MRI alone sufficient screen in women with familial risk of breast cancer

NEW YORK (Reuters Health) - In women with a familial risk of breast cancer, MRI screening alone is sufficient, German researchers report in the Journal of Clinical Oncology published online February 22nd.

"Guidelines that recommend annual mammography to start at age 25 or 30 had been established on limited scientific evidence in the first place," lead author Dr. Christiane Kuhl told Reuters Health by email.

"Now," she added, "there is growing evidence to suggest that mammography is of little -- if of any -- value in young women who have access to quality assured breast MRI."

Dr. Kuhl of the University of Bonn and colleagues prospectively studied 687 asymptomatic women with a total of 1679 annual screening rounds. All had family risk factors for breast cancer, and each woman received some combination of clinical breast exams, mammography, ultrasound, and MRI.

A subset of 371 women additionally underwent 869 screening rounds with half-yearly ultrasonography and clinical breast exams.

During a mean follow-up of more than 29 months, the researchers diagnosed ductal carcinoma in situ in 11 women and invasive breast cancer in 16.

All of the cancers were detected during annual screening. Ultrasound and mammography had a similar breast cancer yield (6.0 versus 5.4 per 1000), and combining the two produced a non-significant improvement (7.7 per 1000).

The cancer yield with MRI alone was significantly greater, however (14.9 per 1000). Adding ultrasonography did not change the yield, and adding mammography did not significantly improve it (16.0 per 1000).

Positive predictive values were 48% for MRI, 39% for mammography and 36% for ultrasound.

Given these findings, "we feel that it is time to revise existing guidelines to reflect this advance in knowledge," Dr. Kuhl said.

She continued, "This is important because current guidelines will subject high-risk women to a substantially higher lifetime glandular (radiation) dose, imposed on less radiation-tolerant fibroglandular tissue, for a predictably substantially lower -- if any -- diagnostic benefit compared with women undergoing regular mammographic screening."

In an editorial, Dr. Jan G. M. Klijn of Erasmus University Rotterdam, The Netherlands points out that while this and other studies "have shown that early detection of breast cancer, especially by MRI screening, is realistic....many radiologists and oncologists think that it is still too early to abandon mammography."

"Future studies will be needed to confirm the very high MRI sensitivities (and specificities) for both invasive cancer and ductal carcinoma in situ reported by Kuhl et al using comparable technology and quality-controlled protocols," Dr. Klijn said.

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