The new study shows that PET is a promising molecular imaging technique for personalized therapy. Molecular imaging and nuclear medicine provide the possibility of determining the invasiveness and aggressiveness of malignant tumors in the uterus earlier on, before disease progresses. With this technique, physicians gain the advantage of a more precise diagnosis along with the ability to better predict the tumor's growth patterns and plan for the most appropriate therapeutic treatment strategy.
In the study, the researchers used a specialized form of PET imaging called "estrogen receptor expression imaging" for 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) to evaluate diagnostic accuracy. All patients underwent preoperative PET scans with 18F-fluoroestradiol (18F-FES)—a tracer that has been successfully used in diagnosing breast cancer—and 18F-fluorodeoxyglucose (18F-FDG) to compare differences in tracer accumulation.
The researchers confirmed that endometrial carcinoma reduces estrogen dependency with accelerated glucose metabolism as it progresses to a higher stage or grade. By combining the two tracers, researchers were able to use a new index of uptake ratio that can better predict pathologic stages and aggressiveness of tumors. The results of the study were encouraging, with the combined techniques having 86 percent accuracy.
For endocrine-related tumors (including endometrial cancer), tumors vary from well-differentiated and close in character to the tissue of origin to poorly differentiated tumors, which bear less resemblance to the tissue of origin. The well-differentiated tumors tend to be more slow-growing and less aggressive than poorly differentiated tumors. They also retain their endocrine function and/or responsiveness.
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.
MEDICA.de; Source: Society of Nuclear Medicine