PET/CT PREDICTORS IN TNBC
10. ULUDAĞ MEME KANSERİ SEMPOZYUMU, Bursa, Türkiye, 26 - 28 Haziran 2026, ss.60-61, (Tam Metin Bildiri)
- Yayın Türü: Bildiri / Tam Metin Bildiri
- Basıldığı Şehir: Bursa
- Basıldığı Ülke: Türkiye
- Sayfa Sayıları: ss.60-61
- Bursa Uludağ Üniversitesi Adresli: Evet
Özet
Objective:
The KEYNOTE-522 regimen has improved pathological complete response and survival outcomes in high-risk early-stage triple-negative breast cancer [1, 2]. However, pretreatment biomarkers that can predict pathological complete response in this setting remain limited. FDG PET/CT may provide noninvasive information on tumor glucose metabolism and whole-body metabolic tumor burden. High pretreatment tumor SUVmax and low total metabolic tumor volume have been associated with pathological complete response in TNBC patients treated with neoadjuvant chemotherapy with or without pembrolizumab [3]. Therefore, this study aimed to evaluate the predictive value of pretreatment FDG PET/CT-derived parameters for pathological complete response in patients receiving KEYNOTE-522–based neoadjuvant chemoimmunotherapy.
Methods:
We retrospectively evaluated patients treated with neoadjuvant systemic therapy who had available pathological response data. Pathological complete response was used as the primary endpoint. Candidate predictors included baseline clinical characteristics, biopsy-derived pathological variables, laboratory indices, and pretreatment 18F-FDG PET/CT parameters. PET-derived variables included SUVmax, visual uptake grade, tumor-to-liver and tumor-to-contralateral breast ratios, FDG-positive nodal disease, and nodal metabolic ratios. Post-treatment PET1 and ΔSUVmax parameters were assessed only in patients whose PET1 reflected systemic treatment response and were considered exploratory. Continuous and categorical variables were analyzed using Wilcoxon rank-sum and Fisher’s exact tests, respectively. ROC analysis, diagnostic performance metrics, and Benjamini–Hochberg correction were applied where appropriate. Postoperative variables were excluded from primary predictor analyses.
Results:
Eleven patients were included, and pathological complete response was achieved in five patients (45.5%). Lower clinical T stage showed the strongest trend toward association with pathological complete response (median cT stage, 1 vs. 2; p=0.055; AUC=0.833). Similarly, cT≥2 was less frequent among patients with pathological complete response than among those without pathological complete response (16.7% vs. 80.0%; p=0.080; AUC=0.817). Among pretreatment PET/CT-derived parameters, higher contralateral breast SUVmax showed exploratory discriminatory potential for pathological complete response (p=0.167; AUC=0.767), whereas lower PET0 nodal-to-liver SUVmax ratio showed a similar trend (p=0.191; AUC=0.750). Ki-67 also demonstrated an exploratory association, with lower values observed in patients achieving pathological complete response (p=0.196; AUC=0.750). PET1/ΔSUVmax analysis was feasible in four patients and was considered exploratory.
Conclusions:
In this preliminary cohort, lower clinical T stage and selected pretreatment 18F-FDG PET/CT-derived parameters showed potential exploratory associations with pathological complete response after neoadjuvant systemic therapy.