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Complexity, Confusion, Uncertainty – Age Based Mammography Screening. Richard L. Theriault , D.O. F.A.C.O.I. Professor Department of Breast Medical Oncology The University of Texas M D Anderson Cancer Center Houston, Texas. Disclosures.
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Complexity, Confusion, Uncertainty – Age Based Mammography Screening Richard L. Theriault, D.O. F.A.C.O.I. Professor Department of Breast Medical Oncology The University of Texas M D Anderson Cancer Center Houston, Texas
Disclosures • I have no conflicts of interest in relation to this presentation • I will not be discussing investigational use of pharmaceuticals or devices
Objectives • Define screening • Consider populations who may benefit from screening mammography • Understand the concepts of Number Needed to Screen (NNS) and Number Needed to Harm(NNH) in relation to outcomes for mammography screening
Evidence Based Medicine • Requires the integration of best research evidence with our clinical expertise and our patient’s unique values and circumstances • Evidence Based Medicine Strauss S. et al Third Edition
Screening for Breast Cancer with Mammography - Outline • Rationale for screening • Population screening- who is at risk? Sex, age, race, genetics, family history • Individual screening – who is at risk? Sex, age, endocrine history • What is the evidence for mammography screening? • Potential benefits • Potential harms • Who decides when and how to screen? • NNI, NNH
Clinical Case Presentation A 42 year old woman requests advice and counsel regarding screening for cancer. She is concerned because her friend has recently been diagnosed with Stage III breast cancer and has been told she has an “awful” prognosis. Do you recommend screening studies for breast cancer? What do you tell her about risks and benefits of screening?
Screening • Early diagnosis of pre-symptomatic disease among well individuals in the general public • Goal – live longer or better
Requirements for Screening • Disease should be an important health problem –approximately 200,000 new breast cancer patients per annum USA • Disease should be detectable at an asymptomatic stage (preclinical) • Early stage treatment should lead to better patient outcomes • Screening test effective and accurate
Breast Cancer Sojourn Time and Lead Time • Sojourn time (ST) - duration of time that an occult breast cancer can be detected before symptoms • Lead time (LT) – the amount of time actually gained by screening before symptoms
Breast Cancer Sojourn Time and Lead Time • Mean sojourn time by age • 2 - 2.4 years age 40-49 • 2.5 - 3.7 years age 50-59 • 3.5 - 4.2 years age 60-69 • 4 - 4.1 years age 70-74 • Theoretically screening should detect “early” cancer, i.e. before clinically symptomatic
Breast Cancer Survival (5 year) in Relation to Disease Stage • Stage 0 98% in situ • Stage I >90% tumor 2 cm or less • Stage II >85% lymph node positive(+) • Stage III >60% tumor >5 cm, lymph node + • Stage IV >20% systemic disease • Diagnosis at lower stage ought to lead to better outcomes, therefore if screening leads to early detection (lower stage) the prognosis and survival should be better
Population ScreeningBreast Cancer Incidence and Age • Age 40-49 - 1 in 69 • Age 55-59 – 1in 42 • Age 60-69 – 1in 29 • Smith R A et al CA Cancer J Clin 2010;:99-119
Screening Recommendations and Justification • Generally accepted that mammography screening reduces breast cancer specific mortality for women age 50 - 70 • Little screening data over age 70 • It has been recommended that annual screening mammography begin at age 40 for women at “average risk” for breast cancer
Population Screening –Healthy WomenCochrane Review 2009– Screening for Breast Cancer with Mammography • Randomized trials screening vs. no screening • Pub Med (through November 2008) • 8 trials, 1 excluded due to bias • 600,000 women • Trials (3) with adequate randomization – no reduction in breast cancer mortality at 13 years • Trials (4) with suboptimal randomization significant mortality reduction RR 0.75 • RR for all 7 trials .81 (95% CI 0.74- 0.87) • Number of lumpectomies and mastectomies significantly larger in the screened group RR 1.31 • Nielsen G PC Cochrane Database of Systematic Reviews 2009, Issue 4; 2009
Population Screening –Healthy WomenCochrane Review 2009– Screening for Breast Cancer with Mammography • Review estimated 15% relative risk reduction in overall breast cancer mortality • 30% over diagnosis and over treatment • For every 200 women invited to screening throughout 10 years one will have life prolonged • 10 healthy women will be diagnosed as having breast cancer and be treated unnecessarily
Population Screening –Healthy WomenCochrane Review 2009– Screening for Breast Cancer with Mammography • “It is not clear whether screening does more harm than good”.
The Controversy • U.S. Preventive Services Task Force Recommendations for Screening for Breast Cancer • “The USPSTF recommends against routine screening mammography in women age 40 -49 years”. • “The decision to start regular screening mammography before the age of 50 years should be an individual one and take into account patient context, including the patient’s values regarding specific benefits and harms”. • Annals Int Med 2009;151:716-726
USPSTF Issues • Lower sensitivity and specificity for mammography in women age 40-49 • Over diagnosis of breast cancer • False positive, false negatives, additional imaging and biopsies • Radiation exposure – unknown risk related to radiation dose over time • Procedure related pain • Anxiety, distress and psychological concerns • Annals Int Med 2009;151:716-726
USPSTF Review - Data sources • Randomized controlled trials • Cochrane Central Register of Controlled Trials • Cochrane Database of Systematic Reviews • Meta Analysis - 8 randomized controlled trials • End point - breast cancer specific mortality • Annals Int Med 2009;151:716-726
Mammography Sensitivity and Specificity • Sensitivity 77-95% - proportion of people with the target disorder who have a positive test result • Specificity 94-97% -proportion of people without the target disorder who have a negative result • Annals Int Med 2009;151:716-726
How good is Mammography? Performance measures for 3,603,832 Screening Mammograms From Diseases of the Breast Fourth Edition p94
Controversy – Interpreting the Evidence • USPSTF • Mortality reduction estimates with screening mammography • 15% age 39-49 • 14% age 50-59 • 32% age 60-69 • No effect age70-74 How much mortality benefit is enough to warrant “routine” screening?? • Ann Int Med 2009;151:727-737
Cancers Detected per USPSTF Report • Age 40-49 - 1.8 invasive, 0.8 non-invasive • Age 50-59 - 3.4 invasive, 1.3 non-invasive • Age 60-69 - 5.0 invasive, 1.5 non-invasive • Age 70-79 - 6.5 invasive, 1.4 non-invasive • Age 80-89 - 7.0 invasive, 1.5 non-invasive • Ann Int Med 2009;151:727-737
USPSTF - Yield per Screening Round • Number of mammograms per case of invasive breast cancer • Age 40-49 - 556 • Age 50-59 - 294 • Age 60-69 - 200 • Age 70-79 -154 • Age 80-89 – 143 • Ann Int Med 2009;151:727-737
USPSTF Number of Additional Imaging Studies and Biopsy(ies) By Age at Screening • Age 40-49 - 47, 5 • Age 50-59 - 22, 3 • Age 60-69 - 14, 2 • Age 70-79 - 10, 2 • Age 80-89 - 8, 1.5 • Ann Int Med 2009;151:727-737
Clinical Context • Age 39-49 - Number needed to invite (NNI) to screen 1904, to prevent one breast cancer death • Age 50-59 – NNI 1339 • Conclusion – “Women age 40-49 experience the highest rate of additional imaging whereas their biopsy rate is lower than that for older women”. • “Mammography screening at any age is a tradeoff of a continuum of benefits and harms”. • Ann Int Med 2009;151:727-737
Another Perspective - Critique of the USPSTF Recommendations • No scientific basis for age 50 thresh hold • Lowest possible mortality benefit used in breast cancer specific mortality calculations • Computer models favored over direct data • Decrease in deaths mostly due to screening, not therapy • Breast cancer not trivial in women in their 40’s • No data to support only screening high-risk women • Annual screening from age 40 saves the most lives • Screening anxiety is not equal to death from breast cancer • All women should be informed of risks and benefits • Kopans D Radiology 2010;256 15-20
What to do? Cancer Risk Assessment • An individualized evaluation of a patient’s risk for cancer based on history and physical examination • Examination of breasts and nodal basins • Patient age • Family history – three generations preferred • Race/ethnicity • Endocrine history – menarche, pregnancies, exogenous hormone exposure • Prior biopsy – ADH, ALH • Diet • Physical activity • Environmental exposures - ETOH, XRT • Personal cancer history – Hodgkin’s Disease, XRT
Clinical Case Presentation • 42 y/o Caucasian woman • Family history – 2 first degree relatives with breast cancer, age 45 and 75 • Nulliparous • One prior breast biopsy – benign • “moderate” ethanol intake • Is this person average risk? • Should she have screening?
Cancer Risk Assessment Tools • Gail model (www.cancer.gov/bcrisktool) • Claus Model • BRCAPRO for BRCA 1 and 2 assessment
Screening Recommendations - Society of Breast Imaging and ACR • Annual Mammographic screening from age 40 • Women at increased risk – BRCA mutations - annually starting at age 30 • Women with histories of mantle irradiation – annually beginning 8 years after radiation but not before age 25 • Women with mothers or sisters with pre-menopausal breast cancer –beginning age 30 but not before age 25, or 10 years earlier than the age of diagnosis of the youngest affected relative whichever is later • Lee C H et al J Am Coll Radiol 2010;7:18-27
American Cancer Society Recommendations for Breast cancer Screening • Breast self examination – beginning in early 20’s (no data on risk reduction) • Clinical Breast examination – beginning in 20-30’s and every three years (no data on risk reduction) • Mammography – annually beginning age 40 • Smith R A et al CA A Cancer J Clin 2010;99-119
Breast Cancer Screening with Mammography - Conclusions • The mammography screening recommendations of the United States Preventive Services Task Force, American Cancer Society and the American College of Radiology/Society of Breast Imaging all differ based on reviews and judgments of the same evidence base
Breast Cancer Screening with Mammography - Conclusions • Evidence review of the Cochrane Systematic Review suggests the risks of population screening may outweigh the benefits • USPSTF review concludes there is a 15% breast cancer specific mortality relative risk reduction with screening age 50-70 • Evidence review from the USPSTF suggests potential harms may outweigh the risks of “routine annual screening” in women age 40-49 • Others examining the same “evidence” contend that there is no justification for excluding women age 40-49 from screening programs
Breast Cancer Screening with Mammography - Conclusions • For women >70-75 years there are too few data to make an evidence based recommendation and screening recommendations must be individualized • All agree that “best research evidence“ is lacking – poor study conduct, poor randomizations, different study designs, objectives, populations, end points, relative risk reductions reported
Breast Cancer Screening with Mammography - Conclusions • All agree “best interests” of the patient are the primary consideration • All agree the patient’s values and preferences must be considered • All agree that the clinician must engage the patient in discussion of the relative risks, harms and burdens of testing in relation to individual benefit expected
Clinical Case Presentation • 42 year old women with anxiety regarding her friend’s breast cancer diagnosis • 2 first degree relatives with breast cancer • Nulliparous • Prior breast biopsy • Risk assessment >1.67 % • SCREEN