Background: The incremental value of 18FDG PET/CT in patients with breast cancer (BC) compared to conventional imaging (CI) in clinical practice is unclear. The aim of this study was to evaluate the management impact and prognostic value of 18 F-FDG PET/CT in this setting.
Methods: Sixty-three patients who were referred to our institution for suspicion of BC relapse were retrospectively enrolled. All patients had been evaluated with CI and underwent PET/CT. At a median follow-up of 61 months, serial clinical, imaging and pathologic results were obtained to validate diagnostic findings. Overall Survival (OS) was estimated using Kaplan Meier methods and analyzed using the Cox proportional hazards regression models.
Results: Forty-two patients had a confirmed relapse with 37 (88%) positive on CI and 40 (95%) positive on PET/CT. When compared with CI, PET/CT had a higher negative predictive value (86% versus 54%) and positive predictive value (95% versus 70%). The management impact of PET/CT was high (change of treatment modality or intent) in 30 patients (48%) and medium (change in radiation treatment volume or dose fractionation) in 6 patients (9%). Thirty-nine patients (62%) died during follow-up. The PET/CT result was a highly significant predictor of OS (Hazard Ratio [95% Confidence Interval] =4.7 [2.0-10.9] for PET positive versus PET negative for a systemic recurrence; p = 0.0003). In a Cox multivariate analysis including other prognosis factors, PET/CT findings predicted survival (p = 0.005). In contrast, restaging by CI was not significant predictor of survival.
Conclusion: Our study support the value of 18 F-FDG PET/CT in providing incremental information that influence patient management and refine prognostic stratification in the setting of suspected recurrent breast cancer.