Using diffusion-weighted MRI derived apparent diffusion coefficient as a predictive biomarker of tumor response in non-Hodgkin lymphoma

Background

Diffusion-weighted MRI (DW-MRI) is a radiation free, non-invasive diagnostic imaging technique detecting random movement of water molecules in vivo. Extent of diffusion in fluids and tissues can be assessed quantitatively using apparent diffusion coefficient (ADC). The aim of this study was to determine usefulness of DW-MRI with ADC calculation for early prediction of tumor response in patients with non-Hodgkin lymphoma (NHL).

Methods

DW-MRI was performed in 26 patients (13 males and 13 females, mean age 55 years, range 26-76) with NHL at baseline, after 1 cycle and at the end of induction chemotherapy. The largest not necrotic lymph node was chosen as a target lesion for serial size and ADC measurement. End of treatment tumor response was categorized as complete (CR) or non-complete using revised International Working Group criteria.

Results

Target lesion ADC (mean ± SD) increased from 0.81 ± 0.33 × 10⁻³ mm²/c at baseline to 1.16 ± 0.44 × 10⁻³ mm²/c after 1 cycle of chemotherapy resulting in average increase of 50.3 ± 48.4%. The earliest ADC increase was noted on day 3 after start of chemotherapy. Product of two perpendicular diameters of target lesion decreased from 3407.7 ± 3583.7 mm² to 2359.2 ± 2813.2 mm² from baseline to after 1 cycle respectively giving average decrease of 36.4 ± 22.0%. Pre-treatment ADC was significantly lower in patients with CR than non-CR – 0.65 ± 0,15 × 10⁻³ mm²/s and 0.94 ± 0,39 × 10⁻³ mm²/s respectively (p  25% predicted CR with a sensitivity of 83%, specificity of 67% and an accuracy of 75%. When two parameters were combined prediction accuracy increased to 83%.

Conclusions

DW-MRI with ADC calculation can be used for pretreatment and early during treatment tumor response prediction in patients with NHL. Combination of pretreatment ADC and ADC change post 1 cycle of chemotherapy increases prediction accuracy.

Clinical trial identification

Legal entity responsible for the study

N.N. Alexandrov National Cancer Center of Belarus

Funding

Ministry of Health

Disclosure

All authors have declared no conflicts of interest.