Women at increased risk for breast cancer are regularly screened with MRI. In the Netherlands, guidelines state that supplemental mammography is recommended from the age of 30 in these women. The purpose of this study is to investigate the added value of mammography when breast MRI is available.METHOD AND MATERIALS
An IRB approved, retrospective review of our intermediate and high risk breast cancer screening program was performed, analyzing 9582 screening breast MRI examinations and 6555 screening mammograms from 2776 women screened in the period from January 2003 to January 2014. Screening indication and age were obtained from patient records. These data were linked to the Netherlands Cancer Registry to identify all breast cancers. Of the cancers identified, imaging records were evaluated for mode and modality of detection.RESULTS
In total 179 cancers were identified, of which 137 cancers were screen detected. Thirteen out of 137 were detected by mammography alone (detection rate of 2/1000 screening mammograms). Of those, eight (62%) were found to be ductal carcinoma in situ (DCIS). The median age at detection was 55 ± 9.84 years. Twelve (92%) of the breast cancers detected with mammography alone were detected above the age of 40. Three (23%) were detected in BRCA mutation carriers (5% of all screen detected cancers in BRCA mutation carriers). Two of those cancers were diagnosed as DCIS in women above the age of 50.CONCLUSION
The added value of mammography in high risk screening is very limited: only 13/137 (9%) of the screen detected cancers were detected by mammography alone and most are DCIS. Mammography is especially questionable in women under the age of 40 and in BRCA mutation carriers. Consequently, the age to start mammography in intermediate and high risk screening needs to be reconsidered.CLINICAL RELEVANCE/APPLICATION
There is no ground for mammography on top of MRI for early detection of breast cancer in women at increased risk below the age of 40. In older women the added value is still very limited.