Abstract P6-14-06: Oral etoposide (VP-16) in heavily pre-treated metastatic breast cancer: A multicenter national observational study

Abstract

Abstract Background 20-30% of breast cancer (BC) patients will develop distant metastases. Despite important improvement achieved in the management of metastatic BC (MBC), median overall survival (OS) still ranges from 14 to 50 months, depending on tumor subtypes. Patients often receive many successive lines of therapy over the course of their disease. Few data on efficacy of 3rd and subsequent lines of chemotherapy are available. Although oral etoposide has been used for years in heavily pre-treated MBC patients, real-life data supporting its efficacy are lacking. Methods The primary objective was to assess progression free survival (PFS) in MBC patients having started oral etoposide as 3rd line chemotherapy or more, using the French Epidemiological Strategy and Medical Economics (ESME) database, established in 2014 by Unicancer. Secondary objectives were overall survival (OS) and descriptive and prognostic analyses. Results Of 16703 MBC patients included in the ESME program and covering the 2008-2014 period, 323 received at least 14 days of oral etoposide. Amongst them, 5 were men, 46 received etoposide as 1st or 2nd line chemotherapy, and 7 had no information available regarding line of treatment, leaving 265 for analysis. All received oral etoposide, 255 as monotherapy while 10 pts combined with trastuzumab for HER2+ MBC. Patients' and tumour characteristics are shown in table 1. The mean line of chemotherapy with oral etoposide was 5 (range 3-12). With a median follow-up of 32.2 months [CI95%: 22.0-42.1], median PFS and OS (from initiation of oral etoposide) were 3.1 months [95% CI 2.8-3.7] and 7.4 months [95% CI 6.0-9.9], respectively. No predictive factor for PFS could be identified (age at MBC diagnosis, BC subtype, number of metastatic sites, presence of visceral metastases, disease-free interval, line of treatment). Only a trend for longer PFS was seen in patients > 50 years old, with longer disease-free interval and receiving etoposide earlier. Triple-negative MBC had shorter OS compared to other subtypes (p=0.03). Of note, OS was stable around 7 months for subsequent lines following a 3rd line of chemotherapy. n%Age at MBC diagnosis< 50 yo8331.3≥ 50 yo18268.7Primary BC subtypeER+ HER2-16662.6HER2+3814.3Triple negative5621.1ND51.9Number of metastatic sites115458.1≥ 211141.9Visceral metastasisNo13249.8Yes13350.2Disease-free intervalde novo4015.16-24 months4115.524-60 months7427.9> 60 months11041.5Chemotherapy line36323.846524.554717.764316.3≥ 74717.7 Conclusions Oral etoposide may achieve significant disease control in heavily pre-treated MBC, with a 3.1-month median PFS and independently from prognostic factors. Moreover, etoposide has the major advantage of an oral drug administered at home with a low cost. A case-control study is ongoing. Citation Format: Lerebours F, Carton M, Bacrie J, Pierga J-Y, Rouzier R, Saghatchian M, Dalenc F, Mailliez A, Levy C, Firmin N, Debled M, Leheurteur M, Desmoulins I, Lefeuvre C, Goncalves A, Uwer L, Ferrero J-M, Eymard J-C, Petit T, Mouret-Reynier M-A, Piot I, Perrocheau G, Caillot C, Perol D. Oral etoposide (VP-16) in heavily pre-treated metastatic breast cancer: A multicenter national observational study [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 P6-14-06.