Impact of pre-operative positron emission tomography in gallbladder cancer

Current pre-operative staging methods for gallbladder cancer (GBC) are suboptimal in detecting metastatic disease. Positron emission tomography (PET) may have a role but data are lacking.

Patients with GBC and PET assessed by a hepatobiliary surgeon in clinic between January 2001 and June 2013 were retrospectively reviewed. Computed tomography (CT)/magnetic resonace imaging (MRI) were correlated with PET scans and analysed for evidence of metastatic or locally unresectable disease. Medical records were reviewed to determine if PET scanning was helpful by preventing non-therapeutic surgery or enabling resection in patients initially deemed unresectable.

There were 100 patients including 63 incidental GBC. Thirty-eight patients did not proceed to surgery, 35 were resected and 27 patients were explored but had unresectable disease. PET was positive for metastatic disease in 39 patients (sensitivity 56%, specificity 94%). Five patients definitively benefitted from PET: in 3 patients PET found disease not seen on CT, and 2 patients with suspicious CT findings had negative PET and successful resections. In a further 12 patients PET confirmed equivocal CT findings. Three patients had additional invasive procedures performed owing to PET avidity in other sites. Utility of PET was higher in patients with suspicious nodal disease on CT [odds ratio (OR) 7.1 versus no nodal disease, P = 0.0004], and in patients without a prior cholecystectomy (OR 3.1 versus post-cholecystectomy, P = 0.04).

Addition of PET to conventional cross-sectional imaging has a modest impact on management pre-operatively particularly in patients without a prior cholecystectomy and to confirm suspicious nodal disease on CT.