Background
Treatments for advanced or metastatic breast cancer (aBC/mBC) are associated with gastrointestinal (GI) toxicities. The objective of this study was to assess the association between GI toxicities in mBC/aBC and health-related quality of life (HRQoL) and economic burden.
Methods
We conducted a comprehensive literature search of the Cochrane Central Register of Controlled Trials (2017), NHS Economic Evaluation Database (2016), Embase (1988 – 2017 week 34), and Ovid MEDLINE (1946 to August 2017). Eligible studies evaluated an intervention/comparator treatment in adult patients (age ≥18 years) with aBC/mBC and reported a direct connection between GI toxicities (ie, diarrhea, constipation, nausea, vomiting) and HRQoL and economic evidence. All studies published from January 2000 to August 2017 were assessed for eligibility. Editorials, case reports, conference abstracts, and studies of early, locally advanced, or inflammatory BC were excluded. Abstract and title screening, and full-text screening were conducted by single reviewers. Data were extracted by a single reviewer and verified by a second. Results were synthesized narratively.
Results
Database searches identified 3,428 articles; an additional 16 articles were identified through other sources. Ninety-four studies underwent full-text review, of which 27 reported a direct connection between GI toxicities and HRQoL (n = 11) and economic burden (n = 19). Some studies reported both HRQoL and economic data.
Patients identified treatment-related adverse events (AEs), such as GI events, as an important aspect of treatment that can affect therapy choice, discontinuation, and switching. Generally, patients with mBC had lower HRQoL than other BC groups, and increasing toxicity was associated with a greater degree of HRQoL impairment. When patients were asked to rank which AEs they most wanted to avoid, only pain ranked higher than nausea and vomiting. In a willingness to pay study, women with mBC were willing to pay $3,894 (2014 USD) per year to avoid severe diarrhea and $3,211 to avoid severe nausea.
Gastrointestinal events were among the costliest class of AEs, with mean costs as high as $4,809 (2016 USD) per episode; costs increased by 24% if events were persistent or recurrent.
Conclusions
Gastrointestinal toxicities are common in patients with aBC/mBC and have significant consequences for HRQoL and system-level economic outcomes. Frequency and implications of GI effects of treatment regimens should be considered carefully during patient counseling,, prescribing and coverage decisions in metastatic breast cancer.
Citation Format: Disher T, Siddiqui M, Mitra D, Cameron C, Zhan L, Iyer S. GI toxicities in metastatic breast cancer: A comprehensive literature review [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-33.
