Abstract P1-05-32: Outcomes of diagnostic breast imaging in young women (less than 50 years old)

Abstract INTRODUCTION The incidence of breast cancer is on the rise in the younger population, with 23 percent of all breast cancer diagnoses occurring in those under the age of 50. In Canada, screening mammography in women at average risk of breast cancer is recommended after the age of 50. Breast cancer in younger women is biologically more aggressive with greater rates of recurrence and metastatic disease. The sensitivity of mammograms to detect clinical breast abnormalities may be reduced due to increased breast density in this age group, leading to potential delayed diagnosis and poor outcomes. The frequency of false-negative diagnostic mammograms in young women is unknown. The purpose of this study is to describe the outcomes of diagnostic breast imaging in young women undergoing investigations for abnormal clinical breast findings and the frequency of delayed breast cancer diagnosis (more than 6 months after initial diagnostic mammography). METHODS We conducted a retrospective electronic chart review in women at average risk of breast cancer, aged between 30 and 50, who underwent diagnostic mammograms and/or breast ultrasounds (US) at our institution between 2018 to 2019 for symptomatic clinical presentations (breast pain, palpable mass, nipple discharge or breast skin changes). Patients undergoing routine screening mammograms were excluded. We collected demographics, findings of initial and follow-up breast imaging (using the Breast Imaging Reporting and Data System (BI-RADS) & breast density), and breast cancer diagnosis timelines where applicable. The primary outcome measure was the frequency of delayed breast cancer diagnosis defined as > 6 months from initial diagnostic imaging. Secondary outcomes included completion of recommended follow-up investigations and their outcomes, total number of breast cancer diagnoses and stage. The study was approved by the local research ethics board and the results were summarized using descriptive analysis. RESULTS We reviewed 400 electronic charts and identified 171 eligible patients. Mean age was 38 years; initial breast imaging included both diagnostic mammogram and US in 168 (87%), US alone in 20 (12%) and mammogram alone in 3 (2%) patients. Breast density was not routinely reported during this time frame. Ninety patients (53%) had benign findings (BIRADS 1 and 2), 41 (24%) had probable benign findings requiring short-term follow-up (BIRADS 3) while 30 (18%) patients had findings suspicious of malignancy (BIRADS 4&5) with biopsy recommended for diagnosis. In the BIRADS 3 group, 93% had recommended follow-up at a median of 7.6 months. Breast US alone was the most common subsequent investigation of which 15 % were benign lesions (BIRADS 1 & 2) and 68% remained in the BIRADS 3 category, while none were scored BIRADS 4 or 5. Among patients with BIRADS 4 & 5 scores, 83% underwent recommended biopsy at a median time of 3 weeks. Ten (6%) out of all 171 patients were diagnosed with breast cancer, all of which had BIRADS 4 or 5 on initial diagnostic imaging. Stage distribution was as follows: stage 0 - 2 patients, stage 1- 7 patients and stage 2 - 1 patients with no locally advanced or metastatic disease. The mean time from initial imaging to breast cancer diagnosis was 1.5 weeks (range 1 to 22 weeks). None of the patients had delayed breast cancer diagnosis in our cohort. CONCLUSION More than half of patients with clinical breast findings in our cohort had benign findings on diagnostic mammogram and/or US (BIRADS 1&2) with no subsequent breast diagnosis. Majority of patients requiring further investigations (BIRADS 0, 3, 4 and 5) underwent recommended follow-up (imaging or biopsy). Ultimately, a total of 10 patients were diagnosed with breast cancer at a median time of 1.5 weeks from original diagnostic imaging with no delayed breast cancer diagnosis. We, therefore, conclude that diagnostic mammograms and US are appropriate diagnostic investigations for clinical breast concerns in women between 30-50 years. Citation Format: Navdeep Dehar, Joseph N. Samuel, Doris Jabs, Wilma Hopman, Mihaela Mates. Outcomes of diagnostic breast imaging in young women (less than 50 years old) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-05-32.