Abstract:

Aim: To observe the change in apparent diffusion coefficient (ADC) value after chemoradiotherapy in lung cancer and to investigate the ability of the change in ADC values to detect response to treatment earlier than computed tomography (CT). Material and Methods: This prospective study was performed in patients with a confirmed diagnosis of stage III-IV lung cancer and included 25 patients who underwent T2-weighted MR, diffusionweighted images (DWI), CT, and FDG PET/CT. Thoracic diffusion MRI and CT examinations were performed on patients who received chemoradiotherapy. Post-therapy; Thoracic diffusion MRI was repeated one week after the two cycles of chemotherapy and two weeks after the end of the radiotherapy, while post-therapy CT was performed four or five weeks after therapy. Before and after treatment, ADCmin, ADCmean, and SUVmax values were compared with each other. Results: Data analysis revealed a statistically insignificant inverse correlation between the pre-therapy ADCmin and SUVmax (r=- 0.36; p=0.077) with ADCmean and SUVmax (r=-0.283; p=0.170). Post-therapy repeated measures revealed that increased ADCmin values were significantly higher with the tumor size change (r=- 0.872; p=0.000) and median size (r=-0.847; p=0.001) tumor on CT. Conclusion: ADC measurements with DWI may be a new prognostic marker in lung cancers predicting early response to chemotherapy in lung cancer.

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