Trial Information

The Role of 3-Deoxy-3[18]Fluorothymidine Positron Emission Tomography (FLT-PET) in Proliferation of Colorectal Liver Metastases

Aim of the Study:

Validation of FLT-PET as a proliferation marker for colorectal liver metastases, so that
the risk of recurrence in patients with resected colorectal liver metastases can be assessed
in a noninvasive method.

Study Design:

Validation study (n=40) to determine the correlation between quantitative FLT-PET (in this
study determined before resection of the colorectal liver metastases) and the histologically
determined proliferation index in the resected specimen of the metastases ('golden
standard'). If correlation is established, the correlation between the proliferation and
recurrence rate studied is also (n=80).

Study Population:

Patients with colorectal liver metastases.

Intervention:

FLT-PET scan

Scientific Basis of Study:

Several reports show that presence or absence of extrahepatic disease is a determining
prognostic factor. Patients with extrahepatic disease are rarely suited for resection of the
liver metastases. Recently several papers describe that the proliferation index of the liver
metastases is another determining prognostic factor. Patients with a high proliferation
factor have a worse prognosis. For both of these determining factors, it seems that PET
diagnostics play an essential role and contribute to better selection of patients suitable
for resection.

Diagnostics on Proliferation:

Seeing that the proliferation rate is preoperatively not determined without a biopsy (which
is contraindicated due to dissemination), all patients with colorectal liver metastases
(with no signs of extrahepatic deposits) are resected, without knowledge of the
proliferation. FLT is a marker that visualizes proliferation and thus seems an ideal
candidate to determine the proliferation rate in a noninvasive method. As of yet no
validation studies of FLT-PET in colorectal liver metastases have been described.

Evaluation:

Quantitative histologic data are correlated with the quantitative FLT-PET data. If the
correlation is higher that 0.85, this correlation is established. If this correlation is
found, the inclusion of patients will be extended from 40 to 80 patients, seeing that this
will give us the opportunity to correlate clinical data with the histological data. (alpha =
0.05, one-sided, beta = 0.90, assuming that an acceptable difference in sensitivity between
both tests is 0 and an unacceptable difference is 0.02). If this correlation is significant,
a new study will be proposed with the introduction of neoadjuvant chemotherapy, where the
selection will be determined on basis of the proliferation rate.