The role of basal metabolic and volumetric 18F-FDG PET/CT parameters and their changes in predicting pathological complete response in breast cancer patients receiving neoadjuvant chemotherapy.

Objective: The aim of this study is to investigate the roles of pre- and post- treatment quantitative fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) parameters including maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) and their rate of change in predicting pathological complete response (pCR) in patients with local and locally advanced invasive breast cancer receiving neoadjuvant chemotherapy (NAC).

Subjects and methods: Ninety-eight patients who received NAC after being diagnosed with local and locally advanced invasive breast cancer between January 2017 and September 2021 were retrospectively included in our study. Molecular subtypes of all patients were determined. Maximum SUV, MTV, TLG, percent change in SUVmax (ΔSUVmax), ΔMTV, and ΔTLG obtained from PET/CT scans performed before and after NAC were calculated. The cut-off, AUC, sensitivity, and specificity values of these parameters in predicting pCR were calculated using receiver operating characteristic (ROC) curves.

Results: ΔTMTV (cut-off 94.01%, AUC: 0.846), ΔTTLG (cut-off 97.36%, AUC: 0.870), B2MTV (cut-off<1.75, AUC: 0.764), B2TLG (cut-off<2.11, AUC: 0.764), B2SUVmax (cut-off<1.58, AUC: 0.767), ΔBMTV (cut-off 93.67%, AUC: 0.851), ΔBTLG (cut-off 97.22%, AUC: 0.870), ΔBSUVmax (cut-off 84.99%, AUC: 0.846) calculated using ROC curves were found to significantly predict pCR with high sensitivity and specificity.

Conclusion: We concluded that metabolic and volumetric PET/CT parameters, the rates of their change, and metabolic response during NAC may be important variables in predicting pCR in patients with breast cancer.