First experiences in screening women at high risk for breast cancer with MR imaging

Abstract

Women with a genetic predisposition for breast cancer are often advised surveillance with physical examination twice a year and mammography once a year from 25 years onwards. However, the sensitivity of the mammography decreases when breast tissue is dense and this is seen in 40–50% of women under 50 years. We therefore investigated whether magnetic resonance imaging (MRI) in addition to the normal surveillance could detect cancers otherwise missed. In 109 women with over 25% risk of breast cancer, MRI was performed because over 50% dense breast tissue was seen at mammography and no suspect lesion was seen at the previous screening. MRI detected breast cancers in three patients (2.8%) occult at mammography and with no new palpable tumor, twice at stage T1bN0 and T1cN0 once. Two cancers were expected. MRI was false positive in six women, resulting in two benign local excisions because ultrasound or fine needle examination confirmed suspicion. We had no false negative MRI results. MRI proved true benign in four BRCA 1/2 gene mutation carriers at histologic examination. Preoperative wire localization of the malignancies detected at MRI proved necessary as the tumor was not palpable in the lumpectomy specimen nor visible at specimen radiology. The extra cost of breast MRI in addition to mammography and physical examination was ∉uro13.930 per detected cancer. The cost of the detection of one breast cancer patient in our national screening program is ∉uro9000. During follow-up of patients with a familial risk in whom the first breast cancer was detected at MRI, MRI detected two recurrent cancers in stage T1bN0 and T1cN0 and one contralateral cancer T1aNo. Breast MRI is promising in screening young women at high risk for breast cancer, as it can advance the detection of cancers still occult at mammography and physical examination; but the cost may be considerable.