WHO criteria called three times as many colorectal cancers high grade as AJCC — with similar agreement between pathologists

The edition in brief

Today's pathology edition leads on colorectal cancer grading. In a Histopathology study, five gastrointestinal pathologists graded 100 scanned colorectal adenocarcinomas under WHO 5th edition, WHO 6th edition and two-tier AJCC 8th edition criteria. Agreement was substantial under all three (Fleiss kappa 0.730 for WHO6, 0.731 for AJCC8, 0.655 for WHO5), but WHO criteria labelled an average of about 34 tumours high grade against about 12 under AJCC. The 6th edition WHO classification of soft tissue and bone tumours adds 19 new entities, replaces 'variant' with 'morphological pattern' and refines essential and desirable criteria for different resource settings. A Japanese single-centre review of 371 requests for a commercial comprehensive genomic profiling assay found 14.0% cancelled before submission and 13.8% of returned results only qualified; low tumour content was the only independent predictor of failure, and in qualified cases tumour mutational burden was assessable in 31.7% and microsatellite instability in 19.5%. A multicohort H&E-based score (TIGERS) for resected pancreatic ductal adenocarcinoma added modest prognostic information to clinicopathological models. A BMJ stepped-wedge trial of 2267 Barrett's surveillance patients found acetic acid chromoendoscopy did not raise the neoplasia detection rate (7.4% vs 7.1%). The pearl covers recording tumour content before molecular testing.