The Case for Screening: Mammography Can Save Lives

December 31, 2006

Breast cancer causesmore deaths than anycancer except lung cancer inwomen of all ages. In womenbetween the ages of 40and 59 years, it is the leadingcause of cancer death.1

Breast cancer causesmore deaths than anycancer except lung cancer inwomen of all ages. In womenbetween the ages of 40and 59 years, it is the leadingcause of cancer death.1How mammographyhelps. Breast cancer incidencehas been risingsteadily since formal tumorregistries began in 1932.However, screening mammographyhas broughtabout a shift toward presentationat an earlier stage inthe disease. Between 1983and 1996, the incidence ofstage I invasive cancers increased117%, while the incidenceof cancers detectedin stages II to IV decreasedabout 15%.2Early detection hasobvious benefits. Less aggressivetreatments can beused. The need for systemicchemotherapy andaxillary dissection, withtheir associated morbidity,is often obviated.There is also good evidencethat mammographyis associated with a significantreduction in breast cancermortality. The most importantstudy to supportthis conclusion is a Swedishstudy that showed a 40% to45% reduction in breast cancermortality with mammographicscreening; thestudy included about a thirdof the women in Sweden.3,4Risks of mammography.The risk that cancerwill develop as a result ofradiation from mammographyis low. The dose usedin a complete, 2-view mammogramis small--a fractionof that used in a spinalradiograph.5 Moreover,breasts in women of screeningage (Table 1) are lessradiosensitive than those ofyounger women. There are3.5 additional cancers peryear in every 1 millionwomen older than 35 yearswho are irradiated for mammogramsalone.6There are also risksassociated with false-positiveand false-negative results.However, the AmericanCollege of Radiology(ACR) makes continual effortsto improve the qualityof mammograms. The ACRaccredits only those facilitieswhose staff of radiologistsincludes at least onewho specializes in mammography.Most facilitieswith a large group of radiologistsalso offer routinedouble-reading of mammograms,which improves detectionrates. In addition,the ACR offers ongoingphysician and technologisteducation programs.Importance of patienteducation. The primarycare practitioner has a veryimportant role in the battleagainst breast cancer--that of patient educator. Discusswith patients the benefitsof screening mammography.Studies by the NationalCancer Institute haveshown that patients aremore likely to get mammogramsif their physician recommendsthat they do so.Advise patients to useACR-accredited facilities. Ifpossible, have them obtaintheir mammograms at thesame facility each time;when prior results are availableat the time of interpretation,there is less need foradditional views and fewerunnecessary callbacks. Ifmammograms cannot bedone at the same facility,advise patients to havetheir previous films sent tothe interpreting facility.Suggest that patients staggertheir annual mammogramand yearly physicalexamination at 6-month intervalsto maintain constantsurveillance.Explain to patients thata recent negative mammogramshould not give thema false sense of security,and stress the importanceof seeking immediate medicalattention if they notice apalpable abnormality.

References:

REFERENCES:


1.

Greenlee RT, Hill-Harmon MB,Murray T, et al. Cancer statistics,2001.

CA Cancer J Clin

. 2001;51:15-36.

2.

Ries L, Kosary C, Hankey B, et al.

SEER Cancer Statistics Review, 1973--1996

. Bethesda, Md: National CancerInstitute; 1996.

3.

Tabar L, Vitak B, Chen HH, et al.The Swedish Two-County Trial twentyyears later.

Radiol Clin North Am

.2000;38:625-652.

4.

Duffy SW, Tabar L, Chen HH, et al.The impact of organized mammographyservice screening on breast carcinomamortality in seven Swedishcounties.

Cancer

. 2002;95:458-469.

5.

Dahnert W.

Radiology Review Manual

.4th ed. Baltimore: Williams &Wilkins; 1999:456-457.

6.

Dahnert W.

Radiology Review Manual

.4th ed. Baltimore: Williams &Wilkins; 1999:463-464.