Abstract P6-01-01: Patterns of disease progression in patients with local and metastatic breast cancer as evaluated by whole-body MRI

Abstract

Abstract Background Clinical evaluation of palpable breast or chest wall disease is important in the assessment of response to systemic therapy in patients with combined local and metastatic breast cancer. However, there is a lack of data describing the patterns of progressive disease (PD) in relation to local and metastatic sites in patients on systemic anti-cancer therapy (SACT). Whole-body magnetic resonance imaging (WB-MRI) provides detailed information about the extent and distribution of local and metastatic disease in breast cancer. Recent published data has shown the superiority of WB-MRI over body CT scans at identifying sites of disease and therapy response. This retrospective study is designed to analyse the patterns of PD on WB-MRI, in patients on first line SACT for combined local and metastatic breast cancer. Methods Patients with stage IV disease at first diagnosis, or those previously treated for early breast cancer with local (breast or chest wall) and metastatic recurrence were included. Patients were eligible for analysis if they had a baseline WB-MRI prior to starting first line SACT for metastatic disease, and subsequent WB-MRIs for response assessment up to the point of PD and a change in SACT. Patient information and SACT data were collected from contemporaneous medical records. Data on sites of disease and sites of progression were collected from the original WB-MRI reports. All WB-MRI scans were performed using a published WB-MRI protocol. Results Thirty-one patients were suitable for analysis. Eighteen had metastatic disease at first presentation of breast cancer. Thirteen had both local and metastatic disease recurrence, 8 after previous mastectomy and 5 after previous breast-conserving surgery. Mean age of patients at metastatic diagnosis was 58.3 years (range 31 – 86 years). Fifteen patients received first-line chemotherapy, 10 with Her2-targeted therapies. Sixteen received first-line hormonal therapy. None of the patients progressed first in local disease and/or regional nodes only. Seven patients (22.6%) had evidence of first PD in their loco-regional disease along with concurrent PD at metastatic sites. Twenty-four patients (77.4%) had evidence of first PD at metastatic sites without progression of loco-regional disease. Of the 26 patients with bone metastases, 20 had PD of bone disease. Two patients without bone disease at baseline had new bone lesions evident at first PD. Of the 8 patients with liver metastases, 4 had progression of liver disease. Five patients without liver disease at baseline had new liver lesions evident at first PD. None of the patients had a change in SACT performed for clinical disease progression only. Conclusions PD identified by WB-MRI occurs most commonly at metastatic sites rather than at palpable sites of loco-regional disease. Therefore, evidence of ongoing clinical benefit of SACT at loco-regional sites of breast cancer on clinical examination may give false reassurance about the disease status at metastatic sites. Regular imaging reassessments are advised for patients undergoing SACT for loco-regional and metastatic disease. Citation Format: Kosmin M, Padhani A, Sokhi H, Thijssen T, Makris A. Patterns of disease progression in patients with local and metastatic breast cancer as evaluated by whole-body MRI [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-01-01.