Abstract 190P
Background
An accurate radiologic staging of patients with newly diagnosed TNBC plays a pivotal role to determine the optimal management and to minimize unnecessary treatments. According to the 2019 ESMO and the 2020 Italian (AIOM) guidelines, a thoracic and abdominal computed tomography (CT) scan can be considered for staging of patients with clinically positive axillary nodes, large tumors, aggressive biology, and suspects of metastases. Fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT scan can be used when conventional methods are inconclusive or, for the ESMO guidelines, can replace traditional imaging in high-risk patients. Our retrospective single-center study aimed to compare PET/CT and CT scan in loco-regional staging of TNBC patients.
Methods
Initial TN stage was determined by mammography and breast ultrasound (US). In candidates to neoadjuvant chemotherapy (NACT), breast MRI was performed as well. All patients included in the analysis underwent a thoraco-abdominal CT scan or a whole-body PET/CT according to clinicians’ preference. Rates of up- or downstaging using different imaging techniques were evaluated and reported in Sankey diagrams.
Results
A total of 127 consecutive TNBC patients were enrolled. 85 out of 127 patients (67%) were staged with CT scan, whereas 42 (33%) with PET/CT. Among those who underwent CT scan, 7/85 (8%) were upstaged after mammography and breast US and 3/85 (4%) downstaged. Among patients who were studied with PET/CT, 9/42 (21%) upstaged and none downstaged. When locoregional staging included breast MRI, the rate of upstaging in the CT scan group was halved to 2% and decreased to 19% for PET/CT.
Conclusions
CT scan and PET/CT may present different accuracy in local staging of newly diagnosed TNBC. In our analysis, PET/CT upstaged a higher rate of TNBC patients (21%) compared to CT scan (4%). Even in presence of MRI, PET/CT scan showed a higher rate of upstaging, and this could be due to a more accurate evaluation of locoregional lymph nodes (in particular supraclavicular nodes) or false positive results. These findings could have an impact on subsequent treatment management and patient outcomes and thus deserve further research.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.