OBJECTIVES: We aimed to explore the real-world utilization of Computerized Tomography (CT) in patients with advanced colorectal cancer (CRC) and investigate whether a more intense use of follow-up CT scan improves patient outcomes.

METHODS: Using Optum’s de-identified Clinformatics® Data Mart Database (2008-2016), we identified patients with CRC, and selected treatment-naïve patients who received combination chemotherapies, fluoropyrimidines with either oxaliplatin (FOLFOX) or irinotecan (FOLFIRI), or capecitabine with either oxaliplatin (XELOX) or irinotecan (XELIRI), combined with bevacizumab. The date of initiation of their 1st treatment was registered as index date. We defined the end of the initial chemotherapy by the emergence of a 60-day gap in chemotherapy or a switch in chemotherapy (from irinotecan to oxaliplatin or vice versa), whichever was earlier. CT scan utilization was assessed between 60 days prior to the index date and 30 days post end of chemotherapy. Days from the index date to the first follow-up CT scan was used as an indicator of follow-up intensity. Cox regression models were performed to assess the association of follow-up intensity and likelihood of treatment switch and survival.

RESULTS: 4,810 patients were included in the analysis. The median (SD) time to the first CT scan post-index was 57 (45) days. The mean and median number of CT scans were 4 and 3, respectively. Patients with an earlier follow-up scan were more likely to switch treatment (HR=0.99 for each day of delayed follow-up, P<0.01). An earlier follow-up was also associated with greater likelihood of death (HR=0.99 for each day of delayed follow-up, P<0.01).

CONCLUSION: A more intensive follow-up schedule was associated with greater likelihood of treatment switch, yet it was not associated with the better survival outcome. Further studies with longer follow up period of CRC patients are required in the future.