B-0323 Apparent diffusion coefficient for evaluating early tumour response to neoadjuvant chemo-radiotherapy in locally advanced cervical cancer: correlation with histopathology. Preliminary results

M. Iacobucci, M. Miccò, A.L. Valentini, B. Gui, A.M. De Gaetano, L. Bonomo | Friday, March 8, 10:30 – 12:00 / Room F1

Purpose: To evaluate diagnostic accuracy of diffusion-weighted magnetic resonance imaging (DWI) in predicting response to neo-adjuvant chemo-radiotherapy (nCRT) in patients with locally advanced cervical carcinoma using apparent diffusion coefficient (ADC). Cervical lesions ADC were correlated with post-surgical histopathology.
Methods and Materials: 24 women (FIGO>IB Bulky) underwent MRI and DWI prior to, after 2 weeks and at the end of nCRT, using 1.5 T scanner. Cervical lesion volume and ADC were measured at each assessment. Radical hysterectomy was performed 4 weeks after MRI. Treatment response was determined based on histopathology and was classified as complete response (CR), residual (RD) or stable disease (SD). Mean ADCs (mADC), ADC increase and volume reduction (VR) rates were compared using histopathology as reference standard
Results: According to histology, 13/24 (54%) had CR, 11/24 (46%) had RD <1 cm. 2 patients presented SD. Before therapy, in the study population mADC was 0.96±0.06×10-³ mm²/s but it was lower in SD (0.76±0.1×10-³ mm²/s). After 2 weeks of nCRT, mADC correlated with tumour response: a) in CR with 23 % percent change (1.20±0.02×10-³ mm²/s vs 0.98±0.06×10-³ mm²/s; P<0.001); b) in RD with 10 % percent change (1.05±0.02×10-³ mm²/s vs 0.93±0.06×10-³ mm²/s; P<0.001). Tumour volume decreased in CR and RD with reduction rate of 48 % and 46 %, respectively. At the end of CRT, no significant differences on ADC between CR and RD (mADC 1.20±0.07×10-³ mm²/s vs 1.17±0.06×10-³ mm²/s; P>1) were observed. All CR had local inflammation at histology.
Conclusion: ADC is early indicator of tumour response in patients with advanced cervical cancer.

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