Provider imaging practices and outcomes of advanced colorectal cancer

To explore the real-world utilization of computerized tomography (CT) in patients with advanced colorectal cancer (CRC) and the associated outcomes.

Using Optum's de-identified Clinformatics® Data Mart Database (2008-2016), we identified patients with CRC receiving combination of chemotherapies (fluoropyrimidines with either oxaliplatin or irinotecan, or capecitabine with either oxaliplatin or irinotecan) combined with bevacizumab as the initial treatment, and its starting date was registered as the index date. End of treatment was defined by the presence of a gap in therapy > 60 days or treatment switch. We assessed the CT scan utilization during the period between 60 days pre-index and 30 days post-end of treatment. Cox regressions were performed to assess the impact of intensity of follow-up CT scans, measured by time to the first scan from the index date, on likelihood of treatment switch and survival.

Among included 4,810 patients, the median (standard deviation) time to the first follow-up scan was 57 (45) days. The mean and median number of CT scans was 4 and 3, respectively. An earlier follow-up scan was associated with significantly greater chance of treatment switch (hazard ratio = 0.99 for each day of delay, P < 0.01), and greater likelihood of death (hazard ratio = 0.99 for each day of delay, P < 0.01).

More intense follow-up increased the likelihood of treatment switch, yet it was not associated with better survival outcome. Further analysis in populations with longer follow-up period is warranted to elucidate the link between CT scan utilization and outcomes.