Utility of PET-CT to evaluate retroperitoneal lymph node metastasis in advanced cervical cancer: Results of ACRIN6671/GOG0233 trial

Objective To assess if FDG PET combined with diagnostic CT improves diagnostic CT accuracy to detect lymph node (LN) metastasis in advanced cervical cancer. Methods A prospective HIPAA compliant ACRIN/GOG multicenter trial was conducted. Patients underwent concurrent diagnostic contrast-enhanced CT (DCT) and PET and pelvic/abdominal lymphadenectomy. Seven independent blinded readers reviewed PET-DCT and DCT one-month apart. Reference standard was surgically removed LN pathology. Accuracy values were calculated at participant level, correlating abdominal (right and left para-aortic/common iliac) and pelvic (right and left external iliac/obturator) LN regions with pathology, respecting laterality. Reader average sensitivities/specificities of PET-DCT vs. DCT were compared with generalized linear mixed models, and AUCs with Obuchowski's method. Results One hundred fifty-three patients had PET-DCT and pathology. Forty-three of 153 patients had metastasis to abdominal LNs. Sample size calculation required review of the first 40 abdominal positive and 40 randomly selected abdominal negative studies. Patients were 24 to 74 years (48.9 ± 10.6) old. Mean sensitivities of PET-DCT/DCT for detection of LN metastasis in abdomen were 0.50 (CI: 0.44, 0.56) and 0.42 (CI: 0.36, 0.48) (p = 0.052) and in pelvis 0.83 (CI: 0.78, 0.87) and 0.79 (CI: 0.73, 0.83) (p = 0.15). Corresponding specificities were 0.85 (CI: 0.80, 0.89) and 0.89 (CI: 0.84, 0.92) (p = 0.21) and 0.63 (CI: 0.54, 0.70) and 0.62 (CI: 0.53, 0.69) (p = 0.83). Mean AUC values were 0.70 (CI: 0.61, 0.79) and 0.68 (CI: 0.59, 0.77) (p = 0.43) and 0.80 (CI: 0.71, 0.88) and 0.76 (CI: 0.67, 0.85) (p = 0.21) respectively. Conclusion Addition of PET to DCT resulted in statistically borderline increase in sensitivity to detect LN metastasis in abdomen in advanced cervical cancer.