Screening for Breast and Prostate Cancer: Who Should be Tested?
Why the Controversy? Brandon P. Combs, MD GIM Grand Rounds 12
February 2013
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OBJECTIVES Make sure we ask (and answer) the right questions
Understand cancer screening basics Review epidemiology of breast
and prostate cancer Understand risks and benefits of screening for
breast and prostate cancer Examine origins of controversy and
common perceptions vs reality Review current screening guidelines
What should we tell our patients?
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A THOUGHT EXPERIMENT If there was a pill that, taken daily
after age 50, would double your lifetime risk of getting cancer
from 10% to 20% but could decrease your lifetime risk of dying from
cancer by 20% (from 3% to 2.4%), would you take it?
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WHATS A SCREENING TEST? No symptoms allowed! Symptoms
DIAGNOSTIC TESTING If you have symptoms you should get tested
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OUTCOMES AND RISK Outcome a health related event that people
care about e.g. avoid death or suffering from disease Risk chance
of experiencing an outcome Risk reduction difference in risk of
some outcome as a result of a test or intervention (chance of
benefit)
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LETS APPLY THESE TERMS! A drug has been shown to reduce the
risk of dying from heart disease from 2% to 1% over a 10 year
period. Which of the following is true? A. Drug reduces risk by 50%
B. Drug reduces risk by 1 percentage point C. 1 out of 100 people
taking drug will avoid death from heart disease D. 99% of people
taking drug get no benefit E. All of these are true
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REQUIREMENTS OF A SUCCESSFUL SCREENING PROGRAM: 1. Screening
advances time of diagnosis of cancers destined to cause death 2.
Early treatment superior to treatment started after patient has
symptoms
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HOW IS BREAST AND PROSTATE CANCER INFLUENCED BY SCREENING?
Esserman L, S.Y.T.I., REthinking screening for breast cancer and
prostate cancer. JAMA: The Journal of the American Medical
Association, 2009. 302(15): p. 1685- 1692. Microscopic Local
Regional Advanced C ANCER P ROGRESSION Death
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HOW IS BREAST AND PROSTATE CANCER INFLUENCED BY SCREENING?
Esserman L, S.Y.T.I., REthinking screening for breast cancer and
prostate cancer. JAMA: The Journal of the American Medical
Association, 2009. 302(15): p. 1685- 1692. Microscopic Local
Regional Advanced C ANCER P ROGRESSION Death Tumor D Tumor C Tumor
B Tumor A
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POTENTIAL IMPACT OF A SCREENING PROGRAM Esserman L, S.Y.T.I.,
REthinking screening for breast cancer and prostate cancer. JAMA:
The Journal of the American Medical Association, 2009. 302(15): p.
1685- 1692. total cancer early advanced BEST CASEWORST
CASEINTERMEDIATE Cancer Diagnosis
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OVERDIAGNOSIS BIAS Wegwarth, O., et al., Do Physicians
Understand Cancer Screening Statistics? A National Survey of
Primary Care Physicians in the United States. Annals of Internal
Medicine, 2012. 156(5): p. 340-349. Overdiagnosed
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LEAD-TIME BIAS Wegwarth, O., et al., Do Physicians Understand
Cancer Screening Statistics? A National Survey of Primary Care
Physicians in the United States. Annals of Internal Medicine, 2012.
156(5): p. 340-349.
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TRUTHS ABOUT SCREENING Lead time time by which diagnosis
advanced by screening compared without screening Overdiagnosis
detection of a cancer by screening that was never going to cause
symptoms in your lifetime DISREGARD SURVIVAL STATS IN
SCREENING!
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HOW COMMON IS PROSTATE CANCER? Chance that an average risk 50
year old man will be diagnosed with prostate cancer in his
lifetime? A. 1% B. 10% C. 20% D. 50% E. 75%
http://seer.cancer.gov/faststats/ Seidman H, Mushinski MH, Gelb SK,
Silverberg E. Probabilities of eventually developing or dying of
cancerUnited States, 1985. CA Cancer J Clin. 1985;35(1):36-56
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WHATS THE RISK OF DYING FROM PROSTATE CANCER? Chance that an
average risk 50 year old man will die of prostate cancer in his
lifetime? A. 1% B. 3% C. 10% D. 25% E. 50%
http://seer.cancer.gov/faststats/
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TRENDS IN DIAGNOSIS AND DEATH FROM PROSTATE CANCER IN USA
Notice large increase in diagnosis When did it start? How does this
compare to decrease in mortality? Hoffman, R.M., Screening for
Prostate Cancer. New England Journal of Medicine, 2011. 365(21): p.
2013-2019. Incidence per 100, 000
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HOWS IT COMPARE TO THE UK? USA diagnosis UK diagnosis USA death
UK death PSA Shibata A, Whittemore AS. Re: prostate cancer
incidence and mortality in the United States and the United
Kingdom. J Natl Cancer Inst 2001;93(14):1109-1110.
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BREAST CANCER
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HOW COMMON IS BREAST CANCER? Chance that an average risk 50
year old woman will be diagnosed with invasive breast cancer in her
lifetime? A. 1% B. 10% C. 25% D. 50% E. 75%
http://seer.cancer.gov/faststats/ Seidman H, Mushinski MH, Gelb SK,
Silverberg E. Probabilities of eventually developing or dying of
cancerUnited States, 1985. CA Cancer J Clin. 1985;35(1):36-56
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WHATS THE RISK OF DYING FROM BREAST CANCER? Chance that an
average risk 50 year old woman will die of breast cancer in her
lifetime? A. 1% B. 3% C. 10% D. 25% E. 50%
http://seer.cancer.gov/faststats/
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TRENDS IN DIAGNOSIS OF BREAST CANCER IN USA Esserman L,
S.Y.T.I., REthinking screening for breast cancer and prostate
cancer. JAMA: The Journal of the American Medical Association,
2009. 302(15): p. 1685- 1692. ALL LOCAL METASTATIC REGIONAL
Incidence per 100, 000
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WOMEN UNDER 40 (USA) Bleyer, A. and H.G. Welch, Effect of Three
Decades of Screening Mammography on Breast-Cancer Incidence. New
England Journal of Medicine, 2012. 367(21): p. 1998- 2005.
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Sequential mammographic screening program introduction Similar
declines in breast cancer mortality USA and Europe, independent of
mammography Bleyer A BMJ 2011;343:bmj.d5630
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QUICK REVIEW TRUE OR FALSE? 1. Detecting more early cancer
proves that cancer screening saves lives 2. Early detection of
cancer can improve 5-year survival even if death isnt postponed by
screening 3. Getting a mammogram decreases your risk of getting
breast cancer
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A 50 YEAR OLD MANS RISK OF DYING OF PROSTATE CANCER IN NEXT 10
YRS WITHOUT SCREENING? (ASSUME AVERAGE RISK, NON-SMOKER) A. 0.2% B.
1% C. 5% D. 10% E. 25%
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A 50 YEAR OLD MANS RISK OF DYING OF PROSTATE CANCER IN NEXT 10
YRS WITH ANNUAL SCREENING? Answer: 0.1% Starting risk: 0.2%
modified risk: 0.1% Percent of 50 y/o men who benefit from
screening: 0.1% or 1/1000 Percent of 50 y/o men who do not benefit:
99.9% or 999/1000 Woloshin S, Schwartz LM, Welch G. The risk of
death by age, sex, and smoking status in the United States: putting
health risks in context. J Natl Cancer Inst. 2008;100:845853.
Medline. doi:10.1093/jnci/djn124 Schrder, F.H., et al.,
Prostate-Cancer Mortality at 11 Years of Follow-up. New England
Journal of Medicine, 2012. 366(11): p. 981-990.
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A 50 YEAR OLD WOMANS RISK OF DYING OF BREAST CANCER IN NEXT 10
YRS WITHOUT SCREENING? (ASSUME AVERAGE RISK, NON-SMOKER) A. 0.5% B.
1% C. 5% D. 10% E. 25%
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A 50 YEAR OLD WOMANS RISK OF DYING OF BREAST CANCER IN NEXT 10
YRS WITH ANNUAL SCREENING? (ASSUME AVERAGE RISK, NON-SMOKER)
Answer: 0.4% Starting risk: 0.5% modified risk: 0.4% Percent of 50
yr old women who benefit from screening: 0.1% or 1/1000 Percent of
50 yr old women who do not benefit: 99.9% or 999/1000
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ARE THESE RESULTS WHAT YOU EXPECTED?
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PROSTATE CANCER PERCEPTIONS AND REALITY Hoffman RM, Lewis CL,
Pignone MP, Couper MP, Barry MJ, Elmore JG. et al. Decision-making
processes for breast, colorectal, and prostate cancer screening:
the DECISIONS survey.. Med Decis Making. 2010;3053S- 64S Lifetime
risk of dying from prostate cancer: Perception Reality Lifetime
risk of being diagnosed with prostate cancer: Perception
Reality
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BREAST CANCER PERCEPTIONS AND REALITY Hoffman RM, Lewis CL,
Pignone MP, Couper MP, Barry MJ, Elmore JG. et al. Decision-making
processes for breast, colorectal, and prostate cancer screening:
the DECISIONS survey.. Med Decis Making. 2010;3053S- 64S
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PATIENTS OVERESTIMATE BENEFITS OF SCREENING Gigerenzer, G., J.
Mata, and R. Frank, Public Knowledge of Benefits of Breast and
Prostate Cancer Screening in Europe. Journal of the National Cancer
Institute, 2009. 101(17): p. 1216-1220 If screen 1000 women 40 yrs
and older every other year for 10 yrs, how many fewer deaths from
breast cancer? If screen 1000 men 50 yrs and older every other year
for 10 yrs, how many fewer deaths from prostate cancer?
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UNWARRANTED CERTAINTY Patients overestimate risk & benefit
74% believed finding cancer early saves lives most or all of the
time 40% felt that 80 y/o declining PSA or mammogram was
irresponsible Hoffman RM, Lewis CL, Pignone MP, Couper MP, Barry
MJ, Elmore JG. et al. Decision-making processes for breast,
colorectal, and prostate cancer screening: the DECISIONS survey..
Med Decis Making. 2010;3053S-64S Schwartz LM, Woloshin S, Fowler FJ
Jr, Welch HG. Enthusiasm for cancer screening in the United
States.. JAMA. 2004;29171-8 Hudson, B., et al., Patients'
Expectations of Screening and Preventive Treatments. The Annals of
Family Medicine, 2012. 10(6): p. 495-502.
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Placed much greater emphasis on survival statistics compared to
mortality reduction One half incorrectly said that finding more
cases of cancer in screened as opposed to unscreened populations
proves that screening saves lives.
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PERCEPTION AND REALITY 1. Exaggerated perception of the risk of
getting and dying of cancer 2. Exaggerated perception of the
benefits of screening What about the harms?
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WHAT ARE THE HARMS FROM PSA SCREENING OVER 10 YRS ? false
positive test: 10-12% unnecessary diagnosis and treatment
(overdiagnosis): 1-3% erectile dysfunction or incontinence: 3%
death: 0.03% Schroder F, Hugosson J, Roobol M, et al. Screening and
prostate-cancer mortality in a randomized European study. N Engl J
Med 2009;360(13):1320-1328. Andriole G, Grubb R III, Buys S, et al.
Mortality results from a randomized prostate-cancer trial. N Engl J
Med 2009;360(13):1310-1319. Moyer, V.A., Screening for Prostate
Cancer: U.S. Preventive Services Task Force Recommendation
Statement. Annals of Internal Medicine, 2012. 157(2): p.
120-134.
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WHAT ARE THE HARMS FROM MAMMOGRAPHY SCREENING OVER 10 YRS ?
false positive test requiring another mammogram or biopsy: 20-50%
biopsy to rule out cancer: 5-20% unnecessary surgery, radiation, or
chemo (overdiagnosis): 0.2 1.0% Woloshin, S. and L.M. Schwartz, How
a charity oversells mammography. BMJ, 2012. 345 Woloshin, S. and
L.M. Schwartz, Numbers Needed to Decide. Journal of the National
Cancer Institute, 2009. 101(17): p. 1163-1165.
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PERCEPTION AND REALITY 1. Exaggerated perception of the risk of
getting and dying of cancer 2. Exaggerated perception of the
benefits of screening 3. Harms often ignored Does public health
messaging help?
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ORIGINS OF CONTROVERSY 5 yr survival when caught early is 98%
Get screened now
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FROM THE AMERICAN CANCER SOCIETY 1970S Give yourself the chance
of a lifetime
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FROM THE UNIVERSITY OF COLORADO The Pink Life Saveraims to
change that by bringing the often life-saving benefits of
mammography to time-saving, convenient locations around the Denver
area.
http://www.uch.edu/conditions/imaging-services/mammograms/pink-life-saver/
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REGARDING PSA TESTS, FROM GENERAL COLIN POWELL Get checked. It
could save your lifeThere are MORE CASES of prostate cancer than
any other major cancer. Every THREE minutes an American man finds
out he has prostate cancer. Nearly 30,000 men will die from
prostate cancer this year.
http://www.prostateconditions.org/pcaw-media-kit
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FROM ZEROCANCER.ORG More than 115,000 men have been tested for
free during the last 12 years, saving countless lives.
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CREDIBLE SOURCES OF INFORMATION Organizations that understand
the distinction between potential benefit and actual benefit
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Moyer, V.A., Screening for Prostate Cancer: U.S. Preventive
Services Task Force Recommendation Statement. Annals of Internal
Medicine, 2012. 157(2): p. 120-134. The USPSTF recommends against
PSA-based screening for prostate cancer It bases its
recommendations on the evidence of both the benefits and harms of
the service, and an assessment of the balance. The USPSTF does not
consider the costs of providing a service in this assessment.
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Screening for Breast Cancer: U.S. Preventive Services Task
Force Recommendation Statement. Annals of Internal Medicine, 2009.
151(10): p. 716-726. The USPSTF recommends against routine
screening mammography in women aged 40 to 49 years. The decision to
start regular, biennial screening mammography before the age of 50
years should be an individual one and take patient context into
account, including the patient's values regarding specific benefits
and harms. The USPSTF recommends biennial screening mammography for
women aged 50 to 74 years.
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NATIONAL CANCER INSTITUTE Screening for breast cancer does not
affect overall mortality, and the absolute benefit for breast
cancer mortality appears to be small. http://www.cancer.gov/
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NATIONAL CANCER INSTITUTE Finding prostate cancer may not
improve health or help a man live longer.
http://www.cancer.gov/
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Probability Extreme Benefit The world of breast and prostate
cancer screening in one graph Extreme Harm Minor HarmMinor
Benefit
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WHAT TO TELL YOUR PATIENTS If you are hearing a lot of
certainty (e.g. you need to get screened) its time to start asking
questions Healthy skepticism is a good thing There is no substitute
for seeing harms and benefits side by side in absolute terms
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WHATS THE RIGHT THING TO DO? There is no right or wrong answer
its a close call We should be experts on the medicine - Patients
are expert on priorities Understand the risks and benefits
Discussion should be evidence based, not fear based Promote
informed, shared decisions
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A THOUGHT EXPERIMENT If you knew that routine PSA testing after
age 50 would double your lifetime risk of getting prostate cancer
from 10% to 20% but could decrease your lifetime risk of dying from
prostate cancer by 20% (from 3% to 2.4%), would you be tested?
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A THOUGHT EXPERIMENT If you knew that getting routine
mammograms after age 50 would double your lifetime risk of getting
breast cancer from 8% to 15% but could decrease your lifetime risk
of dying from breast cancer by 25% (from 3.6% to 2.7%), would you
be tested?
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THANK YOU! Special thanks to: Tanner Caverly, MD Dan Matlock,
MD, MPH