Colon Cancer ScreeningColon Cancer Screening

NingNing

Tang, HMS IVTang, HMS IVGillian Lieberman, MDGillian Lieberman, MD

Ning Tang, HMS IVGillian Lieberman, MD July 2005

2

Ning Tang, HMS IVGillian Lieberman, MD

ObjectivesObjectives

Background on incidence and death rates from Background on incidence and death rates from colon cancercolon cancerPresent recent patient cases of colon cancer, and Present recent patient cases of colon cancer, and the radiographic findingsthe radiographic findingsDiscuss current recommendations for colon Discuss current recommendations for colon cancer screeningcancer screeningPresent modalities for colon cancer screening, Present modalities for colon cancer screening, focusing on modalities that involve the radiology focusing on modalities that involve the radiology departmentdepartment

3

Ning Tang, HMS IVGillian Lieberman, MD

2005 Estimated US Cancer Cases*2005 Estimated US Cancer Cases*

*Excludes basal and squamous cell skin cancers and in situ carcinomas except urinary bladder.Source: American Cancer Society, Cancer Statistics 2005 Presentation.

Men 710,040

Women 662,870 32%32% BreastBreast

12%12% Lung and bronchusLung and bronchus

11%11% Colon and rectumColon and rectum6%6% Uterine corpus Uterine corpus

4%4% NonNon--HodgkinHodgkin lymphoma lymphoma

4%4% MelanomaMelanoma of skinof skin

3% Ovary3% Ovary

3%3% ThyroidThyroid

2%2% Urinary bladderUrinary bladder

2%2% PancreasPancreas

21%21% All Other SitesAll Other Sites

Prostate 33%

Lung and bronchus 13%

Colon and rectum10%Urinary bladder 7%

Melanoma of skin 5%

Non-Hodgkin 4% lymphoma

Kidney 3%

Leukemia 3%

Oral Cavity 3%

Pancreas 2%

All Other Sites 17%

4

Ning Tang, HMS IVGillian Lieberman, MD

2005 Estimated US Cancer Deaths*2005 Estimated US Cancer Deaths*

ONS=Other nervous system.Source: American Cancer Society, Cancer Statistics 2005 Presentation.

Men 295,280

Women 275,000 27%27% Lung and bronchusLung and bronchus

15%15% BreastBreast

10%10% Colon and rectumColon and rectum6%6% OvaryOvary

6%6% PancreasPancreas

4%4% LeukemiaLeukemia

3%3% NonNon--HodgkinHodgkin lymphomalymphoma

3%3% Uterine corpusUterine corpus

2%2% Multiple myelomaMultiple myeloma

2%2% Brain/ONSBrain/ONS

22% All other sites22% All other sites

Lung and bronchus 31%

Prostate 10%

Colon and rectum10%Pancreas 5%

Leukemia 4%

Esophagus 4%

Liver and intra- 3% hepatic bile duct

Non-Hodgkin 3% Lymphoma

Urinary bladder 3%

Kidney 3%

All other sites 24%

5

Ning Tang, HMS IVGillian Lieberman, MD

Patient 1: EJPatient 1: EJ

80 80 yoyo woman with PMH significant for woman with PMH significant for htnhtn, GERD, , GERD, CVACVAMarch 2005: Presents to ER with bilateral lower March 2005: Presents to ER with bilateral lower quadrant, quadrant, crampycrampy abdominal pain x 2abdominal pain x 2--3 months3 months

initially infrequent, now occurring at least 5initially infrequent, now occurring at least 5--1010times per day for the past week times per day for the past week not related to eating not related to eating + flatus, nausea, vomiting (white foamy vomiting) + flatus, nausea, vomiting (white foamy vomiting) last bowel movement was approximately 4 days ago last bowel movement was approximately 4 days ago

6

Ning Tang, HMS IVGillian Lieberman, MD

Patient 1: EJPatient 1: EJ

PSH: CPSH: C--section, hysterectomysection, hysterectomyPE: PE: afebrileafebrile, HR 110, BP 196/95 , HR 110, BP 196/95

hypoactive bowel sounds, hypoactive bowel sounds, abdabd mildly distended and mildly distended and diffusely tender, worse in RLQ and diffusely tender, worse in RLQ and suprapubicsuprapubicregion. region. no rebound or guarding, no rebound or guarding, guaiacguaiac negative.negative.

Abdominal CT scan ordered in EDAbdominal CT scan ordered in ED

7

Ning Tang, HMS IVGillian Lieberman, MD

Patient 1: EJPatient 1: EJ

Courtesy of Jimmy Kang, MD

Thickened bowel wall

Multiple small retroperitoneal lymph nodes, do not meet criteria for pathologic enlargement

Mural calcifications on aorta

•Small bowel loops normal in caliber

•No bowel wall pneumatosis

•No free air in abdomen

8

Ning Tang, HMS IVGillian Lieberman, MD

Transition point

Wall thickening

Courtesy of Jimmy Kang, MD

Patient 1: EJPatient 1: EJ

9

Ning Tang, HMS IVGillian Lieberman, MD

Courtesy of Jimmy Kang, MD

Patient 1: EJPatient 1: EJ

Diffuse dilation of colon, most prominent in ascending, transverse, and segments of descending colon and sigmoid colon

*

* *

10

Ning Tang, HMS IVGillian Lieberman, MD

Courtesy of Jimmy Kang, MD

Patient 1: EJPatient 1: EJ

Diffuse dilation of colon, most prominent in ascending, transverse, and segments of descending colon and sigmoid colon *

*

11

Ning Tang, HMS IVGillian Lieberman, MD

Differential Diagnosis of Focal Sigmoid Differential Diagnosis of Focal Sigmoid Colitis/narrowingColitis/narrowing

Ischemic colitis (24% sigmoid) Ischemic colitis (24% sigmoid) Inflammatory bowel diseaseInflammatory bowel diseaseDiverticulitisDiverticulitisInfectious colitisInfectious colitisNSAIDNSAID--induced colitisinduced colitisColonic carcinomaColonic carcinomaRadiationRadiation--induced colitisinduced colitis

…at this point the differential is quite broad, direct …at this point the differential is quite broad, direct visualization was recommendedvisualization was recommended

12

Ning Tang, HMS IVGillian Lieberman, MD

Courtesy of Jimmy Kang, MD

Patient 1: EJPatient 1: EJPortable abdominal plain film taken the next day confirmed dilated loops of large bowel, cecum

measures approximately 10 cm.

No evidence of megacolon

13

Ning Tang, HMS IVGillian Lieberman, MD

Courtesy of Jimmy Kang, MD

Patient 1: EJPatient 1: EJSingle-contrast gastrograffin

enema conducted on the following day showed complete obstruction in the mid-

sigmoid colon. Filling defect in the lumen suggests a mass.

14

Ning Tang, HMS IVGillian Lieberman, MD

Patient 1: Hospital CoursePatient 1: Hospital CourseBased on the midBased on the mid--sigmoid obstruction seen on the sigmoid obstruction seen on the enema study, surgeons deemed that EJ would require a enema study, surgeons deemed that EJ would require a sigmoid resection. sigmoid resection. IntraIntra--Op: The ascending, transverse, and descending Op: The ascending, transverse, and descending colon were all dilated and thickened. A mass lesion was colon were all dilated and thickened. A mass lesion was palpated in the distal sigmoid. There was no evidence palpated in the distal sigmoid. There was no evidence of extra colonic spread within the abdominal cavity.of extra colonic spread within the abdominal cavity.Pathology: 4cm x 3.6cm highPathology: 4cm x 3.6cm high--grade grade adenocarcinomaadenocarcinoma, , invades through the invades through the muscularismuscularis propriapropria into the into the subserosasubserosa, with no lymph node involvement. Margins , with no lymph node involvement. Margins clear. clear.

15

Ning Tang, HMS IVGillian Lieberman, MD

Patient 2: MMPatient 2: MM67 67 y.oy.o. woman . woman p/wp/w a 3a 3--month history of month history of abdominal pain, weight loss, and rectal bleeding abdominal pain, weight loss, and rectal bleeding Never been screened for colon cancer Never been screened for colon cancer The patient was referred for computed The patient was referred for computed tomography (CT) of the abdomen with tomography (CT) of the abdomen with integrated CT integrated CT colonographycolonography..

16

Ning Tang, HMS IVGillian Lieberman, MD

Courtesy of Vassilios

Raptopoulos, MD

Patient 2: MMPatient 2: MMLow-attenuation, peripherally enhancing lesion in liver, consistent with metastasis (black arrow)

Constricting lesion in distal transverse colon (white arrow)

3-D reconstruction (virtual air-

contrast enema) shows apple-

core-like constriction

17

Ning Tang, HMS IVGillian Lieberman, MD

Courtesy of Vassilios

Raptopoulos, MD

Patient 2: MMPatient 2: MM

Panel A: endoluminal

3-D CT colonoscopy shows the overlapping distal edge of a lesion consistent with colon cancer. Panel B: photograph of the lesion

from colonoscopy.

18

Ning Tang, HMS IVGillian Lieberman, MD

Patient 2: MMPatient 2: MM

MM was admitted for transverse MM was admitted for transverse colectomycolectomy and and excision of liver metastasis. excision of liver metastasis. Pathology showed Stage IV Pathology showed Stage IV adenocarcinomaadenocarcinoma of of the colon. the colon. The patient received chemotherapy after The patient received chemotherapy after surgery, and has been doing well. surgery, and has been doing well.

19

Ning Tang, HMS IVGillian Lieberman, MD

For both of these patients, For both of these patients, screening might have picked up the screening might have picked up the

lesions earlier….lesions earlier….

Unfortunately, compliance with Unfortunately, compliance with screening is poor.screening is poor.

In 2/3 of patients, the initial diagnosis of colorectal In 2/3 of patients, the initial diagnosis of colorectal cancer (CRC) is made cancer (CRC) is made

afterafter

the onset of symptomsthe onset of symptoms

Up-to-date, Screening for colorectal cancer

20

Ning Tang, HMS IVGillian Lieberman, MD

Screening StatisticsScreening Statistics

The percentage of people aged 50 or older who The percentage of people aged 50 or older who reported receiving fecal occult blood testing reported receiving fecal occult blood testing within 12 months was within 12 months was

19.4 percent in 199719.4 percent in 199723.5 percent in 2001 23.5 percent in 2001

The percentages who reported lower endoscopy The percentages who reported lower endoscopy within five years were within five years were

29.9 percent in 199729.9 percent in 199738.7 percent in 2001 38.7 percent in 2001

Source: CDC Behavioral Risk Factor Surveillance System

21

Ning Tang, HMS IVGillian Lieberman, MD

U.S. Preventive Services Task Force U.S. Preventive Services Task Force Colorectal Cancer Screening Colorectal Cancer Screening

Guidelines (2002)Guidelines (2002)

Screen men and women aged 50 and older who Screen men and women aged 50 and older who are at average risk for CRCare at average risk for CRCHigher risk patients (firstHigher risk patients (first--degree relative degree relative dxdx with with CRC before age 60) should begin screening at a CRC before age 60) should begin screening at a younger age.younger age.

U.S. Preventive Services Task Force. Screening for Colorectal CaU.S. Preventive Services Task Force. Screening for Colorectal Cancer: Recommendations and ncer: Recommendations and Rationale. Rockville, MD: Agency for Healthcare Research and QuaRationale. Rockville, MD: Agency for Healthcare Research and Quality, July 2002. lity, July 2002.

22

Ning Tang, HMS IVGillian Lieberman, MD

Up-to-date, Screening for colorectal cancer

Incidence of CRC with ageIncidence of CRC with age

23

Ning Tang, HMS IVGillian Lieberman, MD

U.S. Preventive Services Task Force Colorectal U.S. Preventive Services Task Force Colorectal Cancer Screening Guidelines (2002)Cancer Screening Guidelines (2002)

Screening options include:Screening options include:Fecal occult blood test (FOBT)Fecal occult blood test (FOBT)Flexible Flexible sigmoidoscopysigmoidoscopyColonoscopyColonoscopyDoubleDouble--contrast barium enema.contrast barium enema.

There is insufficient data to determine which There is insufficient data to determine which screening strategy is best. screening strategy is best.

U.S. Preventive Services Task Force. Screening for Colorectal CaU.S. Preventive Services Task Force. Screening for Colorectal Cancer: ncer: Recommendations and Rationale. Rockville, MD: Agency for HealthcRecommendations and Rationale. Rockville, MD: Agency for Healthcare Research are Research and Quality, July 2002. and Quality, July 2002.

24

Ning Tang, HMS IVGillian Lieberman, MD

Regardless of which screening method is used, Regardless of which screening method is used, CRC screening is cost effective CRC screening is cost effective

costing less than $30,000 per additional year of life costing less than $30,000 per additional year of life gainedgained

Choice of screening method should be based Choice of screening method should be based upon patient preferences, medical upon patient preferences, medical contraindications, patient adherence, and contraindications, patient adherence, and available resources for testing and followavailable resources for testing and follow--up.up.

U.S. Preventive Services Task Force. Screening for Colorectal CaU.S. Preventive Services Task Force. Screening for Colorectal Cancer: Recommendations ncer: Recommendations and Rationale. Rockville, MD: Agency for Healthcare Research andand Rationale. Rockville, MD: Agency for Healthcare Research and

Quality, July 2002.Quality, July 2002.

U.S. Preventive Services Task Force Colorectal U.S. Preventive Services Task Force Colorectal Cancer Screening Guidelines (2002)Cancer Screening Guidelines (2002)

25

Ning Tang, HMS IVGillian Lieberman, MD

Menu of TestsMenu of Tests

Fecal Occult Blood Test (FOBT)Fecal Occult Blood Test (FOBT)Flexible Flexible SigmoidoscopySigmoidoscopyDoubleDouble--ContrastContrast Barium EnemaBarium EnemaColonoscopyColonoscopyVirtual Colonoscopy (CT)Virtual Colonoscopy (CT)

26

Ning Tang, HMS IVGillian Lieberman, MD

Fecal Occult Blood Test (FOBT)Fecal Occult Blood Test (FOBT)

GuaiacGuaiac--based test cards are prepared at home by patients based test cards are prepared at home by patients from three consecutive stool samples and forwarded to from three consecutive stool samples and forwarded to clinicians.clinicians.RCTsRCTs show mortality reductions from 15% to 33% from show mortality reductions from 15% to 33% from periodic FOBT screeningperiodic FOBT screeningIntended to pick up early malignancy: large adenomas Intended to pick up early malignancy: large adenomas rarely bleedrarely bleedAmerican Cancer Society (ACS) recommends screening American Cancer Society (ACS) recommends screening annuallyannually

U.S. Preventive Services Task Force. Screening for Colorectal CaU.S. Preventive Services Task Force. Screening for Colorectal Cancer: Recommendations and ncer: Recommendations and Rationale, July 2002. Rationale, July 2002. Glick, S. AJR

2000;174:1529-37.

27

Ning Tang, HMS IVGillian Lieberman, MD

Flexible Flexible SigmoidoscopySigmoidoscopyCan only visualize the lower half of the colon Can only visualize the lower half of the colon

7575--80% only visualize up to sigmoid, identifying only 3080% only visualize up to sigmoid, identifying only 30--40% 40% of lesionsof lesionsIf visualize up to If visualize up to splenicsplenic flexure, identify only 40flexure, identify only 40--50% of 50% of lesionslesions

Small risk of perforationSmall risk of perforationScreening with fecal occult blood testing and flexible Screening with fecal occult blood testing and flexible sigmoidoscopysigmoidoscopy has been shown to reduce mortality has been shown to reduce mortality from colorectal cancer from colorectal cancer ACS recommends screening every 5 years ACS recommends screening every 5 years

U.S. Preventive Services Task Force. Screening for Colorectal CaU.S. Preventive Services Task Force. Screening for Colorectal Cancer: Recommendations and ncer: Recommendations and Rationale, July 2002. Rationale, July 2002. Glick, S. AJR

2000;174:1529-37.

28

Ning Tang, HMS IVGillian Lieberman, MD

Double Contrast Barium EnemaDouble Contrast Barium Enema

The radiologic means of total colonic examination The radiologic means of total colonic examination Liquid barium and air is insufflated in colon via rectumLiquid barium and air is insufflated in colon via rectumCan pick upCan pick up

Ulcers Ulcers Strictures Strictures Polyps Polyps DiverticulaDiverticulaCancer Cancer Other abnormalities Other abnormalities

ACS recommends screening every 5 yearsACS recommends screening every 5 years

29

Ning Tang, HMS IVGillian Lieberman, MD

Barium EnemaBarium Enema

ProsProsNo sedation is needed. No sedation is needed. Complications, such as Complications, such as perforation of the perforation of the colorectal wall, are slight. colorectal wall, are slight. Less costly than Less costly than colonoscopy. colonoscopy.

ConsConsThe test may miss small The test may miss small polyps or sometimes polyps or sometimes even small cancers. even small cancers. Biopsy and polyp Biopsy and polyp removal cannot be done removal cannot be done during testing during testing colonoscopy. colonoscopy. Bowel prep can be Bowel prep can be uncomfortableuncomfortable

30

Ning Tang, HMS IVGillian Lieberman, MD

Iyer

RB et al. AJR

2002;179:3-13. Glick, S. AJR

2000;174:1529-37.

Pedunculated

polyp

Lesions found on barium enemaLesions found on barium enema

Sessile polyp (white arrows)

31

Ning Tang, HMS IVGillian Lieberman, MD

Glick, S. AJR

2000;174:1529-37. Iyer

RB et al. AJR

2002;179:3-13.

Lesions found on barium enemaLesions found on barium enema

3.5 cm flat discoid filling defect (white arrows)

Apple-core lesion in sigmoid colon

32

Ning Tang, HMS IVGillian Lieberman, MD

ColonoscopyColonoscopy

Colonoscopy is the most sensitive (90%) and Colonoscopy is the most sensitive (90%) and specific test for detecting cancer and large specific test for detecting cancer and large polyps, but is associated with higher risks.polyps, but is associated with higher risks.

BleedingBleedingPerforationPerforation

Diagnostic and therapeutic benefitsDiagnostic and therapeutic benefitsACS recommends screening every 10 yearsACS recommends screening every 10 yearsPreferred screening strategy by American Preferred screening strategy by American College of Gastroenterology College of Gastroenterology

U.S. Preventive Services Task Force. Screening for Colorectal CaU.S. Preventive Services Task Force. Screening for Colorectal Cancer: Recommendations and ncer: Recommendations and Rationale, July 2002. Rationale, July 2002.

33

Ning Tang, HMS IVGillian Lieberman, MD

Virtual ColonoscopyVirtual ColonoscopyNonNon--invasive procedure for producing images of the invasive procedure for producing images of the colonic lumencolonic lumenRequires bowel prep similar to colonoscopy, followed Requires bowel prep similar to colonoscopy, followed by installation of air or carbon dioxide through a rectal by installation of air or carbon dioxide through a rectal tubetubeNo need for sedationNo need for sedationMultidetectorMultidetector helical CT scanner used to construct highhelical CT scanner used to construct high--resolution 2resolution 2-- and 3and 3--dimension imagesdimension imagesExam can be performed in 10Exam can be performed in 10--15 minutes15 minutesSmall and flat polyps less well visualized than cancers Small and flat polyps less well visualized than cancers and large polypsand large polyps

U.S. Preventive Services Task Force. Screening for Colorectal CaU.S. Preventive Services Task Force. Screening for Colorectal Cancer: Recommendations ncer: Recommendations and Rationale, July 2002. and Rationale, July 2002.

34

Ning Tang, HMS IVGillian Lieberman, MD

Courtesy of Vassilios

Raptopoulos, MD

Patient 2: MMPatient 2: MM

Endoluminal

3-D CT colonoscopy shows the overlapping distal edge of a lesion consistent with colon cancer.

35

Ning Tang, HMS IVGillian Lieberman, MD

Virtual Colonoscopy: EvidenceVirtual Colonoscopy: EvidenceIn research studies, sensitivity for CT In research studies, sensitivity for CT colonographycolonography varied from 21% to 96%varied from 21% to 96%Overall, specificity was more consistent ~ 86%Overall, specificity was more consistent ~ 86%Sensitivity and specificity increased with polyp Sensitivity and specificity increased with polyp size (94% & 96% for polyps > 1cm)size (94% & 96% for polyps > 1cm)

But based on ideal conditions of bowel prep, But based on ideal conditions of bowel prep, software, method of interpretation, and training.software, method of interpretation, and training.In community practice, sensitivity drops to 55%In community practice, sensitivity drops to 55%

Cotton et al. JAMA. 2004;291:1713-19.Mulhall, BP et al. Ann Intern Med. 2005; 142: 635-50.Pickhardt

et al. NEJM. 2003;349:2191-200.

36

Ning Tang, HMS IVGillian Lieberman, MD

Virtual Colonoscopy: Virtual Colonoscopy: Unanswered QuestionsUnanswered Questions

If a lesion <1cm is found, does it need to be removed If a lesion <1cm is found, does it need to be removed immediately, or can it be followed over time?immediately, or can it be followed over time?If lesion should be removed, can radiologists and If lesion should be removed, can radiologists and gastroenterologists coordinate to perform colonoscopy gastroenterologists coordinate to perform colonoscopy immediately while bowel prepped?immediately while bowel prepped?Is virtual colonoscopy costIs virtual colonoscopy cost--effective? Absolute cost of effective? Absolute cost of virtual colonoscopy ($478) is less than colonoscopy virtual colonoscopy ($478) is less than colonoscopy ($728), but cost per year($728), but cost per year--ofof--lifelife--saved is less for saved is less for colonoscopy (factors in sensitivity, specificity, patient colonoscopy (factors in sensitivity, specificity, patient adherence, etc.). adherence, etc.). No consensus yet on role of virtual colonoscopy in No consensus yet on role of virtual colonoscopy in colon cancer screeningcolon cancer screening

Morrin

MM et al. Lancet. 1999;354:1048-9.Ransohoff, DF. JAMA.

2004;291:1772-4.

37

Ning Tang, HMS IVGillian Lieberman, MD

Patient 3: DGPatient 3: DG

70 70 y.oy.o. man w/CAD . man w/CAD s/ps/p CABG, CABG, htnhtn, , hypercholesterolemia, and CVAhypercholesterolemia, and CVAColonoscopy done at VA hospital, 1/2004. Colonoscopy done at VA hospital, 1/2004.

friable friable fungatingfungating 4 cm mass in the right colon in the opposing 4 cm mass in the right colon in the opposing wall ofwall of the the ileoileo--cecalcecal valve. The mass was biopsied, but valve. The mass was biopsied, but notnot removed. removed.

Biopsy of the mass demonstrated adenoma of the Biopsy of the mass demonstrated adenoma of the ascending colon, with hyperplasia of regional lymph ascending colon, with hyperplasia of regional lymph nodes. nodes. Patient was admitted to BIDMC for laparoscopic right Patient was admitted to BIDMC for laparoscopic right colectomycolectomy, 4/2004., 4/2004.

38

Ning Tang, HMS IVGillian Lieberman, MD

Courtesy of Vassilios

Raptopoulos, MD

Patient 3: DGPatient 3: DG

Pedunculated

polyp

39

Ning Tang, HMS IVGillian Lieberman, MD

Courtesy of Vassilios

Raptopoulos, MD

Patient 3: DGPatient 3: DG

Pedunculated

polyp

40

Ning Tang, HMS IVGillian Lieberman, MD

ReferencesReferencesAmerican Cancer Society. Cancer Statistics 2005 Presentation. From http://www.cancer.org/docroot/PRO/content/PRO_1_1_Cancer_Statistics_2005_Presentation.asp, accessed on July 19, 2005.Cotton et al. Computed tomographic colonography (virtual colonoscopy): a multicenter comparison with standard colonoscopyfor detection of colorectal neoplasia. JAMA. 2004;291:1713-19.Glick, S. Double contrast barium enema for colorectal cancer screening: a review of issues and a comparison with other screening alternatives. AJR 2000;174:1529-37.Iyer RB et al. Imaging in the diagnosis, staging, and follow-up of colorectal cancer. AJR 2002;179:3-13.

41

Ning Tang, HMS IVGillian Lieberman, MD

References (2)References (2)

Morrin MM et al. Virtual colonoscopy: a kinder, gentler colorectal cancer screening test? Lancet. 1999;354:1048-9.Mulhall, BP et al. Metal-analysis: computed tomographiccolonography. Ann Intern Med. 2005; 142: 635-50.Pickhardt et al. Computed tomographic virtual colonoscopy to screen for colorectal neoplasia in asymptomatic adults. NEJM. 2003;349:2191-200.Ransohoff, DF. Colon cancer screening in 2005: status and challenges. Gastroenterology 2005; 128:1685-95.Ransohoff, DF. Virtual Colonoscopy—what it can do vs what it will do. JAMA. 2004;291:1772-4.Rubin, E. M. et al. The virtual apple core of a colonic carcinoma. NEJM 2005;352:2733

42

Ning Tang, HMS IVGillian Lieberman, MD

References (3)References (3)

UpUp--toto--date. Screening for colorectal cancer. April 26, 2005. date. Screening for colorectal cancer. April 26, 2005. www.uptodate.comwww.uptodate.com. Accessed on July 19, 2005.. Accessed on July 19, 2005.U.S. Preventive Services Task Force. Screening for Colorectal U.S. Preventive Services Task Force. Screening for Colorectal Cancer: Recommendations and Rationale. Rockville, MD: Cancer: Recommendations and Rationale. Rockville, MD: Agency for Healthcare Research and Quality, July 2002. Agency for Healthcare Research and Quality, July 2002. ZalisZalis, ME et al. CT , ME et al. CT colonographycolonography reporting and data system: a reporting and data system: a consensus proposal. consensus proposal. Radiology.Radiology. 2005;236:32005;236:3--9.9.

43

Ning Tang, HMS IVGillian Lieberman, MD

With Special Thanks ToWith Special Thanks To

Jimmy Kang, MDJimmy Kang, MDVassiliosVassilios RaptopoulosRaptopoulos, MD, MDLarry Barbaras, our WebmasterLarry Barbaras, our WebmasterGillian Lieberman, MDGillian Lieberman, MDPamela Pamela LepkowskiLepkowski