Scar or recurrent rectal cancer. Positron emission tomography is more helpful for diagnosis than immunoscintigraphy
P. Schlag, B. Lehner, L. G. Strauss, P. Georgi and C. Herfarth
Department of Surgery, University of Heidelberg, Federal Republic of Germany.
We used positron emission tomography and fludeoxyglucose F 18 to assess
metabolic activity of a pelvic mass in 18 patients who had suspected
recurrent rectal cancer. Computed tomography could not differentiate tumor
from scar. All patients presenting increased uptake of fludeoxyglucose F 18
by the mass were proved by histologic studies to suffer from recurrent
tumor. Six of seven patients with low fludeoxyglucose uptake had
nonmalignant lesions. Using immunoscintigraphy in 14 patients with elevated
carcinoembryonic antigen levels, only four of ten recurrences could be
identified by increased antibody accumulation in the mass. On the other
hand, two of four benign lesions were interpreted as being recurrent tumor
because of high uptake. Therefore, only positron emission tomography seems
to be a useful diagnostic tool in the differentiation of recurrent rectal
cancer and scar by providing information about the metabolic activity of a
mass.
