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E1309. Transient Increase in CEA Post-DEBIRI Chemoembolization
Authors
  1. Rishi Thakkar; University of Saskatchewan
  2. Brent Burbridge; University of Saskatchewan
  3. Sahid Ahmed; Saskatchewan Cancer Agency
  4. Kiat Tan; University of Saskatchewan; Western University
Objective:
Previous studies focusing on patients receiving first-line chemotherapy have reported a transient increase in CEA levels lasting less than four months post-treatment, the so-called ‘CEA flare’. Studies have related the flare in CEA to improved tumor response to treatment rather than disease progression (1,2). The purpose of this study is to share our findings regarding an increase in CEA levels post-chemoembolization using drug eluting beads loaded with irinotecan (DEBIRI) in subjects with hepatic metastases from colorectal cancer.

Materials and Methods:
In this retrospective study, 4 subjects (2 males and 2 female), ages 41-68, had their CEA levels recorded prior to and following at least one chemoembolization treatment. Subjects underwent between 1-4 rounds of chemoembolization between July 2015 and December 2016.

Results:
Of the four subjects involved in the study, all demonstrated a ‘CEA flare’ at least once following chemoembolization. Prior to subject one’s initial treatment, his CEA level was 164.2 ng/ml. This increased to 196.4 ng/ml post-DEBIRI. Prior to the second round of chemoembolization, subject one’s CEA level was measured at 193.1 ng/ml, which then rose to 234 ng/ml immediately post-DEBIRI. Following the final round of chemoembolization, the subject’s CEA level declined to 11.5 ng/ml. CEA levels were only measured pre- and post- the first round of treatment for subject 2 and were 220.6 ng/ml and 232.4 ng/ml, respectively. After the final round of chemoembolization, the subject’s CEA level had decreased to 55.8 ng/ml. Subject 3, a 65-year old male demonstrated a significant rise in CEA after his second chemoembolization treatment, with the level increasing from 15.9 ng/ml to 68.7 ng/ml. Similar results were observed during the subject’s final treatment, with pre- and post- CEA values measuring 19.5 ng/ml and 128.6 ng/ml, respectively. Subject four’s CEA levels pre- and post- first treatment were 48 ng/ml and 57.5 ng/ml, respectively. Prior to the second chemoembolization, the subject’s CEA level had decreased to 19.7 ng/ml. Post-embolization, the subject’s CEA level continued to decrease to 17.2 ng/ml. Similar results were identified after the subject’s final round of chemoembolization where pre- and post-treatment CEA values were 6.1 ng/ml and 5 ng/ml, respectively

Conclusion:
For subjects 1-4 it is evident that a CEA flare occurred post-DEBIRI. For subjects 1, 2, and 4 a progressive decline in the CEA level, with subsequent chemoembolizations, was also noted. This may correlate to a decrease in tumor burden. A CEA flare must not be misinterpreted as disease progression and interventional radiologists treating patients with hepatic colorectal metastases should be aware of this and avoid subjecting their patients to further unnecessary treatments.