Impact of Metastatic Colorectal Cancer Stage and Number of Treatment Courses on Patient Health Care Costs and Utilization

Background: Advances in colorectal cancer (CRC) treatment and improved survival rates have led to higher costs associated with treating CRC. Objective: To examine health care costs and utilization by initial CRC stage at diagnosis and the number of lines of treatment received by patients with metastatic CRC. Methods: Adult patients with a diagnosis of CRC made from January 1, 2005 to May 31, 2010 were identified from the Oncology Management registry. Patients with stage IV CRC at initial diagnosis or who had advanced to stage IV CRC at the time of the study were included. Registry data included initial CRC stage and the date of diagnosis. Linked health care claims from a large US health insurance database affiliated with Optum were used to identify health care costs and patient characteristics. Multivariate regression analysis was used to estimate total 4-year health care costs stratified by stage and adjusted for patient characteristics. Follow-up ended at patient death, disenrollment from the health care plan, or study end (November 30, 2010). Results: A total of 598 patients, followed for an average of 653 days after first evidence of metastasis, were included. At initial diagnosis, 91 patients had stages 0 to III CRC, 310 patients had stage IV CRC, and 197 patients had an unknown stage of CRC. The mean unadjusted total cost per patient (medical + pharmaceutical costs) was $252 200; outpatient hospital visits (excluding radiation and surgery) contributed most to the total cost, at a mean cost of $71 334. Hospitalization costs, with or without surgery (mean, $56 862), accounted for 33% of the $176 135 unadjusted mean cost for medical services (ambulatory visits [office and outpatient], emergency department visits, laboratory/radiology services, and inpatient admission). Chemotherapy and biologics were also costly (mean, $31 112 and $38 276, respectively). A general linear model analysis of estimated 4-year total costs showed that both CRC stage at diagnosis and the number of lines of treatment after metastasis had a statistically significant association with cost (P < 0.001). Conclusion: Variables that had a statistically significant association with cost (P < 0.05) were sex, age group, and follow-up Charlson Comorbidity Index score after metastases. After adjusting for the number of lines of treatment received, total 4-year costs were highest among patients who presented with stage IV CRC and lowest among patients who presented with stage III CRC and developed metastatic disease.