Gong C, et al. - Researchers assessed the utility of pretreatment positron emission tomography/computed tomography (PET/CT) ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG)-based heterogeneity for predicting the outcome of first-line treatment in metastatic triple-negative breast cancer (mTNBC). According to findings, heterogeneity index (HI) and the maximum of FDG uptake (MAX) measured among metastatic lesions on pretreatment ¹⁸F-FDG PET/CT scans may be able to predict treatment outcome in metastatic TNBC in clinical practice.

Methods

• Researchers performed this study on mTNBC patients from three clinical trials with whole-body ¹⁸F-FDG PET/CT scan before first-line gemcitabine/platinum.
• They evaluated HI and the MAX across total metastatic lesions (-T) on baseline PET/CT scans.
• They measured HI by MAX divided by the minimum FDG uptake across metastatic lesions.
• Using time-dependent receiver operator characteristics (ROC) analysis, they determined optimal cutoffs.
• Estimation of progression-free survival (PFS) and overall survival (OS) was done using Kaplan-Meier method, and comparison was done by using log-rank test.

Results

• This study included a total of 42 mTNBC patients.
• Compared to patients with low HI-T (<1.9; p=.049) and low MAX-T (< 10.5; p=.001), a significantly shorter median PFS was observed in patients with high HI-T (>1.9) and high MAX-T (>10.5).
• They noted that only high MAX-T had significance for poorer outcome in terms of OS (p=.013).
• In ROC curve analysis, the predictive value of MAX and HI in mTNBC patients was confirmed.
• Findings demonstrated that area under the ROC curve for MAX-T and HI-T was 0.75 and 0.65, implying a higher predictive accuracy than conventional clinical risk factors.