Purpose: Although initial studies have shown the utility of fluorine-18 fluorodeoxyglucose (F-18 FDG) PET in the detection and restaging of recurrent breast carcinoma, scarce literature exists on F-18 FDG PET/computed tomography (CT). This retrospective study was carried out to evaluate the role of F-18-FDG PET/CT in recurrent breast carcinoma and its impact on management.
Materials and methods: Retrospective analysis of data of 111 patients who underwent F-18 FDG PET/CT and were suspected of having recurrent breast carcinoma was carried out. PET/CT imaging was carried out for distant metastases in histologically proven locoregional recurrence in 23 patients, clinically suspicious locoregional recurrence in nine patients, increasing tumour markers in two patients, suspicion of distant metastatic disease in 61 patients or as a part of surveillance in 16 patients. The final diagnosis of recurrence and stage of disease was made after histopathological analysis, correlative imaging and clinical or imaging follow-up of at least 6 months.
Results: The final diagnosis of recurrent breast carcinoma was made in 76 patients and no evidence of recurrence was found in the remaining 35 patients. Locoregional disease requiring local radiotherapy or surgery was diagnosed in 14 patients and distant metastatic disease was diagnosed in 62 patients. FDG PET/CT was true positive in 75 patients, false positive in six patients, true negative in 35 patients and false negative in one patient, with a sensitivity, specificity, positive predictive value and a negative predictive value of 98.7, 85.3, 92.5 and 97.2%, respectively. FDG PET/CT also accurately restaged 22/23 patients with proven locoregional recurrence with an accuracy of 95.45%. Of 53 patients suspected of having distant metastatic disease on other imaging modalities, true distant metastatic disease was diagnosed in 36 patients and FDG PET/CT identified true metastatic disease in 35/36 patients, accurately ruling out metastases in the remaining 17 patients, and was false negative in one patient. In addition to confirming distant metastatic disease, it revealed more metastatic sites in 22 patients. Overall, F-18 FDG PET/CT had a major impact on management in 41% of the 103 patients being analysed for a major change in treatment.
Conclusion: F-18 FDG PET/CT is a very sensitive and specific imaging tool in detecting and restaging recurrent breast carcinoma. It can be a very useful imaging tool for restaging locoregional recurrences, and as a one-stop shop imaging technique to confirm suspicious metastatic disease on conventional imaging and to define the total burden of disease.