Comparison of the diagnostic value of [ Ga]Ga-FAPI-04 PET/MR and [F]FDG PET/CT in patients with T stage ≤ 2a2 uterine cervical cancer: a prospective study.

Purpose: To compare the diagnostic value of [ Ga]Ga-FAPI-04 PET/MR and [F]FDG PET/CT in patients with T stage ≤ 2a2 uterine cervical cancer patients.

Methods: Patients pathologically diagnosed with cervical cancer and with a T stage ≤ T2a2 were prospectively enrolled. All patients underwent whole-body [ Ga]Ga-FAPI-04 PET/MR and [F]FDG PET/CT within 2 weeks, and surgical treatment was performed within 10 days after PET.

Results: Twenty-five patients were enrolled. Twenty patients underwent radical hysterectomy, among which all of them underwent pelvic lymphadenectomy, and 10 patients underwent para-aortic lymphadenectomy. Three patients received merely laparoscopic lymphadenectomy without hysterectomy. Two patients with both [F]FDG and [ Ga]Ga-FAPI-04 lymph node high metabolism were staged as FIGO IIIC1r, and concurrent chemoradiation therapy (CCRT) was performed. [F]FDG and [ Ga]Ga-FAPI-04 had equivalent detection ability on primary tumors, with a positive detection rate of 96.0%. The accuracy of T staging using [F]FDG and [ Ga]Ga-FAPI-04 was relatively 50% and 55.0%. Elevated and underrated staging was due to misdiagnosis of either vaginal infiltration or tumor size. In terms of lymph node metastasis detection, the specificity of [ Ga]Ga-FAPI-04 was 100% (95% CI, 84.6% ~ 100.0%), which was significantly higher than [F]FDG (59.1% (95% CI, 36.4% ~ 79.3%)) (p = 0.004).

Conclusion: [ Ga]Ga-FAPI-04 PET/MR and [F]FDG PET/CT demonstrated an equivalent detection ability on cervical cancer primary tumors. However, [ Ga]Ga-FAPI-04 PET/MR's diagnostic value in lymph node metastasis was significantly higher than [F]FDG PET/CT. [ Ga]Ga-FAPI-04 PET/MR has the potential for more accurate treatment planning, thus clarifying fertility preservation indications for early-stage young patients.