Scientific Session 10 — SS10: Gastrointestinal - Focal Hepatobiliary DiseaseTuesday, April 24, 2018
3082. CTC Screening in Extracolonic Cancer Survivors: Rates of colorectal and extracolonic findings
Larson M*, Pickhardt P. University of Wisconsin School of Medicine and Public Health, Madison, WI
Address correspondence to M. Larson (email@example.com)
Objective: The purpose of this study was to compare the rates of colorectal and extracolonic findings at CT colonography (CTC) screening between patients with and without a personal prior history of other cancers to provide insights for prescreening guidance in this vulnerable population.
Materials and Methods: Over a 160-month interval, 349 adults (mean age, 60.3 years; 67% women) with a positive history of extracolonic cancer [Ca(+)], excluding 271 patients with isolated nonmelanoma skin cancers, underwent CTC screening. This study cohort was compared against 8859 controls (mean age, 57.0 years; 53% women) without a prior cancer history [Ca(–)]. Primary outcome measures included the rates of relevant colorectal (CT Colonography Reporting and Data System, C2–C4) and extracolonic (E3–E4) findings at CTC. The Wilcoxon rank sum test was used to test for statistical significance with post hoc analysis by relative rate (RR).
Both colorectal (C2–C4) and extracolonic (E3–E4) findings were significantly increased in the Ca(+) group versus the Ca(–) control group (p = 0.0283 and p = 0.0236, respectively). Positive colorectal findings were most notably increased among survivors of non–small cell lung cancer (RR, 3.1), head and neck cancers (RR, 3.4), and bladder cancers (RR, 2.2). Further, the proportion of C2–C4 patients undergoing intervention in the Ca(+) cohort was not significantly different from the Ca(–) group. Potentially relevant extracolonic findings (E3) were increased in survivors of hematogenous malignancies (RR, 2.0), whereas likely important extracolonic findings (E4) were increased in survivors of female gynecologic malignancies (RR, 3.4).
Conclusion: Relevant colorectal and extracolonic findings at CTC screening are increased in patients with a previous extracolonic cancer history, particularly among certain cancer subsets. These results provide a basis upon which to council cancer survivors and suggest that CTC may be the method of choice when considering extracolonic findings. Further, as there is no increase in colonic intervention rate by C-RADS score, this study indicates that cancer survivors are likely to react in the same way to positive CTC results as the general population.