Media Releases

Second diagnosis of breast cancer increased by mutation

April 20, 2011

TORONTO, ON – Women with BRCA muta­tions have an extreme­ly high life­time risk of devel­op­ing breast can­cer and an ele­vat­ed risk of devel­op­ing sec­ond pri­ma­ry can­cer in the oppo­site breast, accord­ing to a recent study pub­lished in the British Jour­nal of Can­cer.

The study, Pre­dic­tors of con­tralat­er­al breast can­cer in BRCA1 and BRCA2 muta­tion car­ri­ers, led by Bloomberg Fac­ul­ty of Nurs­ing pro­fes­sor Kel­ly Met­calfe, is the first to inves­ti­gate the pre­dic­tors of con­tralat­er­al breast can­cer in women with a BRCA1 or BRCA2 muta­tion, specif­i­cal­ly report­ing the influ­ence of fam­i­ly his­to­ry. The results indi­cate the risk of con­tralat­er­al breast can­cer declines with age, but increas­es with the num­ber of first-degree rel­a­tives with breast can­cer.

“These results have sig­nif­i­cant clin­i­cal impli­ca­tions and sug­gest that women with a BRCA muta­tion who are diag­nosed with breast can­cer have a high risk of devel­op­ing a new can­cer in the oppo­site breast,” says Met­calfe. “How­ev­er, we have also shown there are treat­ments that can reduce this risk. With this infor­ma­tion, women can make treat­ment deci­sions to reduce their risk of devel­op­ing a new breast can­cer.”

The effect of fam­i­ly his­to­ry was only present for women with a BRCA muta­tion whose ini­tial breast can­cer was diag­nosed at age 49 years or below. For these women, the 15-year risks of devel­op­ing can­cer in the oppo­site breast were esti­mat­ed to be 33, 39 and 50 per cent for women with zero, one, and two or more first-degree rel­a­tives diag­nosed with breast can­cer under age 50, respec­tive­ly.

There are also dif­fer­ences in the risks of con­tralat­er­al breast can­cer in women with a BRCA muta­tion accord­ing to age. Women diag­nosed with breast can­cer younger than 40 years of age had a 15-year risk of 42 per cent for devel­op­ing can­cer in the oppo­site breast com­pared with 19 per cent for women over the age of 50 at the time of diag­no­sis.

The risk is high­est for women with intact ovaries, two or more first-degree rel­a­tives with breast can­cer and who were diag­nosed at age 49 or below, with a 15-year risk of con­tralat­er­al breast can­cer of 68 per cent.

The results demon­strate the impor­tance of know­ing BRCA sta­tus at the time of ini­tial breast can­cer diag­no­sis when mak­ing treat­ment deci­sions. In addi­tion, it’s crit­i­cal to rec­og­nize the mod­i­fiers of con­tralat­er­al breast can­cer in women with BRCA muta­tions to effec­tive­ly coun­sel them on their per­son­al risk and how treat­ment may mod­i­fy this risk. For high-risk women, both oophorec­to­my (removal of the ovaries) and con­tralat­er­al mas­tec­to­my (removal of the oppo­site breast) should be dis­cussed as a com­po­nent of treat­ment to reduce the risk of sec­ond pri­ma­ry can­cer and pre­vent ovar­i­an can­cer.

This research was fund­ed by the Cana­di­an Breast Can­cer Foun­da­tion (Ontario Chap­ter). Met­calfe is sup­port­ed by the Cana­di­an Insti­tutes of Health Research and the Ontario Women’s Health Coun­cil.

The Lawrence S. Bloomberg Fac­ul­ty of Nurs­ing at the Uni­ver­si­ty of Toron­to ranks among the pre­mier nurs­ing pro­grams in the world in both edu­ca­tion and research. In 2007, ours became the first named fac­ul­ty of nurs­ing in Cana­da. We are com­mit­ted to ensur­ing the approx­i­mate­ly 650 stu­dents in our under­grad­u­ate, mas­ters and PhD pro­grams have the high­est qual­i­ty learn­ing expe­ri­ences. More­over, with a Fac­ul­ty com­prised of the country’s lead­ing nurse researchers and edu­ca­tors, major con­tri­bu­tions to knowl­edge, health pol­i­cy and future prac­tice are pro­duced reg­u­lar­ly.

-30-

For a copy of Pre­dic­tors of con­tralat­er­al breast can­cer in BRCA1 and BRCA2 muta­tion car­ri­ers, vis­it: www.nature.com/bjc

For more infor­ma­tion, please con­tact:
Dr. Kel­ly Met­calfe, Asso­ciate Pro­fes­sor,
Lawrence S. Bloomberg Fac­ul­ty of Nurs­ing, Uni­ver­si­ty of Toron­to
416.978.2851 or kelly.metcalfe@utoronto.ca

Sarah Gopaul, Com­mu­ni­ca­tions Assis­tant,
Lawrence S. Bloomberg Fac­ul­ty of Nurs­ing, Uni­ver­si­ty of Toron­to
416.946.3657 or sarah.gopaul@utoronto.ca