMS

Surveillance programs of patients with head and neck cancer (HNC) detect synchronous or metachronous esophageal squamous cell carcinoma (ESCC) in up to 15% of patients. Noninvasive, probe-based confocal laser endomicroscopy (pCLE) technique may improve the diagnosis allowing acquisition of high-resolution in vivo images at the cellular and microvascular levels. The aim of this study was to evaluate the accuracy of pCLE for the differential diagnosis of nonneoplastic and neoplastic Lugol-unstained esophageal lesions in patients with HNC.

METHODS

Twenty-seven patients with HNC who exhibited Lugol-unstained esophageal lesions at surveillance endoscopy were prospectively included for pCLE. Diagnostic pCLE was followed by subsequent biopsies or endoscopic resection of suspected lesions. A senior pathologist was blinded to the pCLE results.

RESULTS

Patients mean age was 59 years (SD = 8.8) and 70.4% were men. All patients were smokers, and 22 patients (81.5%) had a history of alcohol consumption. The locations of HNC were oral cavity (n = 13), larynx (n = 10), and pharynx (n = 4). Thirty-seven lesions in 27 patients were studied. The final diagnoses were ESCC in 17 patients and benign lesions in 20 patients. Sensitivity, specificity, and accuracy of pCLE for the histologic diagnosis of ESCC in patients with HNC were 94.1%, 90.0%, and 91.9%, respectively.

CONCLUSIONS

First, pCLE is highly accurate for real-time histology of Lugol-unstained esophageal lesions in patients with HNC. Second, pCLE may alter the management of patients under surveillance for ESCC, guiding biopsies and endoscopic resection, avoiding further diagnostic workup or therapy of benign lesions.

Epigenetically silenced PTPRO functions as a prognostic marker and tumor suppressor in human lung squamous cell carcinoma

Protein tyrosine phosphatase receptor-type O (PTPRO), a member of the PTP family, has been frequently reported as potential tumor suppressor in many types of cancer. However, the exact function of PTPRO in lung squamous cell carcinoma (LSCC) remains unclear. Bisulfite sequencing and methylation specific polymerase chain reaction (PCR) were used to identify the methylation status of PTPRO in LSCC cells, and quantitative methylation specific PCR was used to evaluate the methylation levels of PTPRO in LSCC patients. Stably expressing PTPRO vectors were constructed and transfected into H520 and SK-MES-1 cells, followed by MTT and colony formation assays, and analysis of tumor weight and volume in in vivo mouse xenograft models. The present study demonstrated that the CpG island of PTPRO exon 1 was obviously hypermethylated in LSCC cells and tissues. The mRNA expression of PTPRO could be restored by treatment with a demethylation agent. Increased methylation and decreased mRNA levels of PTPRO were observed in LSCC samples compared with adjacent healthy tissues, and were associated with poor prognosis of patients. The mRNA expression of PTPRO was negatively correlated with its methylation level in tumors. Functionally, ectopic PTPRO expression in LSCC cells significantly inhibited the proliferation rates, and colony formation, in comparison with control and non-transfected cells. In vivo assays confirmed the inhibitory effect of PTPRO on LSCC cell growth. In conclusion, these data provided evidence that epigenetic regulation of PTPRO impairs its tumor suppressor role in LSCC, and restoration of PTPRO may be a potential therapeutic strategy.

Early squamous neoplasia of the esophagus: The endoscopic approach to diagnosis and management

Considerable focus has been placed on esophageal adenocarcinoma in the last 10 years because of its rising incidence in the West. However, squamous cell cancer (SCC) continues to be the most common type of esophageal cancer in the rest of the world. The detection of esophageal SCC (ESCC) in its early stages can lead to early endoscopic resection and cure. The increased incidence of ESCC in high-risk groups, such as patients with head and neck squamous cancers, highlights the need for screening programs. Lugol's iodine chromoendoscopy remains the gold standard technique in detecting early ESCC, however, safer techniques such as electronic enhancement or virtual chromoendoscopy would be ideal. In addition to early detection, these new "push-button" technological advancements can help characterize early ESCC, thereby further aiding the diagnostic accuracy and facilitating resection. Endoscopic resection (ER) of early ESCC with negligible risk of lymph node metastases has been widely accepted as an effective therapeutic strategy because it offers similar success rates when compared to esophagectomy, but carries lesser morbidity and mortality. Endoscopic submucosal dissection (ESD) is the preferred technique of ER in lesions larger than 15 mm because it provides higher rates of en bloc resections and lower local recurrence rates when compared to endoscopic mucosal resection (EMR).

Clinicopathologic characteristics and management of minute esophageal lesions diagnosed by narrow-band imaging endoscopy

BACKGROUND AND STUDY AIMS

Magnifying narrow-band imaging (NBI) endoscopy enables the diagnosis of minute esophageal neoplasia. We aimed to evaluate clinicopathological diagnosis of minute esophageal neoplasia by using magnifying NBI endoscopy and biopsy.

PATIENTS AND METHODS

In total, 309 patients (127 men and 182 women) with minute esophageal lesions of intrapapillary capillary loop (IPCL) type IV were enrolled. Of these patients, 249 underwent biopsy for histologic diagnosis and also for treatment. Of the 249 patients, 123 underwent follow-up with endoscopy. We analyzed the clinicopathologic characteristics and prognosis of these lesions after biopsy.

RESULTS

Of the 249 biopsied lesions, we histologically diagnosed 11 as high-grade intraepithelial neoplasia (HGIN), 41 as low-grade intraepithelial neoplasia (LGIN), and 197 as non-neoplasia (Non-N) including inflammation. Six of the 11 HGINs and 11 of the 41 LGINs showed slight elevation. Background coloration was observed in 9 of 11 HGINs, 34 of 41 LGINs, and 33 of 197 Non-Ns. Of the 249 biopsied lesions, 147 were microscopically measurable. The average diameter was 1.4 mm for HGINs and 0.8 mm for LGINs. Of the 123 patients who underwent post-biopsy follow-up, 93 (76 %) showed no lesions at the biopsied sites during the NBI examinations and were suspected to have undergone complete resection by biopsy.

CONCLUSIONS

Biopsy was useful for diagnosis and treatment of minute esophageal lesions, diagnosed as IPCL type IV by magnifying NBI endoscopy.

Multicenter, prospective trial of white-light imaging alone versus white-light imaging followed by magnifying endoscopy with narrow-band imaging for the real-time imaging and diagnosis of invasion depth in superficial esophageal squamous cell carcinoma

BACKGROUND

Magnifying endoscopy with narrow-band imaging (ME-NBI) has been used to estimate the invasion depth of superficial esophageal squamous cell carcinoma (SESCC), but the real diagnostic power of ME-NBI remains unclear because of few prospective studies.

OBJECTIVES

To evaluate whether ME-NBI adds additional information to white-light imaging (WLI) for the diagnosis of invasion depth of SESCC.

DESIGN

Multicenter, prospective trial using real-time imaging and diagnosis.

SETTING

Seven Japanese institutions.

PATIENTS

Fifty-five patients with SESCC were enrolled from June 2011 to October 2013, and the results for 49 lesions were analyzed.

INTERVENTIONS

Patients underwent primary WLI followed by ME-NBI, and reports of primary WLI (WLI alone) were completed before secondary ME-NBI (WLI followed by ME-NBI). To standardize diagnosis among examiners, this trial was started after achievement of a mean κ value≥.6 among 11 participating endoscopists.

MAIN OUTCOME MEASUREMENTS

Diagnosis of invasion depth by each tool was divided into cancer limited to the epithelium and the lamina propria mucosa and cancer invading beyond the muscularis mucosae (≥T1a-MM) and then collated with the final pathologic diagnosis by an independent pathologist blinded to the clinical data.

RESULTS

The accuracy of invasion depth in WLI alone and WLI followed by ME-NBI was 71.4% and 65.3% (P=.375), respectively. Sensitivity for ≥T1a-MM was 61.1% for both groups (P=1.000), and specificity for ≥T1a-MM was 77.4% for WLI alone and 67.7% for WLI followed by ME-NBI (P=.375).

LIMITATION

Open-label trial.

CONCLUSIONS

ME-NBI showed no additional benefit to WLI for diagnosis of invasion depth of SESCC. (University Hospital Network Clinical Trials Registry number: UMIN000005632.).

Prevention strategies for esophageal cancer: Perspectives of the East vs. West

Esophageal cancer is the eighth most common cancer worldwide. Esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC) are the two major phenotypes in Western and Eastern countries, respectively. Because of different pathways in carcinogenesis, the risk factors and effective steps for prevention of esophageal cancer are different between EAC and ESCC. The carcinogenesis of EAC is initiated by the acid exposure of the esophageal mucosa from stomach while that of the ESCC are related to the chronic irritation of carcinogens mainly by the alcohol, cigarette, betel quid, and hot beverage. To eliminate the burden of esophageal cancer on the global health, the effective strategy should be composed of the primary, secondary, and tertiary prevention. In this article, we perform a systematic review of the preventive strategies for esophageal cancer with special emphasis on the differences from the perspectives of Western and Eastern countries.