Could GLP-1 drugs help breast cancer patients live longer?

by · News-Medical

A major real-world study links GLP-1 receptor agonists to improved survival and lower recurrence risk in women with breast cancer, but researchers say clinical trials are needed before these drugs can be considered part of cancer care.

Study: Survival and Recurrence With GLP-1 Receptor Agonists in Breast Cancer. Image Credit: zimmytws / Shutterstock

GLP-1RA Breast Cancer Survival Background

BC is the most common cancer among females in the United States (US), and pre-existing conditions like type 2 diabetes (T2D) and obesity elevate the risk of reduced survival, disease progression, and recurrence. Weight-loss interventions to address obesity among BC patients may augment outcomes.

GLP-1RAs are established treatments for weight loss and T2D. However, the potential protective effects of these agents on recurrence and survival in BC patients are unclear.

Breast Cancer EHR Cohort Study Design

In the present study, researchers investigated the associations between GLP-1RA use and all-cause mortality and RFS in patients with BC. The team obtained data from electronic health records of adult female BC patients from a health research network.

GLP-1RA usage was defined as having at least two prescriptions in the six months prior to or any time after BC diagnosis. The study sample was stratified into T2D and obesity cohorts. GLP-1 use was compared to insulin/metformin or sodium-glucose cotransporter 2 (SGLT2) inhibitors in BC patients with T2D or glycated hemoglobin (HbA1c) ≥ 6.5% (T2D cohort), and to non-use in BC patients with obesity (obesity cohort).

The study’s outcomes included all-cause mortality and RFS (i.e., time from BC diagnosis to first metastatic recurrence). Cohorts were balanced on covariates, including demographics, medications, diagnoses, and procedures, using propensity score matching (PSM).

GLP-1RA Mortality and Recurrence Findings

The study included 841,831 BC patients, predominantly White (72%), with a mean age of 69 years. Of these, 652,001 patients with T2D and 573,443 with obesity were included in PSM. In the comparison of GLP-1 use vs non-use, 1,610 BC patients with obesity were included.

The corresponding 10-year estimates were 96% and 87.7% for GLP-1RA use and 88.6% and 90.6% for non-use, respectively. GLP-1RA use was significantly associated with a lower risk of all-cause mortality and metastatic recurrence compared to non-use in BC patients with obesity. However, the authors noted that few patients remained at risk after five years, limiting the precision of later 10-year RFS estimates.

For all-cause mortality, the five-year survival probability was 96.9% with GLP-1RAs and 82.3% with insulin/metformin. At 10 years, the survival probability was 96.9% for GLP-1RA use and 76.4% for insulin/metformin use. GLP-1RA use was significantly associated with a lower risk of all-cause mortality in this cohort compared to insulin/metformin use.

For RFS, the survival probability was 93.4% with insulin/metformin and 97.4% with GLP-1RAs at both five and 10 years. Consistently, GLP-1RA use was associated with a lower recurrence risk than insulin/metformin use. Finally, 4,052 BC patients with T2D were included to compare GLP-1RAs to SGLT2 inhibitors.

For all-cause mortality, the survival probabilities were 86.3% with GLP-1RA use and 88.9% with SGLT2 inhibitors at five years. The corresponding 10-year estimates were 75.5% and 73.4%, respectively.

Breast Cancer Outcomes and Study Limits

In sum, GLP-1RAs were associated with improved all-cause mortality and RFS among adult female BC patients with obesity compared with non-use, and among those with T2D compared with insulin/metformin, while comparisons with SGLT2 inhibitors were less consistent.

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