Abstract P3-02-10: Selective use of MRI and impact on management in breast cancer
Authors: S Jafferbhoy, M Tandon, R Kirby, S Narayanan, S Bajwa, S Salehi Bird, Z Mohd-Isa, S Soumian
Journal: Cancer Research (2017)

Abstract Introduction: Breast cancer can present as a mammographically occult lesion. Lobular carcinoma has the propensity to develop mutifocal and multicentric disease. Studies have suggested that invasive carcinoma with lobular features have similar biological characteristics as invasive lobular carcinoma. In our unit, patients with mammographicaly occult cancer and those with lobular features on core biopsy have a pre-operative MRI scan. The aim of this study is to assess the impact of contrast enhanced MRI on management of these cases. Methods: Over a 3 year period from November 2012 to October 2015, all breast MRI scans were reviewed and those patients with mammographically occult cancer and invasive carcinoma with lobular features on biopsy were included. Demographic data, imaging, pathology and treatment details were collected from Clinical Information System. A size difference of +/-10% between the imaging modalities was considered to be concordant Results: Out of 389 patients with breast MRI for invasive carcinoma, 104 patients with a median age of 57 years were included. 69 patients (66%) were symptomatic and 35 (34%) were screen-detected cancers. 64 patients had lobular features on core biopsy and 40 patients had mammographically occult cancer. In patients with lobular features group, MRI findings were concordant with mammograms in 26 patients (40%) while 38 ( 60%) had additional findings (28% multifocality, 19% non-concordant size, 6% contralateral findings and 7% ipsilateral benign findings). In patients with non- concordant findings, 58% underwent USS and 24% had biopsy following MRI. In the mammographically occult group, USS identified the primary lesion in 32 patients (80%) while 8 patients (20%) had occult lesion both on USS and mammograms. MRI findings were concordant in 90% while 10% had non-concordant findings (6% multifocality and 4% non-concordant size). Following MRI, 8% had another USS and 3% had biopsy. MRI findings changed the treatment plan in 19% cases with lobular features.14% underwent mastectomy instead of wide local excision, 3% primary chemotherapy and 2% bilateral wide local excision. There was a change in treatment plan in 25% of the mammographicaly occult cancers of which only 6% had lesion visible on USS. 15% of mammographically occult cancers had mastectomy instead of WLE and 10% had neo-adjuvant chemotherapy. Conclusion: This study has demonstrated that pre-operative MRI leads to additional investigations. Its impact on management is low if the lesion is mammographically occult but visible on ultrasound. In cases with ultrasound occult cancer and those with lobular features on core biopsy, it changes management in a significant proportion and should therefore be considered as a part of the diagnostic work-up. Citation Format: Jafferbhoy S, Tandon M, Kirby R, Narayanan S, Bajwa S, Salehi Bird S, Mohd-Isa Z, Soumian S. Selective use of MRI and impact on management in breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-02-10.