Chapter 36 - Colorectal++ Flashcards
Muscular anatomy of colon?
Muscularis mucosa, muscularis propria, plica semilunaris (haustra), taenia coli
Vascular supply of transverse colon?
2/3: SMA - right and middle colic
1/3: IMA - L. colic
Vascular supply of ascending colon?
SMA - ileocolic, right colic arteries
Vascular supply of descending colon?
IMA - L. colic
Vascular supply of the rectum?
IMA superior
internal iliac inferior
Vascular supply of sigmoid colon?
IMA - sigmoid a.
% of blood flow to mucosa/submucosa?
80%
What are the watershed areas?
Splenic flexure (Griffith’s point)
Rectum (Sudak’s point)
Neuro control of external sphincter?
CNS (voluntary); inferior rectal branch of internal pudendal n, perineal branch (S4)
What muscle makes up the internal sphincter?
Continuation of circular bands of the rectal muscularis propria (can be resected in low rectal cancer to add 1 cm to resection margin and prevent need for APR - requires external sphincter function).
Measurement from anal verge to anal canal?
0-5cm
Measurement from anal verge to rectum?
5-15cm
Measurement from anal verge to rectosigmoid junction?
15-18cm
Transition point between anal canal and rectum?
Levator ani
Main nutrients of colonocytes?
Short chain fatty acids (butyrate) - produced by microbial breakdown of dietary starches
Prophylaxis for stump pouchitis?
Probiotics - VSL 3
Treatment for infectious pouchitis?
ciprofloxacin or flagyl
What is lymphocytic colitis? How do you dx and manage it?
- Pth: multifactorial, immune response
- Psx: pain w/ chronic, water diarrhea in a 65 F
- Dx: stool cxs, colonoscopy w/ biopsy
- Tx: avoid NSAID, antidiarrheals, budesonide
What is the name of the anterior, rectovesicular/rectovaginal fascia?
Denonvillier’s
What is the name of the posterior, rectosacral fascia?
Waldeyer’s
What are the characteristics of polyps associated with increased cancer risk?
>2cm, sessile, villous
What are the screening guidelines for patients with FAP?
- starting at 10-12y (puberty): annual sigmoidoscopy
- can change to q3y at 40
- as soon as polyps develop, do colectomy
What are the screening guidelines for patients with attenuated adenomatous polyposis coli?
- Starting in late teens, annual colonoscopy
- Type of FAP difficult to distinguish from Lynch
What are the screening guidelines for patients with HNPCC?
- starting at 20-25y, biennial colonoscopy
- also do UA, urine cytology, US, endometrial bx
What is the treatment when polypectomy shows T1 lesion?
Polypectomy only if 2mm margins, well-differentiated, no vascular involvement; otherwise segmental resection
What is the treatment for extensive low rectal villous adenomas with atypia?
Transanal excision (with or without mucosectomy); APR only if cancer is present
What is the treatment for T2 lesion after transanal excision of polyp?
APR or LAR
What will cause a false-positive guaiac?
Beef, Vit C, iron, antacids, cimetidine
Colonoscopy contraindications?
Recent MI, splenomegaly, pregnancy if fluoroscopy planned
What is the 2nd leading cause of cancer death?
Colorectal cancer
Main gene mutations in colon ca?
APC, DCC, p53, k-ras
Most common site of primary colorectal cancer?
Sigmoid
Poor prognostic factors for primary colorectal cancer?
- <40 yrs
- symptomatic patients
- obstruction
- perforation
- rectosigmoid/rectal location
- ulcerative tumor
- blood vessel/lymphatic/perineural invasion
- aneuploidy
- elevated CEA prior to resection
5-year survival rate with liver mets?
25% if resectable and leaves adequate liver function.
Do wedge resection if possible. No need for lobectomy - no survival benefit.
5 year survival with lung mets?
20%
Route of metastasis of colon cancer?
To liver via portal vein, to lung via iliac vein
Route of spine metastasis of rectal cancer?
Can go directly to spine via Batson’s plexus
Goals of resection for colon ca?
En bloc resection, adequate (5 cm, proximal and distal) margins, regional adenectomy (12 nodes)
Treatment for rectal cancer with rectal pain?
APR. Other indications for APR: Poor preop function, external sphincter involvement.
What is the best method of picking up hepatic mets?
Intraoperative ultrasound
Margin needed for LAR?
2cm from levator ani
Side effects of APR?
Impotence and bladder dysfunction (associated with Denonvillier’s dissection - anterior)
Local recurrence higher with rectal or colon ca?
Rectal ca
Advantages of preoperative chemo/XRT in rectal cancer?
Produces complete response in some patients with rectal ca; preserves sphincter function in some
Treatment for low rectal T1 lesion?
Transanal excision if <4cm, negative margins (1cm), well differentiated, no neurologic or vascular invasion; otherwise LAR or APR
Treatment for low rectal T2 or higher?
APR or LAR
Chemo for stage III and IV colon CA (node positive or distant mets)?
Post op chemo (III - 5FU, leucovorin, oxaliplatin; IV - 5FU and leucovorin)
Chemotherapy for stage II and III rectal ca?
Pre op or post op chemo and XRT (5FU, leucovorin, oxaliplatin)
Chemotherapy for stage IV rectal ca?
Chemo and XRT +/- surgery (5FU, leucovorin). Chemo is the priority before resection.
When is postop XRT needed for rectal ca?
T3 tumors (through muscularis propria; locally advanced) or positive nodes (stage III)
Most common site of XRT damage?
Rectum; vasculitis, thrombosis, ulcers, strictures
Gene mutation related to FAP?
APC gene, chromosome 5q21
% of FAP syndromes are spontaneous?
20%
When do polyps present in FAP?
Puberty - why screening starts at 10-12
Surveillance for FAP?
- Surveillance following colectomy: Endoscopic evaluation of the rectum or ileal pouch should be performed annually (or every other year for end-ileostomies)
- Surveillance for upper GI tumors: depends on stage
- Stage 0: Every four years
- Stage I: Every two to three years
- Stage II: Every one to three years
- Stage III: Every 6 to 12 months
- expect to see desmoids, gastric fundus polyps, and periampullary tumors (will kill your patient after their colectomy)
Treatment for FAP?
Total colectomy at age 20; proctocolectomy, rectal mucosectomy and ileoanal pouch
Tumors associated with Gardner’s syndrome (type of FAP)?
- colon ca, desmoids, osteomas (skull, mandible)
- supernumerary teeth
- mesenteric fibromatosis
- soft tissue tumors
Gene mutation associated with Gardner’s syndrome?
APC gene (type of FAP)
Tumors associated with Turcot’s syndrome?
- Colon ca, brain tumors
Gene mutation associated with Turcot’s syndrome?
APC gene (another type of FAP, along with Gardner)
Lynch syndrome inheritance?
Autosomal dominant
Gene mutation associated with Lynch syndrome?
DNA mismatch repair (MMR) gene
Lynch I has increased risk of what?
Colon cancer
Lynch II has increased risk of what?
Colon cancer, ovarian, endometrial, bladder, stomach cancer
What is the Amsterdam II criteria?
Used to diagnose Lynch syndrome
- 3 first degree relatives w/ HNPCC assd ca
- 2 generation penetrance
- 1 relative w/ cancer < 50
- exclude FAP
- verify tumors by path (villous, more dysplasia)
Screening for Lynch syndrome?
- colonoscopy at 25 or 10y before primary relative got cancer q1-2 yrs
- usually, you’ll find right sided cancers
- women need endometrial biopsy q3y, annual pelvic exams, earlier mammograms
% of Lynch syndrome with metachronous lesions?
35%
Tumors associated with juvenile polyposis?
Hamartomatous polyps
Surveillance for juvenile polyposis?
- DRE to help dx, colonoscopy after dx
- polyposis is >5 polyps
- Yearly: PE, CBC, colonoscopy, EGD starting 12 yr
- Total colectomy if cancer develops
Cancer risk with juvenile polyposis? Other characteristics?
- Polyps do not have malignant potential, but patients have increased cancer risk - 68% by 60
- AD; SMAD4, BMPR1A; hamartomatous polyps
- SMAD4 has association w/ HHT (hereditary hemorrhagic telangiectasia - skin, buccal mucosa)
Characteristics associated with Peutz-Jeghers syndrome?
- AD; STK11
- GI hamartoma polyposis, dark pigmentation around mucous membranes (melanin spots) on face and extremities - if both present, dx; if FHx +1, also dx
- colon, pancreas, breast cancer
Surgical options for Peutz-Jeghers? Surveillance?
- Need polypectomy if possible (may be too many to resect) - 2% colon, duodenal cancer risk. No need for ppx colectomy.
- Birth: yearly testicular exams.
- 8 yrs: Colonoscopy. Polyps - q3y scope. No polyps - rpt at 18.
- 18 yrs: monthly breast exams.
- 21 yrs: annual Pap smear and pelvic exam.
- 25 yrs: annual breast MRI/mammogram.
- 30 yrs: annual MRCP.
Other cancers associated with Peutz-Jeghers?
Gonadal, breast, biliary
Characteristics associated with Cronkhite-Canada syndrome?
Hamartomatous polyps, atrophy of nails and hair, hypopigmentation
Malignant potential with Cronkhite-Canada syndrome?
NO malignant potential
Diet associated with sigmoid volvulus?
High-fiber (Iran, Iraq)
Radiographic findings with sigmoid volvulus?
Bent inner tube sign, bird’s beak on gastrograffin enema
Treatment for sigmoid volvulus?
Decompress with colonoscopy (not if having peritoneal signs), bowel prep, sigmoid colectomy on same admission
% of sigmoid volvulus that will decompress with colonoscopy?
80% reduce, 50% recur
Age range for cecal volvulus?
20-30y
% of cecal volvulus that will decompress with colonoscopy?
20%
Treatment for cecal volvulus?
OR for R. hemi; can try cecopexy if colon is viable and pt is frail
Symptoms of ulcerative colitis?
Bloody diarrhea, abdominal pain, fever, weight loss
Layers of colon involved in ulcerative colitis?
Mucosa, submucosa
Location of UC?
Colon only with rare backwash ileitis
Anatomic distribution of UC?
Continguous involvement begining distally, spares anus (unlike Crohn’s)
Likelihood of rectal involvement in UC?
90%
Endoscopic features of UC?
Contiguous mucosal involvement, rectal involvement, mucosal friabilitiy, distorted vascular pattern
Findings on barium enema of UC?
Loss of haustra, narrow caliber, short colon, loss of redundancy
Medical treatment of UC?
- Medical treatment is first line
- Steroids used in acute/severe phase and weaned
- 5-ASA (+/- topical) is for mild and maintenance
- added to steroids for severe
- Infliximab, azathioprine added for steroid failure in severe
- Surgery if no response to these
Clinical diagnosis of toxic megacolon?
Fever, tachycardia, dilated colon on abd xray
Treatment of toxic megacolon?
NGT, fluids, steroids, bowel rest, TPN, abx (treat 50%), then surgery
Pathologic features of Crohn’s disease?
Transmural inflammation, granulomas, fissures, sumbucosal thickening/fibrosis, submucosal inflammation
Distinguishing characteristics of Crohn’s colitis?
Small bowel involvement, asymmetric distribution, rectal sparing common, gross bleeding in 70-75%, fistulization, granulomas
Endoscopic features of Crohn’s disease?
Discontinuous mucosal involvement, aphthous ulcers, relatively normal surrounding mucosa, longitudinal ulcers, cobblestoning, vascular pattern normal
Perforation occurs where in UC?
Transverse colon
Perforation occurs where in Crohn’s?
Distal ileum
Surgical indications for UC/Crohn’s?
Hemorrhage, toxic megacolon, acute fulminant UC, obstruction, dsplasia, cancer, intractability, failure to thrive, long-standing disease, prophylaxis against colon CA
Cancer risk for UC/Crohn’s?
1-2% per year starting 10y after initial diagnosis
Surveillance for UC/Crohn’s? Why? How are results managed?
- annual colonoscopy 8-10y after diagnosis
- biopsy every 10-12 cm of normal/abnormal tissue
- this is when cancer risk increases: rate of 0.5-1.0%/year
- PSC, young dx, pancolitis have increased risk
- risk roughly equivalent in UC and Crohn’s
- if severe colitis, dysplasia, or inability to comply, do colectomy
Most common extraintestinal manifestation of UC in children requiring total colectomy?
Failure to thrive
Extraintestinal manifestations of UC that DO NOT get better with colectomy?
PSC, ankylosing spondylitis
Extraintestinal manifestations of UC that get better with colectomy?
Most ocular problems, arthritis, anemia
HLA associated with sacroiliitis and ankylosing spondylitis?
HLA B27
Treatment for pyoderma gangrenosum?
Steroids
% of carcinoids found in colon and rectum?
15% of all carcinoids
Treatment for low rectal carcinoids <2cm?
WLE with negative margins
Treatment for low rectal carcinoids >2cm or invasion of muscularis propria?
LAR or APR
Treatment for colon or high rectal carcinoids?
Formal resection with adenectomy
What is the Law of LaPlace?
Tension = Pressure x Diameter
Where is colon perforation with obstruction most likely to occur?
Cecum
Causes of colonic obstruction?
1 Cancer, #2 diverticulitis
What is pneumatosis intestinalis?
Air in the bowel wall
associated with ischemia and dissection of air through areas of bowel wall injury
can be benign, such as w/ COPD
What does air in the portal system indicate?
Significant infection or necrosis of the large or small bowel
Treatment for Ogilvie’s syndrome (pseudoobstruction of colon)?
- Rule out peritonitis, dilation <12cm; serial exams
- Check lytes, DC drugs that slow gut (narc, Ca-block, anti-ACh)
- 1-2 days of failure: Neostigmine
- Fail neostigmine (contraindx): colonoscopy with decompression
- Fail or not surgical candidate: perc colostomy
% that are carriers for Entameoba histolytica?
10%, from contaminated food and water with feces that contain cysts
Where does the primary infection occur in amoebic colitis?
Colon
Where does the secondary infection occur in amoebic colitis?
Liver
Risk factors for amoebic colitis?
Travel to Mexico, EtOH, fecal oral transmission
Symptoms of amoebic colitis?
Similar to UC (dysentery); chronic form more common with 3-4 BM/day, cramping, fever
Diagnosis of amoebic colitis?
Endoscopy: ulceration, trophozoites
antiamebic antibodies
Treatment for amoebic colitis?
Flagyl, diiodohydroxyquin
Presentation of actinomyces?
Mass, abscess, fistula, induration; suppurative and granulomatous
Most common location of actinomyces?
Cecum
Treatment for actinomyces
Tetracycline or penicillin, drainage
Treatment for lymphogranuloma venereum?
- Doxycycline, hydrocortisone
- Buboes may need aspiration or I&D
- test for HIV and other STIs
Presentation of lymphogranuloma venereum?
- primary: ulcer
- secondary: inguinal/femoral extension (buboe) weeks later
- anorectal: proctitis, discharge, tenesmus, bleeding
- late: fistula, stricture
- path: genital ulcer dz 2/2 C trachomatis (L1, 2, 3 serovar)
- risk factors: MSM, HIV, travelers, hx of STIs
- dx: NAAT
What causes diverticula?
Straining. Herniation of mucosa through the colon wall at sites where areteries enter the muscular wall; thickening of curcular muscle adjacent to diverticulum with luminal narrowing
Where do most diverticula occur?
L. side (80%) in sigmoid
Bleeding is more common with diverticula on which side of the colon?
Right
Diverticula present in what % of the population?
35%
How long can a stool guaiac stay positive after a bleed?
3 weeks
Where is the bleeding from in hematemeis?
Pharynx to ligament of Treitz
How much blood do you need to make melena?
50cc
What causes azotemia after GI bleed?
Production of urea from bacterial action on intraluminal blood (inc. BUN, total bilirubin)
Arteriography will detect bleeding at what rate?
>0.5ml/min
Tagged RBC scan will detect bleeding at what rate?
>0.1ml/min
not adequate to localize bleeding
What causes diverticulitis?
Perforations in the mucosa in the diverticulum with adjacent fecal contamination
% of patients that will have a complication of diverticulitis?
25%, most commonly abscess formation
Signs of complications of diverticulitis?
Obstruction symptoms, fluctuant mass, peritoneal signs, temp >39, WBCs >20
Treatment of uncomplicated diverticulitis?
Flagys, bactrim, bowel rest for 3-4 days
Indications for surgery for diverticulitis?
Recurrent disease, emergent complications, inability to exclude cancer
Characteristics of colovesicular fistula?
Fecaluria, pneumonuria; more common in men
Treatment for colovesicular fistula?
Close bladder opening, resect involved segment of colon, reanastamosis, diverting ileostomy
Most common cause of lower GI bleeding?
Diverticulosis
% of diverticular bleeding that stops? Recurs?
75%, 25%
Cause of bleeding from diverticulosis?
Disrupted vasa rectum, creates arterial bleeding
Diagnosis of diverticular bleeding?
- Colonoscopy - therapeutic and will localize bleeding
- Arteriogram - therapeutic and will localize bleeding
- TRBC - sensitive, but cannot localize
When is surgery necessary for diverticular bleeding?
If recurrent bleeding episodes, and bleeding is localized, segmental resection can be offered.
If hypotensive and not responding to resuscitation, and source not localized, do subtotal colectomy w/ end ileostomy.
Characteristics of angiodysplasia colon bleeding in comparison to diverticular bleeding?
Usually less severe than diverticular bleeds but more likely to recur (80%)
Soft signs of colonic angiodysplasia on angiogram?
Tufts, slow emptying
Associated cardiac anomaly with colonic angiodysplasia?
Aortic stenosis in 20-30%
Causes of ischemic colitis?
Low-flow state, ligation of IMA at surgery, embolus or thormbus of IMA, sepsis and MI
How is the diagnosis of ischemic colitis made?
Made by endoscopy: cyanotic edematous mucosa covered with exudates; lower 2/3 rectum spared (supplied by middle and inferior rectal artery from internal iliac and internal pudendal arteries)
Symptoms of pseudomembranous colitis?
Watery, green, mucoid diarrhea; pain and cramping
Key finding of pseudomembranous colitis?
PMN inflammation of mucosa and submucosa; pseudomembranes, plaques, ringlike lesions
Most common location of pseudomembranous colitis?
Distal colon
How is the diagnosis of pseudomembranous colitis made?
Fecal leukocytes, stool cultures of C. dif/toxin
Treatment of pseudomembranous colitis?
PO vanc first line; IV flagyl alternative; lactobacillus
When does neutropenic typhlitis (enterocolitis) occur?
Following chemo when WBCs are low
Radiographic finding of neutropenic typhlitis?
Pneumoatosis on plain film
Treatment of neutropenic typhlitis?
Abx; pts will improve when WBC increase
How does TB enteritis present?
Like Crohn’s disease (stenosis)
Treatment of TB enteritis?
INH, rifampin; surgery with obstruction
What pathology can Yersinia present like?
Mimics appendicitis
Treatment of Yersinia?
Bactrim or tetracyclin
Causes of megacolon?
- IBD
- C-diff
- Hirschsprung’s disease
- Trypanosoma cruzi (most common acquired cause, secondary to destruction of nerves
What muscle makes up the external anal sphincter?
Puborectalis - continuous with but separate than levator ani
What is the function of the colon?
recycle nutrients - depends on the metabolic activity of the flora, motility, mucosal absorption and secretion
What is the function of the rectum?
elimination of stool - dehydration of colonic contents, defection
What does the colon absorb?
water (passive), sodium (active), bile acids (passive)
bacteria produces SCFAs that drive the active Na absorbption, so if flora is wiped out (BS ABX), then less Na and H2O is absorbed, then diarrhea is caused
What does the colon secrete?
K - colitis can increase K secretion
Cl - CF and diarrhea inc secretion
What is the definition of diarrhea?
3 loose stools in one day
What is the definition of constipation?
fewer than 3 stools in a week
What does an preop albumin <3.5 mean for a patient undergoing colorectal surgery?
risk factor for anastomotic leak after surgery; delay surgery if possible until nutritionally replete
What contamination level is an elective colorectal procedure classified as? What does this imply?
clean-contaminated: abx ppx 30 min before incision and redosed every 4 hrs
2nd or 3rd gen cephalosporin vs fluoroquinolone/flagyl vs fluoroquinolone/clindamycin vs ertapenem
Characteristics of transverse loop colostomy
- usually used to divert from distal obstruction
- liquid, foul-smelling effluent
- higher risk of prolapse
- only temporary complete diversion
What are the key elements in the enhanced recovery pathway for colorectal surgery?
- appropriate patient selection
- MIS
- periop fluid mgmt
- early feeding
- early ambulation
- multimodal pain control
- outcomes: decreased primary length of stay, total hospital stay, fewer complications
Do colorectal surgery patients require an NGT after every surgery? Do you have to wait for return of bowel fct before feeding?
(ERAS protocol)
no - w/o ngt, pts have early ROBF, fewer complications, and dec length of stay
no - early feeding decreases postop complications and length of stay w/o affecting dehiscence rate or increasing pneumonias or vomiting episodes
Treat a cecocolic volvulus
Right colectomy
After treatment of uncomplicated diverticulitis, when should colonoscopy be performed?
4-6 weeks - exclude neoplasm or other colonic disease (IBD)
What is the most common distal site of diverticular fistula? Diagnose and treat it.
Dome of the bladder (vagina, small bowel, skin are other notable sites)
DX: CT w/ air in the bladder in setting of diverticulitis
Tx: BS Abx initially; colonoscopy to r/o cancer and IBD; elective resection of colon and tract w/ primary anastomosis, dmg to bladder can be repaired primarily w/ Foley drainage for 7 days
What is the most likely location for a colonic volvulus?
sigmoid colon - 2/3 of all cases of colonic volvulus
permitted by elongated bowel w/ lengthy mesentary and narrow parietal attachment
pts: old, chronic constipation, neuropsych conditions on psychotropic drugs
Treat a sigmoid volvulus (same as transverse volvulus)
- assure no need for ex-lap Hartmann: HDS and no peritonitis
- resuscitate
- decompress with rectal tube through rigid proctoscope or flex sig
- confirm w/ radiograph
- leave tube in place for 1-2 days
- completion colonoscopy to exclude cancer
- elective sigmoid resection w/ primary anastomosis
What is Muir-Torre syndrome?
a variant of Lynch associated with sebaceous gland adenomas and carcinomas
What syndromes are hamartomatous colon polyps associated with?
Peutz-Jeghers, juvenile polyposis
MYH is associated with what syndromes?
FAP or Lynch
What are three screening options for colorectal cancer in average-risk individuals?
- start at 50 yrs
- colonoscopy q10y
- double-contrast barium enema q5y
- FOBT yearly + flex sig q5y
- all positive tests should be followed by colonoscopy
What are the screening guidelines for increased risk individuals?
- single small (<1cm) adenoma - scope in 3-6 yrs, resume avg risk screen if negative
- single large (>1cm) adenoma, multiple adenomas, high-grade dysplasia, villous change - scope in 3 yrs x2, resume avg risk screen if neg x2
- resected colon cancer - scope in 1 yr, 3 yrs, q5yrs forever
- CRC or adenomatous polyps in 1st-degree relative <60 yrs or 2 1st-degree relatives at any age - scope at 40 or 10 yrs before earliest, q5-10yrs forever
How does a non-first-degree relative with colon cancer affect risk of personal colon cancer?
Not enough to move the individual from average risk screening
If staging colorectal cancer and colonoscopy cannot be completed, what should be done?
- CT colonography or air contrast barium enema
- If cannot do above, pt needs colonoscopy before 1 year after surgery
Clinically stage colorectal cancer
- colonoscopy (or CT colonography, air-contrast barium enema)
- CT CAP w/ oral and IV contrast
- consider PET or MRI pending above findings
Don’t forget CEA.
What additional study is required to stage rectal cancer
in addition to full colonoscopy and CT CAP, endoscopic ultrasound or MRI is required to determine depth of invasion
- this affects neoadjuvant chemo/XRT decision
- similar to esophageal staging
What are the T stages of CRC?
- invades submucosa
- invades muscularis propria
- invades through muscularis propria into pericolorectal tissues
- (a) visceral peritoneum, (b) other organs or structures
What are the N stages of CRC?
- 1-3
- 4 or more
How do you manage unresectable colon cancer?
- biopsy it for oncologists
- if symptomatic, offer palliative surgery
- need systemic chemotherapy
- tumor may become resectable at this point
the only time colon cancer patients get preoperative chemo is if surgery is not possible (unresectable)
Is there a role for neoadjuvant chemo in resectable colon cancer?
As of now, no. It is only done before surgery in unresectable colon disease. Rectal cancer is different.
How do you manage rectal cancer?
- stage it: CT CAP, CEA, EUS/MRI (local, advanced, or unresectable)
- unresectable: sx get pallx, otherwise chemo +/- radiation, determine if resectable post tx
- node+ or past muscularis propria (stage 3 or T3): neoadjuvant chemoradiation w/ OR in 1-6 wks
- dec local recurrence, no survival benefit
- plan resection: T1 possible endoscopic excision
- high-risk T1 or worse resectable lesion: 2 cm above levator - LAR, otherwise APR
- post resection: upstaged T3/N1: adjuvant chemo
Is CXR acceptable to stage colon cancer?
No. You need CT because it helps establish a baseline for later surveillance.
Where could very distal rectal cancers possibly travel through the lymph nodes?
superficial inguinal
What resection do you do for a cecal or ascending colon tumor?
right hemicolectomy (to take colon supplied by right branch of the middle colic)
What resection is required for colon cancer at the hepatic flexure?
extended right hemicolectomy (to include colon supplied by the middle colic - includes proximal 2/3 of transverse)
What resection should be done for transverse colon cancer?
depending on the location, can be left, extended right, or transverse colectomy
What resection should be done for a tumor at the splenic flexure?
left hemicolectomy
What resection should be done for sigmoid cancer?
sigmoidectomy
What are surgical options for FAP?
- the question is whether to save the rectum
- total colectomy w/ IRA - simpler operation, better bowel fct, requires minimal rectal dz + surveillance
- total proctocolectomy w/ IPAA - difficult operation, worse bowel fct, risk bladder/sexual fct, no CRC surveillance
When is local excision, transanal excision, or transanal endoscopic microsurgery appropriate for rectal cancer?
- T1 or T2 (does not invade past muscularis propria)
- <1/3 of bowel circumference
- clinically and EUS neg nodes
- within 10 cm of anal verge
- higher risk of recurrence with these attempts
Does the rectum have a serosa?
No. This is why T3 is locally advanced.
How are most emergently perforating colon cancers treated?
- emergent lap w/ washout, resection, Hartmann
- select pts can get primary anastomosis
- poor prognosis
What are surgical options for obstructing colon cancers?
- depends on which side and stability
- right: right hemicolectomy w/ primary anastomosis
- left: proximal diversion without resection (often will never reverse ostomy), resect colon partially vs completely +/- anastomosis +/- diversion, stent as bridge to definitive surgery or palliation
- lean toward complete resection in stable patient, lean toward diversion w/o anastomosis in unstable
- for mid/high rectal cancer - diversion only preferred
Does radiation therapy play a major role in colon cancer?
no, as opposed to rectal cancer
What difference does radiation make in rectal cancer?
- no difference in survival
- decreased recurrence
- decreased toxicity if used preop instead of postop
- can save sphincter in low T1/T2 lesions
- used for T3 or Stage III (N+) and above
all who get neoadj chemo/radx need postop chemo (w/o radx); no matter surgical outcome: every patient, every time
When should chemotherapy regimen be given in locally advanced or node positive rectal cancer?
- all of these patients get neoadjuvant chemoradx
- will either need postop chemo or can get pre-op chemo regimen (treats distal disease first, no ostomy while getting chemo, can achieve rapid symptomatic relief; requires close follow up to monitor response)
Postop CRC surveillance
- CEA: q3-6mo x2yrs, then q6mo x5yrs
- CT CAP: q1yr x3yrs
- colonoscopy: at 1 yr, 3 yr, then q5yrs
- if no complete pre-op scope do it within 3-6 mo
The goal of surveillance is to find curable disease in liver, lung, ovary, or anastomotic site. This is why PET scan and “second look surgery” does not help - cause they usually don’t find anything resectable.
What do you do with an elevated postop CEA after CRC resection?
- rpt in 4-6 wks to confirm; if positive…
- changes > 10 ng/ml - suggest active cancer
- changes >35 - virtually diagnostic of cancer
- full body CT
- negative - colonoscopy
- positive - liver, lung, ovarian are curable
After sigmoidectomy is performed with a high ligation of the inferior mesenteric artery, perfusion to the remaining descending colon is via…
the marginal artery from the middle colic branches of the superior mesenteric artery.
In contrast to the minimal mobilization necessary in thinner patients, much more colon often needs to be mobilized to allow the terminal portion to reach the skin without tension. How is this done?
The distal transverse colon frequently needs to be mobilized with removal of the greater omentum from the colon to minimize the amount of tissue within the abdominal wall. Occasionally, it is necessary to divide the inferior mesenteric vein at the lower border of the pancreas. This reduces the tethering that can occur at this level.
When emergency operation is required for toxic megacolon, the safest treatment is generally what?
total abdominal colectomy and ileostomy
For women over the age of 50 with pelvic/adnexal masses suspicious for malignancy (large size w/ high CA 125), what should be recommended?
Laparotomy for likely ovarian malignancy. Not colonoscopy, drainage, or biopsy. True even with a hx of diverticulitis.
Operative exploration should be to evaluate the extent of the disease, then the goal should be for either complete resection or tumor dubulking consisting of hysterectomy, bilateral salpingo-oophorectomy, and omentectomy.
A 36-year-old female with a 10-year history of Crohn’s disease presents with severe perianal disease that has been difficult to control. The patient has multiple complex perianal fistulas refractory to medical management including infliximab and seton placement. MRI shows multiple fistulas passing through the sphincter. Which of the following is the optimal procedure for this patient?
An APR with permanent end-colostomy is appropriate for patients with severe Crohn’s disease confined to the anorectum.
What tumors arise in enterochromaffin cells?
Interstitial cells of Cajal?
- enterochromaffin - carcinoid
- Cajal - GIST
In the patient with a low rectal cancer and extensive metastatic disease, what is the priority?
systemic therapy is often a treatment priority
can do loop colostomy then chemo
Appendiceal masses are often found to be carcinoid. Carcinoid tumors with high-risk histological findings on pathological examination, including mucosal cellular origin, associated with mucin production, lymphovascular invasion, involvement of the lymph nodes of the mesoappendix, size >2 cm, or a positive margin, should receive what surgery?
reoperative right hemicolectomy
When is simple appendectomy sufficient for appendiceal carcinoid?
Less than 1.0 cm in the absence of mesoappendiceal invasion and for tumors 1 to 1.9 cm that lack mesoappendiceal invasion and other adverse histologic features.
No follow up is required.
What happens if you do an appendectomy and pathology comes back as adenocarcinoma?
right colectomy unless the tumor is confined to the mucosa or a well-differentiated lesion that invades no deeper than the submucosa
adjuvant therapy if node-positive (stage III, as normal)
On postoperative day 1 after an abdominoperineal resection, you are called to the bedside to evaluate the colostomy because the nurse believes it appears black. What do you do?
Test-tube evaluation (best test to determine extent, no need for CT): the mucosa is pink and viable just below skin level.
Mucosal ischemia only within the stoma can be safely observed. Aggressive mesenteric stripping is associated with stomal ischemia. If the level of ischemia extends beyond the level of the fascia, into the peritoneal cavity, emergent revision of the colostomy is indicated.
You are operating on a patient with ulcerative colitis and have removed the colon and rectum. You are now constructing the ileal J pouch. What is the ideal length of the ileal J pouch?
15 to 20 centimeters
Describe the operative management and goals for severe/fulminant chronic ulcerative colitis?
The preservation of the superior rectal artery allows for good blood supply for the rectal stump that will aid in healing of the rectal staple line; given that the rectum is spared, the terminal branches of the IMA are spared until proctectomy. In patients with severe disease, proctectomy (with or without IPAA) is deferred until the patient has recovered from the colectomy. High-ligation of the colonic mesenteric vessels is not required, although it may speed the operations also likely adds morbidity. The ileocolic artery should be routinely spared to allow for collateral blood flow to the future J-pouch. The rectum should be divided above the posterior peritoneal reflection in the abdomen above the level of the sacral promontory; dividing the rectum lower than this will make the subsequent completion proctectomy unnecessarily difficult, and if performed in the total mesorectal excision plane, runs risk of inadvertent injury to the hypogastric plexus and pelvic nerves, potentially resulting in bladder and sexual dysfunction.
What is the typical standard medical therapy for severe-to-fulminant chronic ulcerative colitis (CUC)?
IV methylprednisone.
Colorectal cancer resection pathology results reveal a poorly differentiated tumor with signet-ring components. What is the most likely molecular marker associated with this tumor?
MSI - microsatellite instability seen in patients with sporadic colon cancer.
When is segmental colectomy indicated for polyps?
lymphovascular invasion, poor differentiation, less than 2mm margin, piecemeal polypectomy, invasion of the lower third of the submucosa, or central depression or ulceration
20 percent of polyps that are not amenable to endoscopic removal actually harbor an invasive cancer
A 63-year-old woman with microcytic hypochromic anemia, occult blood in the stool, and a weight loss of 10 pounds is found to have bilateral ovarian enlargement on initial physical examination. The most likely diagnosis is…
GI tract malignancy with Krukenberg`s tumors
- stomach is most common primary site
- colon, appendix, and breast are the next most common primary sites
- bilateral in more than 80%
- spread of disease is usually transperitoneal leading to compression of the colon rather than invasion of the mucosa
The most common causes of acute LGI hemorrhage are what?
diverticulosis (24% to 47%), colitis (6% to 26%), neoplasms (9% to 17%), and angiodysplasia (2% to 12%)
Which testing option allows for diagnosis of colonic inertia?
A sitz marker study entails ingestion of radiopaque markers followed by daily radiographs, which allows for monitoring of the radio-opaque markers as they pass through the colon. If these markers are diffusely seen on delayed imaging studies in all 3 segments of the colon, the study becomes diagnostic of colonic inertia. The other modes of study do not adequately assess the motility of the colon.
Discuss stoma reversal. Timing? What percentage cannot be reversed? How can the length be examined? Can laparoscopic reversal be done safely?
- For colostomy reversal, the surgeon should wait at least 12 weeks after the initial operation to allow for edema and dense adhesions to resolve.
- Due to comorbidities, up to 30% of patients are not candidates for Hartman’s reversal.
- The proximal colon should always be evaluated prior to end colostomy reversal to ensure that there are no lesions present.
- Options to examine if the length of the distal bowel is adequate for anastomosis include sigmoidoscopic evaluation of this portion of the bowel or a contrast enema.
- When the procedures could be performed laparoscopically, OR times were shorter, there was less blood loss and a quicker return of bowel function. It was concluded that laparoscopic reversal was superior to the open procedure for these reasons.
A patent presents with complaints of chronic constipation, who has previously tried diet modification and over-the-counter medications. On workup, the patient has Sitzmark study with distal accumulation of markers, and an abnormal functional magnetic resonance imaging (MRI). What is this? What do you do?
These findings on Sitzmarker study combined with an abnormal defecography or functional MRI are consistent with pelvic floor dysfunction. The first step in management of pelvic floor dysfunction is physical therapy and biofeedback training to retrain the pelvic floor muscles to relax properly to allow for normal defecation.
