Impact of PET Imaging on Detection of Extra-Pelvic Metastases in Cervical Cancer at Diagnosis: A SEER-Based Analysis

This study aims to evaluate the quantitative impact of FDG-PET on detecting extra-pelvic metastases in women with cervical cancer, using population-based data, following its approval by US Medicare/Medicaid in 2005 for staging patients without detectable extra-pelvic metastases on CT or MRI scans. Surveillance, Epidemiology, and End Results (SEER) data from eight US registries from 1975 to 2021 were analyzed. The proportions of synchronous metastases “Synchronous/(Synchronous + Metachronous)” were compared between the pre-PET era (1995–1999 and 2000–2004) and the PET era (2010–2014). The estimated fraction of extra-pelvic metastases at initial diagnosis was 35% in the pre-PET era (2000–2004) compared to 46% in the PET era (2010–2014) (absolute difference 11%; p < 0.001). The proportion of undetected metastases decreased from 65% to 54%, indicating that PET identified up to 17% (i.e., [65 − 54]/65) of previously undetectable subclinical metastases. Likewise, the comparison of data from 1995–1999 vs. 2010–2014 showed 29% vs. 46% (absolute difference 17%; p <0.001). The proportion of undetected metastases decreased from 71% to 54%, suggesting that PET identified up to 24% (i.e., [71 − 54]/71) of the previously undetectable subclinical extra-pelvic metastases. In conclusion, up to ≈17–24% of subclinical extra-pelvic metastases, previously undetectable at initial diagnosis, appear to be identified through PET, findings that are consistent with and externally validate our prior population-based observations in non-small cell lung cancer.