Source: Graefes Arch Clin Exp Ophthalmol  |  Posted 7 years ago

By Karla Harby

MIAMI BEACH, FL -- March 28, 2005 -- In a small series of patients, hybrid imaging with positron emission tomography and computed tomography (PET/CT) predicted recurrent ovarian cancer in the retroperitoneal lymph nodes, even when CT findings alone were negative or equivocal.

Hybrid imaging also enabled about 30% of patients to forego surgery that would have been unnecessary, said Robert E. Bristow, MD, associate professor, Johns Hopkins Medical Institute, Baltimore, Maryland, United States.

Dr. Bristow presented these findings here on March 23[^]rd[] at the 2005 Annual Meeting on Women's Cancer of the Society of Gynecologic Oncologists.

PET imaging using intravenous administration of radiolabeled (F-18) fluodeoxyglucose (FDG) reveals malignant cells because of their heightened glucose uptake compared with normal cells. But unlike CT, PET imaging does not provide anatomical landmarks. By performing both studies at the same time, clinicians can create images with the PET findings superimposed on the CT scan, thereby providing the anatomical data that is lacking with PET alone.

In this series, the investigators identified 24 patients with systemic nodal recurrence as shown on PET/CT. Fourteen patients had isolated nodal recurrence and underwent surgical reassessment of targeted nodal basins, and 10 patients had nodal recurrence plus peritoneal or extra-abdominal disease. Seven of these 10 patients did not undergo surgical exploration. Therefore, ?about 30% of patients were excluded from consideration for surgery based on the findings of PET/CT,? Dr. Bristow said.

Of the 143 nodes retrieved, 59 contained recurrent ovarian cancer. PET/CT failed to identify microscopic disease in 59.3% of the pathologically positive lymph nodes. For all target nodal basins, the sensitivity, specificity, positive and negative predictive values, and the accuracy for recurrent ovarian cancer in dissected lymph nodes, were: 40.7%, 94.0%, 82.8%, 69.3%, and 72.0%, respectively (P <.001).

In response to a question from the audience, Dr. Bristow noted that they have not found any correlation between rising CA-125 levels and the ability of PET/CT to predict disease. ?CA-125 needs to be interpreted in the context of each individual patient,? he explained.

?I think PET/CT is going to become the imaging modality of choice as it becomes more affordable and there are more scanners out there in the community,? Dr. Bristow added.

[Presentation title: Combined PET/CT for Detecting Recurrent Ovarian Cancer Limited to Retroperitoneal Lymph Nodes. Abstract 49]