MRI Improves Detection After Breast-Conserving Therapy In Young Breast Cancer Patients

Adding magnetic resonance imaging to mammography improves detection of breast cancer in patients who underwent breast-conserving therapy by the age of 50 years

medwireNews: Combining magnetic resonance imaging (MRI) with mammography could improve detection of early-stage but biologically aggressive tumours relative to mammography alone, albeit at reduced specificity, suggests a study of women who underwent breast-conserving therapy (BCT) at or before the age of 50 years.

The research focused on 754 women who were diagnosed with ductal carcinoma in situ (DCIS) or invasive breast cancer by the age of 50 years and had attended one of six institutions for BCT, the researchers explain in JAMA Oncology.

The patients were recruited to undergo annual MRI screening of their conserved and contralateral breasts for 3 years, as well as mammography and ultrasound imaging.

In all, 17 (2.3%) women were diagnosed with breast cancer, with 12 cases identified in year 1, three in year 2 and two in year 3, giving a mean of 17.8 months from initial surgery to detection. Ten (58.8%) of the tumours were detected in the ipsilateral breast and 41.2% in the contralateral breast; 13 (76.5%) were stage 0 or 1, while one patient had nodal micrometastasis. Most (58.8%) cases were invasive DCIS.

MRI plus mammography had a significantly higher overall rate of cancer detection than mammography alone (8.2 vs 4.4 cases per 1000 examinations), as did ultrasound plus mammography (6.8 cases per 1000).

Adding MRI to mammography resulted in significantly better sensitivity for detection of cancer than mammography alone, at 100% versus 52.9%, whereas adding ultrasound gave a nonsignificant increase in sensitivity to 82.4%.

“Therefore, when women who received BCT at 50 years or younger, especially those with dense breasts, are unable to undergo MRI screenings, ultrasonography might be considered”, remark Woo Kyung Moon, from Seoul National University Hospital in South Korea, and co-authors.

When MRI or ultrasound were used alongside mammography, however, there was a significant decrease in specificity for cancer detection compared with mammography alone, at 87.0% and 87.6% versus 96.0%.

“One of the major drawbacks of MRI screening is its high false-positive rate and, as a result, the associated costs and morbidity,” the researchers observe, with use of MRI associated with a significant increase in the rates of patient recall, biopsy and short-term follow-up compared with mammography alone.

But noting that 47.1% of detected tumours would have been missed with mammography alone, they write: “Considering the harms caused by false-negative findings, the false-positive findings caused by MRI screening examinations might be within acceptable ranges if informed women choose them.”

Woo Kyung Moon et al therefore believe: “Our study results can be used not only to inform patient and clinician decision making regarding the best methods of screening after BCT but also to develop more personalized screening guidelines and recommendations for women at increased risk for breast cancer.”

Reference

Cho N, Han W, Han B-K, et al. Breast cancer screening with mammography plus ultrasonography or magnetic resonance imaging in women 50 years or younger at diagnosis and treated with breast conservation therapy. JAMA Oncol; Advance online publication 22 June 2017. doi:10.1001/jamaoncol.2017.1256

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