Positron Emission Tomography-Computed Tomography for Patients with Recurrent Colorectal Liver Metastases: Impact on Restaging and Treatment Planning

Background. The impact of fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) for patients with colorectal liver metastases (CLM) still is debated. Its relevance could be enhanced in the case of recurrent disease. The current study aimed to elucidate the role of PET-CT in restaging and treatment planning for recurrent CLM. Methods. A series of 352 consecutive patients undergoing their first liver resection for CLM between 2005 and 2014 was reviewed. Of these patients, 224 (63.6 %) had a recurrence. The 107 patients who had received PET-CT at diagnosis of recurrence before chemotherapy were analyzed. CT was available in all cases, and magnetic resonance imaging (MRI) was available in 64 cases. Results. Extrahepatic lesions were found in 59 patients. Liver and lung recurrences were detected with excellent sensitivity by CT/MRI and PET-CT (liver: 100 vs. 96.7 %; lung: 95.8 vs. 95.8 %). In detecting other recurrence sites, PET-CT had higher sensitivity than CT/MRI (91.5 vs. 54.2 %, p < 0.01; lymph nodes: 93.5 vs. 64.5 %, p = 0.011; peritoneum: 80 vs. 20 %, p = 0.023; bones: 87.5 vs. 37.5 %, nonsignificant difference). For 28.8 % (17/59) of the patients, the diagnosis of extrahepatic disease was obtained thanks to PET-CT (39.5 % considering nonpulmonary lesions). PET-CT modified treatment strategy in 16 (14.9 %) patients, excluding from surgery 15 (20.3 %) of 74 patients resectable at CT/MRI. This latter subgroup had a lower survival rate than the patients resectable after PET-CT (2-year survival, 22.7 vs. 77.8 %; p = 0.004), similar to the patients unresectable at CT/MRI (57.6 %). Conclusions. In the authors' experience, PET-CT has offered a relevant contribution to restaging of recurrent CLM. It disclosed one fourth of extrahepatic lesions and prevented worthless surgery for about 20 % of patients.