Adverse Drug Reactions in an Oncological Population: Prevalence, Predictability, and Preventability

A diagnosis of cancer often occurs in patients with multimorbidity and polypharmacy. Cancer can cause an altered physiological environment, placing patients at risk of drug-drug interactions, drug-disease interactions, and adverse drug reactions (ADRs). This study identified that ADRs caused or contributed to one in five hospital admissions of patients with cancer. ADRs were caused by systemic anticancer therapies (SACTs) in 53.3% of cases and non-cancer medications in 45.4% of cases, and a combination of both in 1.3%. ADRs occurred in similar frequencies in older and younger patients secondary to SACTs (8.3% vs. 13.1%, p = .295), non-SACTs (10.7% vs. 8.3%, p = .107), and a combination of both (0% vs. 1.3%, p = .240). The majority of ADRs were predictable (89.3%) and potentially preventable (62.6%). These findings support the need for increased awareness of medication-related adversity in patients with cancer and interventions to minimize their occurrence, thus supporting the American Society of Clinical Oncology guidelines that recommend adults ≥65 years of age receiving chemotherapy have geriatric assessment to identify medical and medication issues.