Preliminary study of carbon-11 methionine PET in the evaluation of early response to therapy in advanced breast cancer.
OBJECTIVE
Breast cancer is one of the principal oncological challenges in the Western world. Currently, there are only a few reliable predictive methods for monitoring treatment. We investigated the ability of carbon-11 methionine ("11C-MET) positron emission tomography (PET) to evaluate early response to therapy in advanced breast cancer.


METHODS
Thirteen patients with metastases in the lungs/pleura, lymph nodes, soft tissue, or bones entered a MET PET study both before and after the first cycle of polychemotherapy (n=4), or after the first month of therapy with hormones (n=5), or low dose weekly cytostatics (n=3). One patient underwent three PET studies: before hormonal therapy, after 1 month of hormonal therapy, and after the first cycle of polychemotherapy (total, 27 studies). MET accumulation in the metastatic sites was measured as standardized uptake values (SUVs), and the pretreatment and post-treatment SUVs were compared with each other and the clinical follow-up data.


RESULTS
A total of 26 different metastatic sites were investigated in 13 patients. All metastases were visible by MET PET except one superficially spreading local skin recurrence, probably because of respiratory movements. Five new metastatic sites were detected. After therapy the SUVs decreased significantly (30-54%; P < 0.05) in all six responding metastatic sites, whereas the SUVs of nonresponding metastases decreased somewhat (11-130/%; n=4), remained stable (+/- 8%; n=10), or increased (13-23%; n=4) (P=NS). The SUVs of two nonresponding metastatic sites decreased clearly. Physiological MET uptake in the salivary glands, the myocardium, and the bone marrow did not disturb the image interpretation.


CONCLUSIONS
MET PET may be useful in assessing the early response to therapy in advanced breast cancer.
Lindholm
Paula
P
Department of Oncology and Radiotherapy, University of Turku, P.O. Box 52, Fl-20521 Turku, Finland. paula.lindholm@tyks.fi
Lapela
Maria
M
Någren
Kjell
K
Lehikoinen
Pertti
P
Minn
Heikki
H
Jyrkkiö
Sirkku
S
D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008715:Methionine / Q000378:metabolism; D008875:Middle Aged; D049268:Positron-Emission Tomography; D012983:Soft Tissue Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary; D016896:Treatment Outcome
C086242:carbon-11 methionine; D008715:Methionine