Prognostic values of ADC and SUV of the primary tumour in cervical cancer patients treated with definitive chemoradiotherapy.

We analysed the correlation of F-fluorodeoxyglucose uptake into primary tumours using the maximum standardised uptake value (SUV) and the mean apparent diffusion coefficient (ADC) values in magnetic resonance imaging (MRI) with the clinical and pathological factors in patients with cervical cancer who were treated with concurrent chemoradiotherapy. The patients were stratified according to the primary tumour pre-treatment ADC and SUV cut-off values. There were significant correlations between the SUV of the primary tumour and tumour size, and the treatment response. The correlation between the ADC and FIGO stage, tumour size, and the lymph node metastasis was significant. The SUV was significantly and inversely correlated with the ADC for cervical cancer (r = -0.44, p <.001). In the multivariate analysis, the primary tumour ADC, treatment response and the lymph node metastasis emerged as significant independent predictors of both OS and DFS, and of the primary tumour SUV for DFS. Tumour size has a borderline significance for OS. High SUV and low ADC of the primary tumour are important predictive factors for identifying high-risk patients with cervical cancer who are treated with definitive chemoradiotherapy. These results point to a future role for the diffusion-weighted MRI and for F-fluorodeoxyglucose positron emission tomography, not only in the staging of cervical cancer but as an aid in the selection of an adjuvant treatment regimen after chemoradiotherapy for individual patients. Impact statement What is already known on this subject? A negative correlation between primary tumour SUV derived from positron emission tomography (PET/CT) and ADC derived from diffusion weighted magnetic resonance imaging (DW-MRI) in various cancer types and cervical cancer has been demonstrated. However, the prognostic value of primary tumour SUV and ADC in cervical cancer patients treated with definitive chemoradiotherapy is not well studied yet. What the results of this study add? The patients with high-risk features (larger tumours, extensive stage, lymph node metastasis) had higher primary tumour SUV and lower ADC values. Primary tumour ADC and lymph node metastasis emerged as significant independent predictors of both overall and disease-free survival. This study demonstrated that the functional biomarkers delivered from PET-CT and DW-MRI are important in predicting the treatment outcomes in the squamous cell carcinoma of cervix treated with definitive chemoradiotherapy, where clinical and radiological findings are very important, since these patients are not staged surgically. What are the implications of these findings for clinical practice and/or further research? Based on these findings, there may be a future role of DW-MRI and FDG/PET-CT not only in the staging of cervical cancer but as an aid in the selection of an adjuvant treatment regimen after chemoradiotherapy (ChRT) for individual patients.