Abstract P2-02-02: Cancer detection rate in high-risk patients on short-term, and long-term follow-up MRI after a benign concordant MRI-guided breast biopsy

PURPOSE: To determine the overall and biopsy site-specific cancer detection rates on short-term and long-term follow-up MRI after a benign concordant MRI-guided breast biopsy in high-risk patients. METHOD AND MATERIALS: A HIPAA-compliant, IRB-approved retrospective review of medical records at a large tertiary care institution was undertaken to identify all the benign concordant MRI-guided breast biopsies performed from January 2005 - December 2011 in high-risk patients that received follow-up MRI. High-risk was defined as having at least one of the following criteria: personal history of breast cancer, high-risk lesion on prior biopsy, family history of breast cancer, BRCA 1 or 2 genetic mutations, or prior history of chest irradiation. All malignant and discordant cases were excluded, as well as those with high-risk lesions on pathology. All longitudinal MRI follow-up (as well as mammographic and ultrasound follow-up) was reviewed through February 2013. Any subsequent biopsies at the MRI-guided biopsy sites were also reviewed. The overall and biopsy site-specific cancer detection rates were determined based on the follow-up MRI studies and electronic medical records. RESULTS: A total 802 MRI-guided breast biopsies were performed from 2005-2011, of which 171 had benign concordant results and MRI follow-up. Of the 171 patients, 118 were classified as high-risk, with 51 with personal history of breast cancer, 16 with high-risk lesion on prior biopsy, 48 with family history of breast cancer, 17 with known BRCA positive status, and 7 with prior history of chest irradiation. The mean age at biopsy was 54.2 years (range 24-78 years). Longest MRI follow-up times were as follows: 12 had 6-12 months, 25 had 1-2 years, 24 had 2-3 years, and 57 had greater than 3 years of follow-up MRI. There were a total of six high-risk patients who had benign MRI-guided biopsies that were diagnosed with cancer on follow-up; only one of these patients was diagnosed via MRI follow-up, while the rest were diagnosed via mammographic or sonographic follow-up. Only one of the six was diagnosed with cancer at the MRI biopsy site on short-term follow-up; the other five were diagnosed with cancer at either a different site in the same breast and/or cancer in the contralateral breast. The one patient who had cancer at the MRI biopsy site on short-term follow-up was diagnosed on six-month follow-up mammography although the MRI remained negative. CONCLUSION: The overall cancer detection rate of MRI for high-risk patients with MRI follow-up after a benign concordant MRI-guided breast biopsy was 1/118; five additional patients were diagnosed via mammographic/sonographic follow-up. The cancer detection rate of short-term follow-up MRI at the biopsy site was 0/118; one patient had MRI-occult cancer diagnosed on a six-month follow-up mammogram. Our data suggests that there is low utility to short-term MRI follow-up after a benign concordant MRI-guided breast biopsy, even in a population of high-risk patients. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-02-02.