A high proportion of older patients with metastatic breast cancer, particularly those with triple-negative disease, do not receive first-line systemic therapy, according to research presented in a poster at the San Antonio Breast Cancer Symposium 2022.
Researchers conducted a retrospective study to evaluate treatment patterns in older patients (70 years and older) with metastatic breast cancer and factors associated with outcomes in this population. The researchers used electronic medical records to obtain data and the Charlson index to assess comorbidities. The study endpoints were proportion and type of first-line systemic therapy, rates of treatment discontinuation due to toxicities, overall survival (OS), and prognostic factors.
A total of 460 patients with metastatic breast cancer treated at a single center were included in the study. The median patient age was 78 years (IQR, 70 to 96). The most prevalent subtype was hormone receptor-positive HER2-negative (HR+/HER2-) breast cancer (71.9%), followed by triple-negative breast cancer (TNBC; 13.9%) and HER2-positive (HER2+) breast cancer (10.8%). Most patients had de novo metastatic disease (68.7%), an ECOG performance status (PS) of 3-4 (68.1%), and a Charlson index score of 7 or lower (76.9%).
The researchers found approximately 10% of patients did not receive systemic therapy for metastatic breast cancer. Among disease subtypes, 34% of patients with TNBC did not receive systemic therapy, compared with 5% of those with HR+/HER2- breast cancer and 6% of those with HER2+ breast cancer (P <.001). The team also found the proportion of patients not receiving systemic therapy was higher among patients with an ECOG-PS of 3-4 (13% vs 3% with ECOG-PS 0-2; P <.001).
Among patients who received first-line endocrine therapy (n=165), 1.8% discontinued due to toxicity. Among patients who received first-line chemotherapy (n=90), 17.8% discontinued due to toxicity. In the overall cohort, 75% of patients died, and breast cancer was the main cause of death (94.2%).
The researchers identified factors associated with increased risk of death, including HER2+ disease (hazard ratio [HR], 1.48; 95% CI, 1.04-2.09; P =.027) or triple-negative disease (HR, 1.52; 95% CI, 1.05-2.20; P =.025), age 80 to 90 years (HR, 1.30; 95% CI, 1.02-1.64; P =.028), ECOG-PS of 3-4 (HR, 2.34; 95% CI, 1.73-3.15; P <.001), and not receiving systemic therapy (HR, 4.48; 95% CI, 2.88-6.98; P <.001).
The team observed a median OS of 29 months for patients treated with systemic therapy and 2.3 months for those who did not receive systemic therapy (P <.001).
“In this cohort of elderly patients with metastatic disease, a high proportion of patients did not receive systemic therapy, and the main cause of death was [breast cancer]. Nevertheless, many factors influence the prognosis and the treatment decision for this population,” the researchers concluded.
Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Vidaurre Mendes S, Zanin Orsi B, Monteiro Vasconcellos J, et al. Overview of the management and factors associated with outcomes of metastatic breast cancer among elderly patients. Presented at SABCS 2022. December 6-10, 2022. Abstract P1-03-05.