The risk of drug-drug interactions (DDI) increases with the number of comedications. The prognostic impact of DDI in oncology is poorly understood.
We included 105 patients with advanced NSCLC, 100 patients with advanced ER-negative breast cancer (BC) and 100 hospice inpatients (HO) with advanced malignancies between 2010 and 2015. Data collected included all anticancer and non-anticancer drugs received, age, gender, presence of CNS metastases, smoking status, ECOG performance status (PS), Charlson comorbidity score and overall survival (OS) from the time of incurable cancer. Potential DDI were assessed using the hospINDEX of all drugs approved in Switzerland in combination with the DDI software - flycicle mode (HCI Solutions, Bern, Switzerland). Primary study objective was to assess the prognostic value of the severity of DDI per patient cohort using Kaplan-Meier statistics, uni- and multivariate Cox regression models. The study had a power of 84% to detect a survival difference of 25%.
The median number of drugs was 5 (range 0 to 15) in all patients, lowest in BC (4) and highest in HO (6). A major risk for DDI was detected in 74 patients (24.3%) overall, including 29 NSCLC patients (27.6%), 25 BC patients (25.0%) and 20 HO patients (20%). The number of drugs was significantly associated with the risk of DDI (p
Severity of DDI is a significant and clinically relevant prognostic factor in advanced BC patients. Prospective trials should evaluate the potential benefit of avoiding polypharmacy in this group of patients. In the meantime, increased caution with polypharmacy seems warranted when treating patients with advanced cancer.
Clinical trial identification
2016-00283 (BASEC, national trial identifier)
Legal entity responsible for the study
Markus Joerger MD-PhD ClinPharm
All authors have declared no conflicts of interest.