Rectal cancer is one of the most frequent malignancies, with incidence of 40 in 100,000. The standard treatment for Locally Advanced Rectal Cancer (LARC, ≥T3; any T, N+) is represented by neoadjuvant chemoradiation therapy (CRT), followed by total mesorectal excision (TME) surgery. CRT enables less invasive surgical treatment and has led to a reduction in local recurrence rates -from 25%-30% to less than 10%- with improved overall survival. 15-30% of patients achieve a pathological complete response (CR) after CRT. For these patients, some authors propose...

Patient population: All patients with biopsy-proven rectal cancer treated in our institution between July 2013 and July 2018 were considered for elegibility. Inclusion criteria were: 1) patients with LARC staged with MRI; 2) availability of MRI staging including DWI performed before and after CRT (about 6-8 weeks after chemoradiotherapy); 3) CRT followed by surgery; 4) availability of pathological reports of surgical specimens. Exclusion criteria were 1) mucinous adenocarcinoma; 2) presence of remote metastases or unresectable primary tumor. A total of 66 patients (39 males, 27...

At pathological evaluation, tumor response was as follows: -TRG 1: 18/66 patients (27,3%) (Fig.3) -TRG 2: 11/66 patients (16,7%) (Fig.4) -TRG 3: 15/66 patients (22,7%) (Fig.5) -TRG 4: 19/66 patients (28,8%) (Fig.6) -TRG 5: 3/66 patients (4,5%) (Fig.7) Histopathologic good responders and poor-responders included 29 patients (44%) and 23 patients (56%), respectively. Non-CR patients were 48/66, accounting for 72,7%. Table 3 shows patients distribution. The correlation between MR-TRG and TRG resulted validated and significant with a ρ = 0.766 and a p value <0.001, indicative...

Qualitative assessment of TRG on post-CRT DWMRI was a good predictor of response after CRT in LARC. Quantitative analysis of DWMRI, through ADC map, is still a moderate predictor of CR. Functional MR technique alone seems no accurate enough to safely predict ypCR, selecting patients eligible for a "wait and see" policy. A multidisciplinary approach, based on the combination of morphological and functional imaging modalities, endoscopic findings, clinical and laboratory data, might provide a sufficient diagnostic accuracy to design a patient-tailored treatment.

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