title: PET imaging with [11C]methyl- L-methionine for therapy monitoring in patients with rectal cancer.
abstract: In this study we evaluated whether positron emission tomography (PET) using the amino acid [11C]methyl- L-methionine (MET) may be used for therapy monitoring in patients with rectal cancer who are undergoing preoperative chemoradiotherapy. A total of 41 MET-PET scans were performed in 26 patients with locally advanced rectal cancers. All patients were examined prior to chemoradiotherapy. In 15 patients, MET-PET was repeated after preoperative chemoradiotherapy (45 Gy radiation dose, 250 mg 5-fluorouracil as continuous infusion). MET uptake prior to and after the completion of chemoradiotherapy was correlated with changes in T stage and histopathological regression. All tumours were visualised with high contrast and had a significantly higher SUV (5.7+/-2.2) than normal rectum (2.7+/-0.9) and all other organs in the field of view except the small intestine (3.9+/-1.7). In all tumours studied prior to and after chemoradiotherapy, MET uptake decreased during therapy (SUV before therapy, 6.2+/-2.3; SUV after therapy, 2.6+/-1.2; P=0.0007). However, the degree of change in MET uptake was not correlated with histopathological tumour response. In conclusion, primary rectal cancer can be imaged with MET-PET. However, for the studied chemoradiotherapy regimen, MET-PET did not allow an assessment of the response to therapy.
authors.affiliation: Department of Nuclear Medicine, Technische Universität München, Ismaningerstrasse 22, Germany. h@wieder.de
authors.forename: Hinrich
authors.initials: H
authors.lastname: Wieder
authors.forename: Katja
authors.initials: K
authors.lastname: Ott
authors.forename: Frank
authors.initials: F
authors.lastname: Zimmermann
authors.forename: Hjalmar
authors.initials: H
authors.lastname: Nekarda
authors.forename: Jens
authors.initials: J
authors.lastname: Stollfuss
authors.forename: Petra
authors.initials: P
authors.lastname: Watzlowik
authors.forename: Jörg-Rüdiger
authors.initials: JR
authors.lastname: Siewert
authors.forename: Ulrich
authors.initials: U
authors.lastname: Fink
authors.forename: Karen
authors.initials: K
authors.lastname: Becker
authors.forename: Markus
authors.initials: M
authors.lastname: Schwaiger
authors.forename: Wolfgang Andreas
authors.initials: WA
authors.lastname: Weber
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008715:Methionine / Q000493:pharmacokinetics*; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology / Q000628:therapy; D012016:Reference Values; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed
chemical_list: D019275:Radiopharmaceuticals; C086242:carbon-11 methionine; D008715:Methionine