Updates on Imaging in Newly Diagnosed Endometrial Cancer
Magnetic resonance imaging (MRI) has generally been the imaging modality of choice for visualizing an endometrial tumor prior to surgery. Integrated fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/MRI has emerged as an important tool to characterize both the endometrial tumor itself and extrauterine spread.
Professor and Deputy Chair
“To summarize, I think that we are trying to identify the best ways to evaluate patients who, perhaps, are not eligible for surgery to better characterize their tumor and/or to aid in radiation planning."
Endometrial cancer is a surgically staged disease, and we are mindful that, around the world, access to specific types of imaging varies across settings. However, imaging after diagnosis and prior to surgery is commonly used in a number of scenarios, including in patients with a high-risk histology and in those who are interested in fertility-sparing treatment.
In the latter group of patients, the goal would be to defer surgical staging until after completion of childbearing, an approach that is limited to patients with low-risk disease. In patients desiring fertility-sparing management, we need to better understand the tumor to determine patient eligibility. MRI is considered the standard of care in that setting, and MRI has generally been preferred for evaluating uterine characteristics such as the size of the tumor, whether the tumor has invaded the myometrium, and whether there is local spread.
Another setting in which patients require imaging is when there is concern that the disease may have spread outside of the uterus prior to the patient’s initial surgery. In those who have a high-risk histology, such as serous carcinoma, clear cell carcinoma, or malignant mixed Müllerian tumors, or in those who have high-grade endometrial cancer, imaging will often be obtained prior to surgery. In these cases, historically, standard computed tomography (CT) scans have been employed for this purpose, but today, a number of different modalities may be used, and the use of PET/CT or PET/MRI has been increasing.
After surgery, no follow-up imaging is recommended for patients who have a low risk for recurrence, whereas, in patients with advanced disease who are receiving chemotherapy or systemic therapy after surgery, we usually use imaging to follow the disease response.
A number of studies have evaluated the sensitivity and specificity of PET/CT, and data have been conflicting. Some studies have shown good sensitivity in detecting peritoneal disease or disease in the lymph nodes. But a prospective study from The University of Texas MD Anderson Cancer Center found that it was not diagnostic for small-volume metastases and that it may not necessarily add value over a regular CT scan.
A newer imaging technology fuses PET imaging with MRI (ie, 18F-FDG PET/MRI). This combines the value of the MRI in looking at the tumor in the uterus with the value of the PET in looking at extrauterine disease. This is a very new technology that is actively being studied, including here, at my institution.
To summarize, I think that we are trying to identify the best ways to evaluate patients who, perhaps, are not eligible for surgery to better characterize their tumor and/or to aid in radiation planning. It appears that the fusion of PET and MRI may add value over PET/CT, although the data are still limited.
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