Prognostic value of FDG-PET SUV changes in cervical cancer following radiation therapy: a retrospective cohort study

This study sought to determine the relationship between cervical cancer recurrence and post-treatment change in standardized uptake value (SUV) of 18F-2-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) in the cervix and lymph nodes.

This retrospective cohort study included patients who received curative intent radiation therapy for biopsy-proven stage I-IVA locally advanced cervical cancer at a single tertiary referral center from 2009 to 2021. The exposure was percent change in SUV from pre- to post-treatment FDG-PET scans at the cervix and lymph nodes. The primary outcome was recurrence rate, and secondary outcomes were overall and progression-free survival. Firth's penalized logistic regression and Cox proportional hazards models were used to assess associations.

55 patients met eligibility criteria. Recurrence rate was 27% (15/55); of these, 33% had local recurrence (5/55) and 67% had distant recurrence (10/55). Median percent decrease of cervical SUV after treatment in those with and without recurrence was similar (71.4 vs 68.8, p = 0.89); this remained consistent when analyzing those with local recurrence only (70.5, p = 0.95). When the percent decrease in cervical SUV was examined in intervals (< 25%, 25-50%, 50-75%, > 75%), this was also not predictive of local (p = 0.91) or overall (p = 0.75) recurrence. Median percent decrease at the most avid and distant lymph node in those with and without recurrence was not significantly different (p > 0.05). Neither change in cervical nor lymph node SUV was associated with overall or progression-free survival.

Changes in SUV after treatment may not be a reliable stand-alone marker for predicting recurrence or survival in locally advanced cervical cancer after treatment with radiation therapy.