The prognostic value of FIGO staging defined by combining MRI and [18F]FDG PET/CT in patients with locally advanced cervical cancer

Abstract

The last version of the FIGO classification recommended imaging tools to complete the clinical assessment of patients with cervical cancer. However, the preferable imaging approach is still unclear. We aimed to explore the prognostic power of Magnetic Resonance Imaging (MRI), contrast-enhanced Computed Tomography (ceCT), and [¹⁸F]-Fluorodeoxyglucose Positron Emission Tomography ([¹⁸F]FDG-PET)/CT in patients staged for locally advanced cervical cancer (LACC, FIGO stages IB3-IVA). Thirty-six LACC patients (mean age 55.47 ± 14.01, range 31-82) were retrospectively enrolled. All of them underwent MRI, ceCT and [¹⁸F]FDG-PET/CT before receiving concurrent chemoradiotherapy. A median dose of 45 Gy (range 42-50.4; 25-28 fractions, 5 fractions per week, 1 per day) was delivered through the external-beam radiation therapy (EBRT) on the pelvic area, while a median dose of 57.5 Gy (range 16-61.1; 25-28 fractions, 5 fractions per week, 1 per day) was administered on metastatic nodes. The median doses for brachytherapy treatment were 28 Gy (range 28-30; 4-5 fractions, 1 every other day). Six cycles of cisplatin or carboplatin were administered weekly. The study endpoints were recurrence-free survival (RFS) and overall survival (OS). Metastatic pelvic lymph nodes at MRI independently predicted RFS (HR 13.271, 95% CI 1.730-101.805; P = 0.027), while metastatic paraaortic lymph nodes at [¹⁸F]FDG-PET/CT independently predicted both RFS (HR 11.734, 95% CI 3.200-43.026; P = .005) and OS (HR 13.799, 95% CI 3.378-56.361; P < 0.001). MRI and [¹⁸F]FDG-PET/CT findings were incorporated with clinical evidences into the FIGO classification. With respect to the combination of clinical, MRI and ceCT data, the use of next-generation imaging (NGI) determined a stage migration in 10/36 (27.7%) of patients. Different NGI-based FIGO classes showed remarkably different median RFS (stage IIB: not reached; stage IIIC1: 44 months; stage IIIC2: 3 months; P < 0.001) and OS (stage IIB: not reached; stage IIIC1: not reached; stage IIIC2: 14 months; P < 0.001). A FIGO classification based on the combination of MRI and [¹⁸F]FDG-PET/CT might predict RFS and OS of LACC patients treated with concurrent chemoradiotherapy.