Chicago, IL—Adverse events related to chemotherapy for metastatic breast cancer lead to a substantial economic burden that is primarily explained by increased inpatient, outpatient, and pharmacy costs, said lead investigator Sara A. Hurvitz, MD, Director of the Oncology Breast Cancer Program at University of California, Los Angeles (UCLA) Jonsson Comprehensive Cancer Center and Assistant Clinical Professor at UCLA School of Medicine, who presented an economic analysis at ASCO 2012.
“An analysis of healthcare costs stratified by the number of adverse events reported by patients showed a clear trend: the economic burden of adverse events increases with the number of adverse events reported,” Dr Hurvitz said. The study is the first to assess costs associated with adverse events during treatment for metastatic breast cancer.
Patients were selected from the PharMetrics Integrated Database, using pharmacy and medical claims from >100 US health plans, representing >70 million lives in the period between 2000 and 2010.
The eligible cohort included 3222 patients who used a taxane (ie, docetaxel, paclitaxel) first-line, capecitabine first-line, taxane second-line, or capecitabine second-line. Patients treated with both classes during the same episode were excluded. The list of adverse events included almost 2 dozen possibilities. Adverse events were seen in each of the 4 study cohorts.
Incremental Monthly Costs
The incremental costs associated with chemotherapy-related complications were estimated by comparing the average costs between the cohorts with and without adverse events for the 4 treatment groups:
- Taxanes first-line: adverse events were associated with a 38.7% increase in monthly costs over patients without adverse events ($3547). These incremental costs were mainly driven by increased inpatient costs and other drug costs (other than those for chemotherapy)
- Taxanes second-line: adverse events were associated with a 69.5% increase in monthly costs ($5320). Incremental costs were mainly driven by incremental pharmacy costs for chemotherapy and other drugs
- Capecitabine first-line: adverse events were associated with a 9% increase in monthly costs ($4933). Incremental costs were mainly driven by inpatient and outpatient costs
- Capecitabine second-line: adverse events were associated with an 82.9% increase in monthly costs ($4933). Incremental costs were mainly driven by outpatient and inpatient costs.
Increasing Adverse Events per Episode Led to Higher Costs
The more adverse events per episode, the greater the cost of care, the analysis found. For example, for taxane first-line therapy, the mean cost of a treatment without an adverse event episode was approximately $10,000, which rose to approximately $11,000 in the setting of 1 or 2 adverse events, and to almost $15,000 in the setting of >4 adverse events.
For second-line capecitabine, treatment without an adverse event episode cost approximately $6000, but rose to approximately $14,000 in the setting of >4 adverse events.
The average monthly costs per type of adverse event were highest for skin toxicity with taxanes and for constitutional symptoms with capecitabine, both approaching $16,000 on average.
“Further research evaluating the clinical and economic consequences of chemotherapy-related adverse events in a prospective manner can further characterize the effects seen here,” Dr Hurvitz concluded.