POSITRON EMISSION TOMOGRAPHY STUDIES IN PATIENTS WITH LOCALLY ADVANCED AND/OR METASTATIC BREAST-CANCER - A METHOD FOR EARLY THERAPY EVALUATION

Purpose: To investigate if sequential positron emission tomographic (PET) scans With the glucose analog F-18-2-fluoro-2-deoxy-D-glucore ((18)FDG) and/or L-methyl-C-11-methionine (C-11-methionine) in patients with breast cancer could provide early information On the efficacy of Polychemotherapy. Patients and Methods: Sixteen patients With breast cancer(11 with locally advanced tumors, three with recurrent disease in the contralateral breast, two of them with distant and regional metastases, and two with distant metastases) Underwent a baseline and two followup PET Scans after the first and third/fourth polychemotherapy course, Tumor response was determined clinically/radiographically after three/four polychemotherapy courses. Results: Five patients were investigated with (18)FDG, seven with both C-11-methionine and (18)FDG, and four with Only C-11-methionine before polychemotherapy. C-11-methionine presented a more distinct visualization of primary/contralateral breast cancers in five of seven patients when compared with (18)FDG. Twelve of 16 patients demonstrated a response using conventional methods after the third/fourth course of polychemotherapy, Eight of these 12 clinical responders had a significant decrease in tracer uptake at the first PET scan performed 6 to 13 days after the first polychemotherapy course, and these reductions were further augmented after the third/fourth course and corresponded to the conventional therapy evaluation (clinical examination, computed tomography [CT], ultrasonography, and mammography). Conclusion: Our data indicate that PET may be of clinical value in predicting response to chemotherapy in patients with locally advanced breast cancer and/or metastatic disease earlier than any other method used. (C) 1995 by American Society of Clinical Oncology.