Screening for Breast and
Prostate Cancer:
Who Should be Tested?
Why the Controversy?
Brandon P. Combs, MD
GIM Grand Rounds
12 February 2013
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?
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?
WHAT’S A SCREENING TEST?
 No symptoms
allowed!
 Symptoms
DIAGNOSTIC
TESTING
 If you have
symptoms you
should get tested
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)
LET’S 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
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
HOW IS BREAST AND PROSTATE
CANCER INFLUENCED BY SCREENING?
Death
CANCER PROGRESSION
Advanced
Regional
Local
Microscopic
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. 16851692.
HOW IS BREAST AND PROSTATE
CANCER INFLUENCED BY SCREENING?
Tumor D
Death
Tumor C
CANCER PROGRESSION
Advanced
Regional
Local
Microscopic
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. 16851692.
Tumor B
Tumor A
Cancer Diagnosis
POTENTIAL IMPACT OF A
SCREENING PROGRAM
total cancer
early
advanced
BEST CASE
WORST CASE
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. 16851692.
INTERMEDIATE
OVERDIAGNOSIS BIAS
Overdiagnosed
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
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.
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!
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 cancer—United States, 1985. CA Cancer J
Clin. 1985;35(1):36-56
WHAT’S 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/
 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
TRENDS IN DIAGNOSIS AND DEATH
FROM PROSTATE CANCER IN USA

HOW’S IT COMPARE TO THE UK?
USA diagnosis
UK diagnosis
UK death

USA 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.
BREAST CANCER
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.
B.
C.
D.
E.
1%
10%
25%
50%
75%
http://seer.cancer.gov/faststats/
Seidman H, Mushinski MH, Gelb SK, Silverberg E. Probabilities of eventually developing or
dying of cancer—United States, 1985. CA Cancer J Clin. 1985;35(1):36-56
WHAT’S 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/
Incidence per 100, 000
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. 16851692.
ALL
LOCAL
REGIONAL
METASTATIC
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. 19982005.
Sequential
mammographic
screening program
introduction
Similar declines in
breast cancer
mortality USA and
Europe,
independent of
mammography
Bleyer A BMJ 2011;343:bmj.d5630
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 isn’t postponed by
screening
3. Getting a mammogram decreases your risk
of getting breast cancer
A 50 YEAR OLD MAN’S 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%
A 50 YEAR OLD MAN’S 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;100:845–853. Medline.
doi:10.1093/jnci/djn124
Schröder, F.H., et al., Prostate-Cancer Mortality at 11 Years of Follow-up. New England Journal
of Medicine, 2012. 366(11): p. 981-990.
A 50 YEAR OLD WOMAN’S 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%
A 50 YEAR OLD WOMAN’S 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
ARE THESE RESULTS WHAT
YOU EXPECTED?
PROSTATE CANCER –
PERCEPTIONS AND REALITY
100
90
80
70
60
50
40
30
20
10
0
Lifetime risk of dying from
prostate cancer:
Perception
Reality
20
Lifetime risk of being diagnosed
with prostate cancer:
Perception
Reality
36
17
3
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;3053S64S
BREAST CANCER –
PERCEPTIONS AND REALITY
100
90
80
70
60
50
40
30
20
10
0
Lifetime risk of dying from
breast cancer:
Lifetime risk of being
diagnosed with breast cancer:
Perception
Perception
Reality
Reality
32
24
12
3
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;3053S64S
PATIENTS OVERESTIMATE BENEFITS OF SCREENING
“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?”
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
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.
 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.”
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?
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.
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.
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?
ORIGINS OF CONTROVERSY
“Get screened now”
“5 yr survival when
caught early is 98%”
FROM THE AMERICAN CANCER
SOCIETY… 1970’S
“Give yourself the chance of a
lifetime”
FROM THE UNIVERSITY OF COLORADO…
“The Pink Life
Saver…aims 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/
REGARDING PSA TESTS, FROM
GENERAL COLIN POWELL…
“Get checked. It could save your life…There 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
FROM ZEROCANCER.ORG
“More than 115,000
men have been
tested for free during
the last 12 years,
saving countless
lives.”
CREDIBLE SOURCES OF
INFORMATION
Organizations that understand the distinction between
potential benefit and actual benefit
“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.”
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 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.”
Screening for Breast Cancer: U.S. Preventive Services Task Force
Recommendation Statement. Annals of Internal Medicine, 2009. 151(10): p.
716-726.
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/
NATIONAL CANCER INSTITUTE
“Finding prostate cancer may not
improve health or help a man
live longer.”
http://www.cancer.gov/
The world of breast and prostate
cancer screening in one graph
Probability
Extreme
Harm
Minor Harm
Minor Benefit
Extreme
Benefit
WHAT TO TELL YOUR PATIENTS
 If you are hearing a lot of certainty (e.g. ‘you
need to get screened’) it’s 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
WHAT’S THE “RIGHT” THING TO DO?
 There is no right or wrong answer – it’s
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
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?
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?
THANK YOU!
Special thanks to:
Tanner Caverly, MD
Dan Matlock, MD, MPH