Correlation of 18F-FLT and 18F-FDG uptake on PET with Ki-67 immunohistochemistry in non-small cell lung cancer.
OBJECTIVE
The nucleoside analogue 3'-deoxy-3'-(18)F-fluorothymidine (FLT) has recently been introduced for imaging cell proliferation with positron emission tomography (PET). We prospectively evaluated whether FLT uptake reflects proliferative activity as indicated by the Ki-67 index in non-small cell lung cancer (NSCLC), in comparison with 2-deoxy-2-(18)F-fluoro-D-glucose (FDG).


METHODS
A total of 18 patients with newly diagnosed NSCLC were examined with both FLT PET and FDG PET. PET imaging was performed at 60 min after each radiotracer injection. Tumour lesions were identified as areas of focally increased uptake, exceeding background uptake in the lungs. For semi-quantitative analysis, the maximum standardised uptake value (SUV) was calculated. Proliferative activity as indicated by the Ki-67 index was estimated in tissue specimens. Immunohistochemical findings were correlated with SUVs.


RESULTS
The sensitivity of FLT and FDG PET for the detection of lung cancer was 72% and 89%, respectively. Four of the five false-negative FLT PET findings occurred in bronchiolo-alveolar carcinoma. The mean FLT SUV was significantly lower than the mean FDG SUV. A significant correlation was observed between FLT SUV and Ki-67 index (r = 0.77; p < 0.0002) and for FDG SUV (r = 0.81; p < 0.0001).


CONCLUSIONS
The results of this preliminary study suggest that, compared with FDG, FLT may be less sensitive for primary staging in patients with NSCLC. Although FLT uptake correlated significantly with proliferative activity in NSCLC, the correlation was not better than that for FDG uptake.
Yamamoto
Yuka
Y
Department of Radiology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan. yuka@kms.ac.jp
Nishiyama
Yoshihiro
Y
Ishikawa
Shinya
S
Nakano
Jun
J
Chang
Sung Soo
SS
Bandoh
Shuji
S
Kanaji
Nobuhiro
N
Haba
Reiji
R
Kushida
Yoshio
Y
Ohkawa
Motoomi
M
D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood; D002289:Carcinoma, Non-Small-Cell Lung / Q000097:blood / Q000000981:diagnostic imaging* / Q000378:metabolism*; D015224:Dideoxynucleosides / Q000493:pharmacokinetics; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D019394:Ki-67 Antigen / Q000097:blood*; D008175:Lung Neoplasms / Q000097:blood / Q000000981:diagnostic imaging* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic
D014408:Biomarkers, Tumor; D015224:Dideoxynucleosides; D019394:Ki-67 Antigen; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C002854:alovudine