Colorectal Flashcards
Compared to the traditional hemorrhoidectomies, using an electrothermal tissue-sealing device is associated with a lower rate of?
Immediate post-op pain- equivalates with traditional at 2 weeks post-op.
Faster return to work
Poor prognostic indicators of anal cancer? (5)
Size >5cm
>2/3 involvement of the anal canal circumference
Other:
Male sex
Presence of nodal disease
Hgb<13
Colonic stens for obstructing cancer vs operation without stens
- what is the incidence of colonic obstruction with malignancy?
- difference in 30d mortality?
- % chance of successful laparoscopic resection?
- surgical site infxn rate?
- most common site of stent migration?
- 30%
- no difference in mortality
- significant improved lap rxn rate (67% with stent vs. 31.4% without)
- SSI lower with stent
- MC site of stent migration is rectosigmoid jxn
When to do follow-up colonoscopies 3 yrs after polypectomy (4)
Low risk vs high risk polyps?
When to rpt at 6mo?
When to do rpt scope after completely resecting cancerous polyp with margin > 2mm?
3 years: - >10 adenomas - tubular adenoma > 10mm - high grade dysplasia - villous adenoma (10, 10, high villain)
Low risk: 1-2 tubular adenomas, <10mm -> 5-10 years
High risk: 3 or more adenomas, or size >10mm -> 3 years
Large polyp removed in piecemeal fashion -> 6 mo
1yr
Multitarget stool DNA test vs. decal occult testing
Sensitivity for cancer vs. adenoma
Specificity?
Multitarget stool DNA: 92% sensitivity for detecting colorectal cancer but 42% for adenoma
Fecal occult: 74% for cancer and 24% for adenomas
Fecal occult specificity is better 96% vs 89
Criteria for transanal excision (4)
1) <3cm
2) <30% circumference
3) within 8cm from anal verge
4) T1
How do you do a ripstein repair? 3 steps
What is it’s most common morbidity? Whats the frequency?
What is the most severe complication?
1) mobilize the rectum
2) put a mesh around the rectum
3) fix the mesh to the presacral fascia
- constipation >50% with pre-op constipation
>10% without pre-op constipation
Most severe: mesh erosion but less common
Long term complications of J-pouch:
- what are the frequencies for sexual dysfunction, stricture, pouchitis
Pouchitis: 30-50%
Stricture: 7-15%
Sexual dysfunction: 1-20%
Treatment for obstetric tear, fecal incontinence?
What about for complex / recurrent cases?
Wrap around sphincteroplasty - mobilize the sphincters and reapproximate without tension
Gracillis muscle transposition with constant low freq stimulation
What innervates the external sphincter?
It is continuous with what muscles?
What innervates the internal sphincters?
Inferior rectal branch of the internal pudendal nerve
+
Perineal branch of the 4th sacral nerve
Continuous with puborectalis and levator ani
Internal sphincters are innervates by autonomic system. Continuous with circular muscle of the rectum.
What is lymphogranuloma venerum?
Treatment?
Treatment should begin immediately to prevent what kind of complications?
Chlamydia infxn
Tetracycline
Rectal stricture, perianal fistulas
When you’re removing a condyloma what skin layer should be removed with it?
Epidermis
What is the cause for urinary retention after hemorrhoidectomy?
Pelvic floor muscle spasm in combination with epidural or spinal anesthesia, pain, excessive fluid
What is a Whitehead hemorrhoidectomy?
Circumferential excision of the internal hemorrhoids just proximal to the dentate line
Most common site of recurrence after colon CA resection?
What is the rate of locoregional recurrence after colon CA rxn?
Liver
Locoregional recurrence: <5%
Colorectal cancer
- what is the difference between T4a vs. T4b?
- difference between N1 vs. N2a vs. N2b
- what is stage IIC? IIIC?
- T4a: invades through the visceral peritoneum. Includes gross perforation
T4b: other organ - N1: 1-3 nodes
N2a: 4-6 regional nodes
N2b: seven or more nodes - IIC: T4b/N0/M0. Other organ, no nodes
IIIIC:
T4a/N2a/M0
T3-T4a/N2b/M0
T4b/N1-2/M0
What is the most common complication of strictureplasty? and incidence?
Bleeding. Up to 9% of cases
Leak, dehiscence, sbo all occur at about 2%
Recommended age of colonoscopy if father had colon cancer at age 62?
Current NCCN guideline in a pt with one or more first degree relatives who had colon cancer at ANY age is colonoscopy at age 40 or 10 years before the age at which the relative was diagnosed. Whichevers earlier.
Repeat scope every 5 years
dMMR good or bad? Does chemo work or not?
Mismatch repair deficiency considered favorable prognostic factor. Poor response to fluoropyrimidine based chemotherapy
chemo works well for pMMR but poorer prognostication compared to dMMR
Is APC a tumor suppressor or proto-onco? Is it the first step or the last step in the sequence of colon CA development?
HNPCC is associated with what defect?
Is p53 a tumor suppressor or proto onco?
APC is a tumor suppressor. First step. Then K-ras, DCC, p53
HNPCC: microsatellite instability
P53 is tumor suppressor
What supplies the transverse colon after an extended right?
What does Arc of riolan connect?
Marginal a. of drummond
Connects middle colic and left colic. Smaller contribution than marginal a. of drummond
What is the best prognostic indicators for resecting liver met after colon cancer?
Good response to chemo is the best prog. Indicator
Criteria for local excision of rectal cancer
Size <4 cm Mobile, non-fixed <40% circumference <8 cm from anal verge T1/N0 or T2/N0
Incidence of appendiceal cancer in appendectomy specimen?
~1%
For what kind of tumors is appendectomy sufficient?
It has to be non-epithelial.
Size <2 cm
No involvement of the base.
histologic Grade < II
no goblet cells
Size >2 cm or involvement of base -> right hemi
Required timeframe for something to qualify as chronic appendicitis?
3 or more weeks. At least 1 episode of acute pain.
Mutation in mismatch repair (MMR)
Which colonic syndrome?
Lynch syndrome
Microsatellite instability
Which colonic syndrome?
Lynch syndrome
Screening recommendations for FAP
Flex sig starting at 10-15
Upper endoscopy starting at 25-30
When do you offer surgery for pts with FAP?
As soon as you start to see polyps
Young, <50yo pt with right sided colon cancer. Suspect what?
HNPCC
T3N0 colon CA in a pt with HNPCC. Chemo or no?
No. HNPCC have better prognosis stage for stage. T3N0 actually doesn’t benefit from getting chemo
Recommended surgical treatment for pts with HNPCC for young pt vs. older pt?
Younger: subtotal colectomy with IRA
older: segmental colectomy
Other associated cancers for HNPCC?
Uterine, gastric, GU tumors
Screening recommendation for known HNPCC?
Colonoscopy starting at age 20-25
Endometrial aspiration starting at age 25-35
Describe the haggitt classification
For pedunculated polyps
Haggitt 0: not invading muscularis
Haggitt 1: invades through the muscularis but only in the head
Haggitt 2: invades the level of the neck
Haggitt 3: invades any part of the stalk
Haggitt 4: invades into the Submucosa of the bowel wall below the stalk but above the muscularis propria
Proto oncogene or tumor suppressor?
- APC
- K-ras
- p53
- DCC
- APC: Tumor suppressor. Defect in APC -> No tumor suppression
- K-ras: proto oncogene
- p53: tumor suppressor
- DCC: tumor suppressor
Margin and # nodes you need for colon CA?
5cm margin, 12 nodes
Run of the mill T3N0 colon cancer. Chemo or no?
Yes chemo. HNPCC T3N0 don’t need chemo
this is stage IIa
stage IIb: T4a N0
stage IIc: T4b N0
IN THE HINDGUT, where is GIST found most frequently?
Rectum
Over GIST frequency
gastric pacemaker cells Stomach (50-70%) > small bowel (25-35%) > colorectal (5-10%) > mesentery/omentum (7%) > esophagus (<5%) > duodenum
Rate of bleeding required to detect GI bleed on angio?
At least 1mL/min
RBC scan: 0.1-0.5mL/min
Rate of bleeding required to detect bleeding on tagged RVC scan?
0.1-0.5mL/min
Angio: 1mL/min
What is the risk of colonic perforation in pts with recurrent uncomplicated diverticulitis?
<5%