 DWI-MRI seems effective in pre-treatment prediction of treatment outcome. Tumor hypoxia mediates chemoradiation resistance, leading to selection of aggressive tumor cell clones with the capacity to evade tumor microenvironment by increased anaerobic glycolysis and angiogenesis. Apparent diffusion coefficient ADC, which indirectly measures tissue density, can be used to determine the likelihood of tumor response to treatment. High ADC before treatment has shown to predict an unfavorable response. Tumors with low ADC values on presentation generally respond better to treatment. An increased ADC in patients during and after nCRT could be used to predict early pathologic response i.e. discrimination of responders and non-responders to nCRT. 