Patterns of colorectal cancer care in the United States: 1990-2010.

Abstract

684 Background: Colorectal cancer (CRC) incidence and mortality have declined in the U.S. over the past two decades. Much of the decline can be attributed to screening and advances in treatment. Few studies have evaluated the extent to which recommended therapies have been adopted in community settings and temporal changes in patterns of care. Methods: Patients diagnosed with stages II and III CRC were randomly sampled from the population-based Surveillance, Epidemiology, and End Results (SEER) program in 1990-91, 1995, 2000, 2005, and 2010 (n=7,056). Treatment data were obtained through medical record review and physician verification. We described the receipt of adjuvant chemotherapy among colon cancer patients and preoperative or postoperative radiation therapy among rectal cancer patients. Log-binomial regression was used to examine factors associated with receipt of therapy. Results: Receipt of adjuvant chemotherapy increased among stages II and III colon cancer patients from 1990 (stage II: 22%, stage III: 55%) to 2005 (stage II: 32%, stage III: 72%) and decreased in 2010 (stage II: 29%, stage III: 65%). Chemotherapy regimens changed over time; there was an increase in the use of capecitabine (3% in 2000 to 24% in 2010) and oxaliplatin (6% in 2000 to 79% in 2010). Stage III colon cancer patients who were older (75-79 years: RR 0.82, 95% CI 0.72, 0.94; ≥80 years: RR 0.36, 95% CI 0.27, 0.49) or had a comorbidity score ≥ 2 (RR 0.54, 95% CI 0.34, 0.86) were less likely to receive adjuvant chemotherapy. Receipt of radiation therapy among stages II and III rectal cancer patients increased across all study years from 46% to 66%, with a shift toward preoperative therapy in 2005. From 2005 to 2010, receipt of neoadjuvant chemoradiation followed by surgery and postoperative chemotherapy nearly doubled (11% in 2005 to 21% in 2010). Increasing age (75-79 years: RR 0.60, 95% CI 0.48, 0.75; ≥80 years: RR 0.34, 95% CI 0.25, 0.45) was associated with lower chemoradiation use in rectal cancer. Conclusions: Our findings demonstrate increased adoption of adjuvant therapies for both colon and rectal cancer patients and differences in therapy receipt by age, comorbidity, and diagnosis year. Improved receipt of adjuvant therapies in the community may further reduce CRC mortality.