Carcinomainsitu(ductalorlobular)8.0–10.025%–30%
Ionizingradiation1.1–1.43.6%–4.6%
Mammographicdensity3.0–7.010%–23%
Postmenopausalobesityandweightgain1.1–3.03.6%–10%
Postmenopausalhormonereplacement1.1–3.03.6%–10%
Alcoholconsumption1.1–1.43.6%–4.6%
Alcoholconsumption1.1–1.43.6%–4.6% aRelativeriskisthelikelihoodofdevelopingcancercomparedtoawomanwithnoriskfactors—whoserelativeriskis1.0.Absolutelifetimeriskisthefractionofwomenexpectedtodevelopinvasivecarcinomawithoutariskreducingintervention.Forwomenwithnoriskfactors,thereisabouta3%chanceofdevelopinginvasivebreastcancer.bThemostcommonfamilyhistoryisamotherwhodevelopedcanceraftermenopause.Thishistorydoesnotincreasetheriskofherdaughters.
hyperplasia,increasednumbersofbothspindledmyoepithelialcellsandepithelioidluminalcellsexpandductalandlobularspaces(
Fig.19.25B
Proliferativediseasewithatypiaincludesatypicallobularhyperplasia(ALH)andatypicalductalhyperplasia(ADH).ALHcloselyresembleslobularcarcinomainsitu(LCIS)andADHcloselyresemblesductalcarcinomainsitu(DCIS)(bothdescribedlater),butaremorelimitedinextent.ThecellsinADHareuniforminappearanceandformsharplymarginatedspacesorrigidbridges(
Fig.19.25C
Breast carcinoma is the most common malignancy of women globally (excluding nonmelanoma skin cancer) and causes the majority of cancer deaths in women.
Although the incidence in the United States decreased slightly in 2002 and then stabilized (changes attributed to a decrease in the use of postmenopausal hormone therapy and a plateau in the number of women undergoing mammographic screening), the worldwide incidence and mortality is increasing at an alarming rate. The major factors underlying this trend in developing countries are thought to be social changes that increase breast cancer risk—specifically, delayed childbearing, fewer pregnancies, and reduced breastfeeding—combined with a lack of access to optimal health care.
Fig.19.25Benignepithelialbreastdisease.(A)Nonproliferativedisease.Anapocrinecystisshownthatisacommonfeatureofnonproliferativebreastdisease.(B)Proliferativebreastdiseaseischaracterizedbyincreasednumbersofepithelialcells,asinthisexampleofepithelialhyperplasia.(C)Proliferativebreastdiseasewithatypia.Theproliferatingepithelialcellsaremonomorphicinappearanceandpileuptoformabnormalarchitecturalstructures.
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The lifetime risk of breast cancer is 1 in 8 for women living to age 90 in the United States. It is predicted that about 250,000 breast cancers will be diagnosed in 2016 and about 40,000 women will die of the disease—a toll among cancers second only to lung cancer. Since the mid-1980s the mortality rate has dropped from 30% to less than 20%. The decrease is attributed to both improved screening, which detects some cancers before they have metastasized, and more effective systemic treatment.