Introduction/Background Curative treatment for locally advanced cervical cancer is chemo-radiotherapy and intrauterine brachytherapy. Early identification of patients who are not responding adequately allows treatment adaptation. This has the potential to improve overall survival, spare unnecessary side-effects and reduce healthcare costs associated with ineffective treatment. Diffusion-weighted magnetic resonance imaging (DW-MRI) and fluorodeoxyglucose-positron emission tomography (FDG-PET) may be used to enhance assessment of response during and after chemo-radiotherapy allowing prompt treatment adaptation.

Methodology A feasibility non randomised cohort study of PET-MRI is currently recruiting cervical cancer patients having definitive chemo-radiotherapy. PET-MRI imaging is added to the standard of care at baseline and week 5 of treatment. A patient experience questionnaire is completed at baseline and week 5. Apparent diffusion coefficient (ADC) for DW-MRI and standardised uptake values (SUV) for PET-MRI were derived, comparing baseline to week 5 and within each scan to investigate the distribution of imaging parameters obtained from areas of responding, progressing and stable disease.

Results Six patients have been recruited. Two patients did not undergo week 5 imaging. All patients found the imaging attendances acceptable. All patients had a significant reduction in SUVmax in week 5 compared to pre-treatment. All patients had an increase in ADC during treatment which was significant for patient 2 & 3. A significant correlation was seen in reduction of SUVmax and increase in ADC, r=0.98, p value=0.0172 (95% CI 0.39–0.0.99).

Conclusion Early data suggests additional imaging to obtain biological data during chemo-radiotherapy is feasible with no detrimental impact on patient experience. Identification of a non-responding ‘biological target volume’ using ADC and SUVmax parameters could allow personalisation of brachytherapy, delivering a high dose boost to residual disease. This study identifies the feasibility of PET-MRI as an imaging biomarker.

Disclosure Nothing to disclose.