Long-term survivor characteristics in HER2-positive metastatic breast cancer from registHER

Abstract

Background: Data characterising long-term survivors (LTS) with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) are limited. This analysis describes LTS using registHER observational study data.

Methods: A latent class modelling (LCM) approach was used to identify distinct homogenous patient groups (or classes) based on progression-free survival (PFS), overall survival, and complete response. Demographics, clinicopathologic factors, first-line treatment patterns, and clinical outcomes were described for each class. Class-associated factors were evaluated using logistic regression analysis.

Results: LCM identified two survivor groups labelled as LTS (n=244) and short-term survivors (STS; n=757). Baseline characteristics were similar between groups, although LTS were more likely to be white (83.6% vs 77.8%) with oestrogen receptor-positive (ER+) or progesterone receptor-positive (PgR+) disease (59.4% vs 50.9%). Median PFS in LTS was 37.2 (95% confidence interval (CI): 32.9-40.5) vs 7.3 months (95% CI: 6.8-8.0) in STS. Factors associated with long-term survival included ER+ or PgR+ disease, metastasis to node/local sites, first-line trastuzumab use, and first-line taxane use.

Conclusions: Prognostic variables identified by LCM define a HER2-positive MBC patient profile and therapies that may be associated with more favourable long-term outcomes, enabling treatment selection appropriate to the patient's disease characteristics.

Trial registration: ClinicalTrials.gov NCT00105456.

Figure 1

Site of first disease progression among short-term survivors (STS), long-term survivors (LTS), and all treated patients. Abbreviation: CNS=central nervous system.

Figure 2

Kaplan–Meier estimates of progression-free survival (A) and overall survival (B) of the short-term survivor (STS) and long-term survivor (LTS) latent classes. Abbreviations: CI=confidence interval; NE=not estimable; OS=overall survival; PFS=progression-free survival.

Figure 3

Logistic regression analysis examining prognostic factors associated with short-term survivors (STS). Abbreviations: CI=confidence interval; CNS=central nervous system; CVD=cardiovascular disease; ECOG=Eastern Cooperative Oncology Group; ER=oestrogen receptor; PgR=progesterone receptor; OR=odds ratio.

Figure 4

Cox proportional hazards model for overall survival. Abbreviations: CI=confidence interval; CNS=central nervous system; CVD=cardiovascular disease; ECOG=Eastern Cooperative Oncology Group; ER=oestrogen receptor; HR=hazard ratio; PgR=progesterone receptor.