Page 1 Breast Cancer Screening USPSTF Grades Breast cancer is the - - PDF document

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The Breast Cancer Screening Controversy

Asian Health Symposium 2019

Judith M.E. Walsh, MD, MPH

Division of General Internal Medicine Women’s Health Center of Excellence University of California, San Francisco

1 Disclosures

• I have no conflicts of interest

2 Principles of screening

• Detection while patient is asymptomatic

– High sensitivity

• Early detection reduces the risk of death

from the cancer – randomized trials

• The number of false positives is

acceptably low

– High specificity

– Reasonably high prevalence of disease

• Ideally few harms

3 USPSTF

• Rigorous review of existing peer-reviewed

evidence

• Ratings reflect the strength of the

evidence on the benefits and harms of a preventive service

• No consideration of costs
• ACA: Must cover A or B ratings

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USPSTF Grades

Grade Evidence Recommendation A High certainty of substantial net benefit Provide B High certainty of moderate net benefit Moderate certainty of moderate/substantial net benefit Provide C Moderate certainty that net benefit is small Selectively

• ffer/provide

D No net benefit or harms outweigh benefits Do not provide I Insufficient evidence regarding balance of benefits and harms

5 Breast Cancer Screening

• Breast cancer is the most common cancer in

women and the second leading cause of cancer death

• Screening mammography reduces breast

cancer mortality

• Risk increases with age
• Pre-menopausal breast tissue is dense

– Decreased sensitivity

6 Breast Cancer in Asian Women

• Overall incidence of breast cancer is

lower in Asian women than in Caucasians –Rates are increasing

• Breast density is higher in Asian

women

• Screening rates are lower in Asian

women

7 Breast Cancer Screening

• Qingling is a 52 year old woman with

no family history of breast cancer. Her last mammogram showed “dense breast tissue” and she was told to discuss next steps, with you, her PCP.

• You perform a clinical breast

examination, which is normal.

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Breast Cancer Screening

• What do you recommend to

Qingling? –Breast ultrasound and mammogram –Breast MRI and mammogram –Digital breast tomosynthesis –Standard digital mammography

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U.S. screening guidelines: no agreement

Organization Starting age Stopping age Frequency Comments

United States Preventive Services Task Force (USPSTF) 50 74 Biennially Screening for age 40-49 = Grade C recommendation American Cancer Society (ACS) 45 As appropriate based on life expectancy Annually, then biennially

• nce age

≥55 Continue screening as long as good health, life expectancy > 10 years. American College

• f Obstetricians

and Gynecologists (ACOG) 40 As appropriate based on life expectancy Annually Consider cessation

• f screening at age

75.

10 USPSTF vs American Cancer Society Recommendations

Age USPSTF 2015 ACS 2015

40-44 None (or biennial) None 45-49 None (or biennial) Annual 50-54 Biennial Annual 55-74 Biennial Biennial 75+

Insufficient evidence for or against Biennial if good health and life expectancy ≥10 yrs

American Cancer Society Guidelines. JAMA 2015;314(15):1599-1614

11 When to start

• Age is the most important risk factor

for breast cancer

• Because of lower prevalence,

screening younger women leads to many more false positives

• Younger women have denser breasts

– Mammography quality

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When to stop?

• What is the patient’s 10 year life

expectancy?

• What are co-morbid conditions?
• Would woman want surgery, chemo,

XRT?

• E Prognosis Cancer Screening

13 Harms Of Screening

• Over-diagnosis

– Cancers diagnosed that never would cause symptoms: patients receive all the costs and harms of treatment – Estimates: 10% to 30% of invasive breast cancers plus much of DCIS

• False positives

– Anxiety – Additional tests including biopsies – One-third of total screening cost

• Radiation exposure

– One breast cancer for 3000 women screened annually for 10 years

Jorgensen, BMJ, 2009

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Impact of mammographic screening in U.S.

Welch NEJM 2013

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Screening has also led to large increase in detection of ductal carcinoma in situ (DCIS)

Li CEBP 2005

10 20 30 40 50 60 70 80 90 100 1975 1980 1985 1990 1995 2000 2005 Incidence rate (per 100,000) Year of diagnosis

Figure 2. SEER9 Age-adjusted incidence rate of breast cancer by stage (1973-2005)

In situ Rate Localized Rate Regional Rate Distant Rate

Localized

DCIS

Metastatic

Li CEBP 2005

Screening era

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Breast Cancer Deaths Randomized Trials, all ages

Age, years Deaths Averted Screening 1,000 Women Over 10 Years 95% confidence Interval 40 to 49 0.3 0 to 0.9 50 to 59 0.8 0.2 to 1.7 60 to 69 2.1 1.1 to 3.2 70 to 74 1.3 0 to 3.2 75+ Unknown

• 50 to 69

1.3 0.6 to 0.2 Bottom line: Greatest screening benefit in women aged 60-69; smaller, and possibly no, screening benefit in women aged 40-49

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False-Positive Results and Breast Biopsies per 1000 women

Harms of One-Time Mammography Screening, by age

Outcome 40-49 50-59 60-69 70-74 False-positive mammogram 121 (12%) 93 (9%) 81 (8%) 70 (7%) Breast biopsies recommended 16 (1.6%) 16 (1.6%) 17 (1.7%) 18 (1.8%) Biopsies per cancer diagnosed 10 6 3 3

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Estimated annual mammography screening costs in the US

Screening the 40 million women in the US aged 50-74 costs $4.72 billion per year Screening the 22 million women in the US aged 40-49 costs an additional $1.32 billion per year

20 2010 0 costs: O’Do Donohue et al An Ann Intern Med 20 2014; 4;160: 60:145 45-153 153

19 Breast Density

• Relative amount of radio-opaque (white)

elements to radiolucent (black) fat on the image.

• Increased breast density can obscure

detection of benign mass or cancer

• Radiographic finding

– Does not correlate with physical exam

• Associated with increased risk of breast cancer

diagnosis but not increased risk of breast cancer mortality

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Breast Density

• A: almost entirely fatty
• B: Scattered areas of fibroglandular

density

• C: Heterogeneously dense

– May obscure small masses

• D: Extremely Dense

– Lowers sensitivity of mammography

21

State breast density legislation

• Requires notification of

women with heterogeneously dense or extremely dense breasts

• Exact wording specified by

law: decreased sensitivity and increased risk for BC

• No mandate for insurance

coverage of supplemental screening in most states

22 Breast Screening Technologies

• Digital Mammography
• Digital Breast Tomosynthesis
• Breast MRI
• Breast Ultrasound

23 Digital mammography

• Standard of care
• Compared with film mammography, higher

sensitivity, same specificity in women < 50 years old, dense breasts – Sensitivity 78% versus 51% film – Specificity 90%

• Worse in women 65 and older

– Sensitivity 53% versus 69% film

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Digital Breast Tomosynthesis

• Digital Breast Tomosynthesis (DBT) as a primary screening

strategy

Yaffe Breast Cancer Research 2008 10:209 http://www.nydailynews.com/

25 Mammography and Dense Breasts

• No evidence on screening

techniques and mortality

• Digital mammography is more

sensitive than film for women with dense breasts

• Is tomosynthesis preferred?

– Not standard of care – Insurance coverage

26 USPSTF: DBT

• Digital Breast Tomosynthesis (DBT) as a primary

screening strategy

– Benefit: Reduces recall rate and increases cancer detection rates compared to conventional mammography – Harm: twice as much radiation; unknown rate of over

• diagnosis. May increase biopsy rates
• No evidence on mortality, morbidity, or QOL
• “Insufficient evidence to fully assess benefits and

harms”

27 Parked outside UCSF 28

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MRI Screening

• Does MRI have a role for screening in

high risk women?

– MRI is a very sensitive method of breast imaging and has been used as a diagnostic tool in women with breast cancer – Not influenced by breast density – Specificity is variable – Expensive

29

Supplemental screening: better outcomes?

MRI Ultrasound (US) Tomosynthesis (DBT) Advantages

• Most sensitive
• No radiation
• Well-tolerated
• Relatively

inexpensive

• Similar cancer

detection rate, fewer false positives Limitations

• High false

positive rate

• Overdiagnosis
• IV contrast
• Claustrophobia
• Expensive
• High false

positive rate (low PPV)

• Operator-

dependent

• Not as sensitive

as MRI

• Limited evidence

base (newer)

• Limited

availability

USPSTF Grade I: January 2017

30 Impact For Clinical Practice

• MRI may be useful in screening high risk

women

• The effect of MRI screening on mortality is

not known

• MRI is not currently recommended for

screening average risk women

• Ultrasound adds little to mammography
• Tomosynthesis is promising

31 Bottom Line: Breast Cancer Screening for All Women

• 40-49 informed consent

– Digital if decide to screen: now standard

• 50-74 screen every 2 years
• 75+ informed consent – not if life

expectancy less than 10 years

• Don’t promote SBE, promote breast

awareness

• BRCA risk equivalent: MRI

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Breast Cancer Screening For Asian Americans

• Screening guidelines target all women
• Screening rates are lower in Asian

Americans than in other ethnic groups

– Explore barriers to screening

• Breast density is higher in Asian women

Clinical significance unclear

33

Questions?

34