Morphology Matters: A Critical Reappraisal of the Clinical Relevance of Morphologic Criteria From the 2019 WHO Classification in a Large Colorectal Cancer Cohort Comprising 1004 Cases.

The 2019 World Health Organization (WHO) classification of colorectal carcinoma (CRC) profoundly reclassified CRC subtypes and introduces tumor budding as a second major grading criterion, while condensing conventional grade into a 2-tiered system. So far it remains largely unexplored how these parameters interact with each other and whether they truly have an independent impact on patient prognosis. We reclassified a large single-center cohort of 1004 CRCs spanning 2 decades for adjusted WHO grade (low vs. high), tumor budding (Bd1/Bd2/Bd3), and CRC subtype (adenocarcinoma not otherwise specified, micropapillary, mucinous, serrated, medullary, adenoma-like, signet-ring cell, mixed adenoneuroendocrine carcinoma/neuroendocrine carcinoma, undifferentiated) according to the criteria of the 2019 WHO classification. We investigated the interaction of these parameters, their connection to stage/microsatellite status, and their significance for patient survival in the different subgroups. Specific subtypes other than adenocarcinoma not otherwise specified represented one third of all CRCs and were unevenly distributed throughout stage and microsatellite subgroups. Subtypes, WHO grade and tumor budding profoundly impacted all survival parameters (P<0.001 for all analyses), with CRC subtypes and tumor budding-but not WHO grade-being stage-independent prognosticators for all survival comparisons. WHO grade had very limited prognostic value in CRC subtypes, while tumor budding retained its strong prognostic impact in most scenarios. Accurate delineation of CRC subtypes introduced in the 2019 WHO classification provides strong stage-independent prognostic information, arguing that they should be considered in pathology reports and in clinical trials. Of the morphology-based grading schemes included in the 2019 WHO, tumor budding outperforms WHO grade.

Cellular Dissociation Grading Based on the Parameters Tumor Budding and Cell Nest Size in Pretherapeutic Biopsy Specimens Allows for Prognostic Patient Stratification in Esophageal Squamous Cell Carcinoma Independent From Clinical Staging.

Initial treatment planning in esophageal squamous cell carcinoma mainly relies on clinical staging. Recently, a highly prognostic grading system based on the cellular dissociation parameters Tumor Budding and Cell Nest Size has been proposed for resected esophageal squamous cell carcinoma. To probe for the transferability and relevance of this established novel grading system in the pretreatment setting, we evaluated Tumor Budding/Cell Nest Size in pretherapeutic biopsies of either primarily resected (cohort 1, n=80) or neoadjuvantly treated (cohort 2, n=75) esophageal squamous cell carcinoma. Grading data were correlated with clinicopathologic and survival parameters. High Tumor Budding Activity and small Cell Nest Size in pretherapeutic biopsies were strongly associated with shortened overall survival, disease-free survival, and disease-specific survival in both cohorts. A modified histopathologic grading system incorporating both factors termed "Cellular Dissociation Grade" showed excellent prognostic demarcation between well (G1), moderately (G2), and poorly differentiated (G3) carcinomas in both scenarios (overall survival: cohort 1: P<0.001; cohort 2: P=0.009) and was predictive for a high pathologic tumor stage and the presence of nodal metastases in primarily resected patients. Multivariate analyses revealed the Cellular Dissociation Grade to be a predictor of poor outcome in the pretherapeutic setting independent of clinical stage (overall survival, disease-free survival, and disease-specific survival: P<0.001). Hazard ratio for disease-free survival was 3.19 for G2 and 5.66 for G3 carcinomas compared with G1 neoplasms. Our data not only prove the transferability of histopathologic grading based on Tumor Budding/Cell Nest Size to biopsy specimens in esophageal squamous cell carcinoma, but also demonstrate that the Cellular Dissociation Grade is a strong outcome predictor in this entity even in the pretreatment scenario. Therefore, we believe that this novel type of grading has the ability to serve as a powerful histology-based pretherapeutic biomarker, that might supplement clinical staging for choosing the most suitable therapy decision.

Tumor Budding and Cell Nest Size Are Highly Prognostic in Laryngeal and Hypopharyngeal Squamous Cell Carcinoma: Further Evidence for a Unified Histopathologic Grading System for Squamous Cell Carcinomas of the Upper Aerodigestive Tract.

Squamous cell carcinoma (SCC) is the most common cancer of the head and neck region including-among others-laryngeal (LSCC) and hypopharyngeal (HSCC) subsites. LSCC/HSCC are heterogenous diseases with respect to patient outcome. Currently, tumor stage-based patient stratification is essential to predict prognosis and thus selection of the appropriate treatment modalities. In contrast, the prognostic impact of the current HSCC/LSCC grading system according to the WHO classification is limited. Recently, a novel grading system based on tumor budding activity (BA) and cell nest size (CNS) has been introduced for SCC in different anatomic regions of the upper aerodigestive tract. To test and transvalidate this grading scheme in LSCC and HSCC, we retrospectively correlated BA, CNS, and additional histomorphologic parameters with clinicopathologic data of 157 treatment-naive patients. In doing so, we demonstrate that a 3-tiered novel grading system (well-differentiated [nG1], intermediately [nG2], and poorly differentiated [nG3]) based on a sum score for BA and CNS is highly and independently prognostic for patient survival in LSCC/HSCC, strongly outperforming the current WHO grading scheme with a hazard ratio for disease-specific survival of 6.6 for nG2 and 13.4 for nG3 cases (P<0.001). This finding contributes to a growing body of evidence that a CNS and BA-based pan-entity grading system in SCC might be useful and seems to capture differences in underlying SCC biology crucial for survival.