MR imaging features and tumor biomarkers of screen-detected and non- screen detected breast cancers: preliminary results of a comparative study

Purpose: To investigate differences in clinical features, MRI findings and tumor biomarker characteristics in screen-detected (SCD) and non-screendetected (NSCD) cancers. Material and methods: A total of 62 women (mean age, 48.4 years; range, 33-68 years) with biopsy confirmed breast cancer who underwent preoperative breast MRI were retrospectively evaluated by two expert radiologists. The women were divided into two groups according to the mode of cancer detection (Group A: screen- detected, Group B: non-screen/symptomatic cancer) and clinical, histopathological, MRI characteristics and biomarker features in each group were evaluated. Results: NSCD tumors had significantly greater size (3.5 cm vs. 2.1 cm) and Ki-67 expression (68.4% vs. 41.7%) in comparison to SCD cancers. NSCD cancers were less likely to have strongly positive progesterone receptors (Pr) and more likely to have Ki-67 > 15% or positive nodal status (47.4% vs. 8.3%). Increased breast density (ACR C and D: 78.9% vs. 50%ACR A and B) and intense background parenchymal enhancement (BPE, moderate/marked: 42.1% vs. 8.3% minimal/mild) were significantly more frequent in NSCD cases. Conclusion: NSCD cancers had higher prevalence of poor prognostic characteristics in comparison to SCD tumors, including larger tumor size, higher Ki-67 index, and positive nodes. Increased fibroglandular tissue and intense BPE were both strongly associated with NSCD cancers, supporting their use as potential MR biomarkers in breast cancer risk models.