Low-dose metronomic chemotherapy as an efficient treatment option in metastatic breast cancer\u2014results of an exploratory case\u2013control study

S Krajnak,A Hasenburg,K Almstedt,W Brenner,A.-S Heimes,A Lebrecht,M Schmidt,C Schnatz,R Schwab,G.-M Makris,M J Battista,F Haertner

doi:10.1007/s10549-020-05711-5

Abstract

PurposeThere is growing interest in low-dose metronomic chemotherapy (LDMC) in metastatic breast cancer (MBC). In this retrospective case–control analysis, we compared the efficacy of LDMC and conventional chemotherapy (CCT) in MBC.MethodsEach LDMC patient receiving oral cyclophosphamide (CTX) (50 mg daily) and methotrexate (MTX) (2.5 mg every other day) was matched with two controls who received CCT. Age, number of chemotherapy lines and metastatic sites as well as hormone receptor (HR) status were considered as matching criteria. Primary endpoint was disease control rate longer than 24 weeks (DCR). Secondary endpoints were progression-free survival (PFS), duration of response (DoR) and subgroup analyses using the matching criteria.Results40 cases and 80 controls entered the study. 30.0% patients with LDMC and 22.5% patients with CCT showed DCR (p = 0.380). The median PFS was 12.0 weeks in both groups (p = 0.218) and the median DoR was 31.0 vs. 20.5 weeks (p = 0.383), respectively. Among younger patients, DCR was 40.0% in LDMC vs. 25.0% in the CCT group (p = 0.249). DCR was achieved in 33.3% vs. 26.2% non-heavily pretreated patients (p = 0.568) and in 36.0% vs. 18.0% patients without multiple metastases (p = 0.096), respectively. In the HR-positive group, 30.0% LDMC vs. 28.3% CCT patients showed DCR (p = 1.000). Among triple-negative patients, DCR was achieved in 30.0% LDMC and 5.0% CCT patients (p = 0.095).ConclusionsWe demonstrated a similar efficacy of LDMC compared to CCT in the treatment of MBC. Thus, LDMC may be a valuable treatment option in selected MBC patients.

Highlights

Metastatic breast cancer (MBC) is an incurable but treatable disease
DCR Disease Control Rate, PFS progression-free survival, PD progression disease, SD stable disease, partial response (PR) Partial response, complete response (CR) Complete response. In this retrospective case–control study 120 MBC patients were evaluated regarding the efficacy of the chemotherapy treatment
The impact of metronomic CTX/MTX in our cohort of hormone receptor (HR)-positive and HER2-negative MBC patients as measured by DCR after 24 weeks of treatment was in line with previous studies [11,12,13]

Summary

Introduction

Metastatic breast cancer (MBC) is an incurable but treatable disease. it is crucial to achieve disease control with preservation of quality of life (QoL) [1]. It is assumed that LDMC is not a different way of administering chemotherapy but a truly new treatment option [3, 8, 9] This alternative strategy has been used especially in elderly patients, not eligible for a CCT [8]. To the best of our knowledge, there is insufficient experience regarding the efficacy of metronomic chemotherapy, compared to CCT in MBC. In this retrospective case–control study, the efficacy of metronomic administered CTX/MTX and CCT was compared in matched pairs and subgroup analyses were performed to define patients in which LDMC might be a more effective treatment option

Results

Discussion

Findings

Compliance with ethical standards