Population-based trends in positron emission tomography (PET) utilization after resection for colon cancer.

Abstract

365 Background: While most colon cancer staging and treatment guidelines do not routinely include PET imaging, its use has been increasing. The primary aim of this study is to evaluate the trends in PET utilization during the first 2 years after diagnosis of colon cancer. Methods: A retrospective cohort study of patients ≥ 65 years old with colon cancer who underwent surgical resection in the Surveillance, Epidemiology, and End Results-linked Medicare database (2001-2007, Medicare Part A/B only) and had at least 2 years of follow-up was performed. PET utilization was assessed using the test for trends and multivariate logistic regression for patient, tumor and treatment response characteristics. Results: Of 28,762 patients who underwent primary resection of colon cancer, 3,897 (13.6%) had at least one PET scan within 2 years after surgery. The utilization rate steadily increased from 7.5% in 2001 to 18.7% in 2007 (p = 0.01). A total of 7,175 PET scans were performed on 3,897 patients, among which 2,348 (60.2%) had 1 PET scan, 834 (21.4%) had 2 PET scans and 715 (18.4%) had >2 PET scans. The majority of PET scans were performed within 2 months after surgery (n=1314) and a 2ndpeak was observed at 9 months. Additional factors significantly associated with increased PET scan use included SEER region, stage, and grade (Table). Conclusions: The utilization of PET scans after colon cancer resection has steadily increased since 2001 with the majority of PET scans being performed within 2 months after surgery and its use was subject to geographic variation. Further study is needed to examine the impact of this pattern on long-term oncologic outcomes. [Table: see text]