Treatment patterns of older adults with metastatic breast cancer in community practices.

Abstract

e13063 Background: The median age at diagnosis of breast cancer is 62 with 45% of patients over the age of 65. At diagnosis, up to 5% of patients will have metastatic breast cancer (MBC) and up to 30% of patients with early-stage disease will develop MBC. There are no clear guidelines on how to treat older adults with MBC (OA-MBC) due to their poor representation in clinical trials. This lack of recommendations can often lead to under treatment of OA-MBC. This study evaluated the self-reported treatment patterns of practitioners in community practices for OA-MBC and evaluated the actual treatment their OA-MBC patients received. Methods: This is a secondary analysis of a multi-phase trial which initially evaluated the gaps in practice patterns that exist in the assessment and management of OA-MBC and did a prospective comparison between the older patient’s geriatric assessment and provider’s clinical assessment. In this analysis we focused on the practice patterns in the community. Physicians completed questionnaires detailing their front-line treatment choices for each subcategory of MBC in women over the age of 65. Data was then collected on patients in these physicians’ practices including their current line of treatment, treatment regimen, comorbidities, performance status and demographics. The appropriateness of treatment choice was then evaluated based on MBC subcategory and line of treatment using the NCCN guidelines for breast cancer. Patient and physician characteristics and treatment choices were summarized using descriptive statistics. Results: 44 providers from 9 community practices located in PA, DE, NJ, MT, and WA participated. Majority of providers were Caucasian (57%) and had been in practice for >11 years (53%). 100 patients were evaluated from these practices between December 2016 – April 2019. Median age 73 (65-90). In response to front-line therapy choices, 27/44 (61%) providers selected endocrine only therapy for HR+ but in practice, 29/37 (78%) of HR+ patients were treated with combination endocrine & CDK 4/6 inhibitors. For HER2+, 20/44 (45%) providers selected trastuzumab + chemotherapy for front-line therapy and in practice 8/8 (100%) of patients received this combination. For TNBC, 37/44 (84%) providers agreed with sequential single agent chemotherapy over combination and in practice 6/7 (86%) patients received this. Including all lines of therapy, 84/100 patients were treated in accordance with NCCN guidelines. Conclusions: Despite the lack of older adult guidelines, our community-based practitioners are treating the majority of their OA-MBC patients appropriately and in accordance with NCCN guidelines. In our cohort of OA-MBC there was no evidence of under treatment, however, due to the lack of sufficient data in this patient population it is not clear that this approach is beneficial. Additional research is needed to refine the treatment approach of this unique patient population.