Contribution of metastatic therapies on mortality reduction in breast cancer

Developments in screening tools, early-stage treatment, and metastatic treatment have resulted in impressive reductions in breast cancer mortality across all molecular subtypes compared with no intervention. In the last 2 decades, the introduction of novel metastatic therapies has been essential to the improved survival of patients with breast cancer.

Based on 6 simulation models of the Cancer Intervention and Surveillance Modelling Network (CISNET), Prof. Jennifer Caswell-Jin (Stanford University, CA, USA) and co-investigators aimed to assess whether advances in metastatic therapies have resulted in a reduced population-level breast-cancer mortality in the last 2 decades [1]. The contribution of screening and early-stage therapy on mortality reduction in patients with breast cancer was assessed in previous research [2].

In 2019, the combination of screening, early-stage treatment, and metastatic treatment resulted in a reduced overall mortality of patients with breast cancer of 58% compared with no intervention. The largest reduction was observed in the ER-positive/HER2-positive subpopulation (71%), whereas the least progress was made in patients with triple-negative breast cancer (40%). In addition, the reduction in mortality rates in patients with ER-negative/HER2-positive or ER-positive/HER2-negative were 61% and 59%, respectively.

According to Prof. Caswell-Jin, the relative contribution of metastatic therapies to reduced mortality varies over time, depending on the distribution of transitioning therapies. When metastatic therapies are transitioned to early-stage therapies, the relative contribution of metastatic therapies to the improvement in overall survival is decreased. In 2019, 19% of the overall mortality reduction was attributed to metastatic therapies. Furthermore, metastatic therapies have improved the median overall survival of patients with ER-positive/HER2-negative breast cancer after distant recurrence from 2.0 to 3.5 years in the last 2 decades. Correspondingly, the median overall survival after distant recurrence increased from 1.2 to 1.8 years in ER-negative/HER2-negative patients, from 2.3 to 4.8 years in ER-positive/HER2-positive patients, and from 2.2 to 3.9 years in ER-negative/HER2-positive patients (see Figure).

Figure: Median survival after distant recurrence for HER2-positive (up) and HER-negative (down) subtypes [1]



“Steady introduction of new metastatic treatments in the last 2 decades has been essential to the observed mortality reduction in patients with breast cancer,” concluded Prof. Caswell-Jin.

1. Caswell-Jin J, et al. Contributions of screening, early-stage treatment, and metastatic treatment to breast cancer mortality reduction by molecular subtype in U.S. women, 2000-2017. Abstract 1008, ASCO 2022 Annual Meeting, 3‒7 June, Chicago, IL, USA.
2. Plevritis SK, et al. JAMA. 2018;319(2):154–164.

Copyright ©2022 Medicom Medical Publishers



Posted on 5 August 2022