18F-fluorodeoxyglucose positron-emission tomography-computed tomography to diagnose recurrent cancer

Background: Sometimes the diagnosis of recurrent cancer in patients with a previous malignancy can be challenging. This prospective cohort study assessed the clinical utility of F-18-fluorodeoxyglucose positron-emission tomography-computed tomography (F-18-FDG PET-CT) in the diagnosis of clinically suspected recurrence of cancer. Methods: Patients were eligible if cancer recurrence (non-small-cell lung (NSCL), breast, head and neck, ovarian, oesophageal, Hodgkin's or non-Hodgkin's lymphoma) was suspected clinically, and if conventional imaging was non-diagnostic. Clinicians were asked to indicate their management plan before and after F-18-FDG PET-CT scanning. The primary outcome was change in planned management after F-18-FDG PET-CT. Results: Between April 2009 and June 2011, 101 patients (age, median 65 years; 55% female) were enroled from four cancer centres in Ontario, Canada. Distribution by primary tumour type was: NSCL (55%), breast (19%), ovarian (10%), oesophageal (6%), lymphoma (6%), and head and neck (4%). Of the 99 subjects who underwent F-18-FDG PET-CT, planned management changed after F-18-FDG PET-CT in 52 subjects (53%, 95% confidence interval (CI), 42-63%); a major change in plan from no treatment to treatment was observed in 38 subjects (38%, 95% CI, 29-49%), and was typically associated with F-18-FDG PET-CT findings that were positive for recurrent cancer (37 subjects). After 3 months, the stated post-F-18-FDG PET-CT management plan was actually completed in 88 subjects (89%, 95% CI, 81-94%). Conclusion: In patients with suspected cancer recurrence and conventional imaging that is non-diagnostic, F-18-FDG PET-CT often provides new information that leads to important changes in patient management.