Real-world Registry Data for Older Patients with MBC

There are limited data for older patients with metastatic breast cancer (MBC), particularly relating to patterns of recurrence, treatment patterns, and survival outcomes. Therefore, a large prospective cohort of older patients with MBC treated at a single center examined disease presentation, treatments, and outcomes in a real-world setting.

This single-center study included patients aged >60 years who received treatment for MBC between 1999 and 2022 with ≥1 years of follow-up from time of MBC diagnosis. Eligible patients were classified into five 5-year age groups (60-65; 66-70; 71-75; 76-80; >80 years) and two broader groups of 60 to 70 years and >70 years.

The analysis population included a total of 1115 patients diagnosed with MBC (median follow-up, 2.9 years). Median age at MBC diagnosis of the study population was 66.3 years; the majority of patients were White and had hormone receptor (HR)+/HER2− (70.7%; n=788). Sample sizes were smaller for patients with HER2+ (n=131) and triple-negative disease (n=194).

In the comparison of patients aged 60 to 70 years versus >70 years, there were no differences in disease characteristics such as grade and disease sites at MBC diagnosis except for bone; however, there was a significant increase in the proportion of patients with HR+/HER2− disease with age (HR+/HER2−, 69%; >70 years, 76%; P=.02). In the HR+/HER2− cohort receiving first-line therapy (n=783), older patients received endocrine therapy more frequently (HR+/HER2−, 77.8%; >80 years, 94.7%) and chemotherapy less frequently (60-65 years, 22.2%; >80 years,5.3%) compared with the younger patients. The majority of patients received a first-line trastuzumab-containing regimen in the HER2+ cohort (89%) or ≥1 chemotherapies in the triple-negative cohort (94%).

The most common reason for discontinuation of first-line therapy was progressive disease; there was no difference in rates of discontinuation due to toxicity by age. Across disease subtypes, the proportion of patients receiving ≥3 lines of chemotherapy decreased with older age. Enrollment in a clinical trial in the MBC setting significantly decreased with increasing age (60-65 years, 40%; >80 years, 13%; P =.0004).

Survival outcomes were significantly worse for older patients regardless of subtype, with median overall survival (OS) of 4.4 years in ages 60 to 65 and 2.7 years in ages >80 (P<.005). In the HR+/HER2− subtype, 37.8% of patients aged 60 to 65 years and 23.7% of patients aged >80 years were alive at 2 years; 42.9% of patients with HR−/HER2+ disease were alive at 2 years and 0% in the other subtypes. The triple-negative cohort had poor survival outcomes regardless of age, with median survival of <2 years.

Real-world data from this large, prospective, single-institution cohort of older patients with MBC indicated poor survival outcomes with increasing age, particularly for those aged >80 years.

Source:

Hughes M, Patterson A, Newman A, et al. Patterns of presentation, treatment and survival for older patients with metastatic breast cancer (MBC): results from a large prospective registry. Presented at the 46th San Antonio Breast Cancer Symposium Annual Meeting, December 5-9, 2023; San Antonio, TX: Abstract PO2-10-07.