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5 slides generated from the cancer page, with a quiz from the open benchmark and speaker notes that cite the sources. Arrow keys move between slides; Print gives one slide per page.
Serrated adenocarcinoma is a form of bowel cancer that grows out of sessile serrated polyps rather than ordinary adenomas, keeping their saw-tooth pattern. Most cases carry a KRAS or BRAF mutation and the BRAF-mutant ones are often mismatch-repair deficient. It is treated like other bowel cancer, with the BRAF and mismatch repair results guiding drugs when it has spread.
The WHO classification recognises serrated adenocarcinoma as a colorectal adenocarcinoma type with serrated glands, eosinophilic cytoplasm and vesicular nuclei, arising through the serrated pathway of sessile serrated lesions and traditional serrated adenomas (Nagtegaal 2020). In 42 serrated adenocarcinomas, KRAS and BRAF mutations were present in 45 and 33 percent against 27 and 0 percent of non-serrated carcinomas; BRAF mutation was specific for serrated adenocarcinoma and marked a subset with gene methylation and a tendency to microsatellite instability, while the high KRAS rate suggests many KRAS-mutant colorectal cancers arise from serrated precursors (Histopathology 2011). In 89 cases KRAS mutation (42.7 percent) was more prevalent than BRAF (25.8 percent), MGMT loss was more frequent than in conventional carcinoma (50.6 against 25.3 percent), and most serrated adenocarcinomas were microsatellite stable, differing from sporadic MSI-high carcinomas (International Journal of Cancer 2012).
How it differs from its parent: its precursor is the sessile serrated lesion rather than the adenoma, so it is the histology behind the right-sided BRAF-mutant and CpG island methylator cancers on the colorectal and BRAF pages, and its KRAS-mutant, microsatellite-stable majority has a worse outlook than the MSI-high minority.
| Setting | Approach | Guideline |
|---|---|---|
| All stages | Treated as the colorectal page by stage and molecular status: encorafenib with cetuximab for BRAF V600E metastatic disease, checkpoint inhibitors for MSI-high disease. | not mapped |