AJR: Breast MRI screening beneficial for some with previous cancer
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Breast MRI screening of women with only a personal, not familial, history of breast cancer was clinically valuable in finding malignancies for 12 percent of all cases, with a reasonable biopsy rate of 39 percent, found a study published in the August issue of the American Journal of Roentgenology.  

Sandra Brennan, MB, and her colleagues from the department of radiology, breast imaging section at Memorial Sloan-Kettering Cancer Center in New York City conducted their study to determine whether women with only a personal history of breast cancer and without indications for MRI screening under current American Cancer Society guidelines would benefit from screening.

The researchers retrospectively reviewed 1,699 breast MRI exams performed from 1999 to 2001. They focused on 144 women, who under current American Cancer Society guidelines would not be included in MRI screening. The women (average age 49 years) previously had breast cancer, but had no family history of breast cancer and had at least one year of follow-up with MRI. 

The EMR, including radiology reports and clinical notes, was leveraged to determine which patients developed recurrence. The authors reviewed the records of the 1,699 breast MRI exams performed during the selected time period to identify women with both a personal and family history of breast cancer who commenced a screening MRI exam during that time, in order to compare them with the group of women with a personal history only.

The researchers found that 44 of the 144 women (31 percent) underwent biopsies which were prompted by MRI examination. The biopsies revealed malignancies in 17 women (12 percent) and benign findings in 27 women (19 percent). In the 17 women with detected cancer, seven also had benign biopsy results and in total, 18 malignancies were found, including 17 carcinomas and one myxoid liposarcoma. Of the 17 cancers, 12 (71 percent) were invasive, five (29 percent) were ductal carcinoma in situ and 10 (59 percent) were minimal breast cancers (node-negative invasive breast cancer less than one centimeter in size).

Ten of the 17 cancers were detected by MRI alone, which were more likely to be ductal carcinoma in situ or minimal breast cancers, the authors said. MRI screening resulted in a total of 61 biopsies, with a positive predictive value of 39 percent. In addition, prior breast cancer histology, menopausal status and breast density had no significant impact on cancer detection rate, they wrote. 

“Cancers discovered were those benefiting from early detection, with more than half of the MRI-detected cancers being minimal breast cancers,” said Brennan and colleagues. Noting that although screening MRI is costly and can generate benign biopsies and short-term follow-ups, the authors believe that the modality can benefit certain cohorts of patients with a personal history of breast cancer, including those who have not had a preoperative MRI at the time of initial cancer diagnosis and those who have not undergone hormonal therapy.

“A randomized prospective trial would best determine the effectiveness of MRI screening in women with a personal history of breast cancer and that data from other institutions should be assessed to determine whether our conclusions are supported,” the study concluded.