ASCRS Ch20 — Anal Cancer

Citation: Sands DR, Mahmoud NN. "Anal Cancer." In: Steele SR, et al. (eds.), The ASCRS Textbook of Colon and Rectal Surgery, 4th ed. Springer Nature Switzerland AG; 2022. pp. 357–373 (PDF pp. 363–373 of the combined textbook file, read together with pp. 374–382 which incidentally captured the opening pages of ASCRS Ch21). Source file: raw/ASCRS Textbook 4th Ed.pdf (full 1,198-page textbook; cite by page range within the single PDF). First chapter of Part III ("Malignant Disease"), immediately following ASCRS Ch19's close of Part II ("Anorectal Disease").

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

Scope

Twentieth chapter of the sequential full-textbook ingest (see ASCRS Ch01 - Anatomy and Embryology for the ingest's scope/plan). Covers anal cancer as the chapter title's headline entity (epidemiology, evaluation/AJCC 8th-edition TNM staging, anal anatomy relevant to staging, perianal vs. anal canal SCC as histogenetically distinct entities, chemoradiotherapy as the primary treatment for anal canal SCC — Nigro protocol, ACT I, RTOG 98-11, ACT II — inguinal lymph node metastases, surgery's limited/salvage role, HIV-specific treatment guidance, surveillance) plus the other, much rarer malignancies that occur at the same anatomic site: anal adenocarcinoma, verrucous carcinoma (Buschke-Löwenstein tumor), melanoma, perianal Paget disease, basal cell carcinoma, and gastrointestinal stromal tumor (GIST).

Key content

Filed as a single new comprehensive condition page, Anal Cancer — mirroring the chapter's own organization across all these entities rather than splitting into per-histology pages, matching the pattern already used for Anorectal Sexually Transmitted Infections and Pruritus Ani. Closes three forward references flagged since ASCRS Ch17–19: Colorectal Anatomy & Embryology (anal transition zone anatomy), Anorectal Sexually Transmitted Infections (HPV/HIV background, and specifically reconciles this chapter's Verrucous Carcinoma section with that page's Giant Condyloma/ Buschke-Löwenstein section — same entity, two chapters' framing), and Pruritus Ani (Paget disease/Bowen's disease/cloacogenic carcinoma named there as refractory-pruritus differentials). Also cross-links Anal Intraepithelial Neoplasia (AIN as anal SCC's precursor lesion), Rectal Cancer (anal adenocarcinoma staged/treated similarly), Gastrointestinal Stromal Tumors (GIST) (fuller GIST biology, anal GIST is rare and inherits that page's content), and Colorectal Cancer Staging (TNM) (explicitly distinguished as a different TNM schema — that page covers colon/rectal cancer staging from a different source).

Limitations

• Textbook chapter, not primary literature; cited trial data (Nigro protocol history, ACT I, RTOG 98-11, ACT II) are the chapter authors' synthesis, not independently re-verified against the primary trial publications.
• AJCC 8th-edition TNM staging table (Table 20.4) summarized at a high level on the resulting page, not reproduced digit-for-digit — flagged there as a summary, not a staging-determination replacement.
• The verrucous carcinoma / Buschke-Löwenstein classification controversy (benign-with-invasion- potential vs. SCC variant) is explicitly reported by the chapter as unresolved, and the malignant- transformation-rate figures given here (40–60%) are not fully reconciled against Ch18's figure (up to 56%) — both reported as their respective sources state them.
• This 20-page Read call ended mid-chapter into ASCRS Ch21 ("Presacral Tumors," Kelley & Dozois, book p. 375+) since Ch20 concluded before the per-call page cap — Ch21's opening content (Introduction, Anatomic Considerations, Clinical Presentations, Physical Examination, Imaging Studies, start of Preoperative Biopsy) was incidentally captured but is not reflected on any wiki page yet; it will be re-read as part of Ch21's own ingest.

Relevance

Twentieth entry in the ASCRS ingest, and the first chapter of Part III ("Malignant Disease"). Adds one new comprehensive condition page and closes three previously-flagged forward references. Chapter 21, "Presacral Tumors," is next.