Comparison of diagnostic efficacy on F-18 FDG PET/CT and tumor marker SCC-Ag with PAP smear in recurrent uterine cervix cancer

Objectives The early detection of recurrence of cervix cancer after treatment completion as well as early diagnosis provides patients an opportunity to more curative treatment. We compared the diagnostic efficacy of recurrent cervix cancer between F-18 FDG PET/CT and SCC-Ag with PAP smear.

Methods One hundred thirty-nine patients (mean age: 55±11 years) with uterine cervix cancer showing complete remission after treatment from January 2006 to December 2009 were enrolled in this study. All patients were performed PET/CT, PAP smear and laboratory study for SCC-Ag. Patients with elevated serum level of SCC-Ag (>2.7 ng/ml) or positive PAP smear and with positive PET/CT result were evaluated whether the cancer was recurred by pathologic confirmation or clinical follow-up.

Results Of the 139 patients, 22 patients (16%) were confirmed to have recurrence clinically and/or histologically (local recurrence: 8, lymph node metastasis: 9, peritoneal seeding or distant metastasis: 5). Of 22 patients with recurred disease, 13 patients were showed elevated serum SCC-Ag or positive PAP smear (but, 1 patient had false-positive finding) and the other 9 patients were showed false-negative finding. In the PET/CT, 21 patients were showed positive result (no one had false-positive finding) and only 1 patient was showed false-negative finding. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of SCC-Ag with PAP smear and PET/CT were 59%, 99.1%, 92.8%, 92.8%, 92.8% and 95.4%, 100%, 100%, 99.1%, and 99.2%, respectively.

Conclusions In comparison of the diagnostic efficacy of recurrent cervix cancer between SCC-Ag with PAP smear and PET/CT, PET/CT showed more superior results in the sensitivity, specificitiy, PPV, NPV and accuracy than those of SCC-Ag with PAP smear. Therefore, we expect the PET/CT is useful, single diagnostic tool for follow-up of patients with cervix cancer