A meta-analysis exploring the role of PET and PET-CT in the management of potentially resectable colorectal cancer liver metastases

BACKGROUND: Positron emission tomography (PET), alone or combined with computed tomography (CT), potentially enhances detection of occult metastatic colorectal cancer. METHODS: We compared the impact of PET/PET-CT with conventional imaging, versus conventional imaging alone, in patients with potentially resectable colorectal cancer liver metastases. MEDLINE, EMBASE, and CENTRAL were searched for studies investigating PET/PET-CT to determine resectability. Outcomes included overall (OS), disease-free survival (DFS), change in surgical management, and futile laparotomy. Evidence quality was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. A pre-specified protocol was registered in PROSPERO. RESULTS: Of 4034 articles, two randomized trials (n = 554), and 11 non-randomized studies (n = 2251) were included. PET/PET-CT did not improve OS (hazard ratio [HR] 0.94, 95% CI 0.69-1.26, moderate quality) or DFS (HR 1.01, 95% CI 0.82-1.26, moderate quality). In the two trials, PET/PET-CT changed surgical management in 8% of cases (95% CI 5-11%, high quality), and did not significantly reduce futile laparotomies (risk ratio 0.59, 95% CI 0.24-1.47, low quality). Among non-randomized studies, PET/PET-CT changed surgical management in 20% of cases (95% CI 17-22%, very low quality) and reduced futile laparotomies (odds ratio 0.51, 95% CI 0.32-0.81, very low quality). CONCLUSIONS: Moderate-quality evidence suggests that preoperative PET/PET-CT does not improve OS or DFS in patients with colorectal cancer liver metastases. These results do not support routine use of PET/PET-CT in patients with potentially resectable disease. The main limitation of this study was the lack of randomized studies.