Published in:
01-08-2013 | Original Article
Diagnostic performance of 18F-fluorothymidine PET/CT for primary colorectal cancer and its lymph node metastasis: comparison with 18F-fluorodeoxyglucose PET/CT
Authors:
Masatoyo Nakajo, Masayuki Nakajo, Yoriko Kajiya, Megumi Jinguji, Nobuaki Nishimata, Shunji Shimaoka, Tohru Nihara, Kuniaki Aridome, Sadao Tanaka, Yoshihiko Fukukura, Atushi Tani, Chihaya Koriyama
Published in:
European Journal of Nuclear Medicine and Molecular Imaging
|
Issue 8/2013
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Abstract
Purpose
To examine the diagnostic performance of 18F-fluorothymidine (FLT) PET/CT in primary and metastatic lymph node colorectal cancer foci in comparison with 18F-fluorodeoxyglucose (FDG) PET/CT.
Methods
The study population comprised 28 patients with 30 newly diagnosed colorectal cancers who underwent surgical resection of the primary lesion and regional lymph nodes after both FLT and FDG PET/CT. The associations between SUVmax levels and pathological factors were evaluated using the Mann-Whitney U or Kruskal-Wallis test. Differences in diagnostic indexes for detecting nodal metastasis between the two tracers were estimated using the McNemar exact or χ
2 test.
Results
All 30 primary cancers (43.0 ± 20.0 mm, range 14 – 85 mm) were visualized by both tracers, but none of the FLT SUVmax values exceeded the FDG SUVmax values in any of the primary cancers (6.6 ± 2.4 vs. 13.6 ± 5.8, p < 0.001). The sensitivity, specificity and accuracy for detecting nodal metastasis were 41 % (15/37), 98.8 % (493/499) and 94.8 % (508/536) for FDG PET/CT, and 32 % (12/37), 98.8 % (493/499) and 94.2 % (505/536) for FLT PET/CT, respectively. The sensitivity (p = 0.45), specificity (p = 0.68) and accuracy (p = 0.58) were not different between the tracers. Nodal uptake of FLT and FDG was discordant in 7 (19 %) of 37 metastatic nodes. There were ten concordant true-positive nodes of which six showed higher FDG SUVmax and four showed higher FLT SUVmax, but the difference between FDG and FLT SUVmax was not significant (5.56 ± 3.55 and 3.62 ± 1.45, respectively; p = 0.22).
Conclusion
FLT has the same potential as FDG in PET/CT for the diagnosis of primary and nodal foci of colorectal cancer despite significantly lower FLT uptake in primary foci.