Clinical impact of FDG PET-CT in patients with potentially operable metastatic colorectal cancer

Aim: To assess the clinical impact of 2-[18F]-fluoro-2-deoxy-D-glucose (FDG) positron-emission tomography–computed tomography (PET-CT) in patients with potentially resectable metastatic colorectal cancer. Materials and methods: One hundred and two patients with potentially resectable metastatic colorectal cancer underwent FDG PET-CT in addition to conventional imaging over an 18-month period. The findings were compared to conventional imaging, with histological or clinico-radiological validation. The impact on subsequent management was evaluated using information from clinico-radiological databases. Results: Of 102 patients (mean age 67 years, range 27–85 years), 94 had liver, five had isolated lung, and three had limited peritoneal metastases. In 31 patients (30%) PET-CT had a major impact on subsequent management, by correctly clarifying indeterminate lesions on conventional imaging as inoperable metastatic disease in 16 patients, detecting previously unsuspected metastatic disease in nine patients, identifying occult second primary tumours in three patients, and correctly down-staging three patients. PET-CT had a minor impact in 12 patients (12%), no impact in 49 cases (48%), and a potentially negative impact in 10 cases (10%). Following PET-CT, 36 (35%) patients were no longer considered for surgery. Of those remaining operative 45 of 66 (68%) underwent potentially curative metastatic surgery. In this cohort PET-CT saved 16 futile laparotomies. Conclusion: FDG PET-CT has a valuable role in selected patients with metastatic colorectal cancer by improving staging accuracy and characterizing indeterminate lesions and helps triage patients to the appropriate treatment.