English summary: BREAST MRI IN THE PREOPERATIVE STAGING OF PATIENTS ELIGIBLE FOR BREAST CONSERVATION SURGERY

Background

The aim of this study was to evaluate the effectiveness of breast MRI in the detection of multifocal breast cancer in patients presumed eligible for breast conservation therapy (BCT).

Methods

We retrospectively reviewed the medical records of 73 consecutive patients (74 cancers) with biopsy proven breast cancer in North-Karelian Central Hospital. All patients had complete mammography and US workup of both breasts prior to MRI. The inclusion criteria for MRI were: invasive lobular carcinoma (ILC) (n =23); invasive ductal carcinoma (IDC) in dense breasts (BI-RADS density 3, 4) (n =38), and high nuclear grade (>2cm) or high/intermediate nuclear grade DCIS in dense breast area (n =13). The MRI findings were correlated to the final pathology report.

Results

All invasive index tumours were detected with MRI. Five of 13 DCIS tumours did not have specific diagnostic features. MRI correctly detected multifocal tumours in 20 patients (27%), of which 5 were multicentric. MRI was false negative in an additional 4 cases, and false positive in 4. Three occult cancers (4%) were diagnosed in the contralateral breast. The sensitivity, specificity and overall accuracy of MRI in the detection of multifocal breast cancer were 83%, 92% and 89%, respectively.

Conclusion

MRI is useful and highly accurate in the detection of primarily mammography and US occult multifocal and multicentric breast cancer. MRI should be considered routine practice in the evaluation of ILC and IDC in dense breasts prior to BCT.