ASCRS Ch41 - Endometriosis

Chapter 41, "Endometriosis," ASCRS Textbook of Colon and Rectal Surgery, 4th edition. Authors: Horace Chua and Michael J. Snyder. Book pp. 715–728 (title page through References).

Textbook reference chapter (not primary literature), Part IV/benign-and-miscellaneous material. Primarily a gynecologic-disease chapter — epidemiology, etiology theories, diagnosis, and staging systems are gynecology-focused throughout — but colorectal surgeons are frequently involved via combined procedures when disease infiltrates the bowel, and the Surgical Management section covers bowel-resection technique in detail. Given the chapter's center of gravity sits outside this wiki's colorectal-surgery core, ingestion here is a lighter-touch structural summary rather than full reconciliation: only the colorectal-relevant subset (diagnosis modalities a CRS surgeon would use, and surgical management of bowel-involving disease) backs a new page, Colorectal Endometriosis; the gynecologic epidemiology/staging/oncology/medical-management material is summarized here for reference but not elaborated onto a dedicated wiki page.

Structure

• Introduction/Epidemiology: definition (ectopic endometrial glands/stroma outside the uterus); affects ~10% of reproductive-age women; delayed diagnosis (often years from symptom onset).
• Etiology: two leading theories — Sampson's retrograde menstruation theory vs. coelomic metaplasia; genetic and immune-dysregulation contributing factors; theories not mutually exclusive.
• Clinical Manifestations: dysmenorrhea, dyspareunia, chronic pelvic pain, infertility; bowel-specific symptoms (dyschezia, cyclical rectal bleeding, constipation, tenesmus) when disease infiltrates the rectosigmoid — the colorectal-relevant presentation.
• Diagnosis: Table 41.1 biomarkers (CA-125 poorly sensitive/specific); imaging — transvaginal ultrasound (TVUS, first-line), pelvic MRI, rectal endoscopic ultrasound for bowel-wall-layer involvement depth; the "negative sliding sign" on TVUS as a marker of pouch-of-Douglas obliteration/rectal adhesion; colonoscopy has a limited diagnostic role (mucosa often spared even with transmural disease — lesions are typically extrinsic/submucosal).
• Classification: r-ASRM staging (Fig 41.4, the traditional 4-stage system, poorly predictive of pain/fertility outcomes); ENZIAN classification (Fig 41.5, purpose-built for deep infiltrating endometriosis (DIE), compartmentalizes rectovaginal septum/uterosacral/bladder/bowel involvement); Endometriosis Fertility Index (Fig 41.6, prognostic for post-surgical fertility).
• Endometriosis and Cancer: association with clear cell (CCOC) and endometrioid (EOC) ovarian cancer subtypes; elevated but still low absolute risk ratios; malignant transformation of DIE lesions themselves is rare.
• Treatment — Medical Management: Table 41.2 pathophysiology rationale (estrogen-dependence); Table 41.3 agents — NSAIDs (symptom control only), combined OCPs (first-line hormonal suppression), GnRH agonists (with add-back therapy for bone-density protection), progestins, aromatase inhibitors (refractory disease). Medical therapy does not address mechanical bowel obstruction from DIE.
• Treatment — Surgical Management: laparoscopic approach standard; technique selection by lesion size/depth/location — shaving (superficial disease, lowest complication rate), disc excision (focal full-thickness disease <3cm), segmental resection (larger/circumferential/multifocal disease, or stenotic lesions); complication rates 2.9–25% depending on DIE extent and whether bowel resection performed (anastomotic leak, stricture, fistula, voiding dysfunction); Kuhn/KFSP-type sexual-function comparison data across the three techniques; colorectal anastomotic stenosis management post-resection (endoscopic dilation first-line, redo surgery for refractory cases).
• Recurrence After Surgery: Table 41.4 risk factors (young age at surgery, incomplete excision, higher r-ASRM stage); recurrence range 6–67% depending on definition/follow-up duration/technique.
• Conclusion/References: chapter closes with an emphasis on multidisciplinary (gynecology–colorectal) management for bowel-involving disease.

Open items / gaps

• Gynecologic-specific content (etiology theories, r-ASRM/ENZIAN/EFI staging detail, medical therapy agents, ovarian cancer association) is summarized above at the textbook level only and is out of scope for further wiki elaboration absent a colorectal-specific angle.
• The complication-rate range (2.9–25%) and recurrence range (6–67%) are wide, textbook-level syntheses without primary-study breakdown — see Colorectal Endometriosis's Open items.
• Chapter 42 ("Benign Colorectal Disease Trauma of the Colon and Rectum," Askari R, Salim A, Martin M) begins next — reading in progress as of this entry.