Optimal processing of ESD specimens to avoid pathological artifacts

Clinical outcomes of colorectal neoplasm with positive resection margin after endoscopic submucosal dissection

A positive resection margin after colorectal endoscopic submucosal dissection (ESD) is associated with an increased risk of recurrence. We aimed to identify the clinical significance of positive resection margins in colorectal neoplasms after ESD. We reviewed 632 patients who had en bloc colorectal ESD at two hospitals between 2015 and 2020. The recurrence rates and presence of residual tumor after surgery were evaluated. The rate of additional surgery after ESD and recurrence rate were significantly higher in patients with incomplete resection (n = 75) compared to patients with complete resection (n = 557). When focusing solely on non-invasive lesions, no significant differences in recurrence rates were observed between the groups with complete and incomplete resection (0.2% vs. 1.9%, p = 0.057). Among 84 patients with submucosal invasive carcinoma, 39 patients underwent additional surgery due to non-curative resection. Positive vertical margin and lymphovascular invasion were associated with residual tumor. Lymphovascular invasion was associated with lymph node metastasis. However, no residual tumor nor lymph node metastases were found in patients with only one unfavorable histological factor. In conclusion, a positive resection margin in non-invasive colorectal lesions, did not significantly impact the recurrence rate. Also, in T1 colorectal cancer with a positive vertical resection margin, salvage surgery can be considered in selected patients with additional risk factors.

Comparison of two pathological processing methods for large endoscopic submucosal dissection (ESD) specimens

AIMS

Accurate histopathological evaluation of the endoscopic submucosal dissection (ESD) specimens is essential for clinicians to guide further triage and management. This study aimed to report a novel processing technique for large ESD (≥4 cm) specimens.

METHODS

92 patients with colorectal neoplasms who had undergone ESD were included. 46 ESD specimens were treated with conventional handling process, while the rest 46 cases were given the optimised method. Macrobiocassettes and L-shaped embedding moulds were applied in the optimised method. We evaluated the efficacy of this improved procedure in terms of the number of paraffin blocks, storage space and time consumption of pathological assessment.

RESULTS

The average diameter of ESD specimens was 4.5±0.4 cm and 4.7±0.5 cm in the control and test group (p=0.023), respectively. In control group, 398 paraffin blocks of 46 cases were obtained. With the same cases number and larger lesion size, only 276 blocks were achieved in test group (p<0.001). As for the storage space, the total volume of paraffin blocks and slides (4554.0 cm3 and 1207.5 cm3) of optimised method was significantly reduced compared with the control group (6208.8 cm3 and 1741.3 cm3) (p=0.001, p<0.001). In addition, the optimised method was superior to the conventional one in shortening time consumption of pathological assessment (164.5 min and 269.0 min, p<0.001).

CONCLUSIONS

The optimised technique not only reduced the workload and storage space, but also facilitated accurate pathological assessment.

Low risk of local recurrence after a successful en bloc endoscopic submucosal dissection for noninvasive colorectal lesions with positive horizontal resection margins (R-ESD study)

BACKGROUND : During endoscopic submucosal dissection (ESD), the normal mucosa is cut under constant optical control. We studied whether a positive horizontal resection margin after a complete en bloc ESD predicts local recurrence.

METHODS

 In this European multicenter cohort study, patients with a complete en bloc colorectal ESD were selected from prospective registries. Cases were defined by a horizontal resection margin that was positive or indeterminate for dysplasia (HM1), whereas controls had a free resection margin (HM0). Low risk lesions with submucosal invasion (T1) and margins free of carcinoma were analyzed separately. The main outcome was local recurrence.

RESULTS

 From 928 consecutive ESDs (2011-2020), 354 patients (40 % female; mean age 67 years, median follow-up 23.6 months), with 308 noninvasive lesions and 46 T1 lesions, were included. The recurrence rate for noninvasive lesions was 1/212 (0.5 %; 95 %CI 0.02 %-2.6 %) for HM0 vs. 2/96 (2.1 %; 95 %CI 0.57 %-7.3 %) for HM1. The recurrence rate for T1 lesions was 1/38 (2.6 %; 95 %CI 0.14 %-13.5 %) for HM0 vs. 2/8 (25 %; 95 %CI 7.2 %-59.1 %) for HM1.

CONCLUSION

 A positive horizontal resection margin after an en bloc ESD for noninvasive lesions is associated with a marginal nonsignificant increase in the local recurrence rate, equal to an ESD with clear horizontal margins. This could not be confirmed for T1 lesions.

A mucosal recovery software tool for endoscopic submucosal dissection in early gastric cancer

Background

Due to the limited diagnostic ability, the low detection rate of early gastric cancer (EGC) is a serious health threat. The establishment of the mapping between endoscopic images and pathological images can rapidly improve the diagnostic ability to detect EGC. To expedite the learning process of EGC diagnosis, a mucosal recovery map for the mapping between ESD mucosa specimen and pathological images should be performed in collaboration with endoscopists and pathologists, which is a time-consuming and laborious work.

Methods

20 patients at the Zhejiang Provincial People's Hospital, Affiliated People's Hospital of Hangzhou Medical College from March 2020 to July 2020 were enrolled in this study. We proposed the improved U-Net to obtain WSI-level segmentation results, and the WSI-level results can be mapped to the macroscopic image of the specimen. For the convenient use, a software pipeline named as "Pathology Helper" for integration the workflow of the construction of mucosal recovery maps was developed.

Results

The MIoU and Dice of our model can achieve 0.955 ± 0.0936 and 0.961 ± 0.0874 for WSI-level segmentation, respectively. With the help of "Pathology Helper", we can construct the high-quality mucosal recovery maps to reduce the workload of endoscopists and pathologists.

Conclusion

"Pathology Helper" will accelerate the learning of endoscopists and pathologists, and rapidly improve their abilities to detect EGC. Our work can also improve the detection rate of early gastric cancer, so that more patients with gastric cancer will be treated in a timely manner.

Artificial Intelligence Assisted Topographic Mapping System for Endoscopic Submucosal Dissection Specimens

Background

Endoscopic submucosal dissection (ESD), a minimally invasive surgery used to treat early gastrointestinal malignancies, has been widely embraced around the world. The gross reconstruction of ESD specimens can facilitate a more precise pathological diagnosis and allow endoscopists to explore lesions thoroughly. The traditional method of mapping is time-consuming and inaccurate. We aim to design a topographic mapping system via artificial intelligence to perform the job automatically.

Methods

The topographic mapping system was built using computer vision techniques. We enrolled 23 ESD cases at the Peking Union Medical College Hospital from September to November 2019. The reconstruction maps were created for each case using both the traditional approach and the system.

Results

Using the system, the time saved per case ranges from 34 to 3,336 s. Two approaches revealed no significant variations in the shape, size, or tumor area.

Conclusion

We developed an AI-assisted system that would help pathologists complete the ESD topographic mapping process rapidly and accurately.

Pathologic Evaluation of Large Colorectal Endoscopic Submucosal Dissections: An Analysis of 279 Cases With Emphasis on the Importance of Multidisciplinary Work and Establishing Examination Protocols

Background. Endoscopic submucosal dissections (ESDs) allow removal of large gastrointestinal tumors and help patients avoid major oncologic surgery. In this study, the challenges and development of approaches toward successfully handling ESDs were analyzed in 279 colorectal specimens (114 rectal, 47 left, 118 right colonic; 90% adenoma with/without carcinoma). Methods. Each specimen was processed according to an established protocol including gross photography, mapping, and total submission for histopathologic examination. Results. Mean lesion size was 4.2 cm (range: 0.5-22 cm; 28% ≥5 cm; 6% ≥10 cm). Invasive carcinoma was present in 38 cases (14%), which had a mean overall tumor size of 3.8 cm (range: 1.1-17.5 cm), and mean largest size of the invasive component was 0.93 cm (range: 0.04-3 cm). Fifteen cases were staged as pT1a (submucosal invasion of <1000 µm) and 13 cases as pT1b (submucosal invasion of ≥1000 µm). En-bloc and R0 resection rates were 99.3% and 90.6%, respectively. Conclusion. Various histopathologic challenges were encountered, which were carefully evaluated by dedicated pathologists with familiarity to the subtleties in handling and reporting these specimens. We recommend these specimens to be prepared in the endoscopy suite, submitted to the Pathology Department oriented, pinned, and placed into copious amount of fixative. Total sampling, gross photography, mapping, and proper fixation are crucial components in the histopathologic evaluation. Micromeasurement of invasion depth and substaging per European/Japanese guidelines as well as accurate measurement of the distance from the resection margins are highly recommended. In conclusion, ESD is an adequate method that can be successfully implemented in a tertiary care center to perform en-bloc and margin-free resections of clinically selected large colorectal superficial lesions.