ASCRS Ch22 — Sporadic and Inherited Colorectal Cancer: How Epidemiology and Molecular Biology Guide Screening and Treatment

Citation: Glasgow SC, Hardiman KM. "Sporadic and Inherited Colorectal Cancer: How Epidemiology and Molecular Biology Guide Screening and Treatment." In: Steele SR, et al. (eds.), The ASCRS Textbook of Colon and Rectal Surgery, 4th ed. Springer Nature Switzerland AG; 2022. pp. 397–412 (PDF pp. 402–417 of the combined textbook file — captured across two Read calls, PDF pp. 394–413 and PDF pp. 414–433; the second call's tail incidentally captured all of ASCRS Ch23, "Management of Malignant Polyps," which is documented separately). Source file: raw/ASCRS Textbook 4th Ed.pdf (full 1,198-page textbook; cite by page range within the single PDF). Third chapter of Part III ("Malignant Disease").

Type: Specialty textbook chapter (reference/background, not primary literature).

Scope

Twenty-second chapter of the sequential full-textbook ingest (see ASCRS Ch01 - Anatomy and Embryology for the ingest's scope/plan). Covers sporadic CRC (epidemiology, risk factors, molecular biology — CIN/CIMP/MSI pathways, driver mutations, chromosomal/epigenetic alterations, consensus molecular subtypes CMS1–4, right-vs-left CRC biology and treatment response, screening/ treatment) and young-onset CRC (epidemiology, management, genetics); and inherited CRC — Lynch syndrome (genetics, diagnosis/testing models, variants — Turcot, Muir-Torre, familial CRC X — screening, surgical and medical treatment including immunotherapy), POLE/POLD1-related hereditary cancer (PPAP), familial adenomatous polyposis (genetics, extracolonic manifestations, screening, genotype-guided surgical decision-making), MUTYH-associated polyposis, serrated polyposis syndrome, and the hamartomatous polyposis syndromes (juvenile polyposis, Peutz-Jeghers syndrome, Cowden syndrome).

Key content

This chapter substantially overlaps several already-ingested pages sourced from an earlier Sabiston chapter (Hereditary Colorectal Cancer Syndromes, Lynch Syndrome, Familial Adenomatous Polyposis (FAP), Hamartomatous Polyposis Syndromes), so — per the wiki's established practice of extending/enriching rather than duplicating — this chapter's content was reconciled into those existing pages rather than creating new duplicate ones: Lynch Syndrome gained diagnosis/testing-model detail (PREMM5/MMRpro, universal screening, next-gen sequencing alternative, BRAF V600E discriminator), full Lynch syndrome variant coverage (Turcot, Muir-Torre, familial CRC X), aspirin chemoprevention (CAPP2 trial), extended-vs-limited-colectomy outcome data, and a new Medical treatment section (immunotherapy for MSI-H tumors); Familial Adenomatous Polyposis (FAP) gained genotype-guided IPAA-vs-IRA decision-making and quality-of-life/fecundity data; Hamartomatous Polyposis Syndromes gained a new Cowden syndrome section and a PJS mTOR-inhibitor chemoprevention note; Hereditary Colorectal Cancer Syndromes gained a new POLE/POLD1-related hereditary cancer (PPAP) section and an updated syndromes-at-a-glance table. Two genuinely new topics were also created: Sporadic & Young-Onset Colorectal Cancer (a new page — epidemiology, risk factors, right-vs-left biology, screening/treatment, YO-CRC), and a new Serrated polyposis syndrome subsection on Colorectal Polyps. Colorectal Cancer Molecular Pathways was extended with a new Clinically relevant mutations (RAS/BRAF) section and CMS right-vs-left distribution detail.

Limitations

• Textbook chapter, not primary literature; extensive cited data (Vieira dietary meta-analysis, CAPP2 aspirin RCT, Lieu YO-CRC mutation-rate study, Kalady/Parry/Natarajan/Haanstra Lynch-surgery series, Church/Gunther/Lovegrove FAP-surgery series) are the chapter authors' synthesis, not independently re-verified against primary publications.
• The ACS-vs-NCCN screening-age discrepancy (45 vs. 50 for average-risk screening) is reported exactly as the chapter frames it — an active, unresolved guideline conflict.
• PPAP's precise CRC lifetime risk is not quantified by the chapter — reported as not-well- quantified rather than estimated.

Relevance

Twenty-second entry in the ASCRS ingest, third chapter of Part III ("Malignant Disease"). Unlike most prior chapters, this one's primary work was reconciliation — enriching four existing pages with substantial new detail rather than creating standalone new pages, plus two genuinely new additions (a new page and a new subsection). A useful demonstration that the wiki's de-duplication discipline scales to a chapter with heavy pre-existing overlap. Chapter 23, "Management of Malignant Polyps," was incidentally captured in full during this chapter's second Read call and is documented separately.