Endoscopic submucosal dissection specimens in early colorectal cancer: lateral margins, macroscopic techniques, and possible pitfalls

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.

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.

Optimal processing of ESD specimens to avoid pathological artifacts

BACKGROUND

En bloc endoscopic submucosal dissection (ESD) has been recently introduced as a treatment for precancerous/neoplastic gastrointestinal conditions. The aim of the present study was histological assessment of en bloc ESD specimens.

METHODS

Fifty-three ESD specimens were positioned over a cellulose acetate support (40 specimens; 12 from the upper gastrointestinal tract and 28 from the lower gastrointestinal tract) or pinned with nails on polystyrene or cork (13 specimens; 7 from the upper gastrointestinal tract and 6 from the lower gastrointestinal tract). We cut consecutive 2 mm-thick sections stained with hematoxylin and eosin. From the first and the last sections, we obtained a second slide, after a 180° rotation and re-embedding. The quality of ESD samples was scored as inadequate, suboptimal and adequate, based on the amount of crushing, shearing and stretching artifacts that were scored from 0 (absent) to 2 (diffuse or maximum). From the sum of these we obtained a global artifact score (GAS).

RESULTS

Removed lesions were: adenocarcinoma (5 cases), neuroendocrine tumor (NET) G1 (1 case), premalignant conditions, including adenomatous polyps (41 cases) and hyperplastic lesions (6 cases). A positive deep surgical margin was found in 8/53 cases (15%): high- and low-grade dysplastic glands were detected in 5 cases, low-grade adenocarcinoma in 2, and NET cells in 1. Dysplastic glands were detected in the lateral surgical margins of 12 ESD specimens (23%). Among the ESD specimens positioned on the cellulose acetate support, apart from the modifications due to electrocoagulation, 2 (5%) showed shearing modifications. In the group of ESD specimens fixed with nails, 5 (38%) showed shearing, 10 (77%) crushing artifacts, 11 (85%) stretching and 11 (85%) multiple holes caused by the nails. On the basis of these data all histological specimens from ESD on cellulose acetate were adequate (GAS 0-1).However, in the group of ESD fixed with nails, 1 was adequate (GAS 0), 11 suboptimal (GAS 2-5) and 1 inadequate (GAS 6).

CONCLUSIONS

Specific devices including cellulose support and adequate sampling blocks can be helpful to perform accurate histological assessment of ESD specimens after en bloc ESD for precancerous/neoplastic gastrointestinal lesions, with complete analysis of the status of the margins and the entirely en bloc evaluation of the lesion.