Age and comorbidity in relation to treatment and survival outcomes in triple-negative breast cancer: A Swedish nationwide registry-based study

Introduction

Patients with cancer and comorbidities often experience a longer time-to-diagnosis and significantly worse clinical outcomes. Here, we evaluate the association between age, Charlson Comorbidity Index (CCI), treatment given, and patient survival, thereby identifying common non-breast cancer-related causes of death in patients with triple-negative breast cancer (TNBC).

Materials and Methods

Population-based registry data were retrieved for patients diagnosed with primary invasive TNBC in Sweden between 2007 and 2021 (n = 7145). Multivariable Cox regression analyses were performed for disease-specific survival and overall survival was calculated using a landmark time set at six months post-diagnosis, the likely timeframe for treatment initiation. Multivariable logistic regression models were computed for age, comorbidity, and treatment. Weighted CCI (CCIw) was stratified into CCIw 0, CCIw 1–3, and CCIw 4–10.

Results

Approximately 42 % of patients were ≥ 65 years of age and 30 % had comorbidities (27 % CCIw 1–3 and 3 % CCIw 4–10). Two or more comorbidities were common in patients ≥65 years. Patients in the CCIw 4–10 group were significantly older (72 years vs. 68 years for CCIw 1–3 vs. 58 years for CCIw 0) and had locoregional spread and larger tumors. Individuals with comorbidities were less likely to receive neoadjuvant chemotherapy, breast-conserving surgery, or postoperative treatment, and had a higher risk of death due to non-breast cancer-related causes. Patients ≥75 years had a higher risk of breast cancer-related death up to eight years after the landmark time and death from other causes thereafter. Furthermore, older (≥75 years) and patients with comorbidities had the lowest five-year survival probabilities. Other neoplasms (26 %; e.g., lung, pancreas, and ovarian cancer) and cardiovascular disease (24 %) were the leading causes of non-breast-cancer-related death, particularly in patients ≥50 years of age.

Discussion

Patients with TNBC and comorbidities are less likely to receive specific treatment modalities and experience worse survival outcomes. Other malignant neoplasms are the leading cause of death for patients ≥50 years of age.