The prognostic role of baseline and post neoadjuvant chemotherapy [18F]FDG PET/CT in triple-negative breast cancer: preliminary results of the TRINE-PET trial

Aim/Introduction: triple-negative (TN) is recognized as the most aggressive breast cancer (BC) subtype and is still associated to short life expectancy. Although TNBC is a well-established [18F]-FDG (FDG)-avid tumor at Positron Emission Tomography/Computed tomography (PET/CT), literature lacks of evidence regarding the prognostic value of FDG PET in these patients. The objective of TRINE-PET, a retrospective multicenter Italian study, aims to correlate FDG PET/CT results and survival outcomes in TNBC patients across various clinical settings of the disease. Materials and Methods: 23 Italian centers retrospectively collected data relative to FDG PET/CT scans performed in TNBC patients, either at baseline or after neoadjuvant chemotherapy (NAC), with a minimum of 2 years of follow-up. In patients who underwent NAC, pathological complete response (pCR) and response according to PERCIST criteria at FDG PET/CT were collected. A per-site PET based analysis was conducted and the survival outcomes (and death) were compared in each category by using log-rank test. The correlation between categorial variables was assessed using the chi-squared test. Results: FDG PET/CT scans from 130 patients at baseline and 66 patients post-NAC were considered. Overall, lymph node and distant metastases were detected in 69 (53%) and 11 (8.5%) patients at baseline, and in 19 (28.8%) and 9 (13.6%) patients post NAC. In the baseline group (median followup of 3.5 years), 34 (26.2%) patients had disease progression, and 20 (15.4%) passed away. In the post-NAC group (median followup of 3.7 years), 21 (31.8%) patients had disease progression, and 17 (25.8%) passed away. The presence of N+ and M+ disease on FDG PET strongly correlated with both progression (all p<0.05) and death (al p<0.01) in both clinical settings. pCR after NAC was achieved in 29 (56.9%) out of 51 patients with available data. According to PERCIST criteria, a complete metabolic response was observed in 34 (51.5%) patients. PERCIST response on FDG PET/CT significantly correlated with pCR (p <0.0001) and with both progression (p<0.0001) and death (p<0.0001). Conclusion: a strong correlation was observed between N+ or M+ disease at baseline or post-NAC FDG PET/CT and survival outcomes in TNBC patients. Response to NAC assessed according to PERCIST criteria at FDG PET/CT was significantly correlated with both pCR and survival outcomes.