Nuclear Medicine Review

The value of [18F]FDG PET/CT examination in the detection and differentiation of recurrent ovarian cancer

The exact role of positron emission tomography with fluorine-18-deoxyglucose ([18F]FDG PET/CT) in an early diagnosis of relapsed ovarian cancer is not clearly defined. The aim of the study was to assess the value of [18F]FDG PET/CT in the detection and differentiation of recurrent ovarian cancer. Eighty-four patients with suspected recurrent ovarian cancer underwent [18F]FDG PET/CT examination. Results of PET/CT were analyzed taking into account clinical data of the patients, histological diagnosis, and 6-month follow-up. The [18F]FDG PET/CT examinations showed abnormal findings in 67 patients (79.76%). There were 63 true positive results (75.00%), 14 true negative (16.67%), 4 false positive (4.76%), and 3 false negative (3.57%) results. Sensitivity, specificity, positive and negative predictive values of [18F]FDG PET/CT were 95%, 78%, 94%, and 82%, respectively. In patients with elevated serum Ca 125 concentration (n = 43), sensitivity and specificity of [18F]FDG PET/CT was 95.00% and 66.67%, respectively. Recurrence was confirmed in 22 (88.00%) of 25 patients referred for [18F]FDG PET/CT due to suspected relapse in imaging tests. A high frequency of recurrent ovarian cancer detected in the [18F]FDG PET/CT examinations due to increased Ca 125 concentration in patients without clinical symptoms and without changes in other imaging tests confirmed the usefulness of [18F]FDG PET/CT in such cases. In patients with suspected recurrent ovarian cancer implied in radiological findings, [18F]FDG PET/CT results in most cases differed from the original results of imaging examination. Our results showed high accuracy of [18F]FDG PET/CT in the evaluation of recurrent ovarian cancer and presented this diagnostic method as a useful tool in detecting and differentiating suspected lesions in this group of patients.

Diffuse peritoneal carcinomatosis and Sister Mary Joseph nodule in ovarian carcinoma — exquisite demonstration of the peritoneal reflections on [18F]FDG PET/CT

A case involving a 64-year-old woman with ovarian carcinoma on maintenance therapy who underwent 18-fluorodeoxyglucose positron emission tomography with computed tomography ([18F]FDG PET/CT) restaging due to rapid cancer antigen 125 (Ca-125) rise. This revealed recurrent disease within the pelvis and large volume, peritoneal carcinomatosis including an avid umbilical deposit, consistent with the rarely seen Sister Mary Joseph nodule (SMJN). This case elegantly demonstrates not only the anatomy of the peritoneal surfaces through avid disease deposition but also highlights the sensitive depiction of disease burden in peritoneal carcinomatosis, including the detection of rare manifestations such as SMJN.

[18F]FDG PET/CT and CA-125 in the evaluation of ovarian cancer relapse or persistence: is there any correlation?

Ovarian cancer relapse can be diagnosed by serum tumor markers measurements and 18F-fluorodoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT) findings. The aim of our study was to analyze the potential relationship between cancer antigen 125 (CA-125) and PET/CT results in patients affected by ovarian cancer. Ninety-two [18F]FDG PET/CT scans in sixty-one patients with diagnosis of ovarian cancer were analyzed and compared to CA-125 values. PET/CT results were compared to other imaging modalities, histology or follow-up data in order to define its diagnostic accuracy. PET/CT studies were analyzed qualitatively and semiquantitatively by measuring the maximum and mean standardized uptake value body weight max (SUVbw max, SUVbw mean), maximum SUV lean body mass (SUVlbm), maximum SUV body surface area (SUVbsa), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of hypermetabolic lesions. All measurements were compared with CA-125 values. Twenty PET/CT studies were true negative, sixty-three true positive, five false positive and four false negative with sensitivity of 94%, specificity of 80%, negative predictive value of 83%, positive predictive value of 93% and accuracy of 90%. CA-125 levels were significantly correlated with PET/CT results and all PET/CT semiquantitative parameters. CA-125 cutoff values of 17 UI/mL is the best compromise between sensitivity and specificity in discriminating between positive and negative PET/CT result. [18F]FDG PET/CT has good accuracy in evaluating patients with relapse or persistance of ovarian cancer. CA-125 levels were significantly correlated with metabolic PET/CT parameters.