Comparison of the histopathological characteristics of large colorectal laterally spreading tumors according to growth pattern

Is endoscopic mucosal ablation a valid option for treating colon polyps?

The present letter to editor is related to endoscopic mucosal ablation (EMA). EMA is safe and effective in the treatment of colonic polyps when endoscopic resection is not possible or available, but the indication of EMA should be determined for a further large number of studies. EMA should be used with caution for larger lesions.

Two histologic compartments in nonpolypoid conventional colon adenomas

Two intertwined compartments coexisting in nonpolypoid conventional (i.e. tubular or villous) adenomas are highlighted in this review: one built of dysplastic tissue on top and the other portraying crypts with irregular, corrupted shapes, albeit lined with normal epithelium, below. The latter compartment has remained unattended in the literature. Recently, however, the histologic characteristics of the nondysplastic compartment in nonpolypoid conventional adenomas were closely examined, and some of its biological attributes were unveiled. Studies with the proliferation marker ki67 showed that the crypts with irregular, corrupted shapes in the nondysplastic compartment displayed haphazardly distributed proliferating cell-domains. Given that the proliferating cells are generated by stem cells, the relocation of proliferating cell-domains in those crypts seems to be the result of a reorganization of the stem cells within the crypts. The abnormal distribution of proliferating cells, the finding of p53-upregulated cells, and of crypts in asymmetric fission suggest that the crypts in that compartment are histo-biologically altered, probably somatically mutated. This new information might contribute to unravel the riddle of crypto-histogenesis of nonpolypoid conventional adenomas of the colon. More research along these lines is necessary, before the biology of the crypts in the nondysplastic compartment can be fully translated into molecular terms.

Pathological Analysis and Endoscopic Characteristics of Colorectal Laterally Spreading Tumors

Objective

This study aims to analyze the endoscopic and pathological characteristics of colorectal laterally spreading tumors (LSTs) to assist malignant risk stratification to inform selection of the appropriate treatment strategy.

Methods

Patients with colorectal LST were selected as retrospective study objects. Characteristics, including endoscopic findings and the most common site of LSTs of different diameters and histological types, were analyzed. The risk factors for malignancy in colorectal LST were explored by multivariate logistic regression analysis.

Results

LSTs with diameters of ≥20 mm were found mainly in the rectum and mainly with granular-mixed (G-M) morphology (36% and 44.6%, respectively; p < 0.05), while LSTs with diameters of <20 mm were found mainly in the ascending colon and mainly with granular-homogenous (G-H) morphology (40.9% and 46.2%, respectively; p < 0.05). Adenoma was the main histological type in patients with tumors of all diameters. However, the cancerization rate of LSTs was 31% in patients with tumor diameter ≥20 mm, while there was no invasive cancer in patients with tumor diameter < 20 mm. In the low-grade dysphasia (adenoma) group, most of the lesions were located in the ascending colon and most had the morphology LST-G-H (35.8% and 39.2%, respectively; p < 0.05). In the cancerization group, most of the lesions were located in the rectum, with the morphology LST-G-M (51.6% and 67.2%, respectively; p < 0.05), and the diameter was larger than that of the adenoma group (33.84 ± 17.99 mm vs 21.68 ± 8.99 mm).

Conclusion

The rectum was the most common site for an LST with a diameter ≥20 mm and cancerization, of which the morphology was mainly LST-G-M (endoscopic submucosal dissection is the preferred treatment for this type of LST). LST malignancy was found to be correlated with lesion diameter, location, and morphological appearance.

Application value of pre-cutting endoscopic mucosal resection in treatment of colorectal laterally spreading tumors

BACKGROUND

Endoscopic mucosal resection (EMR) with precutting (Pre-cut-EMR) is an improvement on the basis of EMR, which combines the technical advantages of EMR and endoscopic submucosal dissection (ESD) to form a new endoscopic resection method and is more and more widely used in clinical practice. This study preliminarily explored the clinical value of Pre-cut-EMR in the treatment of colorectal laterally spreading tumors (LSTs) through retrospective analysis.

AIM

To explore the application value of Pre-cut-EMR in the treatment of colorectal LSTs.

METHODS

A total of 84 patients with colorectal LSTs who were treated at our department from January 2016 to December 2019 were selected as the research subjects. The clinical data of all patients were retrospectively analyzed to summarize the clinical characteristics of colorectal LSTs. All patients underwent Pre-cut-EMR, and the average operation time, overall resection rate, complete resection rate, and the incidence of complications were recorded. Colonoscopy was performed at 3, 6, and 12 mo after the operation to evaluate the recurrence. The relevant literature on ESD treatment of colorectal LSTs was retrieved through China HowNet and Wanfang Database, and the pre-cut-EMR group and ESD group were compared for the curative effect on colorectal LSTs.

RESULTS

The average diameter of colorectal LSTs in the 84 cases was 25.6 mm. The endoscopic morphological classification was mainly granular. According to Kudo pit classification, types Ⅲ and Ⅳ were common, with type ⅢL being the most common. Tubular adenoma and villous adenoma were common pathological types. All 84 patients with colorectal LSTs underwent endoscopic resection successfully. One of them converted to ESD and one to EPMR. The pre-cut-EMR resection rate was 97.6%, and the average operation time was 24.5 min. There were three cases with positive basal margins, and the complete resection rate was 96.4%. Two cases of bleeding and one case of perforation occurred during the operation, and the complication rate was 3.6%. None of the 78 patients who were followed had recurrence, and the recurrence rate was 0%. Compared with the research data obtained by Xu et al, Yu et al, and Qiuhai et al, the operation time of the Pre-cut-EMR group was significantly lower than that of the ESD group (χ² = 21.037, P = 0.001), but there was no statistical difference in the overall resection rate, complication rate, complete resection rate, or recurrence rate compared with the ESD group (P > 0.05).

CONCLUSION

Pre-cut-EMR is effective and safe for colorectal LST treatment, and has high clinical value. This surgical method deserves to be widely promoted due to its simplicity, being easy to learn, and low equipment requirements.

Blue laser imaging combined with JNET (Japan NBI Expert Team) classification for pathological prediction of colorectal laterally spreading tumors

BACKGROUND

Blue laser imaging (BLI) can provide useful information on colorectal laterally spreading tumors (LSTs) by visualizing the surface and vessel patterns in detail. The present research aimed to evaluate the diagnostic performance of BLI-combined JNET (Japan NBI Expert Team) classification for identifying LSTs.

METHODS

This retrospective, multicenter study included 172 LSTs consisted of 6 hyperplastic polyps/sessile serrated polyps, 94 low-grade dysplasias (LGD), 60 high-grade dysplasias (HGD), 6 superficial submucosal invasive (m-SMs) carcinomas, and 4 deep submucosal invasive carcinomas. The relationship between the JNET classification and the histologic findings of these lesions were then analyzed.

RESULTS

For all LSTs, non-experts and experts had a 79.7% and 90.7% accuracy for Type 2A (P = 0.004), a sensitivity of 94.7% and 96.8% (P = 0.718), and a specificity of 61.5% and 83.3% (P = 0.002) for prediction of LGD, respectively. The results also demonstrated 80.8% and 91.3% accuracy for Type 2B (P = 0.005), a sensitivity of 65.2% and 83.3% (P = 0.017), and a specificity of 90.6% and 96.2% (P = 0.097) for predicting HGD or m-SMs. For LST-granular (LST-G) lesions, Type 2A in experts had higher specificity (65.6% vs. 83.6%, P = 0.022) and accuracy (81.8% vs. 91.2%, P = 0.022). Type 2B in experts only had higher accuracy (82.5% vs. 92.0%, P = 0.019). However, no significant differences were noted for any comparisons between non-experts and experts for LST-non-granular (LST-NG) lesions.

CONCLUSIONS

BLI combined with JNET classification was an effective method for the precise prediction of pathological diagnosis in patients with LSTs. Diagnostic performance of JNET classification by experts was better than that by non-experts for all examined LST or LST-G lesions when delineating between Type 2A and 2B, but there was no difference for the identification of LST-NG lesions by these two groups.