Mam­mo­grams found to be less cru­cial

Los Angeles Times - - The World - Thomas H. Maugh II thomas.maugh @latimes.com

Re­cent ad­vances in breast can­cer aware­ness and treat­ment have made rou­tine mam­mog­ra­phy less cru­cial in de­tect­ing can­cer and mit­i­gated its value in re­duc­ing deaths, re­searchers re­ported Wed­nes­day.

Al­though the World Health Or­ga­ni­za­tion and U.S. au­thor­i­ties have found pre­vi­ously that mam­mog­ra­phy re­duces deaths from breast can­cer by about 25%, the new study in the New Eng­land Jour­nal of Medicine de­ter­mined that the death rate dropped by only 10% af­ter the in­tro­duc­tion of rou­tine mam­mog­ra­phy in Nor­way.

The re­duc­tion was “far less than we ex­pected,” said Dr. Mette Kalager, a sur­geon at Oslo Uni­ver­sity Hos­pi­tal and the study’s lead author. In fact, dur­ing the pe­riod cov­ered by the study, the death rate among women over 70 — who did not un­dergo mam­mog­ra­phy but re­ceived the same care as younger women — dropped by 8%. That sug­gests that the ben­e­fit of mam­mog­ra­phy may have been as lit­tle as 2%, Kalager said.

In an ed­i­to­rial ac­com­pa­ny­ing the re­port, Dr. H. Gil­bert Welch of the Dart­mouth In­sti­tute for Health Pol­icy and Clin­i­cal Prac­tice in Le­banon, N.H., called the re­ported ben­e­fit “dis­ap­point­ingly small.” But, he noted, “it is quite plau­si­ble that screen­ing mam­mog­ra­phy was more ef­fec­tive in the past than it is now.”

As more tu­mors are dis­cov­ered ear­lier be­cause of in­creased aware­ness and more ef­fec­tive treat­ments are em­ployed, Welch said, mam­mog­ra­phy be­comes less valu­able. Based on the new re­sults, he said, 2,500 women would have to be screened for 10 years for one to avoid death from breast can­cer. Mean­while, at least 1,000 of those women would re­ceive at least one false­pos­i­tive re­sult and five to 15 would be di­ag­nosed and treated for a con­di­tion that was never go­ing to bother them.

Dr. Otis W. Braw­ley, chief med­i­cal of­fi­cer of the Amer­i­can Can­cer So­ci­ety, agreed that height­ened aware­ness con­trib­utes to ear­lier de­tec­tion of breast can­cer, im­prov­ing over­all out­comes. Nonethe­less, he said in a state­ment, “the to­tal body of the sci­ence sup­ports the fact that reg­u­lar mam­mog­ra­phy is an im­por­tant part of a woman’s pre­ven­tive health­care.”

The U.S. Pre­ven­tive Ser­vices Task Force con­cluded last year that screen­ing about 1,300 women ages-50 or older to save one life was ben­e­fi­cial, but that screen­ing 1,900 in their 40s to save one life was not. An es­ti­mated 192,000 new cases of breast can­cer are ex­pected to be di­ag­nosed in the United States this year, and the dis­ease will cause about 40,000 deaths.

If the re­sults from the Nor­we­gian study are con­firmed, mam­mog­ra­phy could soon be viewed more like PSA screen­ing of men for prostate can­cer. Ma­jor health groups no longer rec­om­mend rou­tine PSA screen­ing. Rather, they sug­gest that the de­ci­sion to screen should be made af­ter a con­sul­ta­tion be­tween physi­cian and pa­tient in which they dis­cuss the ben­e­fits and the risks.

That could be­come the rou­tine pro­ce­dure for breast can­cer as well, ex­perts said.

For their study, Kalager and his col­leagues took ad­van­tage of the fact that Nor­way, a coun­try of 4.8 mil­lion peo­ple, has a gov­ern­ment­funded health sys­tem and com­plete com­put­er­ized med­i­cal records. In 1996, Nor­we­gian au­thor­i­ties ini­ti­ated a pi­lot mam­mog­ra­phy screen­ing pro­gram in four of the coun­try’s 19 coun­ties, in which women be­tween the ages of 50 and 60 were in­vited to un­dergo screen­ing ev­ery two years. All 19 coun­ties also had to de­velop mul­ti­dis­ci­plinary teams for treat­ing breast can­cer pa­tients.

Be­gin­ning two years later and over a pe­riod of nine years, the screen­ing pro­gram was ex­tended to the re­main­ing 15 coun­ties. That al­lowed the re­searchers to an­a­lyze four groups: women who lived in coun­ties where screen­ing was con­ducted be­tween 1996 and 2005, women who lived in coun­ties where screen­ing did not oc­cur dur­ing that pe­riod, and two closely matched con­trol groups from the years be­fore screen­ing be­gan.

Dur­ing the pe­riod of the study, the re­searchers iden­ti­fied 40,075 women who de­vel­oped breast can­cer. They found that the death rate was re­duced by 7.2 deaths per 100,000 per­son-years in the screen­ing group and by 4.8 deaths per 100,000 years in the non-screen­ing group com­pared with the his­tor­i­cal con­trols. That cor­re­sponds to a 10% de­crease in mor­tal­ity in the screen­ing group.

Dr. Joanne Mor­timer, a med­i­cal on­col­o­gist and di­rec­tor of women’s can­cer pro­grams at the City of Hope med­i­cal cen­ter in Duarte, noted that the United States does not — ex­cept in rare in­stances — have the same sort of mul­ti­dis­ci­plinary teams to treat breast can­cer that are com­mon in Nor­way and the rest of Europe. Given that dif­fer­ence, she added, mam­mog­ra­phy is likely to make a larger con­tri­bu­tion to pre­vent­ing deaths here.

Dr. Stephen Sener, a breast can­cer sur­geon at USC’s Keck School of Medicine and a for­mer pres­i­dent of the Amer­i­can Can­cer So­ci­ety, also noted that al­though all women in the coun­ties where screen­ing pro­grams were in­vited to join, only 77% did.

And an un­known pro­por­tion of women in the coun­ties with­out screen­ing pro­grams may have got­ten mam­mo­grams from pri­vate sources. “The statis­tics are prob­lem­atic from the getgo,” he said.

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