Objective: To evaluate the clinical impact of fluorodeoxyglucose (FDG)-PET/computed tomography (CT) scan on restaging breast cancer patients with rising tumor markers and negative or equivocal findings in conventional imaging studies.
Methods: We studied 46 patients with breast cancer of an average age of 57.6 years (ranging from 38 to 68 years). All patients were referred for an FDG-PET/CT scan because of elevated tumor markers, without any other obvious clinical or laboratory sign of relapse. Conventional imaging study results were either negative (29 out of 46 patients) or inconclusive (17 out of 46 patients). All patients underwent a whole-body FDG-PET/CT scan in a combined PET/CT. The findings were confirmed by a follow-up at least 9 months later, and when it was possible, final diagnosis was obtained by histopathology.
Results: In 34 out of 46 patients, an FDG-PET/CT scan showed sites of increased metabolic activity, indicating active disease. In 23 out of 46 patients, the therapeutic approach and further clinical management were affected. The FDG-PET/CT scan was true-positive in 33 patients, false-positive in one patient, false-negative in five patients, and true-negative in seven patients. On the basis of our results in this population, an FDG-PET/CT scan had a sensitivity of 86.8%, a specificity of 87.5%, and an accuracy of 86.9%. The positive predictive value was 97.1% and the negative predictive value was 58.3%. Clinical management was affected in 50% of these patients.
Conclusion: The FDG-PET/CT scan plays an important role in restaging breast cancer patients with rising tumor markers and negative or equivocal findings in conventional imaging techniques, with a consequent significant clinical impact on further management in these patients.