Introduction
toxicity, toxicities, urinary incontinence, sexual dysfunction, tumour
BOWEL DYSFUNCTION, DISEASE LOCAL, DISEASE, URINARY INCONTINENCE, TUMOUR, REGRESSION, RECTAL CANCER
The achievement of pathological complete response (pCR) after neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal cancer (LARC) is associated with better disease local control (LC) and improvement in overall survival (OS) [It must be considered that the response to nCRT is highly variable in LARC, with pCR rates ranging from 11–42% [Different techniques and technologies can be applied to increase the dose on macroscopic disease, such as external beam RT, brachytherapy and contact therapy (CRX) in selected cases, but how to effectively delivery the dose boost still represents an open issue [Although these techniques are generally characterised by favorable acute toxicity rates, it should also be considered that highly variable treatment-related toxicity rates impacting on quality of life (QoL) have been described, such as bowel dysfunction, urinary incontinence and sexual dysfunction [In addition to specific dosimetric issues, there is also great interest about which imaging technique represents the best solution to support the dose boost planning and determine treatment response. MRI has recently emerged as the main imaging modality for staging and treatment response assessment in rectal cancer [In this context, MRI-guided radiotherapy (MRIgRT) appears to be the next logical step due to the advantages of being able to exploit daily MR imaging for innovative treatment planning and response monitoring throughout the treatment [Identifying possible factors that can predict response to nCRT, in order to be able to select patients for intensive therapy protocols, represents therefore an urgent and fascinating clinical challenge.One of the most promising of such MR imaging-based biomarkers is the tumour early regression index (ERI) [The main objective of this interim analysis is to report on feasibility and safety results in terms of acute toxicities.