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Case Presentation. Patient F.B. is a 64 year old African-American male, referred from an outside M.D. for OB( ) stool and anemia. Patient was scheduled for colonoscopy based on the above indications.PSH: nonePMH: HTNhyperlipidemia. Case Presentation. SH:EtOH: 1-2 beers/day, 6-pack on weekends x 40 yearsTobacco:
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1. GI Grand RoundsOctober 1, 2004 Yoshi Makino, M.D.
USC Department of Internal Medicine
2. Case Presentation Patient F.B. is a 64 year old African-American male, referred from an outside M.D. for OB(+) stool and anemia. Patient was scheduled for colonoscopy based on the above indications.
PSH: none
PMH:
HTN
hyperlipidemia
3. Case Presentation SH:
EtOH: 1-2 beers/day, 6-pack on weekends x 40 years
Tobacco: ž ppd x 40 years
Drugs: Marijuana in youth; without h/o IVDA
ROS:
Denies h/o BRBPR, melena, stool caliber changes, nor weight loss. Without h/o GERD or other upper GI complaints.
4. Case Presentation Allergies: NKDA
Medications
Pravachol 40 mg PO daily
HCTZ 25 mg PO daily
Atenolol/Chlorthalidone 50 mg / 25 mg PO daily
Quinapril 40 mg PO daily
Norvasc 10 mg PO daily
Cardura 2 mg PO daily
EC ASA 81 mg PO daily
Darvocet or Tylenol 500 mg prn pain/HA
5. Laboratories
6. Colonoscopy Poor prep
Anus: small IH
Sigmoid: 2 cm flat polyp, s/p bx
Transverse colon: one diminutive polyp and a 1.5 cm sessile polyp, s/p bx
Ascending colon: multiple 2-9mm sessile polyp, s/p bx
7. Biopsy Results 8 of 11 polyps biopsied showed tubular adenoma
Of these 8 polyps, 2 also showed areas of focal increased glandular complexity and high grade dysplasia
8. Colonoscopy Images
9. Colonoscopy Images
10. What Now?
11. Family History
12. Attenuated FAP
13. Objectives Overview
Clinical Features
Diagnosis
Genetics
Management
14. FAP Overview Familial colorectal cancers account for < 5% of all cases of colon cancer
Yangming et al. AJG 2002;97(7)1822-1827.
Familial Adenomatous Polyposis (FAP) was first described by Lockhart-Mummery in 1925 as a disease with clear dominant inheritance
Adenomatous Polyposis Coli (APC: 5q21) gene identified by Kinzer and Groden in 1991
15. Attenuated FAP In 1990, Lynch et al described two families with right-sided colonic flat adenomas with more polyps than HNPCC but fewer than FAP
Lynch also observed later age of onset of colon cancer, and a paucity of rectal adenomas
Lynch et al. Cancer. 1990 Sep 1;66(5):909-15.
Initially called hereditary flat adenoma syndrome, later called attenuated FAP
16. Clinical Features Less than 100 adenomas, typically morphologically flat
Polyps primarily located proximal to the splenic flexure, sparing the rectum
Diagnosed at mean age of 44 years, and cancers at a mean of 56 years
Hernegger et al. Dis Colon Rectum. 2002 Jan;45(1):127-136.
17. Extracolonic Manifestations High association with gastric fundic polyps
Extracolonic cancers similar to FAP, including:
duodenal and periampullary tumors (5-10%)
pancreatic (2%)
thyroid (2%)
Gastric (0.5%)
Congenital Hypertrophic Retinal Pigment Epithelium (CHRPE), osteomas and desmoids are rarely seen
Hernegger et al. Dis Colon Rectum. 2002 Jan;45(1):127-136.
18. Comparison of Hereditary Colorectal Diseases
19. Distinguishing Flat Polyps
20. High-resolution Chromoendoscopy
21. High-resolution Chromoendoscopy Conventional dyes (e.g. 0.9% indigo carmine) or florescent dyes used in conjunction with a high-resolution endoscope (410k 850k pixels vs standard scopes 100k 200k pixels)
Hyperplastic polyps
a characteristic pit pattern of orderly arranged circular dots, morphologically similar to surrounding normal mucosa.
Adenomatous Polyps
surface grooves occasionally with a sulcus-like appearance
In a recent multicenter trial by Eisen et al., chromoendoscopy had a sensitivity of 82% and specificity of 82% in distinguishing the above polyps
22. Gastric Fundic Gland Polyps Fundic gland polyps account for 50% of all gastric polyps and are observed in 0.8-1.9% of all patients undergoing EGD
Studies estimate 52-88% of FAP patients have gastric fundic glands polyps
Unlike colonic adenomas, the number of gastric fundic gland polyps is not attenuated in AFAP
Burt. Gastro 2003;125:1462-1469.
Prevalence of duodenal and gastric adenomas is unknown, varying from 93% in one series to 0% in another
Lynch. Cancer. 1995. / Rozen. Jpn J Cancer Res. 1999
23. Endoscopic Features Polyps are sessile, hemispherical elevations, at times with a waist but no clear stalk
1 mm to 5 mm in diameter
Color is pale, pink, resembling surrounding mucosa
On biopsy, polyps chunk off or detach entirely at the base
Usually fewer than 10 polyps in sporadic cases, versus hundreds in FAP and AFAP
Burt. Gastro 2003;125:1462-1469.
24. Gastric Fundic Gland Polyps
25. Diagnostic Criteria for AFAP Leppert et al suggest a set of diagnostic criteria for the disease
A positive family history of colorectal cancer with at least one of the following criteria
CRC at any age
> 5 colorectal adenomas
2-4 adenomas and multiple gastric fundic polyps
Leppert et al. N Engl J Med 1990; 322:9.
Later studies suggest a fourth criteria
Number of colorectal adenomas must be < 100
Knudsen et al. Familial Cancer. 2003;2:43-55
26. Problems with the Criteria No consensus exists on the exact definition of AFAP
Cases of AFAP have been reported with adenomatous polyps in excess of 100
The age at which adenoma counts should be made is undefined
Burt et al investigated 120 patients from 2 families with AFAP (5 mutation) revealing median number of 25 polyps, with a range of 0-470 polyps Burt et al. Gastro. 2004;127:444-451
27. Extreme Phenotypic Variability
28. The Genetics of AFAP Spirio et al in 1993 identifies four mutations at the 5 end (exon 3) of the APC gene in seven families with AFAP
Spirio et al. Cell. 1993; 75: 951-7.
Since then, 38 distinct mutations have been identified
5 to codon 175 (15)
3 to codon 1596 (12)
Exon 9 (10)
Deletion of entire allele (1)
29. APC Gene Mutations
30. APC Mutation Phenotypes
31. A Model for Mutation and FAP APC gene is a classic tumor suppressor gene, primarily down-regulating intercellular ß-catenin activity and ultimately slowing cell cycle entry and progression
Dominant negative model suggests that the mutated gene product forms homodimers with the wild-type protein, causing lowered or abolished tumor suppressor activity
32. APC, ß-catenin and E-cadherin
33. An Explanation for Attenuation? 5 to codon 175
Mutation in this region affect the homodimer forming domain of the APC gene (amino acids 6-57)
Interactions between mutated and wild-type proteins are reduced
3 to codon 1596
Gene product not detectable by Western blot analysis
Suggests mRNA or protein degradation
Exon 9
Even wild-type allele undergoes significant physiological splicing in this region
Alternate splicing pathways may skip over mutation
34. MYH Mutations MYH along with OGG1 and MTH1 are proteins involved in the repair G:C to T:A transversions due to oxidative stress from 8-hydroxyguanine
Recently, inherited variants of the MYH gene have been associated with colorectal polyposis with a recessive pattern of inheritance
Al Tassan et al. Nat Genet. 2002;30:227-232.
Jones et al. Hum Mol genet. 2002;11:2961-2967.
35. MYH Mutation and AFAP MYH-associated polyposis is phenotypically similar to attenuated FAP
Later age of onset of polyposis than FAP
Polyps usually < 100, but counts of 500 have also been reported
Mutations in MYH may lead to G:C to T:A transversions in the APC gene
However, autosomal recessive pattern
36. MYH Mutation and AFAP In a recent study, Wang et al analyzed 984 patients with high risk for genetic mutation
313 patients with 1-3 adenomatous polyps on colonoscopy
444 patients with history of CRC
140 patients referred for probable FAP
18 patients with biallelic mutations were identified
2 patients with colorectal cancer at age > 51
16 patients with 20 - 500 adenomatous polyps
No patients with polyp counts < 20 had a biallelic MYH mutaition
Wang et al. Gastro. 2004;127:9-16.
37. Genetic Testing for AFAP Clinical criteria for AFAP met
Greater than 5 to 10 and less than 100 colorectal adenomas
2-4 adenomas and multiple gastric fundic polyps
First-degree relatives of a person with a known APC mutation, regardless of polyp status
A person with multiple adenomas who is a relative of a person with a known APC mutation
Grady. Gastro. 2003;124:15741594
38. Role of MYH Testing in AFAP At this time, there are insufficient clinical data regarding the role of MYH mutations
in people with adenomatous polyposis to make any recommendations regarding the use of MYH mutation analysis in the clinical management of these individuals.
39. Recap of Disease Course Generally age at onset and progression to cancer (44 and 56 years respectively) is 15 years later than that of classic FAP
Lesions usually proximal to the splenic flexure
Rectal sparing
Gastric fundic gland polyps commonly seen
40. Surveillance Recommendations Surveillance must be by colonoscopy
Due to lesions proximal to splenic flexure
Contrasts with screening by flexible sigmoidoscopy in classic FAP
Colonoscopy starting at 1017 years, annually
EGD starting at 30 years, every 13 years, depending on polyp status in duodenum
Grady. Gastro. 2003;124:15741594
41. Management Increased risk of colon cancer, but exact risk remains unknown (general consensus is roughly 60-80%)
Similar to FAP, disease progression from adenoma to carcinoma is not accelerated
Colonoscopy
Unlike FAP, there is a sufficiently low number of colonic polyps to make polypectomy practical
Burt et all. Gastro. 2004;127:444-451.
EGD
Best treatment of gastric fundic gland polyps is presently unknown
Burt. Gastro 2003;125:1462-1469.
42. When to Perform Colectomy? The exact risk of colon cancer is unknown in AFAP, but estimated between 60 80%
In FAP patients, The American Society of Colon and Rectal Surgeons recommends colectomy between ages 15 to 18
Church and Simmang. Dis Colon Rectum, August 2003.
No clear consensus exists for AFAP
15 year delay in onset of disease would suggest colectomy at age 30
In a series of 120 patient with AFAP by Burt et al., first CRC was at a mean age of 58 years (range of ages 29 to 81), with 12 patients over the age of 60 with intact colons
Burt et all. Gastro. 2004;127:444-451.
43. Type of Surgery Three main surgical options
Colectomy and ileorectal anastomosis (IRA),
Proctocolectomy with ileostomy (TPC)
Proctocolectomy with ileal pouch-anal anastomosis (IPAA)
As AFAP almost always spares the rectum, present consensus is for IRA, with subsequent surveillance by flexible sigmoidoscopy annually
Bülow et al. Gastro. 2000;119:14541460.
Church and Simmang. Dis Colon Rectum, August 2003.
44. Pharmacologic Therapy Treatment with sulindac and celecoxib may also reduce polyp burden
Giardiello et al. N Engl J Med 1993;328:1313-1316.
Steinbach et al. N Engl J Med 2000;342:194652.
In 1999, FDA approves celecoxib as a treatment for patients with FAP
Dosage: celecoxib 400 mg PO BID
To reduce the number of adenomatous colorectal polyps in familial adenomatous polyposis (FAP), as an adjunct to usual care (e.g., endoscopic surveillance, surgery).
FDA Application NDA 21-156 & 20-998/S007
45. Celecoxib and FAP
46. Sulindac and FAP 15 case series and at least 4 randomized, controlled trials have proven the efficacy of NSAIDs (primarily sulindac) in reducing the adenoma burden of persons with FAP
However, in a recent trial by Giardiello, sulindac did not significantly reduce or delay the emergence of colorectal adenomas in prephenotypic FAP patients
Definitive clinical outcomes (e.g., reductions in CRC morbidity and mortality or changes in surveillance practices) have yet to be proven.
Hawk et al. Gatro. 204;126:14231447.
Giardiello et al.N Engl J Med 2002;346:10541059.
47. Conclusions Attenuated FAP is a rare cause of CRC, accounting for <0.1% annually
However, distinguishing AFAP from sporadic polyps is critical as the lifetime risk for CRC may be as high as 60-80%
Suspicion for AFAP should be heightened in:
the presence of > 5-10 colonic polyps (especially proximal distribution)
2-4 adenomas and multiple gastric fundic polyps
Family history should be obtained, and genetic testing should be offered to all first degree relatives
48. Conclusions Annual colonoscopy with polypectomy may be sufficient to prevent progression of disease
Pharmacologic therapy with celecoxib/ sulindac may further aid in reducing polyp burden
No consensus yet regarding need for colectomy, however when required, IRA is believed to be sufficient
49. The Future of AFAP AFAP remains a poorly defined entity
While most literature associates AFAP with specific APC mutations, recent literature suggest MYH mutations may also be seen in this disease Wang et al. Gastro. 2004;127:9-16.
Consensus on a gold-standard test for AFAP is required to reliably report and follow the course of this disease
Cumulative lifetime polyp counts
To better understand progression of disease
To reach a consensus regarding age that polyp count should be made
50. Patient Follow-up Patient had an EGD on 9/20/2004 to evaluate for gastric fundic gland polyps and periampullary disease
No significant lesions found
Patient underwent genetic counseling at Norris Comprehensive Cancer Center on 9/24/2004, and is presently pending results of genetic testing
51. Acknowledgements
Dr. Laurie DeLeve
Dr. Mark Ewing
GI Consult Team
This presentation is available at:
http://www.makino.net/gastro
52. Fight On USC!