To scan or not to scan: An evaluation of preoperative MRI use in primary breast cancer assessments.

Abstract

e14146 Background: Breast cancer (BC) is the most common invasive cancer in adult females.The role of preoperative MRI in assessing the extent of primary breast cancer remains controversial. This study’s objective is to determine if MRIs performed after the diagnosis of invasive/non-invasive-breast cancer will identify additional breast cancers. We hypothesize that preoperative MRIs will result in the discovery of additional significant lesions, leading to changes in surgical treatment. Methods: A retrospective study of 389 BC patient charts were reviewed, dated from January 2000- July 2019. Files were collected from an office in the Breast Cancer Surgery Department. Information on each patient’s imaging studies, treatment, demographics, surgery, and pathology were collected and stored in anonline cloud system. Summary statistics, including proportions, percentages, and difference of proportion hypothesis tests were utilized to interpret the data. All statistical tests were conducted at a 95% confidence interval. Results: We reviewed the charts of 335 patients that met eligibility criteria. In 221 newly diagnosed cancers, a preoperative MRI was taken before treatment. 127 cancers (57.5%)showed additional finding.In BC patients with additional preoperative MRI findings, we observed 61.4%true positive and 38.6%false positive results. These values are comparable to prior studies.We determined that the treatment plan was altered in 17.6%of all patients who received an MRI and in 30.7%of patients with a true positive MRI finding, which is also consistent with previous literature.A majority of the treatment changes were from Lumpectomy to Mastectomy. Conclusions: Literature on MRI use in BC diagnosis exists; our study differs by focusing on newly diagnosed breast cancers.We discovered 35.3% of preoperative MRIs identified a true additional finding in known breast cancer. In addition, our true positive rate (61.4%) and false positive rate (22.2%) of MRI findings is comparable to those of previous studies. Plans were changed in 30.7% of additional findings supporting the idea that preoperative MRI studies are useful when organizing surgical treatment. Further studies to demonstrate the impact on local recurrence rates and overall survival, may clarify the true role of pre-operative MRI in these cases.