Preoperative staging of cervical cancer: is 18-FDG-PET/CT really effective in patients with early stage disease?

Objective: Nodal status is one of the most important findings in patients with early-stage cervical cancer that requires post-surgical adjuvant therapies and influences prognosis of patients. The purpose of this study was to determine the diagnostic accuracy of 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F-FDG-PET/CT) in the detection of nodal metastases.

Methods: From 2004 to 2010 women with Ib1-IIa <4cm cervical cancer underwent 18F-FDG-PET/CT followed by radical hysterectomy and pelvic lymphadenectomy in our institution. 18F-FDG-PET/CT images were analyzed and histopathological findings served as the reference standard. Diagnostic performance of 18F-FDG-PET/CT in nodal disease detection was reported in terms of accuracy value. A sub analysis of women with tumor diameter <2cm (group 1) or 2-4cm (group 2) was performed in order to verify the efficacy of 18F-FDG-PET/CT in each group.

Results: One hundred fifty-nine women were enrolled. 65% had squamous histotype and 51% had grade 3 disease. Median number of nodes dissected was 29 (range 11-61). 28/159 women (18%) showed nodal metastases. Overall patient-based sensitivity, specificity, positive and negative predictive value of 18F-FDG-PET/CT for detection of nodal disease were 32.1%, 96.9%, 69.2%and 87.0% respectively. Among the 97 (61%) women included in group 1, 8 had nodal metastases (8.2%) and 2 was discovered through 18F-FDG-PET/CT (25%), while 20/62 women of the group 2 (32.3%) had nodal involvement, of which 7 (35%) was detected by 18F-FDG-PET/CT.

Conclusions: This study showed that 18F-FDG-PET/CT had low sensitivity and had a minimal clinical impact in the pretreatment planning of stage Ib1-IIa <4cm cervical cancer.