Abstract B95: Disparities in cancer drug use in the geriatric patient
Authors: McKoy June M , Lau Denys T 
Published: December 2010

Background: Many older patients with cancer have multiple co-morbidities requiring multiple medications in addition to their anticancer therapies. Ensuring appropriate medication use in this population, including adequate treatment dosage and adhering to treatment guidelines, is therefore a public health priority. We reviewed the epidemiological literature regarding anticancer treatment administration to older cancer patients.

Methods: We conducted a systematic literature review of population-based, epidemiological studies published between 1983 and 2006 on medication use involving chemotherapy and hormonal therapy among cancer patients aged 65 and older. Articles were classified into content areas based on processes of care and adverse drug reactions. Searches were conducted using PubMed, CancerLit, and Ageline. Medical subheadings were used to supplement searches. Only population-based, epidemiological studies published in English between 1983 and 2006 that examined medication use involving anticancer therapies (chemotherapies and hormonal therapies) and included cancer patients 65 years and older were included. Articles were systematically reviewed and classified based on Chassin's paradigm of quality problems in health services use: underuse, overuse, and misuse. For this study, underuse reflected the use of substandard, low-intensity anticancer drug therapies or the omission of standard drug treatments. Overuse included greater than appropriate use of pharmaceuticals, such as polypharmacy or over-dosage. Misuse included avoidable improper use of anticancer therapies, such as inappropriate drug choices, and adverse interactions among drugs or between pharmacotherapies and co-morbidities.

Results: A total of 78 articles were identified. Sixty five articles about overuse, underuse, and misuse of medications involving anticancer therapies among older cancer patients were identified: 64 (98%) evaluated underuse, 1 (2%) overuse, and none evaluated misuse. An additional 13 retrieved articles focused on ADRs associated with chemotherapy or hormonal therapy administration to older patients with cancer. One article reported overuse of hormonal treatments in elderly cancer patients with localized prostate cancer. The 64 articles on underuse were further subcategorized into under-treatment (n=47), deviation from treatment criteria (n=16), and patient non-adherence (n=1). Forty-seven studies described under-treatment, operationally defined as: no therapy, less frequent administration, and other non-standard anticancer treatment regimens. Seven studies analyzed medical records and primarily included data from one geographical location or healthcare system. Breast cancer was the most frequently studied cancer diagnosis, being the focus of 22 studies on under-treatment (47%). Thirty-nine of these studies reported that advanced age, regardless of physiologic condition, was a significant risk factor for under-treatment in anticancer therapy. Conclusions: 98% of the epidemiological studies on processes of care associated with use of anticancer therapies among older patients with cancer evaluated underuse. Since cancer cases are expected to rise as the population ages and a tandem increase in the complexity of drug regimens is expected, additional research needs to focus how decisions are made relative to the utilization of cancer therapies older patients.

Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):B95.