Diagnostic Performance of 18F-FDG-PET and Diffusion-weighted MRI in the Assessment of Stage IB to IIB2 Cervical Squamous-cell Carcinoma Response to Concomitant Radiochemotherapy and Brachytherapy

Rationale: The benefit-risk ratio of surgery following concomitant radiochemotherapy and brachytherapy remains to be defined in cervical squamous-cell carcinoma (SCC) treatment. Scarce studies evaluated the interest of 18F-FDG-PET and MRI in the assessment of response to treatment before surgery. A positive predictive value of 75% was found in a small study making 18F-FDG-PET a promising tool to assess tumor response and guide surgical approach. Diffusion-weighted MRI was also described as an early and sensitive indicator in other diseases. Objectives: The main objective of this study is to evaluate the sensitivity of 18F-FDG-PET in the assessment of cervical cancer response to radiochemotherapy and brachytherapy. Secondary objectives focus on 18F-FDG-PET specificity and likehood ratios as well as diffusion-weighted MRI diagnostic performances. Method: We will conduct a prospective cohort study of 148 women with a stage IB to IIB2 cervical SCC recruited over 2.5 years in 24 centers in France. Each patient will undergo a 18F-FDG-PET and a diffusion-weighted MRI before surgery and 8 weeks after completion of the brachytherapy. The total follow-up duration (study participation) of patients will be 11 weeks : inclusion after completion of radiochemotherapy and brachytherapy, 8 weeks until 18F-FDG-PET and diffusion-weighted MRI, and 3 weeks until surgery. Expected results: 18F-FDG-PET and diffusion-weighted MRI could constitute a reliable tool to assess response to radiochemotherapy and brachytherapy in cervical SCC treatment. If so it could improve clinical practices and be helpful to decide whether the patient needs surgery or not after radiochemotherapy and brachytherapy.