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CANCER SCREENING 2008: Updates and Evidence

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Title: CANCER SCREENING 2008: Updates and Evidence


1
CANCER SCREENING 2008 Updates and Evidence
  • Leah Karliner, MD, MCR
  • Assistant Professor of Medicine
  • Division of General Internal Medicine
  • UCSF

2
OUTLINE
  • Evaluating Screening Tests general principles
  • Colon cancer screening which test is best?
  • Prostate cancer screening to screen or not to
    screen?
  • Ovarian cancer to screen high risk?

3
PRINCIPLES OF SCREENING
  • Disease has high prevalence
  • Disease has serious consequences
  • Detectable preclinical phase
  • Treatment for presymptomatic disease is more
    effective than after symptoms develop
  • Positive impact on clinical health outcomes
    early detection reduces cancer mortality

4
EFFECTIVENESS OF TEST
  • Tests should be simple, inexpensive and
    acceptable with a high sensitivity and
    specificity
  • Number of false positives is acceptably low

5
EFFECTIVENESS OF TEST
  • Questions to be answered when evaluating/comparing
    tests
  • Who will be tested?
  • What tests will it supplement or replace?
  • Is the new test safer?
  • Is the new test less costly?
  • Is the test more specific (excluding cases of
    non-disease)?
  • Is the new test more sensitive (detecting more
    cases of disease)?
  • Is wide-spread use of the test feasible in
    practice?

6
SCREENINGOTHER CONSIDERATIONS
  • Involving patients in the decision
  • What are the patients co-morbid conditions?
  • Associated life expectancy, feasibility of
    treatment, effects of treatment on quality of
    life?
  • What will you do with the results?

7
OUTLINE
  • Evaluating Screening Tests general principles
  • Colon cancer screening which test is best?
  • Prostate cancer screening to screen or not to
    screen?
  • Ovarian cancer to screen high risk?

8
COLON CANCER
9
COLORECTAL CANCER Principles of Screening
  • Disease has high prevalence Second most common
    form of cancer in the U.S.
  • Disease has serious consequences second highest
    cancer mortality rate overall in U.S.
  • Detectable preclinical phase polyps
  • Treatment for pre-symptomatic disease is more
    effective than after symptoms develop - yes
  • Screening reduces cancer mortality
  • Several studies have shown that screening with
    fecal occult blood test (FOBT) or sigmoidoscopy
    is associated with a reduction in colorectal
    cancer mortality

10
COLON CANCER SCREENING RECOMMENDATIONS
  • U.S. Preventive Services Task Force recommends
    screening all persons over 50
  • Benefits of screening outweigh potential harms
  • Quality of evidence, magnitude of benefit and
    potential harms vary with each method
  • Unclear which is the best test FOBT, FOBT plus
    sigmoidoscopy, colonoscopy

11
Changing Incidence
  • Colon cancer incidence rates
  • decreased for White and Asian-Pacific Islander
    men and women in U.S. from 1995-2004
  • were stable for African American, Latino and
    Native American men and women
  • Decrease in incidence largely due to screening
    and removing pre-cancerous polyps
  • Disparities in incidence rate decline also likely
    due to disparities in screening rates
  • Espey et al. Annual report to the nation on the
    status of cancer, 1975-2004, featuring cancer in
    American Indians and Alaska Natives. Cancer. Oct
    15, 2007.

12
AVAILABLE TESTS
  • Tests should be simple, inexpensive and
    acceptable with a high sensitivity and
    specificity ????
  • Commonly used tests
  • Fecal occult blood test
  • Sigmoidoscopy
  • Colonoscopy
  • Newer tests
  • CT Colonography
  • Fecal DNA testing

13
WHICH TEST?
  • Are the tests equally safe?
  • Are the tests equally costly?
  • Are the tests equally specific?
  • Are the tests equally sensitive?
  • Is wide-spread use of the test feasible in
    practice?

14
TEST ISSUES
  • Sigmoidoscopy
  • Fair evidence for reducing mortality
  • Sigmoidoscopy alone can miss proximal neoplasia
    a positive test needs to be followed by
    colonoscopy
  • GFOBT
  • Good evidence for reducing mortality
  • Trials used 6 sample every 1-2 years
  • Positive test needs to be followed by colonoscopy
  • FIT (fecal immunochemical test)
  • More sensitive than GFOBT somewhat less specific
  • Specific to human globin no dietary
    restrictions less direct stool handling

15
FIT compared to GFOBT
  • Screening Populations 3 cohort studies
  • FIT appear to be more sensitive in detecting CRC
    and large 1cm adenomas than Hemoccult II
  • FIT appear to be somewhat less specific (higher
    false positive rates) than Hemoccut II
  • FIT GFOBT
  • (Hemoccult II)
  • Sensitivity 57 - 82 32 - 50
  • Specificity 95 96 98

16
IS COLONOSCOPY BETTER?
  • Two observational studies of patients undergoing
    colonoscopy
  • Goals
  • prevalence and location of colonic neoplasia in
    asymptomatic patients, and
  • Assess risk of proximal advanced neoplasia in
    patients with or without distal neoplasia
  • Did NOT assess morbidity and mortality

17
IS COLONOSCOPY BETTER?
  • Colonoscopy showed some lesions that would have
    been missed by sigmoidoscopy alone
  • distal polyps were a predictor of proximal
    neoplasia,
  • but some patients with proximal neoplasia did not
    have distal polyps
  • If sigmoidoscopy alone had been done and if every
    adenomatous polyp triggered colonoscopy, 80 of
    high risk lesions would have been detected

18
SCREENING COLONOSCOPY?
  • Would proximal lesions have been detected by
    FOBT?
  • No assessment of morbidity and mortality

19
SCREENING COLONOSCOPY?
  • More sensitive than FOBT/sigmoidoscopy
  • More specific than FOBT
  • Higher risk (diagnostic colonoscopies have 1/2000
    perforation rate with polypectomy 1/500-1000)
  • More costly? (USPSTF says all of these screening
    methods are probably cost-effective)
  • Presumed to save lives because used as diagnostic
    test in FOBT studies, but at higher rate than
    FOBT?
  • Feasibility in practice dependent on availability
    of gastroenterologists and insurance coverage

20
CT COLONOGRAPHY
  • Non-invasive colon imaging method using thin
    section CT
  • Test characteristics in large 2003 study 3-D
    scan
  • N1,233 average risk individuals, single site
  • Sensitivity
  • 94 for polyps 8 mm
  • 89 for polyps 6 mm
  • Specificity
  • 96 for polyps 10 mm
  • 80 for polyps 6 mm
  • Pickhardt, 2003

21
CT COLONOGRAPHY
  • Multicenter study of screening population
  • 615 participants at 9 hospitals
  • Two-dimensional scans
  • Sensitivity
  • 55 for lesions 10 mm
  • 39 for lesions 6 mm
  • Specificity
  • 96 for lesions 10 mm
  • 91 for lesions 6 mm
  • Cotton, 2004

22
CT COLONOGRAPHY
  • Kim et al NEJM Oct 4, 2007
  • Single site 3-D scans
  • Comparison of diagnostic findings in two parallel
    large case series of CT colonography (3,120) and
    optical colonoscopy (3,163)
  • If CTC patient had polyp 6mm then offered same
    day therapeutic colonoscopy (7.9)
  • Found
  • similar rates of advanced neoplasia (3.2 vs
    3.4)
  • a few more invasive cancers found on CTC (n14 vs
    4)
  • 5 times as many polypectomies done in colonoscopy
    group

23
CT COLONOGRAPHY
  • Cornett et al Am J Gastroenterology June 2008
  • 159 patients with positive result on screening
    CTC
  • Subsequent optical colonoscopy
  • CTC overall miss rate 18.9 (25/132) but only
    6.2 (4/65) for polyps gt9mm
  • Of the 4 large polyps missed, 2 had poor CTC
    colonic distention, 3 were sessile
  • False positive CTC referral (no polyp seen on
    optical colonoscopy) 5

24
CT COLONOGRAPHY
  • Requires bowel prep and insufflation
  • Patients do not necessarily prefer over
    colonoscopy (50-50 in Kim et al study)
  • Test interpretation is very time consuming
  • Cost effectiveness
  • Assuming 100 sensitivity and specificity
  • To replace colonoscopy, it would have to be less
    than 50 the cost of colonoscopy and compliance
    would have to be 15-20 better
  • Sonnenberg, 1999

25
FECAL DNA TESTING
  • DNA alterations in colorectal cancer can be
    detected in the stool
  • Potential advantages
  • Non-invasive
  • No preparation
  • Detection along entire length of the colon

26
FECAL DNA TESTING
  • Evaluated as a screening test in asymptomatic
    individuals aged 50 and older
  • Fecal DNA test (21 mutations), Hemoccult II and
    colonoscopy
  • 4404/5486 completed all three aspects of the
    study
  • Subgroup of 2507 patients were analyzed
  • Imperiale, 2004

27
FECAL DNA TESTING
Fecal DNA Hemoccult II
Sensitivity for invasive cancer 51.6 12.9
Sensitivity for invasive cancer/adenoma with high grade dysplasia 40.8 14.1
Sensitivity for advanced neoplasia 18.2 10.8
Specificity 18.2 10.8
28
FECAL DNA TESTING
  • 20 of the subjects either did not provide
    samples or did not have colonoscopy
  • Many were aged 65 and over
  • Both FOBT and fecal DNA had relatively low
    sensitivities compared with what was expected
    based on prior studies

29
FECAL DNA REMAINING QUESTIONS
  • Are health outcomes improved?
  • Even if we assume benefit based on FOBT trials,
    how much?
  • Do the benefits outweigh the risks?
  • Public expectations about accuracy of DNA testing
  • Frequency of testing? Interval unclear
  • Cost
  • 400 to 800 vs 3 to 40 for FOBT

30
WHICH TEST?
  • Most preventable cases of colon cancer are found
    in those who have never been screened
  • If we screened with the currently available tests
    at the recommended intervals, we could make a big
    impact particularly in ethnic minorities who
    have lower screening rates than whites
  • Any screening is better than no screening for
    reducing colorectal cancer mortality

31
SCREENING FOR HIGH RISK POPULATIONS
  • Family History
  • 1st degree relative with colon CA or adenomatous
    polyp diagnosed at age lt60, or 2 1st degree
    relatives with colon ca at any age
  • Screening colonoscopy age 40 or 10 years prior to
    earliest family diagnosis
  • Repeat screen every 5 years
  • 1st degree relative colon CA/adenomatous polyp
    diagnosed at age 60, or two 2nd degree relative
    with colon ca at any age
  • Screened as average risk persons, starting age 40
  • Familial Adenomatous Polyposis (FAP)
  • Annual sigmoidoscopy starting age 10-12
  • HNPCC
  • Colonoscopy q1-2 years beginning age 20-25 or 10
    years prior to earliest CA diagnosis in family

32
SCREENING FOR HIGH RISK POPULATIONS
  • History of Adenomatous Polyps
  • surveillance based on pathology and number of
    adenomas at most recent prior colonoscopy
  • Any adenoma w/high grade dysplasia or villous
    features, or multiple adenomas (3)
  • Repeat colonoscopy in 3 years
  • 1-2 small (lt1cm) tubular adenomas w/ low grade
    dysplasia only
  • Repeat colonoscopy in 5 years-10 years

33
OUTLINE
  • Evaluating Screening Tests general principles
  • Colon cancer screening which test is best?
  • Prostate cancer screening to screen or not to
    screen?
  • Ovarian cancer to screen high risk?

34
Prostate Cancer
35
PROSTATE CANCER SHOULD WE SCREEN?
  • Disease has high prevalence Most commonly
    diagnosed cancer in U.S. men
  • 10 lifetime risk
  • 30 of men have prostate cancer at autopsy
  • Disease has serious consequences variable
    prostate cancer may be a benign disease for many
    men
  • Detectable preclinical phase ?PSA
  • Treatment for pre-symptomatic disease is more
    effective than after symptoms develop - Does
    early detection do more good than harm or vice
    versa?
  • Complications of prostate cancer treatment
  • 8.4 incontinence
  • 60 impotence
  • Prostate Cancer Outcomes Study 24 month follow up
  • Screening reduces cancer mortality ???

36
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37
DOES SCREENING DECREASE MORTALITY? EPIDEMIOLOGIC
EVIDENCE
  • Prostate cancer mortality has decreased following
    the introduction of prostate cancer screening
  • Reduction in mortality followed an initial
    increase in incidence
  • Due to PSA screening?
  • Changes in treatment?
  • Serendipitous effects of non-cancer-directed
    treatments?

38
IS TREATMENT OF EARLY DISEASE EFFECTIVE?
  • Does treatment of early prostate cancer reduce
    morbidity and mortality?
  • Radical prostatectomy vs. watchful waiting
  • RCT of 695 men
  • reduction in all-cause mortality, reduction in
    prostate cancer specific mortality, metastatic
    disease and local progression
  • Absolute reduction in prostate ca specific
    mortality
  • 30 in prostatectomy group vs. 50 in watchful
    waiting group
  • 5-year follow-up 2 fewer deaths in prostatectomy
    group
  • 10 year follow-up 5.3 fewer deaths in
    prostatecomy group
  • Bill-Axelson, NEJM 2005

39
RANDOMIZED CLINICAL TRIALS
  • 46,000 men underwent DRE and PSA
  • 11 year follow-up
  • 23 of invited group and 6.5 of comparison group
    underwent screening
  • Decrease in prostate cancer mortality, but small
    numbers of deaths overall
  • (10/7,348 screened vs. 74/14,231 unscreened
    NNS263)
  • Labrie, Prostate 2004

40
ONGOING RCTs
  • PLCO trial sponsored by the NCI
  • Intervention group (38,350) annual screens (PSA x
    5 and DRE x 3) vs. usual care (38,355) in healthy
    men 55-74
  • Enrolled 1992-2001 following for 13 years
  • European Randomized Study of Screening for
    Prostate Cancer (ERSPC) 8 countries
  • Randomizing close to 220,000 men to screening
    with PSA, DRE (and for positive tests transrectal
    ultrasound) vs usual care
  • Results expected between 2008-2010

41
DIGITAL RECTAL EXAMINATION
  • One-third of prostate cancers occur in areas
    which can be reached
  • Higher sensitivity performed by urologists
  • An abnormal digital rectal examination increases
    the likelihood of prostate cancer somewhat
  • A negative examination does not change the
    likelihood of a clinically significant prostate
    cancer
  • Low sensitivity of the examination

42
PSA SCREENING TEST ISSUES
  • 15 of men over the age of 50 have an elevated
    PSA
  • PSA gt10 ng/ml
  • 66 have prostate cancer
  • PSA 4-10 ng/ml
  • 22 have prostate cancer

43
PSA SCREENING TEST ISSUES
  • Levels of 4.0 ng/ml or less have typically been
    considered to be normal
  • Results from the Prostate Cancer Prevention Trial
    show that prostate cancer is not rare even in
    these men
  • 27 cancer in those with PSA 3.1 to 4.0
  • 24 in those with PSA 2.1 to 3.0
  • 17 in those with PSA 1.1 to 2.0
  • 10 in those with PSA 0.6 to 1.0
  • 7 in those with PSA up to 0.5
  • How many cancers would be clinically important?
  • Thompson IM et al, NEJM, 2004

44
Risk Calculation
  • Based on date from the Prostate Cancer Prevention
    Trial
  • Can use for men
  • age 50
  • without a h/o prostate cancer,
  • who have undergone PSA and DRE for screening
    within the past year
  • Assesses risk for biopsy positive prostate cancer
    and risk for high grade disease
  • Takes into account age, ethnicity, PSA and DRE
    results, history of negative biopsy
  • Thompson IM Ankert DP CMAJ June 19, 2007
  • www.compass.fhcrc.org/edrnnci/bin/calculator/main.
    asp

45
PROSTATE CANCER SCREENING RECOMMENDATIONS
  • USPSTF insufficient evidence to recommend for or
    against routine screening for prostate cancer
    using PSA or DRE in men lt75
  • PSA can detect early prostate cancer, but
    inconclusive evidence about whether early
    detection improves health outcomes
  • Discussion age 50-75 (or age 45 for high risk
    African American 1st degree relative with h/o
    prostate ca)
  • Recommends against screening in men gt75
  • ACP individualize the decision to screen after
    discussion with patient about potential benefits
    and harms
  • ACS offer PSA and DRE annually starting at age
    50, or age 40-45 for high risk (African American
    strong family history) men asking their doctor
    to decide should be screened

46
OUTLINE
  • Evaluating Screening Tests general principles
  • Colon cancer screening which test is best?
  • Prostate cancer screening to screen or not to
    screen?
  • Ovarian cancer to screen high risk?

47
OVARIAN CANCER
48
OVARIAN CANCER SHOULD WE SCREEN?
  • Disease has high prevalence 8th most common
    cause of CA in women
  • Disease has serious consequences Usually
    diagnosed late (gt60 stage III or IV) 5th cause
    of CA death in women
  • High risk group family history
  • Lifetime risk of ovarian cancer
  • No affected relatives 1.2
  • One affected relative 5
  • 2 affected relatives 7
  • Hereditary syndrome 40
  • Treatment for pre-symptomatic disease is more
    effective than after symptoms develop Ovarian
    cancer limited to the ovaries is associated with
    a much higher survival rate
  • Overall 50 year survival 35
  • Early stage survival 90
  • Does screening decrease mortality ???

49
OVARIAN CANCER SCREENING TECHNIQUES
  • Serum CA-125 assay
  • Trans-vaginal ultrasound
  • Serum CA-125 plus ultrasound

50
OVARIAN CANCER SCREENING CLINICAL TRIAL
  • 22,000 U.K. women
  • Annual screening vs no screening for 3 years with
    7 year follow-up
  • Screening
  • CA-125
  • Ultrasound if elevated CA-125
  • Surgical evaluation if ultrasound abnormal
  • Slight increase in mean survival
  • No difference in mortality
  • Jacobs et al, Lancet 1999

51
OVARIAN CANCER SCREENING CONCLUSIONS
  • Many women must be screened to detect a few cases
  • Small increase in survival
  • Is it worth it?
  • Low disease prevalence limits utility of the
    tests despite high sensitivity and specificity

52
SCREENING RECOMMENDATIONS
  • USPSTF potential harms outweigh potential
    benefits
  • NIH Consensus Conference Insufficient evidence
  • Many organizations recommend annual pelvic
    examination
  • No evidence
  • Although there are no data regarding screening in
    high risk women (family history BRCA1 and BRCA2
    carriers HNPCC), experts recommend
  • annual screening with recto-vaginal pelvic
    examination, CA-125 and trans-vaginal ultrasound
  • BRCA1 and BRCA2 carriers can consider
    prophylactic oophorectomy

53
FUTURE TRIALS
  • PLCO Trial
  • 74,000 women aged 55-74
  • CA-125 at entry and annually for 5 years
  • Annual transvaginal ultrasound
  • 13 year follow-up
  • Novel biomarkers are being investigated
  • United Kingdom Trial of Ovarian Cancer Screening
  • RCT 200,000 women with 7 year follow-up to
    complete in 2010
  • CA-125
  • Ultrasound if elevated CA-125
  • Surgical evaluation if ultrasound abnormal

54
SUMMARY OF RECOMMENDATIONS
  • Ovarian cancer
  • maybe in high risk women only otherwise await
    PLCO trial
  • women at high risk should consider oral
    contraceptives (37 reduction in incidence)

55
SUMMARY OF RECOMMENDATIONS
  • Colon cancer any screening is better than no
    screening, use commonly available tests
  • Consider CT colonography if your center has 3-D
    technology, experienced radiologists, willing
    patient population, easy access to follow-up
    colonoscopy
  • Await further research on fecal DNA
  • Prostate cancer discuss pros and cons of PSA
    with eligible men age 50-70 await PLCO trial
  • Consider using risk calculation in discussion of
    screening and in discussion of biopsy

56
WHERE TO GO FOR THE EVIDENCE
  • U.S. Preventive Services Task Force
  • http//www.ahrq.gov/clinic/uspstfix.htm
  • American Cancer Society Guidelines for Early
    Detection of Cancer
  • http//www.cancer.org/
  • National Cancer Institute
  • http//www.cancer.gov/cancertopics/screening
  • Technology Evaluation Center / Blue Cross - Blue
    Shield Association
  • http//www.bcbs.com/tec/whatistec.html
  • California Technology Assessment Forum / Blue
    Shield of California Foundation
  • http//www.ctaf.org/

57
ADDITIONAL SYLLABUS SLIDES
  • LUNG CANCER

58
LUNG CANCER
59
LUNG CANCER Principles of Screening
  • Disease has high prevalence In US in 2007, there
    will be an estimated 213,380 new cases of lung
    cancer
  • Disease has serious consequences 1 cause of
    cancer mortality for both men women in US
  • Detectable preclinical phase ???
  • Treatment for pre-symptomatic disease is more
    effective than after symptoms develop when
    detected in Stage I, improves 5-year survival
    from 15 to 40-70
  • Screening reduces cancer mortality
  • Neither x-rays nor sputum cytology screening
    reduces mortality, what about CT scans?

60
LOW DOSE SPIRAL COMPUTERIZED TOMOGRAPHY (LDCT)
  • Helical, volumetric studies (like conventional
    chest CT)
  • Continuous data acquisition
  • Scans entire lung in lt 20 seconds (single breath
    hold)
  • No IV contrast
  • More radiation exposure than CXR, less than
    conventional CT

61
Published English-language studies of LDCT
screening for lung cancer
  • 1 cross-sectional
  • 6 longitudinal cohort studies
  • 1 randomized control trial feasibility pilot
    study comparing LDCT to CXR
  • 4 studies with high risk populations
    (smokers/former smokers)
  • 4 studies with mixed-risk populations (ranging
    from 46-86 smokers)

62
Published English-language studies of LDCT
screening for lung cancer
  • Overall the studies show that LDCT
  • can detect lung cancer
  • tends to detect early stage (Stage I) cancers
    (53-93 of cancers found at baseline screen)
  • The studies with high-risk only populations
  • 1.2-2 prevalence of lung cancer on LDCT
  • 0.6-2 incidence of lung cancer on
    follow-up/annual screens
  • One study compared mortality to historical
    controls and found no difference (Swenson et al)
  • 2.8/1000 person-years in CT screened population
    versus 2.0/1000 person years in Mayo Lung Project
    participants

63
LDCT screening for lung cancer
  • Henschke et al Oct 2006 NEJM results of the
    International- Early Lung Cancer Action Project
  • (I-ELCAP)
  • 83 smokers 12 second hand smoke 5
    occupational exposure
  • N31,567
  • Extensive protocol for follow-up of abnormal
    scans
  • Formal adjudication of all cases
  • Longitudinal cohort study
  • Baseline screen by LDCT
  • Follow-up screen for most participants
  • No comparison group

64
LDCT screening for lung cancer
  • Baseline Screen (n 31,567)
  • 4,186 positive test
  • 405 (1.3) lung cancers
  • Annual Screen (n27,456)
  • 1,460 positive test
  • 74 (0.27) lung cancers
  • 5 cases interim diagnoses of lung cancer
  • 412/484 (85) Stage I
  • Estimated 10-year lung cancer specific mortality
    (average follow-up 5 years)
  • All cancers 20
  • For Stage I cancers 12

65
Potential Biases
  • Lead-time bias
  • Screening identifies disease earlier, but does
    not increase actual survival
  • False increase in apparent survival time by
    diagnosing cases earlier
  • From Newman Kohn, 2006

66
Potential Biases
  • Length-time bias
  • False increase in apparent survival time by
    diagnosing more indolent disease
  • From Newman Kohn, 2006

67
Potential Biases
  • Overdiagnosis bias (pseudo-disease bias)
  • False increase in apparent survival time by
    misclassifying detected abnormality as disease
    which would never have presented clinically
  • Volunteer bias
  • People who participate in screening trials may
    be inherently different (healthier) than those
    who do not
  • --healthier habits,
  • --better access to health care, and
  • --different education and income levels

68
LUNG CANCER SCREENING RECOMMENDATIONS
  • The U.S. Preventive Services Task Force (USPSTF)
  • evidence is insufficient to recommend for or
    against screening asymptomatic persons for lung
    cancer with either low dose computerized
    tomography (LDCT), chest x-ray (CXR), sputum
    cytology, or a combination of these tests.

69
LDCT screening for lung cancer potential harm
  • Up to 93 of the non-calcified nodules gt4mm found
    in the studies have been false-positives
  • All require follow-up conventional CT to
    surgical biopsy
  • All follow-up carries some risk increased
    radiation exposure to bleeding/infection/death
  • Risks of higher radiation exposure due to LDCT at
    regular intervals are unknown

70
LDCT screening for lung cancer
  • LDCT promising modality to screen for lung cancer
    and find it early
  • Studies to date have not been designed to account
    for potential biases
  • Do not yet have convincing data that LDCT
    screening for lung cancer leads to decreased
    mortality.
  • Ongoing large NCI RCT National Lung Screening
    Trial
  • Results anticipated in 2009

71
Smoking Cessation!
  • Lung cancer incidence rates have stabilized in
    women and are declining in men in the U.S.
  • True across race-ethnicities
  • Espey et al. Annual report to the nation on the
    status of cancer, 1975-2004, featuring cancer in
    American Indians and Alaska Natives. Cancer. Oct
    15, 2007.
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