Does the pretreatment tumor sampling location correspond withmetabolic activity on 18F-FDG PET/CT in breast cancer patientsscheduled for neoadjuvant chemotherapy?

Purpose: To define the correlation between the core biopsy location and the area with highest metabolicactivity on 18F-FDG PET/CT in stage II-III breast cancer patients before neoadjuvant chemotherapy. Also,we would like to select a subgroup of patients in which PET/CT information may optimize tumor sampling.Methods: A PET/CT in prone position was acquired in 199 patients with 203 tumors. The distance andrelative difference in standardized uptake value (SUV) between core biopsy localization (indicated bya marker) and area with highest degree of FDG uptake were evaluated. A distance ?2 cm and a relativedifference in SUV ?25% were considered clinically relevant and a combination of both was defined as non-correspondence. Non-correspondence for different tumor characteristics (TNM stage, lesion morphologyon MRI and PET/CT, histology, subtype, grade, and Ki-67) was assessed.Results: Non-correspondence was found in 28 (14%) of 203 tumors. Non-correspondence was significantlyassociated with T-stage, lesion morphology on MRI and PET/CT, tumor diameter, and histologic type.It was more often seen in tumors with a higher T-stage (p = 0.028), diffuse (non-mass) and multifocaltumors on MRI (p = 0.001), diffuse and multifocal tumors on PET/CT (p < 0.001), tumors >3 cm (p < 0.001),and lobular carcinomas (p < 0.001). No association was found with other features.Conclusion: Non-correspondence between the core biopsy location and area with highest FDG uptake isregularly seen in stage II-III breast cancer patients. PET/CT information and possibly FDG-guided biopsiesare most likely to improve pretreatment tumor sampling in tumors >3 cm, lobular carcinomas, and diffuseand multifocal tumors. © 2013 Elsevier Ireland Ltd. All rights reserved.