Abstract 250P
Background
FDG-PET/CT remains an optional modality in primary breast cancer guidelines. Thus, we aimed to investigate the clinical impact of FDG-PET/CT for staging high-risk primary breast cancer.
Methods
Women with high-risk primary breast cancer were enrolled between September 2017 and August 2019 at Odense University Hospital, Denmark. Conventional with/without MRI mammography was performed prior to staging by FDG-PET/CT. We studied the accuracy of FDG-PET/CT for detection of distant metastases, the effect on change of treatment, and the prevalence of incidental findings. Biopsy and follow-up were used as reference standard for accuracy analysis.
Results
Of 103 women, 40 (38.8%) were upstaged to more advanced disease by FDG-PET/CT. Half of these, 24 (23%) were diagnosed with distant metastases and referred for medical non-curative treatment. Six-teen patients (16%) were upstaged to more advanced loco-regional disease, leading to more extensive radiotherapy. Among the 24 women with distant metastases, breast surgery could have been spared in six and was omitted in 18. Sensitivity and specificity for diagnosing distant metastases were 1.00 (95% confidence interval: 0.86-1.00) and 0.95 (0.88-0.99), respectively. Twenty-nine incidental findings were detected in 24 women (23%), leading to further examinations in 22 and diagnosis of eight (8/22, 36%) synchronous diseases: cancer (n=4), thyroiditis (n=2), aorta aneurysm (n=1) and meningioma (n=1).
Conclusions
FDG-PET/CT had substantial impact on staging and change of treatment in women with high-risk primary breast cancer, and further examination of incidental findings was considered clinically relevant. Our findings suggest that FDG-PET/CT should be considered for primary staging in high-risk primary breast cancer to improve treatment planning.
Clinical trial identification
NCT03358589.
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Centre for Personalized Response Monitoring in Oncology (PREMIO), Odense University Hospital, Odense, Denmark Odense University Hospital University of Southern Denmark Astrid Thaysens grant Qvesehls Grant.
Disclosure
All authors have declared no conflicts of interest.