Cancer detection

CANCER DETECTION AND SCREENING

DR. ADONIS A. GUANCIA

7

7.2

8.2

10.7

11.2

11.4

12.5

12.5

13.6

14.8

32.4

0 5 10 15 20 25 30 35

Nasopharynx

Thyroid Gland

Larynx

Gastric

Skin

Rectal

Liver

Lymph Node

Colon

Prostate

Lung

Top Ten Leading Cancer Site in Male 2000 - 2009

11.3

16.5

16.6

18.8

20.7

21.2

22.8

23.3

24.1

119.9

0 20 40 60 80 100 120

Lymph Node

Thyroid Gland

Prostate

Corpus Uteri

Lung

Head and Neck

Ovary

Cervix

Colorectal

Breast

Ten Leading Cancer Sites by Gender Adjusted 2000 - 2009

Five-year Relative Survival (%)* during Three Time Periods By Cancer Site

*5-year relative survival rates based on follow up of patients through 2003. †Recent changes in classification of ovarian cancer have affected 1996-2002 survival rates.Source: Surveillance, Epidemiology, and End Results Program, 1975-2003, Division of Cancer Control andPopulation Sciences, National Cancer Institute, 2006.

Site 1975-1977

1984-1986

1996-2002All sites 50 53 66Breast (female) 75 79 89Colon 51 59 65Leukemia 35 42 49Lung and bronchus 13 13 16Melanoma 82 86 92Non-Hodgkin lymphoma 48 53 63Ovary 37 40 45Pancreas 2 3 5Prostate 69 76 100Rectum 49 57 66Urinary bladder 73 78 82

Breast Cancer Screening

Effective Screening Test Disease incidence should be high Diagnosed at early stage but

without any signs Early diagnosis and treatment

should be more effective than late treatment

Benefit of early treatment should be higher than the cost and harmfulness of screening

Breast Cancer: Risk Factors (Unchangeable)

Being a woman

Age

Genetic factors - mutations in BRCA1 or BRCA2; 50-60% of women inheriting a BRCA1 mutation from either parent will have breast cancer by age 70

Family history of breast cancer (not related to BRCA mutations)

Personal history of hyperplastic breast disease

Breast Cancer Risk Factors (Unchangeable)

Personal history of breast cancer

Race: incidence is higher in Caucasian compared with African-American, Hispanic or Asian women

Radiation treatment: chest irradiation as a child/young woman can significantly increase risk of developing breast cancer

Menstrual history: early menarche (<12 yr) or late menopause (>50yr) has some association with increased risk. Also nulliparous, or first childbirth at >30 yrs.

Breast Cancer Risk Factors Lifestyle Associated

Oral contraceptives - remains controversial

Hormone replacement therapy - >5 years of therapy with combined estrogen and progesterone may increase risk

Not breast feeding

Diet and obesity; physical activity

Smoking - still being investigated

Alcohol - 2-5 drinks/day can increase risk x 1.5 over non-drinkers.

Does Mammography Reduce Breast Cancer Mortality?

Mortality Reduction in Screening Patients

Study Age Mortality reduction (%)

HIP 40-64 24Malmö 45-69 19Sweeden 40-74 32Edinburgh 45-64 21Stockholm 40-64 26Canada-1 40-49 -3Canada-2 50-59 -2Gothenburgh39-59 16

All studies 39-74 24

CA Cancer J Clin 2003; 53:141-169

At What Age Mammography Screening Should Start?

All women starting at 40 years old should be screened with mammography

What Intervals Mammographic Screening Should be Done?

EVERY YEAR

Digital Mammography Provide equivalent detection level

compared with conventional mammography

Offers a lower average dose of radiation

Easier access to images and computer-assisted diagnosis

Superior in pre and postmenopausal women with dense breast and women under the age of 50

Breast US

It is more subjective than

mammography Could not detect

microcalcifications Sonographic contrast is week

between tumor and adipous tissue Documentation is problematic Not useful for screening

Breast MRI

Expensive Higher sensitivity with lower

spesificity Not safe for detection of

microcalcification Useful for additional screening

method for high risk women having mammography

MRI for Evaluation of the Breast

Highly sensitive but high false positive rate

Useful for screening BRCA patients May be useful in staging known

breast cancer May become an important screening

modality

Other Imaging Modalities

Tc99m sestamibi scan (Miraluma) Tomosynthesis (variation of

mammogram)

Breast Cancer Risk Factors

Greatly increased risk RR>4.0 Inherited genetic mutations for breast

cancer ≥ 2 first degree relatives with breast

cancer diagnosed at early age Personal history of breast cancer Age >65 (increasing risk with increasing

age to 80)

Screening for High Risk Women

Mammographic screening should be start at 30 years of age (rarely before this age)

Screening interval can be shorter (e.g. 6 mos)

MRI can be added US can be added

Screening Guidelines for the Early Detection of

Breast Cancer, American Cancer Society

Yearly mammograms are recommended starting at age 40.

A clinical breast exam should be part of a periodic health examination, about every 3 years for women in their 20s and 30s. Asymptomatic women aged 40 and older should continue to undergo a clinical breast exam, preferably annually*.

Beginning in their early 20s, women should be told about the benefits and limitations of breast-self examination. Women should know how their breasts normally feel and report any breast changes promptly to their health care providers.

Beginning at age 40 years, annual CBE should be performed prior to mammography

Cervical Cancer Screening

Cervical Screening

incidence decreased > 50% the past 30 years American Cancer Society estimates 11,270

new cases of cervical cancer in the United States in 2009, with 4,070 deaths from the disease

Cervical Screening

should begin at 21 years of age Screening done regardless of the age of onset

of sexual intercourse

Cervical Screening

Even at a high rate of infection with HPV in sexually active adolescents,

invasive cervical cancer is very rare in women younger than 21 years old.

Cervical Screening

Cervical cytology screening :

21–29 years, every 2 years using conventional or liquid-based cytology.

30 years and older with three consecutive cervical cytology test results that are negative for CIN and malignancy may be screened every 3 years

> 65 years old no testing.

Cervical Screening

May require more frequent cytology screening Women who are infected with human

immunodeficiency virus (HIV) Women who are immunosuppressed (such as those

who have received renal transplants) Women who were exposed to diethylstilbestrol in

utero Women previously treated for CIN 2, CIN 3, or

cancer

Cervical Screening

It has been demonstrated, however, that the rate of dysplasia decreases as the number of sequential negative Pap test results increases

Cervical Screening

Formal cost-effective analysis of data from this national program showed that the most cost-effective strategy for cervical cancer screening is cytology testing no more often than every 3 years in women with prior normal screening test results

Cervical Screening

May discontinue cytology screening with three or more negative cytology test results in a row and no abnormal test results in the past 10 years.

HPV

70 % of cervical cancer result from infection with HPV 16 and 18

90% of Genital wart are caused by 6 and 11

HPV vaccination guidelines

Organization/Nation Start Vaccine Catch Up

ACIP 11-1213-2 6

American College of Ob-Gyn 9-26

American Cancer Society 11-18None

World Health Organization 9-13

Future ?

Anal Pap smears 4000 cases of anal cancer in women in 2003

and in contrast to cervical cancer the rates are increasing

Lung Cancer Screening

Lung Cancer High Risk Factors

55 – 74: > 30 pack years smoking historyceased smoking < 15 years

> 50 years > 20 pack year smoking historyone additional risk factor

Prevalence of Stage I Lung Cancer in CT Screening Trials

% Stage II-ELCAP 85Mayo69Turino 73

Randomized TrialsLSS 43Depiscan 38DANTE 57

NELSON 64

Drawbacks or Limitations to CT Screening for Lung Cancer

Many nodules that require follow-up Potential Psychological Impact Surgery for Benign Disease Lung Cancer Deaths in Screened

Participants Interval Cancers (failure of screening) Potential Overdiagnosis Cases

PLCO trial

Prostate Lung Colo-rectal Ovarian Cancer Screening Trial

Determine effects of screening in mortality among men and women aged 55 to 74

Completed in 2005

PLCO Final Results Randomized 154,900 Individuals

Age 55-74 to CXR or Usual Care (4 years)

Screening Adherence Was 86% Baseline and 79-84% Yearly– 11% Screening Done in Usual Care

JAMA 2011; 306: 1865-1873

PLCO: Chest X-ray vs. Usual Care

JAMA 2011; 306: 1865-1873

• Annual Screening with CXR (4 years) Did Not Reduce Lung Cancer Mortality Compared to Usual Care.

• In Subset Analysis of NLST Eligible Participants, There Was No Mortality Reduction in the Chest X-ray Screened Arm.

Lung Cancer Risk Predictions:PLCO

Incidence Rate of Lung Cancer: per 10,000 Person Years on Control Arm (Intervention) Never Smoker: 2.5 (3.3) Former Smoker: 18.7 (19.3) Current Smoker: 71.4 (79.9)

Tammemagi et al. JNCI 2011; 103: 1058-68

National Lung CancerScreening Trial (NLST)

CP1066773-57

SmokerFormer smoker30 pk yrAge 55-74

SmokerFormer smoker30 pk yrAge 55-74

40,000PLCO40,000PLCO

10,000ACRIN10,000ACRIN

RandomizedRandomized

Low-dose fast spiral CTLow-dose fast spiral CT

CXRCXR

YearsYears

00 11 22

National Lung Cancer Screening Trial

August 2002 - April 2004 Enrollment Three rounds of screening through September

2007 Followed for Events through December

31, 2009 Median F/U = 6.5 years; Max 7.4 years

Adherence to Screening 95% on CT arm: 93% on CXR Average annual rate of CT in CXR arm was

4.3%

NEJM 2011 epub June 29 NEJM.org


CT CXRAbnormal Screen 24.2% 6.9%

False Positive 96.4% 94.5%

Clinically Significant other abnormalities 7.5% 2.1%

Total Lung Cancers 1,060 941

LC per 100,000 person - years 645 572



Diagnostic F/U of Positive Screen CT CXR• Imaging 58% 78%

– PET 8% 8%

• FNA 1.8% 3.5%

• Bronchoscopy 3.8% 4.5%

• Surgical: Mediastinoscopy, Thorascopy, or Thoracotomy 4.0% 4.8%



CT CXRTotal Lung Cancers 1,060 941

Screen-detected Lung Cancer 649 279

Lung Cancer after Negative Screen 44 137

Either Missed Screening or After Screening Phase 367 525


National Lung CancerScreening Trial


• 20% Mortality Reduction from Lung Cancer

• 6.7% All Cause Mortality Reduction

• 320 Persons Needed to be Screened with LDCT to Prevent One Death

NCCN Guidelines Screening with LDCT is

Recommended for High-Risk Individuals Meeting the NLST Criteria (2A)

Also Recommend Screening for (2B)– Age >50 Years and ≥20 Pk Years and One

Additional Risk Factor Other Than Second Hand Smoke

NCCN.org accessed 11/8/2011

Lung Cancer Susceptibility Locus Identified

15 q 251) Amos et al. Nature Genetics 2008; 40:616-

22.2) Hung et al. Nature 2008; 452:633-37.

15 q 241) Thorgeirsson et al. Nature 2008; 452:638-

42. (Associated with nicotine dependence, lung cancer and vascular disease)

Potential Biomarkers for Screening

Airway epithelial cells Gene expression profiling Chromosomal aneusomy – FISH Gene methylation

Blood biomarkers Serum proteins Autoantibodies to tumor antigens Gene expression profiles in PBMC

Breath analysis of VOC Urine markers of carcinogens

Early CDT-Lung Blood Test 573 case/control study with match for

age sex and smoking Sensitivity 40%; Specificity 90%; Accuracy

88% Detect some cancers 3-5 years in advance

of symptoms Autoantibodies to 6 cancer antigens

P53; NY-ESO-1; CAGE; GBU4-5; Annexin 1 and SOX2

Murray et al Ann Oncol ePub Feb 2010 and ASCO posters 2010

New York Times

Volatile Compounds in Exhaled Breath Analysis of Lung Cancer Patients

1/3 of compounds detected by solid phase microextraction were hydrocarbons Aromatic hydrocarbons Alcohols Aldehydes Ketones Esters Sulfur compounds Nitrogen containing compounds Halogenated compounds

Ligor M et al. Clin Chem Lab Med 2009; 47:550-60.

Prostate Cancer Screening

ACS Screening Recommendations

Prostate Cancer Early Detection Guidelines

> 50 years with at least a 10 year life expectancy should receive information regarding possible benefits and limitations of finding and treating prostate cancer early, and should be offered both the PSA blood test and digital rectal exam annually

Men in high risk groups (African Americans, men with close family members---fathers, brothers, or sons---who have had prostate cancer diagnosed at a young age) should be informed of the benefits and limitations of testing and be offered testing starting at age 45

.

Types of Tests

Diagnostic Tests - Tests done because of an identified problem (disease is suspected)

Screening Tests -Test done on people who have no symptoms of disease

There is widespread agreement on the use of diagnostic tests for prostate cancer

Screening for prostate cancer is much more controversial

What are Tests for Prostate Cancer?

Changes in the PSA Era

.

Tyrol, Austria

42% mortality reduction

Olmstead County, Minnesota

22% mortality reduction

SEER

Decreased mortality in white men

Department of Defense

Increased early stage disease

Does screening for Prostate Cancer save lives?

.

Prostate cancer death rates have fallen during the PSA era, but it is not clear this is primarily due to screening

Other possible reasons for this decline:

Disease is found earlier because of

increased awareness

utilization of diagnostic PSA testing

Improved treatments


.

False negative results

False positive results

Overdiagnosis


.

False negative results� PSA and DRE “normal”, but cancer is

present� May lead to false reassurance, delayed

diagnosis

Research has shown that no cut-off value of PSA is completely reliable to rule-out cancer� Prostate Cancer Prevention Trial end of

study biopsies found cancer in some men with PSA less than 1.0 ng/ml


Population Screening with PSA

4.0+

PSA 4+ 7.6%Positive biopsy 25%High grade 19%

Screen 10,000 Men

PSA 4+ 760Cancer 190High grade 36

PSA <4 9240Cancer 1386 High grade 208“Normal PSA” 92.4%

Positive biopsy 15%High grade 15%

<4.0

PSASEER, PCAW, Prostate Cancer Prevention Trial Data

.


False positive results PSA and/or DRE abnormal, but no cancer

found

Can lead to worry, additional tests, and increased costs


.


False positive results

Overdiagnosis Some (many?) cancers found by screening

grow very slowly and will never cause problems


New Findings in Screening

.

Results from 2 major, long-term studies reported this year – their findings conflict

ERSPC (European Randomized Screening for Prostate Cancer)

PLCO (Prostate, Lung, Colon and Ovarian)


ERSPC

Began in 1991 in seven European countries

162,000 men aged 55 to 69 randomized to screening vs usual care

Median follow-up about nine years

ERSPC

Findings More cancers detected with screening

5990 cancers in screening group 4307 cancers in control group

Fewer prostate cancer deaths in screening group

261 deaths in screening group 363 deaths in control group

Conclusion: 20% lower prostate cancer deaths in screening group

ERSPC Multiple concerns/questions:

Minimal-to-no participation of men of African origin Different screening and follow-up protocols

Different PSA levels and DRE usage Variable treatment and outcomes (quality questions)

To prevent one prostate cancer death 1410 men screened 48 men treated (with attendant risks, side-effects,

complications)

Bottom line Screening every 4 years, with PSA threshold of 3

ng/ml may decrease chance of prostate cancer death Unclear how this correlates to current U.S. pattern of

annual screening with different PSA “triggers” (2.5 – 4.0 ng/ml)

High level of overdiagnosis and overtreatment with this approach (although these numbers are likely to go down after longer follow up period)

Relevance of findings to African American men unclear

PLCO

Began in 1993, ten U.S. Centers 73,000 men aged 55 to 74

randomized to screening annually vs routine follow-up

Median follow-up about ten years

PLCO

Findings At 7 years, screening found more cases of

cancer 2,820 prostate cancers in annual screening group 2332 cases in “usual care” group

More prostate cancer deaths in screening group 7 years: 50 deaths among annually screened compared

with 44 in usual care group 10 years: 92 deaths in annually screened vs 82 in usual

care Conclusion – No mortality benefit with screening

Prostate cancer deaths similar in both groups Overall death rate slightly higher in screened (not

statistically significant)

PLCO Questions/concerns with study

44% of men had at least one PSA test prior to study May have excluded more aggressive prevalent cancers Selectively included men with prostate cancers not

detected by PSA screening (bias against showing a screening effect)

Many men in the “usual care” group were screened during the course of the study Initially powered for 20% contamination, later revised to

38% PSA screening in control group : 40% first year; 52% by

year 6 Less than half of those with a positive screen result had

a biopsy Insufficient African American participation (< 5%) to

allow specific analysis of outcomes in this group Bottom line – no difference in death rates at 10

years between intensively screened and less-intensively screened men

Relevance of these findings to African American men is unclear

Treatment OptionsNew Findings in Treatment

JAMA, September 2009

Watchful Waiting

Study published September 2009 14,500 men aged 65 + with localized

prostate cancer No active treatment for at least 6 mos

following prostate cancer diagnosis At 10 years, 9% of men had died of prostate

cancer 1017 men died of prostate cancer 5721 men died of other causes 7420 men still alive

Approximately 11% African Americans in study population, but authors did not report findings separately for this group

• PSA screening detects cancers earlier.

• Treating PSA-detected cancers may be more effective, but this is uncertain.

• PSA may contribute to the declining death rate but the extent is unclear

• False positives are common. • Overdiagnosis and

overtreatment is a problem, but magnitude is uncertain.

• Treatment-related side effects are fairly common.

Potential Benefits

Summary

Potential Harms

Bottom line: Uncertainty about degree of benefits and magnitude of harms

Screening Recommendations

Current ACS Screening Guidelines

Men age 50 and over with at least a 10 year life expectancy should receive information regarding possible benefits and limitations of finding and treating prostate cancer early, and should be offered both the PSA blood test and digital rectal exam annually

Men in high risk groups (African Americans, men with close family members---fathers, brothers, or sons---who have had prostate cancer diagnosed at a young age) should be informed of the benefits and limitations of testing and be offered testing starting at age 45

Colon Cancer Screening

Average risk Colon cancer

50 years of age No history of adenoma or colon cancer No history of inflammatory bowel disease Negative family history

Increased risk for Colorectal Cancer

Adenoma/sessile serrated polyp History of colorectal cancer Inflammatory bowel disease Positive family history

Colorectal Cancer high risk syndromes

Lynch Syndrome (hereditary nonpolyposis colorectal cancer)

Polyposis syndrome Classical familial adenomatous polyposis Attenuated Familial Adenomatous Polposis MUTYH-Associated Polyposis Peutzh Jeghers Syndrome Juvenile Polyposis Syndrome Serrated Polyposis Syndrome

Colorectal CancerSporadic (average risk) (65%–85%)

Familyhistory(10%–30%)

Hereditary nonpolyposis

colorectal cancer (HNPCC) (5%)Familial

adenomatous polyposis (FAP)

(1%)

Rare syndrom

es (<0.1%)

CENTERS FOR DISEASE CONTROLAND PREVENTION

Normal to Adenoma toCarcinoma

Human colon carcinogenesis progresses by the

dysplasia/adenoma to carcinoma pathway

Benefits of Screening

Cancer Prevention Removal of pre-cancerous polyps prevent

cancer (unique aspect of colon cancer screening)

Improved survival Early detection markedly improves chances

of long term survival

ACS 2003 CRC Prevention and Early Detection Recommendations

Fecal Occult Blood Testing (FOBT) Guaiac

Immunochemical

Flexible Sigmoidoscopy (FSIG)

FSIG + FOBT

Colonoscopy

Double Contrast Barium Enema (DCBE)

The 2008 CRC Guidelines Update was a Joint Effort of 5 Organizations

American Cancer Society

U. S. Multi-Society Task Force on Colorectal Cancer American Gastroenterological Association

American College of Gastroenterology

American Society of Gastrointestinal Endoscopists

American College of Radiology

CRC Screening Guidelines: What Else is New?

Two new tests recommended: stool DNA (sDNA) and computerized tomographic colonography

(CTC) – sometimes referred to as virtual colonoscopy

The guidelines establish a sensitivity threshold for recommended tests

The guidelines delineate important quality-related factors for each form of testing

The full article can be accessed at:http://caonline.amcancersoc.org/cgi/content/full/CA.2007.0018v1

http://caonline.amcancersoc.org/cgi/content/full/CA.2007.0018v1

http://caonline.amcancersoc.org/cgi/content/full/CA.2007.0018v1

2008 CRC Screening GuidelinesBeginning at age 50, both men and women at average risk for developing colorectal

cancer should use one of the screening tests below:

Tests That Detect Adenomatous Polyps and Cancer

Flexible sigmoidoscopy (FSIG) every 5 years*, or

Colonoscopy every 10 years, or

Double contrast barium enema (DCBE) every 5 years*, or

CT colonography (CTC) every 5 years*

Tests That Primarily Detect Cancer

Annual guaiac-based fecal occult blood test (gFOBT) with high test sensitivity for cancer *, ** or

Annual fecal immunochemical test (FIT) with high test sensitivity for cancer*,** or

Stool DNA test (sDNA), with high sensitivity for cancer*, interval uncertain

* Colonoscopy should be done if test results are positive.** For gFOBT or FIT used as a screening test, the take-home multiple sample method should be used.

gFOBT or FIT done during a digital rectal exam in the doctor's office is not adequate for screening.

2008 CRC Guidelines Continue to Emphasize Options Because:

Evidence does not yet support any single test as “best”

Uptake of screening remains disappointingly low Individuals differ in their preferences for one test

or another Primary care physicians differ in their ability

to offer, explain, or refer patients to all options equally

Access is uneven geographically, and in terms of test charges and insurance coverage

Uncertainty exists about performance of different screening methods with regard to benefits, harms, and costs (especially on programmatic basis)

FOBT Sensitivity: Take Home vs. In-Office

Sensitivity of Take Home vs. In-Office FOBT

Sensitivity

FOBT method(Hemoccult II)

All Advanced Lesions

Cancer

3 card, take-home 23.9 % 43.9 %

Single sample, in-office 4.9 % 9.5 %

Collins et al, Annals of Int Med Jan 2005

Stool DNA Test (sDNA)

Rationale Fecal occult blood tests

detect blood in the stool – which is intermittent and non-specific

Colon cells are shed continuously

Polyps and cancer cells contain abnormal DNA

Stool DNA tests look for abnormal DNA from cells that are passed in the stool*

*All positive tests should be followed with colonoscopy

Performance Characteristics of Stool DNA in the Detection of CRC

Three versions of the previously marketed sDNA test have been evaluated Version 1 (K-ras, APC, p53,BAT-26, DIA) was

evaluated in the Imperiale trial

Version 1.1 (K-ras, APC, P53), PreGen-Plus is the currently marketed test

Version 2 (Vimentin only, or Vimentin + DIA) is currently under evaluation and is expected to enter the market in Fall 2008

Earlier and more recent tests were evaluated in smaller, mixed populations

Performance Characteristics of Stool DNA in the Detection of CRC

Testing evaluates stool for the presence of altered DNA in the adenoma-carcinoma sequence

No dietary restrictions No stool sampling (utilizes

the entire stool) Several studies suggesting

strong patient acceptance Testing interval uncertain Uncertainty about the

meaning of false positives

Study with One-Time Testing (v)

Sensitivity for Cancer

Ahlquist, et alGastro, 2000 (1) 91%

Imperiale, et alNEJM, 2004 (1) 51.6%

Syngal, et. alCancer, 2006 (1) 63%

Whitney, et alJ Mol Diagn, 2004 (1.1)

70%

Chen, et alJNCI, 2005 (2) 46%

Itzkowitz, et alDDW-AB, 2006 (2) 88%

Stool DNALimitations

Misses some cancers

Sensitivity for adenomas with current commercial version of test is low

Technology (and test versions) are in transition

Costs much more than other forms of stool testing (approximately $300 - $400 per test)

Not covered by most insurers

Stool DNALimitations (cont.)

Appropriate re-screening interval is not known

Not clear how to manage positive stool DNA test if colonoscopy is negative

FDA issues

Test availability

CT Colonography (CTC)

CTC Image Optical Colonoscopy

Courtesy of Beth McFarland, MD

CT Colonography

Rationale

Allows detailed evaluation of the entire colon

A number of studies have demonstrated a high level of sensitivity for cancer and large polyps

Minimally invasive (rectal tube for air insufflation)

No sedation required

CTC vs. Optical Colonoscopy: Meta-Analyses

Halligan 2005, Mulhall 2005

Polyp Size

CTC performance

>10mm 6-9 mm Cancer

Pooled Sensitivity

85-93% 70-86% 85.7%

Pooled Specificity

97% 86-93% ----

CTC vs. Optical Colonoscopy: Sensitivities for All Polyps

Pickhardt et al, NEJM 2003

Polyp Size

>10mm >8mm >6mm

CTC 92.2% 92.6% 85.7%

Colonoscopy 88.2% 89.5% 90.0%

CTC - Extra-Colonic Findings

Most have limited clinical impact, but some are important:

Asymptomatic cancers outside of colon and

rectum

Aortic aneurysms

Renal and gall bladder calculi

CT Colonography Limitations Requires full bowel prep (which most patients find

to be the most distressing element of colonoscopy)

Colonoscopy is required if abnormalities detected,

sometimes necessitating a second bowel prep Steep learning curve for radiologists Limited availability to high quality exams in many

parts of the country Most insurers do not currently cover CTC as

a screening modality

CT Colonography Limitations Extra-colonic findings can lead to

additional testing (may have both positive and negative connotations)

Questions regarding: Significance of radiation exposure

Management of small polyps

2008 USPSTF Guidelines

U.S. Preventive Services Task Force, Ann Intern Med 2008

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Cancer detection