Objectives:
Neoadjuvant chemotherapy (NAC) is the frequently used treatment option for locally advanced breast cancer (LABC). This study investigated the potential value of
18
fluorine-fluorodeoxyglucose (
18
F-FDG) positron emission tomography/computed tomography (PET/CT) to estimate the pathological complete response (pCR) using maximum standardized uptake value (SUV
max
) and change (ΔSUV
max
) after 3-4 cycles of NAC. Additionally, it was established the relationship between PET/CT imaging findings and histopathological features in LABC patients whose treatment response was evaluated with interim PET/CT.
Methods:
Patients were evaluated with pretreatment and interim PET/CT scans and operated after on NAC. Data on the age of patients, menopausal status, tumor placement, histopathological and molecular subgroups were noted. SUV
max
and ΔSUV
max
of the primary tumor and axillary lymph node (ALN) were calculated from PET/CT review.
Results:
Pretherapy mean SUV
max
of the primary tumor and ALNs were 8.13±4.25 and 7.22±3.58, respectively. The highest mean primary tumor ΔSUV
max
and ALN ΔSUV
max
values were observed to be human epidermal growth factor receptor 2 positivity (p<0.001). SUV
max
-T, SUV
max
-N, ΔSUV
max
-T, and ΔSUV
max
-N values were significantly correlated with the ki-67 index (p<0.001). ΔSUV
max
-T and ΔSUV
max
-N values of pCR (+) patients were statistically higher than the ΔSUV
max
-T and ΔSUV
max
-N values of pCR (-) patients (p<0.001).
Conclusion:
An earlier and more accurate response to NAC can be performed using interim
18
F-FDG PET/CT imaging. ΔSUV
max
levels of the breast tumor and ALNs may act as predictive for pCR in LABC patients receiving NAC.