Specialized PET scan picks up endometrial cancer

October 9, 2009

Comparative uptake of two radiotracers allows characterization of tumor.

PET imaging may be the missing link in the chain needed to find endometrial carcinoma and successfully manage patients with the disease.

This carcinoma is among the most common malignant tumors affecting women. If the disease is caught early, however, the five-year survival rate is better than 90%. Research at the University of Fukui in Japan has shown that a specialized form of PET, called estrogen receptor expression imaging, may find the disease before it reaches advanced stages while eliminating the need for biopsies and other interventions that can render women infertile.

In the study, published in the October issue of The Journal of Nuclear Medicine, PET imaged multiple facets of the tumor phenotype, specifically estrogen receptor expression and glucose metabolism, in 22 patients with endometrial adenocarcinoma and nine patients with endometrial hyperplasia, a thickening of the uterine lining that is a risk factor for developing endometrial cancer.

Data obtained from these PET scans provided the basis for predicting tumor growth patterns, allowing physicians to plan the most appropriate therapeutic treatment strategy, according to Dr. Hidehiko Okazawa, professor in the division of medical imaging at the University of Fukui. Okazawa and colleagues compared differences in the accumulation of two different PET radiotracers: F-18 fluoroestradiol (F-18 FES), a tracer that has been used successfully in diagnosing breast cancer, and 18F-fluorodeoxyglucose (F-18 FDG). Through this comparison, they were able to predict pathologic stages and aggressiveness of tumors with 86% accuracy, according to the researchers.

For endometrial cancer, estrogen receptor expression is related to endocrine responsiveness and indicated by FES uptake. Poorly differentiated tumors often have increased and abnormal breakdown of glucose, indicated by FDG. The combination of the two, as indicated by the study, was better than either alone at indicating the aggressiveness of the tumor.