Transcript Slide 1

Polyps – Where do they
come from and what do you
do with them?!
Ron G. Landmann, MD
Grand Rounds
Department of Surgery
St. Luke’s-Roosevelt Hospital Center
March 21, 2007
Polyps
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Cancer epidemiology
Definition of the malignant polyp
Natural history of adenomatous polyps
Biology of polyps
The anatomy of the polyp
Correlations with Malignancy
Endoscopic polypectomy alone???
Special considerations
* No discussion of technique
Colorectal Cancer – Epidemiology
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Incidence: Approx. 150,000 cases/year
Deaths: Approx. 50,000 deaths/year
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At diagnosis
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10% in situ disease
30% local disease
30% regional disease
30% distant disease
5 year survival, all patients: 50%
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local - 90%
regional - 60%
distant - 5%
U.S. Cancer Statistics Working Group. United States Cancer Statistics: 2003 Incidence and Mortality (preliminary data). Atlanta (GA): Department
of Health and Human Services, Centers for Disease Control and Prevention, and National Cancer Institute; 2006.
Incidence/Prevalence of Polyps
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Adenomatous polyps
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30% of Western population
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Most cancers arise from polyps
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*excludes syndromes
Carcinoma in situ vs. cancer
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 Think
Carcinoma in situ = high grade dysplasia
 Carcinoma in situ ≠ cancer
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Histology
Colorectal cancer is defined
by invasion of/through
muscularis mucosa
Histology
1. Colorectal cancer is
defined by invasion of
muscularis mucosa
2. Lymphatics are located
in submucosa
Genetic model of colorectal tumorigenesis
Colon Cancer Staging
T-stage
Tis
T1
T2
T3
T4
Intraepithelial or invasion of lamina propria
Invades submucosa
Invades muscularis propria
Invades subserosa or pericolic/rectal tissues
Into other organs/perforates visceral peritoneum
N-stage
0
1
2
0 LN
1-3 positive LNs
> 3 positive LNs
Colon Cancer Staging
AJCC 5
Stage
T
N
M 5 year DSS (%)
Colon
Rectum
0
Tis
0
0
I
1-2
0
0
75
70
II
3-4
0
0
65
55
III
Any 1-2
0
45
40
IV
Any Any 1
5
5
Relationship Between TNM Stage
and Survival in Colorectal Carcinoma
CA Cancer J Clin 2004;54;295-308
Treatment of CRC
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Polypectomy
Colonic Resection
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Treatment depends on the risk of lymph node metastasis.
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 Pathology is key!
1. Colorectal cancer is defined by
invasion of muscularis mucosa
2. Lymphatics are located in
submucosa
Incidence of malignant polyps
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Definition
Malignant polyps or T1 lesions (limited to the
submucosa)
 Represent 5% of all adenomas
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Colonoscopy polypectomy series: 2 – 12%
Colorectal resection series: 4 – 9%
Haggitt Level (1985)
Classification of polyps with invasive cancer
Level
Definition
Resected
(N)
+ LN (N)
0
Carcinoma
in situ
1
Invasion of
head
6
0 (< 1%)
2
Invasion of
neck
3
0 (< 1%)
3
Invasion of
stalk
4
0 (< 1%)
4
Invasion of
submucosa
of bowel wall
below polyp
13
4 (31%,
12-25%)
Haggitt RC, Glotzbach RE, Soffer EE, Wruble LD. Prognostic factors in
colorectal carcinoma arising in adenomas: Implications for lesions
removed by endoscopic polypectomy. Gastroenterology 89:328-36,
1985, p 330.
Villuous/sessile (flat) polyps with invasive cancer are by definition Haggitt 4.
Sessile Polyps
Kudo, 1993
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Risk of lymph node metastasis in each sessile lesion is not the
same
Haggitt’s: no detail for sessile lesions
Classification of submucosal invasion:
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Sm1—Invasion into the upper third of the submucosa
Sm2—Invasion into the middle third of the submucosa
Sm3—Invasion into the lower third of the submucosa
High rate of LN metastasis: 12-25%
Sm system
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Able to determine Sm1, Sm2, Sm3 in 97% of
cases
Haggitt Level 1, 2, 3 = Sm1
Haggitt Level 4 = Sm1, Sm2, or Sm3
Endoscopist must properly resect and prepare
specimen
Pathologist must properly section and examine
all layers
Correlations with Malignancy
Morphology
Morphology
Tubular
Tubulovillous
Villous
Incidence
75
15
10
% Malignant
5
20
40
Correlations with Malignancy
Grade
Dysplasia
Mild
Moderate
Severe
% malignant
5
20
30
Correlations with Malignancy
Size
Size (cm) % malignant
<1
1
1–2
10
≥2
50
Muto, 1975
Correlations with Malignancy
Size
Size (cm) % malignant
Size (cm) % malignant
<1
1
1–2
10
≤ 0.5
Negligible
≥2
50
0.6 – 1.5
2
1.6 – 2.5
19
2.6-3.5
43
≥ 3.5
76
Muto, 1975
Nusco, 1997
Relationship between
Size and Morphology
< 1 cm
1-2cm
> 2 cm
Tubular
76%
20%
4%
St. Mark’s Hospital Data
Tubulovillous
25%
47%
28%
Villous
14%
26%
60%
Increased risk of LN Metastasis
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Unfavorable pathologic features of malignant CR
polyps
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Poor differentiation (only on univariate)
Lymphovascular invasion (P < 0.009)
Invasion below submucosa (Haggitt Level 4)
Depth of invasion in Sm3 (P < 0.001)
Site in lower 1/3 of the rectum (P < 0.001)
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Positive resection margin (< 1 mm or 1 HPF)
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Not really – this is inadequate treatment, not an adverse risk factor!
P-values from Nascimbeni et al. N = 353 T1 colorectal sessile lesions
Management of Pedunculated
Malignant Polyps
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Haggitt Level 1, 2, 3
Complete excision or snaring
 Risk of LN metastasis < 1%
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Haggitt Level 4
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Treat as sessile lesions
Management of Sessile Malignant
Polyps
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< 2cm in diameter
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Adequate snare in one piece via colonoscopy
Requires microscopic free margin of at least 2mm
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Piecemeal removal
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Requires further excision/follow-up or resection
High risk factors (LVI, Sm3, distal 1/3 rectum)
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Oncologic resection
Full thickness transanal excision
Lesions amenable to colonoscopic
polypectomy
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Pedunculated or sessile < 2cm
Well/moderately differentiated
No lymphovascular invasion
Haggitt Level 1-3 or Sm1
Close follow-up available
Endoscopically
excision
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Negative resection margins (2mm)
complete
Criteria for Treatment of Malignant
CR Polyps by Polypectomy Alone
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Determined by risk of metastasis
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Low risk of Lymph Node Metastasis
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Pedunculated
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Sessile
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Haggitt Level 1, 2, 3
Level 4 Sm1, Sm2
Sm1, Sm2
High risk of Lymph Node Metastasis
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Lower 1/3 of the submucosa (Sm3)
LVI
Distal 1/3 of rectum
Malignant Colorectal Polyps that
Should have an Oncologic Bowel
Resection
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Lesions in colon
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Lesions in middle third and upper third rectum
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Pedunculated Haggitt Level 4 with invasion into distal third of
submucosa (Sm3) or LVI
Sessile lesions removed with margin < 2mm
Sessile lesions removed piecemeal
Sessile lesions with depth of invasion into distal third of submucosa
(Sm3)
Sessile lesions with LVI
Same as lesions in colon
Lesions in distal third rectum
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Pedunculated Haggitt Level 4 with invasion into distal third of
submucosa (Sm3) or pedunculated lesions with LVI
All sessile lesions
Why not just resect anyway?!
What if ???
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What if it’s clipped in ½?
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Pedunculated
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Sessile
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Unable to determine exact pathologic depth
Requires operative oncologic resection
What if it’s a very small lesion?
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Requires marking/tattoo CIRCUMFERENTIALLY
What if it’s carcinoma in situ?
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It’s not cancer. This is high grade dysplasia. Requires close follow-up.
Unless,
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Requires operative oncologic resection (even if Sm1, Sm2)
What if it’s shredded by forceps?
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Repeat endoscopy.
Require good resection with margin (2mm)
poor margins: repeat endoscopy with good margins
Piecemeal resection: discussion with pathologist and patient
What if it’s a large, non-endoscopically resectable polyp?
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Repeat endoscopy (2nd MD?)
Oncologic resection
Other considerations…
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When in doubt
Repeat colonoscopy
(endoscopy)
 Personally review pathology
 Get a second opinion
 Have a frank discussion with
patient
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Polyps
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Natural history of adenomatous polyps
Biology of polyps
Cancer epidemiology
The anatomy of the polyp
Correlations with Malignancy
Endoscopic polypectomy alone???
Special considerations
Indications for Polypectomy
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What if it’s clipped in ½
What if it’s shredded by forceps?
Pathology…
Marking/tattoo
Chances of Malignancy by histopath and size/morphology
* NO technique **