Role of F-18 FDG PET/CT in Predicting Response to Neoadjuvant Chemotherapy in Invasive Ductal Breast Cancer.

Objective: The role of baseline and post-treatment standardized uptake value (SUV_max) values in predicting pathological response in patients with breast cancer after neoadjuvant chemotherapy (NAC).

Materials and methods: Thirty patients with invasive ductal breast cancer were included in this retrospective study. F-18 fluorodeoxyglucose (FDG) positron emission tomography/computerized tomography (PET/CT) examinations were performed before and after NAC. Pretreatment SUV_max (SUV_max I), post-treatment SUV_max (SUV_max II) and ΔSUV_max values of primary breast cancer were obtained. Breast tumor pathology preparations were examined for the evaluation of tumor response according to the Miller and Payne classification. Patients were grouped as responding to treatment (pCR) and unresponsive to treatment (nonpCR). In all analyses, p<0.05 was considered statistically significant.

Results: The mean age of the 30 patients included in the study was 51.2±11.98 years. In the study-defined grouping, 13 patients (43.3%) were nonresponders and 17 patients (56.7%) were responders. ΔSUV_max was significantly greater in the responders group compared to the nonresponders group, while SUV_max II was lower (p = 0.001 and p = 0.004, respectively). There was no significant difference between the responders and nonresponders in terms of age, tumor diameter, and SUV_max I values. Multivariate logistic regression analysis showed ΔSUV_max to be the only independent predictive factor for pCR.

Conclusion: F-18 FDG PET/CT was an effective method in evaluating the treatment response after NAC in breast cancer, and ΔSUV_max and post-treatment SUV_max can be used to predict the response of the primary tumor to treatment.