Abstract PS7-46: Enrollment of older metastatic breast cancer patients in clinical trials
Authors: Bringuier Michael , Carton Matthieu , Levy Christelle , Patsouris Anne , Pasquier David , Debled Marc , Rigal Olivier , Jacot William , Gonçalves Anthony , Desmoulins Isabelle , De La Motte Rouge Thibault , Bachelot Thomas , Ferrero Jean-Marc , Eymard Jean-Christophe , Dalenc Florence , Mouret-Reynier Marie-Ange , Petit Thierry , Chevrot Michael , Courtinard Coralie , Uwer Lionel , Frenel Jean-Sebastien , Baldini Capucine 
Published: February 2021

Background: About 40% of breast cancer cases occur in women 65 years old (yo) or older and 20% in women over 75 yo. These numbers are expected to increase in the near future. Ironically, older patients remain underrepresented in clinical trials with no improvement in the past decade, although they may present different efficacy/toxicity profiles compared with younger adults. In this context, real life cohorts may bring valuable insight to identify potential barriers to recruitment of older patients with metastatic breast cancer (MBC) in clinical trials. Methods: We used the national Epidemio-Strategy and Medical Economics (ESME) MBC Data Platform, a multi-center real life database using a retrospective data collection process in 18 French Cancer Centers. Cases selected were adult patients with MBC whose first metastasis was treated between January 1st, 2008 and December 31st, 2016. We selected MBC women over 70 yo at the time of MBC diagnosis, with at least one line of systemic treatment and no other cancer in the 5 years before MBC. The primary objective was to describe factors associated with enrollment in clinical trials in older patients, using a multivariable Cox model. Factors included in this model were age (continuous, and by class), period (2008-2011 vs 2012-2016), phenotype (ER+, HER2+, or ER- HER2-), ECOG Performance Status (PS), treatment, metastatic sites (brain, visceral, nodes/bone only) and number, and volume of hospital activity. No geriatric description could be extracted from the database. Results: There were 5846 patients ≥70yo (median age 77) and 15892 patients &lt; 70 yo. Of the older ones, 245 (4.2%) were enrolled in a clinical trial in first line compared with 1602 (10%) for younger ones. Most of the older patients in this cohort (66%) had ER+ HER2+ disease, half had visceral metastases (&lt; 3 metastatic sites in 82%). Median follow-up of older patients was 46.3 months; 95%CI 44.8-49.0. Cause of death was related to disease in 1155 (33.9%) older patients, and related to another cause or unknown in 2156 (63.3%), data were missing for 2441 patients. Median overall survival (OS) was 34.1 months in the older population, 95%CI 32.9-35.4, and specific overall survival was 70.8 months, 95%CI 66.3-80.0. Significant factors identified in the multivariable analysis for enrollment in 1st line treatment clinical trial ≥70 are shown in table. Volume of activity was not identified as one.

By multivariate analysis, participation of older patients to a clinical trial was associated with an increased OS (HR 0.7; 95% CI 0.6-0.8) but not with a better breast cancer specific survival (HR 0.94; 95%CI 0.68-1.29). Conclusions: In this large real-life database, few older MBC patients were enrolled in a trial compared with younger ones. Factors associated with such participation to clinical research were younger age (&lt; 80 yo), good PS, HER2+ disease, and investigational treatment consisting of chemotherapy or targeted therapy. There was a small improvement in accruing older patients between 2007-2011 and 2012-2016 (2.6% versus 5.5%). Most of these factors raise questions on drug availability and perceived potential benefits by investigators and medical teams. Accrual of older patients with cancer in other disease types should be more encouraged.

VariableOR95%CIAge vs 70-75 75-80 80-85 85+0.74 0.47 0.170.54-1 0.31-0.71 0.06-0.37MBC diagnosis period vs 2008-2011 2012-20161.671.23-2.27Phenotype vs Others HER2+1.761.26-2.45PS vs 0 1 2-40.71 0.150.5-1 0.08-0.26Treatment4.88 5.253.08-7.9 3.48-8.14Chemotherapy vs others4.883.08-7.9Targeted treatment vs others5.253.48-8.14

Citation Format: Michael Bringuier, Matthieu Carton, Christelle Levy, Anne Patsouris, David Pasquier, Marc Debled, Olivier Rigal, William Jacot, Anthony Gonçalves, Isabelle Desmoulins, Thibault De La Motte Rouge, Thomas Bachelot, Jean-Marc Ferrero, Jean-Christophe Eymard, Florence Dalenc, Marie-Ange Mouret-Reynier, Thierry Petit, Michael Chevrot, Coralie Courtinard, Lionel Uwer, Jean-Sebastien Frenel, Capucine Baldini. Enrollment of older metastatic breast cancer patients in clinical trials [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS7-46.