Prognostic relevance of [18F]FDG PET/CT in triple-negative breast cancer: Results from the triple negative (TRINE)-PET trial.

PURPOSE: Triple negative breast cancer (TNBC) is an aggressive subtype, still with limited therapeutic options. [18F]FDG PET/CT is widely used in TNBC, but evidence regarding its prognostic value remains limited. The TRINE PET study, promoted by the Italian Association of Nuclear Medicine, aimed to evaluate the prognostic relevance and clinical impact of [18F]FDG PET/CT in a large real world TNBC cohort.

METHODS

This retrospective multicenter study included 389 TNBC patients who underwent 707 [18F]FDG PET/CT scans across 23 Italian Nuclear Medicine Units. Clinical settings were baseline staging (n = 257 patients), post neoadjuvant chemotherapy (n = 111 patients), suspected recurrence (n = 144 patients), and advanced metastatic disease (n = 195 patients). Progression free survival (PFS) and overall survival (OS) were assessed using Kaplan-Meier and Cox regression analyses. The influence of [18F]FDG PET/CT on clinical management was evaluated across all settings.

RESULTS

During a median follow up of 34 months (1-124), disease progression and death occurred in 39.3% and 28.4% of cases, respectively. Across all clinical settings, nodal and distant metastatic involvement at [18F]FDG PET/CT was strongly associated with worse PFS and OS (all p < 0.001). In multivariate analysis, distant metastases at [18F]FDG PET/CT resulted the strongest independent predictor of OS (HR 9.42, 95% CI 3.74-23.75) and PFS (HR 6.57, 95% CI 3.05-14.12), while Ki67 and [18F]FDG uptake at primary tumor did not. [18F]FDG PET/CT findings led to a change in clinical management in 20.8% of all scans, with the highest impact in the advanced metastatic setting (34.9%).

CONCLUSION

In the largest real world multicenter study dedicated to TNBC, [18F]FDG PET/CT demonstrated robust prognostic value across all disease settings. PET detected metastatic involvement emerged as the most powerful predictor of survival; moreover, [18F]FDG PET/CT influenced therapeutic decision in all settings of disease, reaching one in three scans in the advanced metastatic disease. These findings support the systematic integration of [18F]FDG PET/CT into the diagnostic pathways of TNBC.