The Debate on Pelvic Lymphadenopathy Size Significance in Ovarian Cancer Patients

This study attempts to ascertain a reliable cutoff size to determine whether pelvic lymph nodes are metastatic or not in ovarian cancer patients.
We retrospectively reviewed 73 PET/CT scans of 52 female patients with ovarian carcinoma who underwent surgery followed by chemotherapy. The findings of contrast enhanced MDCT were interpreted by two experienced radiologists unaware of the PET/CT findings. At least two experienced nuclear medicine physicians unaware of the contrast enhanced-MDCT findings examined the PET scans in order to localize, characterize and compare these scans to co-registered PET/CT images. A comparative study was done. Lymph node sizes were recorded in short axis diameter with a significant cut off estimated at 7.5 mm. Metabolic activities of different lymph node groups were assessed and the semi-quantitative SUV was calculated. The level of SUV significance was 2.5. Significant metastatic lymph nodes were judged by the assessment of integrated PET/CT results.
Of the 73 scans, 47 showed significant lymph node metastases, with the following sensitivities: 75% (external iliac), 77.8% (internal iliac), and 75% (inguinal). The specificities were 84% (external iliac), 86% (internal iliac), and 54% (inguinal) with a P-value of 0.000 for the external an internal iliac groups and 0.079 for the inguinal group.
To improve detection of malignant pelvic lymph nodes, the size threshold should be decreased to 7.5 mm.