Bengü DURSUN, Hatime Arzu YAŞAR, Çiğdem SOYDAL, Ahmet DEMİRKAZIK
Acta Haematologica Oncologica Turcica - 2026;59(1):27-31
Aim: Non-invasive predictors of pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) are needed in breast cancer (BC). We evaluated whether serial fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) maximum standardized uptake value (SUVmax) metrics [baseline, preoperative, and the percentage change of SUVmax (DeltaSUVmax %)] and complete metabolic response (CMR) are associated with pCR. Methods: This retrospective single-center cohort included patients treated with NAC followed by surgery who underwent paired baseline and preoperative 18F-FDG PET/CT. Primary tumor SUVmax was recorded on both scans, DeltaSUVmax % was calculated, and CMR was defined as complete resolution of pathologic FDG uptake on the preoperative scan. pCR was defined as ypT0/is ypN0. Results: Fifty-six patients were included (median age, 51.5 years). Subtypes were HR+/HER2- (50%), HER2+ (30.3%), and triple-negative BC (TNBC) (19.7%). Overall, pCR occurred in 25% (14/56) and CMR occurred in 35.7% (20/56). Baseline SUVmax differed by subtype (highest in TNBC), and pCR rates varied significantly (lowest in luminal, highest in HER2+). Compared with the non-pCR group, the pCR group had lower preoperative SUVmax (0.68 vs 4.33; p=0.001) and higher DeltaSUVmax % (95.89% vs 54.10%; p=0.001). In univariate logistic regression, lower preoperative SUVmax [odds ratio (OR): 0.64; p=0.04]., higher DeltaSUVmax % (OR: 1.06 per 1% increase; p=0.01), and CMR (OR: 6.75; p=0.01) were associated with pCR. Conclusion: In this retrospective cohort, end-of-NAC 18F-FDG PET/CT findings-especially a low preoperative SUVmax and CMR-were associated with a higher likelihood of pCR while DeltaSUVmax % contributed incremental predictive signal.
