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 (P ET) 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 wi th breast cancer could provide early information On the efficacy of Po lychemotherapy. Patients and Methods: Sixteen patients With breast can cer(11 with locally advanced tumors, three with recurrent disease in t he contralateral breast, two of them with distant and regional metasta ses, and two with distant metastases) Underwent a baseline and two fol lowup PET Scans after the first and third/fourth polychemotherapy cour se, Tumor response was determined clinically/radiographically after th ree/four polychemotherapy courses. Results: Five patients were investi gated with (18)FDG, seven with both C-11-methionine and (18)FDG, and f our with Only C-11-methionine before polychemotherapy. C-11-methionine presented a more distinct visualization of primary/contralateral brea st cancers in five of seven patients when compared with (18)FDG. Twelv e of 16 patients demonstrated a response using conventional methods af ter the third/fourth course of polychemotherapy, Eight of these 12 cli nical responders had a significant decrease in tracer uptake at the fi rst PET scan performed 6 to 13 days after the first polychemotherapy c ourse, and these reductions were further augmented after the third/fou rth course and corresponded to the conventional therapy evaluation (cl inical examination, computed tomography [CT], ultrasonography, and mam mography). Conclusion: Our data indicate that PET may be of clinical v alue in predicting response to chemotherapy in patients with locally a dvanced breast cancer and/or metastatic disease earlier than any other method used. (C) 1995 by American Society of Clinical Oncology.