In locally advanced rectal cancer (LARC), neoadjuvant chemoradiotherapy (CRT) has significantly improved oncological outcomes, with more than 30% of patients achieving a pathological complete response (pCR). Patients with an appropriately assessed complete clinical response (cCR) can often avoid radical surgery, thereby preserving quality of life without compromising survival. This shift has created an urgent need for precise characterisation of tumour regression to facilitate personalised treatment strategies.

Although most studies have investigated the predictive role of MRI in LARC patients following CRT, they have struggled to reliably correlate response to therapy with MRI findings, highlighting the complexity of accurate assessment [1]. Radiologists play a pivotal role in this process, as accurate interpretation of imaging can provide critical insight. This review outlines five key challenges of this technique and proposes potential solutions.