Colon, Rectum, Anal Canal Flashcards
Diverticulitis pathophys
- Diverticulosis = mucosal herniations protruding through intestinal layers and smooth muscle along with natural weakness in muscularis mucosa created by nutrient vessels in wall of the colon. These pouches are lined by mucosa and serosa only
- The condition appears to be associated with low fiber diet, constipation, and obesity
- Diverticula can appear anywhere along GI tract, but mostly in colon and most commonly in sigmoid colon where intraluminal pressures are highest
- Diverticulitis is inflammation of the diverticula. Obstruction of neck of diverticula can result in stasis of intralminal fecal material causing bacterial overgrowth and infection. This can cause:
1) Micro/macro perf (may be walled off by pericoloc fat/mesentery)
2) Abscess (and possible rupture leading to peritonitis)
3) Fistula to adjacent organs or skin (most common in men is colovesicular)
4) Recurrent attacks can yeild scar tissue and narrowing/obstructing of colon - Abscess can be peritoneal or retroperitoneal depending on segment of colon (posterior ascending and descending colon are retroperitoneal)
Prevalence of diverticulitis
Diverticulosis: 5% before age 40
65% before age 85. Usually asymptomatic
15-25% of those with diverticulosis get diverticulitis
- Of these, 75% have just colicky pain and 25% require surgery
20% of patients with diverticulitis are younger than 50
Anatomic prevalence:
- 70% L side of colon
- 75% R sided in Asians
Diverticulitis morbidity/mortality
20-35% with conservatively managed diverticulitis experience recurrence
More severe illness in younger patients, immunocompromised, significant comorbid conditions, and those taking anti-inflammatory meds
Typical history of diverticulitis
1 symptom = LLQ pain
- can mimic many abdominal conditions due to location variability of the diverticula
- Mild disease = localized abdominal pain, colicky pain, change in bowel habits (usually constipation more than diarrhea)
- After perf = fever, anorexia, nausea,vomiting
- If colovesicular fistula = dysuria (90%), pneumaturia (70%), fecaluria (70%)
- Bleeding more common in simple diverticulosis NOT diverticulitis
Workup for diverticulitis
H&P usually enough
Look for leukocytosis with L shift
If ambiguous, do CT
- Pericolic fat stranding (98%)
- Colonic diverticula (84%) - note this is NOT 100%
- Bowel wall thickening (70%)
- Phlegmon or abscess (35%)
Colonoscopy and contrast enema are contraindicated with possible perforation***
Hinchey classification of acute diverticulitis
Stage 1 = Pericolic abscess
Stage 2 = Distant or remote abscess
Stage 3 = Prurulent peritonitis
Stage 4 = Fecal peritonitis
Tx for diverticulitis
Medical Care
- Liquid diet and 7-10d of oral broad-spectrum antibiotics (cipro/metronidazole)
- Long term care = high fiber and low fat diet
Indications for surgery in diverticulitis
1) Free air perforation with fecal peritonitis
2) Suppurative peritonitis secondary to ruptured abscess
3) Abdominal or pelvic absess (unless CT-guided aspiration is possible)
4) Fistula formation
5) Inability to rule out carcinoma
6) Intestinal obstruction
7) Failing medical therapy
8) Immunocompromised
9) Extremes of age
10) Recurrent episodes of acute diverticulitis
What is the surgical approach for diverticulitis?
- If patient has peritoneal signs, consider 2 stage Hartmann
1) Resect inflamed colon, diverting colostomy, and closure of rectal stump
2) Wait 3-6 months for healing of rectal stump before taking down colostomy and making a final primary anastomosis - If preop bowel prep is possible then do a simple resection with primary anastomosis
2 ways to remember some presentations of colorectal cancer
1) “Post-menopausal man with Fe deficiency anemia”
- Cancers on the right generally bleed but don’t obstruct
2) Alternating bowel habits/pencil thin stools
- Cancers on the left generally obstruct but don’t bleed
Prevalence of CRC
3 most diagnosed malignancy and #2 leading cause of cancer death in men and women
Screening for CRC
Start at age 50
Colonoscopy every 5-10 years
OR
double contrast barium enema every 5 years
OR fecal occult blood + flex sig every 5 years
Risk factors for CRC
1) Environment - high fat, low fiber diet and cigarette smoking
2) Crohns and UC
3) Previous colorectal, breast, ovarian, uterine cancer
4) Genetic
- FAP (100% will have cancer by 30s or 40s) so treated with total proctocolectomy. In FAP we also see gastric, duodenal polyps, and periampullary cancers
- Gardners - skull and desmoid tumors
- Turcots - brain tumors
- HNPCC “Lynch” - 80% chance of CRC. Higher risk for endometrial, stomach, and ovarian
Polyps
Benign: hyperplastic, hamartomas, inflammatory. P-J and juvenile polyps unlikely to become malignant
Malignant potential: adenomatous. Tubular, villous (bad), tubulovillous. Pedunculated. Sessile (bad)
Presenting symptoms for CRC
Blood in stool: Melena if in right colon which can be detected by guaiac. Possible hematochezia is very distal.
Anemic symptoms and labs: Tired, dizzy, microcytic anemia
Weight loss
Ddx for heme-positive blood
1) Diverticular disease
2) Colon carcinoma
3) IBD
4) benign polyps
5) vascular ectasia
6) ischemic colitis
7) rectal ulcers
8) hemorrhoids
Lymphatic drainage for CRC
Found in colonic mesentery, mesorectum and para aortic area
Low lying cancer in anal canal can go to deep inguinal nodes and tumors of the anus may spread to superficial inguinal nodes
Staging for CRC
LFTs to check for liver mets
Rectal exams, abdominal/pelvic CT for finding mets
Endorectal US for staging local tumors and finding out depth of invasion
TMN
T1 = submucosa T2 = muscularis propria T3 = Subserosa T4 = other organs
N1 = mets to 1-3 nodes N2 = 4 or more
Stage 1: T1-2 N0 M0 5yr = 90%
Stage 2: T3-4 N0 M0 5yr = 75%
Stage 3: Any T N1-N3 M0 5yr=50%
Stage 4: Any T Any N M1 5yr 5%
Untreated liver mets have median survival of less than 1 year. If treated surgically there’s 30-40% 5 year survival
Surgical tx for CRC
Single lesion - segmental resection with 2cm margin
Synchronous lesion - hemicolectomy or sigmoid colectomy
Role of laproscopy is up in the air
Bowel prep
- mechanical prep (clear liq 24hrs, lyte solution and enema)
- intraluminal antibacterial (neomycin, metronidazole)
- parenteral antibiotics 30mins before incision
Chemo for CRC
Stage 3 patients and some stage 2
6 months 5FU and leucovorin
Radiation for CRC
Stage 2 or 3 rectal cancer
Follow-up for CRC
CEA preOp. Follow it postop to determine recurrence
PET in pts with known recurrent disease to the liver
H&P should be done every 3 months for 2 years then every 6 months for 5 years
CEA q3m x 2yrs then q6m x 5yrs
Colonoscopy 1y postop and 3-5 yrs if negative for polyps
How does the colonoscopy alter follow-up for suspected CRC?
If it finds polyp…get the path
1) benign: Now q5-7yrs (in case you missed one the first time)
2) Carcinoma in situ. Get CT for staging, resect primary, and FOLFOX
- come back for colonoscopy q3-5y
If the scope showed giant fungating mass then get CT for staging, resect primary, and FOLFOX. Scope 1 yr postop and q3-5y after
FOLFOX
FOLinic acid (leucovorin)
F = 5FU
OXaliplatin
Colon embryo
Midgut = up to mid-transverse
Hindgut = rest to prox anus
Ectoderm = distal anus
Dentate line = transition from hindgut to ectoderm
Blood supply to colon
Based on embryo
Midgut = SMA
Hindgt = IMA
Distal anus = internal pudendal branches (branch of internal iliac)
Internal iliac = middle and distal rectum via middle rectal and inferior rectal arteries (branch of internal pudendal)
Widest part of colon
Cecum…narrows progressively after that
Which parts of the colon are retroperitoneal?
Ascending colon, descending colon, posterior hepatic and splenic flexures (all but cecum, transverse and sigmoid)
Watershed areas of colon
Ileocecal area
Junction of descending and sigmoid
Splenic flexure
Lymphatic drainage of colon
Colon, rectum and anus generally follow arterial supply (ileocolic nodes, superior mesenteric nodes, etc)
Anal canal above dentate line = inferior mesenteric node
Lower anal canal = inguinal nodes
Microbio of colon
Colon sterile at birth
Normal flora = 99% anaerobic (Bacteroides)
1% aerobic (E Coli)
IBS
Abnormal state of intestinal motility modified by psychosocial factors for which no anatomic cause can be found
Often a wastebasket diagnosis for a change in bowel habits with ab pain after other causes have been ruled out
Constipation
Diarrhea definition
Passage of > 3 loose stools/day
In hospitalized patient, a workup may be indicated to rule out infectious or ischemic causes
In outpatient, diarrhea may occur due to extensive small bowel resection (short bowl syndrome), due to disruption of innervation, or even as an expected outcome (gastric bypass)
Diagnosis of diarrhea
Stool sample for enteric pathogens and C Dif toxin
Check stool for WBCs (IBD or infectious colitis), RBCs without WBCs (ischemia, invasive infectious diarrhea, cancer)
Treatment of diarrhea
Individualized based on treatable cause, and is addressed with specific problems that may cause it (colitis, ischemia)
Postvagotomy diarrhea
In 20% of patients after truncal vagotomy
Denervation of extrahepatic biliary tree and small bowel leads to rapid transit of unconjugated bile salts into colon
This impedes water absorption and causes diarrhea
Cholestyramine is the tx. If it fails, surgical reversal of a segment of small bowel to prolong transit time and increase absorptive capacity may be needed
Pseudomembranous colitis def
An acute colitis characterized by formation of adherent inflammatory exudate overlying the site of mucosal injury
Most common due to overgrowth of C Dif (gram positive, anaerobic, spore-forming bacilis)
Typically occurs after broad spectrum antibiotics (esp clinda, ampicillin, cephalosporin) kill normal intestinal flora
Signs of Pseudomem colitis
Vary from self-limited diarrhea to invasive colitis with megacolon or perforation as complications
Dx of of pseudomem colitis
Detection of c dif toxin in stool; proctoscopy or colonoscopy if dx uncertain
Tx of pseydomem colitis
Stop offending antibiotic
Give flagyl or vanc PO (if patient can’t tolerate PO give IV metronidazole)
Put patient on contact iso
High rate of recurrence (20%) despite high response rate to treatment
Radiation-induced colitis
Associated with XRT to pelvis usually for endometrial, cervical, prostate, bladder or rectal cancer
Risk = atherosclerosis, diabetes, HTN, old age, adhesions from previous surgery
Chance of getting it is dose-dependent:
6,000 = Most
Signs of radiation induced colitis
Early (during course of XRT): n/v, cramps, diarrhea, tenesmus, rectal bleeding
Late (weeks to years after): tenesmus, bleeding, abscess, fistula involving rectum (rectal pain, stool per vagina)
Dx of radiation-induced colitis
Early = Plain abdominal film, barium enema
Late = Barium enema, CT
Cause of radiation-induced colitis
Early = mucosal edema, hyperemia, acute ulceration
Late = submucosal arteriolar vasculitis, microvascular thrombosis, wall thickening, mucosal ulcerations, strictures, perforation
Tx of radiation-induced colitis
Early = treat symptoms
if no improvement, decrease dose of XRT or D/C treatment
Late = treat with stool softener, topical 5-ASA, corticosteroid enema
- strictures = gentle dilation or diverting colostomy after excluding cancer
- Rectovaginal fistual = prox colostomy and low colorectal anastomosis or coloanal temporary colostomy
ischemic colitis definition
Acute or chronic intestinal ischemia secondary to decreased intestinal perfusion or thromboembolism
Embolus or thrombus of IMA
Poor perfusion of mucosal vessels from arteriole shunting or spasm
Often affects the splenic flexure
Ischemic colitis incidence and risk factors
Most common in elderly
Risk:
1) Old age
2) s/p AAA repair (early postop)
3) HTN
4) CAD, AFib
5) Cocaine abuse
6) Prothrombotic conditions
7) Sickle cell anemia
Most common setting for ischemic colitis is early postop period following AAA repair when impaired blood flow through IMA may put colon at risk
Signs of ischemic colitis
Mild lower abdominal pain and rectal bleeding, classically after AAA repair
Pain more insidious in onsert than small bowel ischemia
Diagnosis of ischemic colitis
Clinical Hx
Plain abdominal XR - may reveal pneumatosis (air in bowel wall) or thumbprinting (submucosal edema)
CT - may show segmental thickening of bowel wall
Colonoscopy may show pale mucosa with petechial bleeding
Tx of ischemia colitis
If mild = IVF and observe
If mod (fever and high WBC) = IV Abx
Severe (peritoneal signs) = exlap with colostomy
Ulcerative colitis def
Inflammation confined to mucosal layer of colon that extends from rectum proximally in continuous fashion. Autoimmune
Incidence of UC
Age btw 15-40 and 50-80 (bimodal)
Whites 4x > blacks
Industrialized»_space; developing nations
Risks for UC
1) Jewish
2) White
3) Urban dwelling
4) Positive FHx
5) Nicotine LOWERS risk (unlike Crohn’s)
Signs of UC
Mild (confined to rectum or rectosigmoid): intermittent rectal bleeding, passage of mucus from rectum, mild diarrhea
Mod: Freq loose, bloody stools. Mild abdominal pain, low-grade fever
Severe: Freq loose stools, severe abdominal pain, bleeding necessitates blood transfusion. Patients may have rapid weight loss
Dx of UC
Flex Sig with histolopathologic eval of biopsies
Barium enema: “Lead Pipe” appearance of colon due to loss of haustral folds, but no longer test of choice
Treatment of UC
Medical: Similar to Crohn’s
1) Mild/Mod = 5-ASA, corticosteroids PO or per rectum.
2) Severe = IV steroids
3) Proctitis = topical steroids
4) Refractory = immunosuppresion
Surgical
1) Indication = failure of medical therapy, increasing risk of cancer in long-standing disease, bleeding, perforation
2) Procedure = Proctocolectomy (curative)
3) If patient is acutely ill and unstable due to perf, a diverting loop colostomy is indicated. Once stabilized, the patient may undergo more definitive procedure
4) In Chrohns, the treatment is stricturoplasty and segmental resections bc recurrence is the rule and the goal is to preserve as much healthy intestine as possible
Prognosis for UC
1-2% risk of cancer at 10 years and 1%/year after that
Crohn’s vs UC complications
UC
1) Perf
2) Stricture
3) Megacolon
4) Cancer
Crohns
1) Abscess
2) Fistula
3) Obstruction
4) Cancer
5) Perianal disease
Is the diverticula in diverticulitis/osis true or false?
False (only mucosa really)
1 site of diverticulitis?
Sigmoid colon
Lower odds as you move proximally
Lower GI Bleed
Bleed distal to ligament of Treitz
Massive = 3+ units of blood within 24h
Most common causes are diverticulosis and angiodysplasia
Other causes are cancer, IBD, ischemic colitis, hemorrhoids
10-20% eventually require surgery despite the fact that 85% initially stop spontaneously
Significant surgery needed when no site identified in an unstable patient bc although
Incidence of diverticulosis vs angiodysplasia
Diverticulosis
50% of patients are > 60
Angio
25% are > 60
Men > women
Character of GI bleeds from diverticulosis vs angiodysplasia
Divertic
Painless
> 60% site of bleeding proximal to splenic flexure
Massive and rapid
Angio
Cecum and ascending colon
Slow
Signs of bleeding from diverticulosis vs angiodysplasia
Both
Melena and/or hematochezia with symptoms of orthostasis
Diagnosis of diverticulosis vs angio
1) first, rule out upper GI bleed with NG lavage
2) To ID site of bleed,
- Colonoscopy
- if >0.5ml/min: bleeding san with Tc-sulfer colloid identifies bleeding. Label lasts up to 24h so patient can be easily rescanned when rebleeding occurs agter negative initial scan
- If >1ml/min angiography (selective mesenteric angio is best method to diagnose angiodysplasia)
Treatment of bleeds from diverticulosis vs angio
1) Resuscitation
2) Therapeutic options if site is ID’d:
- Octreotide
- Embolization
- Vasoconstriction (Epi)
- Vasodestruction with alcohol or sodium compounds
- Coag/cautery with heat
3) If site ID’s but bleeding massive or refractory - segmental colectomy
4) Without ID of bleeding and persistent bleeding in unstable patient, exlap with possible colectomy w/ ileostomy
Cause of angiodysplasia
Chronic intermittent obstruction of submucosal veins secondary to repeated muscular contractions
This results in dilated venules with incompetent precapillary sphincters and thus AV communication
Large bowel obstruction incidence
Mostly in elderly patients
Much less common than SBO
3 most common causes of LBO
1) Adenocarcinoma (65%)
2) Scarring secondary to diverticulitis (20%)
3) Volvulus (5%)
Signs of LBO
Abdominal distention, cramping abdominal pain, nausea, vomiting, obstipation and high-pitched bowel sounds
Dx of LBO
Supine and upright XR - distended proximal colon, air-fluid levels, no distal rectal air
Establish 8-12h history of obstipation; passage of some gas or stool indicated partial SBO, a nonoperative condition
Barium enema - may be needed to distinguish btw ileus and pseudo-obstruction
Tx of LBO
1) Correct fluid and lyte issues
2) NG tube for intestinal decompression (gastric emptying is reflexly inhibited)
3) Broad-spectum IV Abx (Cefoxitin)
4) Relieve obstruction surgically (colonic obstruction is surgical emergency since NG tube will not decompress the colon)
Volvulus def
Rotation of a segment of intestine about its mesenteric axis; characteristically occurs in sigmoid colon (75% of cases) or cecum (25%)
Incidence of volvulus
More than 50% of cases are in patients over 65
Risk factors for volvulus
1) Elderly (esp institutionalized patients)
2) Chronic constipation
3) Psychotropic drugs
4) Hypermobile cecum secondary to incomplete fixation during intrauterine development (cecal volvulus)
Signs of volvulus
LBO
Diagnosis of volvulus
Clinical presentation
Abdominal films - markedly dilated sigmoid colon or cecum with a “kidney bean” appearance
Barium enema - characteristic, “bird’s beak” at areas of colonic narrowing
Treatment of volvulus
Cecal
- R hemicolectomy if vascular compromis
- cecopexy otherwise adequate (suture right colon to parietal peritoneum)
Sigmoid
- Sigmoidoscopy with rectal tube insertion to decompress the volvulus
- Emergent laparotomy if sigmoidoscopy fails or if strangulation or perforation is suspected
- Elective resection in same hospital admission to prevent recurrence (nearly 50% of cases recur after nonoperative reduction)
Psuedo-obstruction (Ogilvie) def
Massive colonic dilation without evidence of mechanical obstruction
Incidence of Ogilvie
More common in older, institutionalized patients
Associated with any severe acute illness, neuroleptics, opiates, malignancy, and certain metabolic disturbances
Risk = recent surgery or trauma, severe infection
Signs of Ogilvie
Marked abdominal distention with mild abdominal pain and decreased or absent bowel sounds
Diagnosis of Ogilvie
Abdominal XR with massive colonic distention
Exclude mechanical cause for obstruction with water-soluble contrast enema and/or colonoscopy
Treatment of Ogilvie
NGT and rectal tube for prox and distal decompression
Correction of lytes
D/C narcotics, anticholinergics, or other offending meds
Consider pharm decompression with neostigmine (cholinesterase inhibitor)
If peritoneal signs develop, patient should get prompt exlap to treat possible perf
Refractory cases may need total colectomy
Malignant potential of a polyp
By size, histo type, and epithelial dysplasia
1) Size
2cm = 40%
2) Histo
Tubular = 5%
Tubulovillous = 20%
Villous = 40%
3) Atypia
Mild = 5%
Mod = 20%
Severe = 35%
Hamartomatous polyp
normal tissue arranged in abnormal config - juvenile polyps and Peutz-Jeghers
Adenoma - carcinoma sequence
Normal - hyperproliferative - early adenoma - intermediate adenoma - late adenoma - carcinoma (- mets)
1) APC gene loss or mutated
2) Loss of DNA methylation
3) Ras mutation
4) Loss of DCC gene
5) Loss of p53
Hemorrhoids
Prolapse of submucosal veins located in the L lateral, R anterior, R posterior quadrants of anal canal
Classified by type of epithelium: I
1) Internal = covered by columnar mucosa (above dentate)
2) External = anoderm (below dentate)
3) Mixed = both types involved
Men = Women
Risk = Constipation, pregnancy, increased pelvic pressure (ascites, tumors), portal HTN
Dx = Clinical Hx, PE, visualize with anoscope
Anal fissure definition
Painful linear tears in anal mucosa below dentate line; induced by constipation or excessive diarrhea
Signs of anal fissure
Pain with defecation
Bright red blood on toilet tissue
Markedly increased sphincter tone and extreme pain on DRE
Visible tear upon gentle lateral retraction of anal tissue
Tx of anal fissure
Sitz bath
Fiber supplements, bulking agents
Increased fluid intake
If nonsurg therapy fails, options include lateral internal spincterotomy or forceful anal dilation
Grading internal hemorrhoids
1) Grade 1
- protrudes into lumen, no prolapse
- sx = bleeding
- tx = nonresectional measures (rubber band ligation, infrared coag, injection sclerotherapy - all this is only above dentate line)
2) Grade 2
- prolapse with straining, spontaneous return
- sx = bleeding, perception of prolapse
- tx = nonresectional
3) Grade 3
- prolapse, requires manual reduction
- sx = bleeding, prolapse, mucous soilage, pruritis
- tx = consider trial of nonresctional; may require excision
4) Grade 4
- prolapse cannot be reduced
- sx = bleeding, prolapse, mucous soilage, pruritis, PAIN (if thrombosed or ischemic)
- tx = excision
Anorectal fistula definition
Tissue tracts originating in the glands of the anal canal at the dentate line that are usually the chronic sequelae of anorectal infections, particularly abscesses
Classifying anorectal fistulas
1) Intersphincteric (#1) - tract stays within intersphincteric plane
2) Transsphincteric - fistula connects the interspincteric plane with the ischiorectal fossa by perforating the external sphincter
3) Suprasphincteric - similar to trans but fistula loops above external sphincter to penetrate the levator ani muscles
4) Extrasphincteric - fistula passes from rectum to perineal skin without penetrating sphincteric complex
Goodsall’s rule
Useful to help predict course of anorectal fistula tract
Draw a line that bisects anus in the coronal plane
Fistulas that start out anterior to the line will course anteriorly in direct route
Fistulas that start out posterior to the line will have a curved path
If the tracts diverge from this rule this raises suspicious for IBD
Anorectal abscess def
Obstruction of anal crypts with resultant bacterial overgrowth and abscess formation within the intersphincteric space
Risk for anorectal abscess
Constipation/diarrhea/IBD
Immunocompromise
Hx of recent surgery or trauma
Hx of colorectal carcinoma
Hx of previous anorectal abscess
Signs and tx for anorectal abscess
Rectal pain, often sudden onset
Associated fever, chills, malaise, leukocytosis, and a tender perianal swelling with erythema and warmth of overlying skin
Tx = surgical drainage
Signs of anorectal fistula
Recurrent or persisten drainage that becomes painful when one of the tracts becomes occluded
Dx of anorectal fistula
Bidigital rectal exam
Anoscopy
If internal opening cannot be identified by direct probing, it should be identified by probing the external opening or by injecting a mixture of methylene blue and peroxide into the tract
Tx of anorectal fistula
Intraoperative unroofing of entire fistula tract with or without placement of setons (heavy suture looped through the tract to keep it patent for drainage and to stimulate fibrosis)
Pilonidal disease def
Cystic inflammatory process generally occuring at or near the cranial edge of gluteal cleft
From trauma to hair follicles and resultant infection
Incidence of pilonidal disease
Mostly young men in late teens to third decade
Signs of pilonidal disease
Can present acutely as an abscess (fluctuant mass) or chronically as a draining sinus with pain at the top of the gluteal cleft
Tx of pilonidal disease
I/D under local anesthesia with removal of involved hairs
Anal cancer incidence
rare
1-2% of colon cancers
Risk for anal cancer
HPV
HIV
Cigarette smoking
Multiple sexual partners
Anal intercourse
Immunosuppressed
Signs of anal cancer
Often asymptomatic
Can present with anal bleeding, a lump, or itching; an irregular nodule that is palpable or visible externally (anal margin tumor) or a hard, ulcerating mass that occupies a portion of the anal canal (anal canal tumor)
Dx of anal cancer
Surgical bx with histo eval
Histo: Anal margin tumors include SCC and BCC, Paget’s ,and Bowen’s. (pagets = adeno in situ, Bowen’s = SCC in situ)
Anal canal tumors are usually epidermoid (SCC or transitional cell/cloacogenic carcinoma) or malignant melanoma
Clinical staging = involves history, PE, proctocolonoscopy, abdominal or pelvic CT or MRI, CXR and LFTs
Tx of anal cancer
Epidermoid: Chemoradiation is mainstay (5-FU, mitomycin C, 3000 cGy XRT - Nigro protocol)
- surgery reserved for recurrence
Other anal margin tumors: wide local excision alone or in combo with radiation and/or chemo works 80% of the time without abdominal-perineal resection if tumor is small and not deeply invasive
Anal canal tumors: local excision not an option; combined chemo (5FU and mitomycin C) with radiation is often successful; abdominal-perineal resection only if follow up bx indicates residual tumor
Prognosis of anal cancer
Anal margin tumors = 80% 5yr
Anal canal
- epidermoid = 50%
- malignant melanoma = 10-15%
