Evaluation of diffusion-weighted imaging (DWI) and MR spectroscopy (MRS) as early response biomarkers in cervical cancer patients

Purpose: To prospectively assess whether choline levels and Apparent Diffusion Coefficient (ADC) values within cervical cancers before, during, and after non-surgical therapy are predictive of tumour response. Patients and methods: Patients undergoing MR examination for staging of cervical cancer, candidate for non-surgical therapy, were prospectively enrolled. According to the status at the end of therapies, patients were divided into responders and non-responders. The final outcome after a 5-year follow-up was classified as No Evidence of Disease (NED) or Progression of Disease (PD). Baseline values of mean ADC and Cho/H2O were compared between responders and non-responders, as well as between patients with NED and PD. The percent variation of ADC and Cho/H2O values over time was compared. P values <0.05 were considered significant. Results: 16 patients were included. There was no significant difference at baseline between responders (n = 12) and non-responders (n = 4), nor between NED (n = 11) PD patients (n = 5), in ADC values and Cho/H2O ratio. There was no significant difference in percent variation of ADC values and of Cho/H2O, comparing responders and non-responders. There was a significant increase in absolute values of ADC from the initial to mid-therapy MRI (p = 0.0001), while Cho/H2O was stable (p value: 0.61). In the four non-responders, the ADC increase was not significant (p value: 0.25), while it was significant in the 11 responders (p value: 0.001). Values of spectroscopy were stable in both responders and non-responders. Conclusions: High increases of ADC values from baseline to mid-therapy MR reflect response to therapies. There were no significant variations in choline/water ratios over time.