Pathology reports after endoscopic submucosal dissection (ESD) should function as risk-assessment tools rather than simply documenting whether cancer was present and whether margins were negative, according to international consensus standards published in Gut. An international panel of 42 experts from 15 countries developed 56 recommendations across seven domains, from submucosal invasion depth to clinical evaluation.
In an interview with GI & Hepatology News, corresponding author Robert Bechara, HonBSc, MD, FRCPC, and coauthors Kareem Khalaf, MD, HBSc, and Huaqi Li, MD, MPH, of the Division of Gastroenterology at St. Michael’s Hospital, University of Toronto, said the key takeaway is that post-ESD pathology reports should function as structured risk-assessment tools.
The authors wrote that the recommendations are intended to make reports more consistent across centers and easier to use in postresection care decisions. ESD allows en bloc resection of early gastrointestinal cancers and provides specimens for detailed pathologic assessment. However, reporting remains variable for key parameters, the authors wrote, that determine curative resection and the need for additional treatment, including submucosal invasion depth and breadth, margin status, lymphovascular invasion, tumor budding, differentiation, histologic subtype, and use of ancillary stains.
“Our consensus paper provides a practical framework for consistently reporting histopathologic features that influence the risk of residual disease and lymph node metastasis,” Dr. Bechara and colleagues said. “For clinicians, having these parameters reported with consistent definitions should facilitate clinical decisions regarding curative status post-ESD and identify patients requiring surveillance, further endoscopic treatment, or surgical evaluation.”
The international panel included 42 experts from 15 countries, including 28 gastrointestinal pathologists and 14 therapeutic endoscopists. Using a modified Delphi process, the group developed 56 recommendations across seven domains: submucosal invasion depth, submucosal invasion breadth, margin evaluation, staining methods, measurement protocols, risk assessment for lymph-node metastasis and tumor budding, and clinical evaluation.
Small reporting differences can affect care
Seemingly small differences in how invasion depth or margins are measured and described can change how a case is classified and managed, Dr. Bechara and his coauthors said.
For example, the consensus recommends using Sm1–Sm3 subclassification only when the muscularis propria is present. Otherwise, submucosal invasion depth should be reported quantitatively in micrometers, rounded to the nearest 100 μm. Submucosal invasion breadth should be reported in millimeters as an adjunct metric, while multifocal or discontinuous invasion should be described separately rather than converted into an unvalidated three-dimensional estimate.
“This can help resolve any ambiguity when interpreting post-ESD pathology reports and clarify subsequent clinical decision making,” they explained.
The panel recommended defining margin positivity as direct tumor contact with the inked surface, and said reliable interpretation depends on immediate pinning, clear orientation, appropriate inking, complete embedding, and systematic parallel sectioning.
The panel also recommended hematoxylin and eosin (H&E) as the baseline stain, with ancillary immunohistochemistry or elastic stains used selectively when routine assessment is equivocal, such as in cases involving possible lymphovascular invasion, distorted architecture, unclear muscularis mucosae integrity, uncertain invasion depth, or difficult margin interpretation. Tumor budding should be reported according to International Tumor Budding Consensus Conference criteria.
Additionally, the authors emphasized that clinicians should not interpret any single pathologic feature in isolation.
“Depth of invasion remains relevant, but it should be considered alongside breadth of invasion, lymphovascular invasion, tumor budding, differentiation, histological subtype, margin status, and patient-specific factors,” said Dr. Bechara and colleagues. “The broader goal is to move from single-parameter decision-making toward a reproducible, composite assessment of oncologic risk in this patient population.”
Shared reporting may support post-ESD treatment decisions
“A standardized pathology report gives the endoscopist, pathologist, surgeon, and oncologist a common language for discussing whether the resection was curative and what should happen next to provide the best care for our patients,” they said.
They added that standardization should reduce situations in which the same histopathologic findings are interpreted differently across centers.
According to the researchers, management should remain risk-based. For example, an otherwise curative resection with a positive lateral margin limited to noninvasive neoplasia may be appropriate for repeat endoscopic treatment or close surveillance. By contrast, a positive deep margin in a T1b or otherwise high-risk lesion should generally prompt staging and multidisciplinary discussion about additional treatment, including surgery.
A close but negative margin also should not automatically be treated as equivalent to a positive margin, Dr. Bechara and colleagues said. Instead, it should be interpreted together with the complete pathologic findings, lesion biology, procedural factors, and the individual patient’s surgical candidacy and preferences.
Implementation requires coordination
The authors cautioned that the recommendations come from a Delphi consensus study and represent expert agreement, rather than prospective validation of every recommendation. Organ-specific criteria and established thresholds still need to be applied.
The authors wrote implementation also requires coordination across the full ESD pathway, beginning in the endoscopy unit.
“Accurate histopathologic reporting begins with gastroenterologists in the endoscopy unit, with immediate pinning and orientation of the specimen, and continues afterwards through our pathologist colleagues, with appropriate inking, complete embedding, systematic sectioning, and standardized interpretation,” the investigators said.
Institutions may need multidisciplinary protocols and training, synoptic templates, and periodic quality review, the authors said. Ancillary stains, for example, should be used selectively when routine H&E assessment is equivocal, rather than automatically in every specimen.
“Submucosal invasion breadth is a promising adjunct measure, but its incremental prognostic value requires further study, and it should not yet be used as an independent indication for surgery,” said Dr. Bechara and colleagues.
The authors identified future priorities, including prospective multicenter validation of the standards, evaluation of their reproducibility and clinical impact, incorporation of standardized data into registries and risk-prediction models, and validation of digital and artificial intelligence–assisted pathology tools to improve measurement consistency.
Dr. Bechara, Dr. Khalaf, and Dr. Li reported no relevant financial disclosures. Several coauthors reported consulting, speaking, honoraria, research, training, and/or other relationships with industry. The study received no specific funding.