Abstract P5-07-09: Fatigue in patients with locally advanced or metastatic breast cancer undergoing single-agent taxane-based chemotherapy: de novo versus relapsed
Authors: Blaes Anne , Gavioli Elizabeth M. , Wakade Renuka , Miracle Santiago , DiTuri Giovanna , DePizzol Maria , Ruffini Pier Adelchi , Sergio Francesco , Leone Manuela , Mantelli Flavio , Allegretti Marcello , Fabi Alessandra 
Published: March 2023

Introduction: Fatigue is a debilitating and persistent condition of exhaustion that interferes with usual functioning. It is the most reported symptom across all cancer patients, and when related to the malignancy itself or to the neoplastic treatment, is referred to as cancer-related fatigue (CRF). Fatigue occurs in nearly all patients with metastatic breast cancer and is associated with poor clinical outcomes and worse quality-of-life. It is subjective and can be assessed from patient self-reports, such as the FACIT-Fatigue scale or Brief Fatigue Inventory, with no current gold-standard, which may lead to under reporting and lack of treatment intervention. Only since 2016, fatigue has been considered as a syndrome and included in the International Statistical Classification of Diseases, 10th edition, Clinical Modification (ICD-10-CM) according to specific criteria. The aim of this real-world data analysis was to describe the prevalence of fatigue, as reported by physicians using ICD-10-CM codes, in patients with locally advanced (Adv) or metastatic (Mtx) breast cancer (BC) undergoing single-agent taxane-based chemotherapy (CT), and to assess whether relapsed subjects had a higher prevalence versus those diagnosed de novo at an advanced stage.

Methods: Electronic health records (EHR) were analyzed from TriNetX, a global research network containing real-world data from approximately 150 million patients in 115 Health Care Organizations (72 in the United States and 42 in the European Union). Using ICD-10-CM codes and structured data only (no medical notes), subjects were identified with a diagnosis of Adv-Mtx BC who underwent CT with single-agent taxane in 2020, 2021 and 2022 (first quarter). After splitting the cohort based on “relapsed” (second- or further line treatment) vs “de novo” (first-line treatment), we assessed the prevalence of fatigue (any type, R53.x) and CRF (R53.0) within the first 3 months after initiation of taxanes.

Results: Among 379,880 BC patients under follow-up in 2021 across the 115 sites, 50,490 (13%) had Adv-Mtx BC, of whom 16,170 (32%) were diagnosed de novo and 34,330 (68%) experienced relapse. The proportion of patients undergoing single-agent taxane-based CT was 7.5% (1,220) and 13.4% (4,590), respectively. Almost one third (28%) of relapsed patients had previously received taxanes. The prevalence of fatigue (any type) and CRF was similar between the “de novo” and “relapsed” groups (24.6% vs 25.7% and 6.6% vs 5.4%, respectively). Overall, 27% and 21% of all fatigue was coded as CRF in the “de novo” and “relapsed” groups, respectively. No relevant differences were observed between 2020, 2021 and 2022 results.

Conclusions: This real-world analysis reveals that at least one in four patients with Adv-Mtx BC undergoing taxane based CT suffer from fatigue, independent of disease history and other factors. Fatigue is an unmet medical need in patients with BC, particularly in patients receiving taxanes.

Table. Fatigue prevalence (as per ICD-10-CM codes) within the first 3 months of single-agent taxane-based CT in patients with locally advanced or metastatic BC diagnosed “de novo” or relapsed in 2021

Citation Format: Anne Blaes, Elizabeth M. Gavioli, Renuka Wakade, Santiago Miracle, Giovanna DiTuri, Maria DePizzol, Pier Adelchi Ruffini, Francesco Sergio, Manuela Leone, Flavio Mantelli, Marcello Allegretti, Alessandra Fabi. Fatigue in patients with locally advanced or metastatic breast cancer undergoing single-agent taxane-based chemotherapy: de novo versus relapsed [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-07-09.