Pretreatment breast MR positively affects therapy

One out of five patients with breast cancer in a Spanish study had her therapeutic approach changed after undergoing contrast-enhanced MR imaging. Meanwhile, Italian researchers found CE MR valuable in detecting bilateral breast cancer.

Dr. Julia Camps-Herrero and colleagues from the Hospital de la Ribera in Valencia evaluated 90 consecutive patients with core biopsy proven breast cancer. All patients received an MR scan prior to treatment, and 28 underwent further MR examination to evaluate response to chemotherapy.

Sequences included T2-weighted and T1-weighted FLASH 3D pre- and postcontrast. Parametric images for maximum enhancement speed, maximum enhancement, 3D reconstruction, speed of enhancement curves, and enhancement curves were analyzed in each patient with dedicated software for breast MR.

MR correctly changed the therapeutic approach in 17 patients. Three patients underwent wider excisions, and nine were upgraded to mastectomy. The remaining five patients were downgraded from surgery to neoadjuvant chemotherapy.

"Pretreatment breast MR is an indispensable tool in breast cancer staging and treatment planning," said Camps-Herrero during a Tuesday scientific session at the ECR.

MR yielded two unnecessary wider excisions and three unnecessary lumpectomies, and it failed to detect multicentric disease in three patients. However, it detected additional foci in 16 patients: 14 true positives, two false positives. A flaw of the study is its short follow-up time of a median 13 months.

"It will be very interesting to wait and see what happens with a longer follow-up," she said.

When questioned about the false positives, she mentioned a study they have begun that uses microbubble contrast-enhanced breast ultrasound to better locate new hypervascular lesions and biopsy them.

In the Italian study, Dr. Federica Pediconi and colleagues from University of Rome "La Sapienza" evaluated 35 patients with proven unilateral breast cancer but with negative contralateral breast at physical exam, ultrasound, and mammography.

Fourteen of 50 consecutive patients had contralateral lesions identified on MR mammography (22%). Biopsy was performed in four patients, while 10 underwent surgery because of highly suggestive malignant lesions according to BI-RADS classification.

Histology demonstrated 11 patients with malignancies and three with fibroadenomas. Contrast-enhanced MR produced no false negatives. Sensitivity was 100%, specificity 92%, and accuracy 94%.

"CE MR mammography could be introduced as a screening exam in patients with proven breast cancer before surgery," Pediconi said.

When questioned about the very high rate of contralateral cancer (22%), Pediconi revealed that many of the patients had dense breasts, which could account for the unusual spike. She also said that a longer follow-up than six months might influence the 100% sensitivity.