Whole-Body 18F-FDG PET and Conventional Imaging for Predicting Outcome in Previously Treated Breast Cancer Patients

This study was conducted to determine the ability of 18 F-FDG PET and conventional imaging (CI) to predict the outcomes in breast cancer patients who have previously undergone primary treatment. Methods: The study population consisted of 61 female patients (median age, 54 y; range, 32-91 y) who were reevaluated with 18 F-FDG PET and Cl after treatment. The median interval between the last treatment and PET was 0.4 y (range, 0-16 y). PET was performed within 3 mo of Cl (median interval, 25 d; range, 2-84 d). To determine the independent impact of PET on outcome, PET images were reinterpreted in a blind fashion. Availability of clinical information after PET scanning (21 ± 12 mo) was required for study inclusion. Study endpoints were clinical evidence of progression of disease or death. Results: Of 61 patients, 19 (31.1%) had no clinical evidence and 38 (62.3%) had evidence of residual or recurrent disease by the end of follow-up. Four patients (6.6%) had died. The positive and negative predictive values (PPV and NPV, respectively) of PET were 93% and 84%, respectively. Cl yielded a PPV of 85% and an NPV of 59%. The prognostic accuracy of single whole-body PET was superior to that of multiple procedures with Cl (90% vs. 75%; P < 0.05). Kaplan-Meier estimates of disease-free survival in patients with negative PET findings compared with those with positive PET findings revealed a significant difference between the 2 curves (log-rank test = 0.001). Kaplan-Meier estimates of disease-free survival stratified by Cl results showed a marginally significant difference between Cl-positive and Cl-negative patients (log-rank test = 0.04). Conclusion: FDG PET can be used to improve prediction of the clinical outcome of previously treated breast cancer patients relative to what is achievable through Cl alone.