Long-term follow up of cervical cancer patients with unexplained squamous cell carcinoma antigen elevation after post-therapy surveillance using positron emission tomography

Aim: We aimed to define the long-term follow-up results in cervical cancer patients with unexplained squamous cell carcinoma antigen (SCC-Ag) elevation (negative conventional imaging studies, computed tomography or magnetic resonance imaging) after definitive treatment using positron emission tomography (PET). Methods: Of the 27 women with unexplained SCC-Ag elevation, 13 died or were alive with disease (12 PET true-positive, one PET false-negative) in our previous report. In this study, we reported long-term follow-up results for all the 14 patients remaining cancer-free at cut-off of our previous analysis (seven with true-negative PET and two with false-positive PET, and five with true-positive PET having received successful curative salvage therapy). Results: The seven patients with true-negative PET studies remained recurrence-free (median follow up, 70 months; range, 11-84). Two patients had pelvic inflammatory disease; their SCC-Ag levels returned to the normal range after eradication of infection. Two other patients had recurrent cystitis, and their SCC-Ag levels normalized at 5 and 36 months, respectively. The two patients with false-positive PET/computed tomography were disease-free 73.5 and 70 months from original PET studies, respectively. In contrast, of the five patients with successful salvage, two are alive without disease (at 80 and 86.7 months), one died of radiation cystitis at 54 months, and two died of their cancer subsequent to previous analysis. Conclusion: Cystitis or pelvic inflammatory disease may cause unexplained elevation of SCC-Ag after definitive treatment. A negative PET study usually indicates absence of disease. PET is a useful tool to identify curable recurrences, especially when SCC-Ag <4 ng/mL.