Colorectal cancer is the third most common malignancy and the fourth leading cause of cancer-related deaths worldwide, accounting for approximately 1,400,000 new cases and about 700,000 deaths worldwide. In recent years, numerous advances have beenmade in the treatment of rectal cancer, both in terms of surgical techniques and adjuvant therapies, leading to an improvement in patient’s outcome. In particular, the advances in neoadjuvant chemoradiotherapy (CRT) have generated the need for accurate preoperative staging to select those patients who can benefit from treatment. In locally advanced...

Patient population: 53 patients (32 males and 21 females; mean age 65 years old, range 41–81 years) witha diagnosis of LARC were enrolled. All patients underwent MRI for local staging beforeand after CRT, followed by TME. Data acquisition All MRI examinations were performed using a 3T system (Discovery 750, General Electric, Milwaukee, Wis, USA) with a phased array surface coil, both at diagnosis and after CRT, a few days before surgery. An appropriate amount or rectal contrast material (US gel) was administered. The MRI protocol...

14 patients wereclassified as TRG3 (26%), 24 as TRG2 (45%), 6 as TRG1 (11%), and no patient as TRG0 (0%). Moreover, 9 patients (17%)underwentcomplete anatomopathological tumor regression (TRG 4). Before CRT, all 27 radiomics features showed a significant relationship with TRG (p<0.05). Tumor volume at baseline did not correlate with the future TRG (r=-0.231, p=0.1). After CRT, the Cluster Prominencevalue resulted to be the best variable for predicting TRG (r=0.291, p=0.037). Volume reduction after CRT was also correlated with TRG (r=-0.277, p=0.047). Cluster Prominence is...

Our findings show thatpost-CRT Cluster Prominenceis the most significant texture analysis feature, with a lower value being significantly correlated with poor tumor regression (TRG 1 or 2) and a higher valuewith pathological complete response (TRG 4), respectively. Imaging biomarkers mightallow early identification of patients who will have a complete or incomplete tumor response to treatment,paving the way toindividualization of medical and/or surgical therapy. Further studies are warrantedto gain a full insight into them.

Michela Gabelloni, MD Third Academic Unit of Diagnostic Radiology Department of Diagnostic Imaging Pisa University Hospital Via Roma, 67 - 56126 Pisa, Italy Telephone: +39 050 992509 Email: [email protected]

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