Fluorine-18-fluorouracil to predict therapy response in liver metastases from colorectal carcinoma.
Prediction of chemotherapy response is still a problem in oncological patients.


METHODS
Studies with PET and 18F-fluorouracil (FU) were used for measurements of drug concentrations in patients with liver metastases from colorectal carcinoma. The PET data obtained before onset of FU chemotherapy were correlated to the growth rate of the metastases after therapy. The final evaluation included 25 metastases obtained in 17 patients. CT preceded the first chemotherapeutic cycle and was repeated within 3-11 mo after onset of treatment. The uptake of the cytostatic agent was evaluated in the liver metastases using the SUV at 120 min after tracer infusion. Tumor growth rate of the metastases was calculated based on CT volumetric data.


RESULTS
The trapping of 18F-FU was highly variable even for multiple metastases in the same patients. Six metastases with high 18F-FU uptake values exceeding 3.0 SUV correlated with negative growth rate values, 5 of 25 metastases with intermediate uptake values ranging from 2.0-3.0 SUV were associated with almost stable growth rate values nearly zero and 14 of 25 metastases with low uptake values <2.0 SUV demonstrated positive growth rate values. Only metastases with a 18F-FU uptake exceeding 3.0 SUV at 120 min postinjection demonstrated a response to therapy. A significant correlation of 0.86 (p < 0.001) was found between the 18F-FU uptake values in the metastases measured before chemotherapy and the growth rate of the lesions after treatment.


CONCLUSIONS
The data show, that FU chemotherapy outcome can be predicted using a single PET study with 18F-FU before onset to therapy.
Dimitrakopoulou-Strauss
A
A
Department of Oncological Diagnostics and Therapy, German Cancer Research Center, Heidelberg.
Strauss
L G
LG
Schlag
P
P
Hohenberger
P
P
Möhler
M
M
Oberdorfer
F
F
van Kaick
G
G
D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D015179:Colorectal Neoplasms / Q000473:pathology*; D005462:Fluorine Radioisotopes; D005472:Fluorouracil / Q000627:therapeutic use*; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000556:secondary*; D011237:Predictive Value of Tests; D011379:Prognosis; D019275:Radiopharmaceuticals; D013997:Time Factors; D014055:Tomography, Emission-Computed
D000964:Antimetabolites, Antineoplastic; D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; D005472:Fluorouracil