18F-FDG PET/CT parameters in precision treatment planning for locally advanced squamous cell carcinoma of the uterine cervix

e17508 Background: Concurrent chemoradiotherapy (CCRT) is the standard of care for locally advanced cervical cancer. We aimed to analyze pretreatment 18 F-fluorodeoxyglucose ( 18 F-FDG) positron emission tomography/computed tomography (PET/CT) parameters and clinicopathological characteristics in patients with locally advanced cervical squamous cell carcinoma (SCC) to establish a scoring system for prognostic stratification. Methods: Cohort 1 consisted of patients with cervical SCC with FIGO (2009) stage III-IVA or stage I-II with positive nodes on PET/CT recruited in AGOG09-001 trial. Cohort 2 consisted of institutional patients treated in 2016-2020 with similar inclusion criteria. Pretreatment clinical characteristics and PET/CT parameters including maximum standardized uptake value (SUVmax) and metabolic tumor volume (MTV) of cervical tumor and nodal SUVmax were assessed for outcomes using the stepwise multivariable Cox regression. Results: With two cohorts combined (Cohort 1, n= 55, Cohort 2, n= 120), the median follow-up for 175 patients was 55 months (range, 2-164). Age (≥66 years old), MTV (≥87.1 mL) of cervical tumor and PET/CT-defined para-aortic lymph node (PALN) metastasis were independent significant adverse predictors for cancer-specific survival (CSS) ( P<0.001, P=0.002, and P=0.033, respectively). Counting each risk predictor as score one, patients with risk score sum 0, 1, 2, 3 had a 5-year CSS of 85.8%, 68.5%, 29.7%, and 0%, respectively ( P<0.001). Conclusions: Age, cervical tumor MTV and PET/CT-defined PALN metastasis are independent risk predictors in locally advanced cervical SCC. Patients with risk score sum 0 may receive CCRT with single-agent cisplatin, while patients with risk score sum ≥1 may consider receiving novel combination therapies or entering clinical trials.