Management of rectal cancer in the era of total neoadjuvant therapy and watch and wait: A multidisciplinary team discussion at the Australasian Gastro-Intestinal Trials Group (AGITG) Annual Scientific Meeting 2022.

Rectal cancer is a common malignancy. The management of rectal cancer has recently evolved and has undergone a paradigm shift with the advent of treatment approaches such as total neoadjuvant therapy and the watch-and-wait approach. However, despite the recently available evidence, there is no consensus on the optimal management approach in the setting of locally advanced rectal cancer. To address some of the controversies, a joint multidisciplinary panel discussion was conducted at the Australasian Gastro-Intestinal Trials Group (AGITG) Annual Scientific Meeting in November 2022. Members from different subspecialties formed two panels and discussed three clinical cases in a debate format. Each case represented some of the complex issues faced by clinicians in this setting. The discussion is now presented in this manuscript, which depicts the different available management approaches and reiterates the importance of a multidisciplinary approach.

Assessment of a single-pass venous phase CT chest, abdomen and pelvis and dual-energy CT in general oncology outpatients.

INTRODUCTION: This study assessed replacing traditional protocol CT-arterial chest and venous abdomen and pelvis, with a single-pass, single-bolus, venous phase CT chest, abdomen and pelvis (CAP) protocol in general oncology outpatients at a single centre. METHODS: A traditional protocol is an arterial phase chest followed by venous phase abdomen and pelvis. A venous CAP (vCAP) protocol is a single acquisition 60 s after contrast injection, with optional arterial phase upper abdomen based on the primary tumour. Consecutive eligible patients were assessed, using each patient's prior study as a comparator. Attenuation for various structures, lesion conspicuity and dose were compared. Subset analysis of dual-energy (DE) CT scans in the vCAP protocol performed for lesion conspicuity on 50 keV virtual monoenergetic (VME) images. RESULTS: One hundred and eleven patients were assessed with both protocols. Forty-six patients had their vCAP scans using DECT. The vCAP protocol had no significant difference in the attenuation of abdominal structures, with reduced attenuation of mediastinal structures. There was a significant improvement in the visibility of pleural lesions (p < 0.001), a trend for improved mediastinal nodes assessment, and no significant difference for abdominal lesions. A significant increase in liver lesion conspicuity on 50 keV VME reconstructions was noted for both readers (p < 0.001). There were significant dose reductions with the vCAP protocol. CONCLUSION: A single-pass vCAP protocol offered an improved thoracic assessment with no loss of abdominal diagnostic confidence and significant dose reductions compared to traditional protocol. Improved liver lesion conspicuity on 50 keV VME images across a range of cancers is promising.

MRI rectal cancer in Australia and New Zealand: An audit from the PETACC-6 trial.

INTRODUCTION: An MRI audit substudy was conducted in patients who underwent an MRI prior to treatment in Australia and New Zealand as part of the PETACC-6 trial in locally advanced rectal cancer. METHODS: A total of 82 patients from 15 centres had rectal MRI scans reviewed for technique, data included in reports and comparison of reports with blinded central reporting by two experienced radiologists. RESULTS: In total, 82% performed minimum T2 sagittal and T2 axial oblique sequences. The high-resolution T2 sequence parameters varied significantly with only 33% obtaining a voxel size of <1.3 mm3 . The rate of inclusion of relevant findings in the reports was T3 distance in mm 21%, N stage 84%, circumferential resection margin (CRM) status 72%, extramural venous invasion (EMVI) status 29% and distance from the puborectalis sling 17%. In total, 31% reports included all of T stage with T3 substage, N stage and CRM involvement. In total, 17% reports included these 3 findings and EMVI. Eleven reports used a template with 82% of these including the first 3 findings. The agreement with central reporters was T stage 76%, N stage 70%, CRM status 57% and EMVI 16%. CONCLUSION: There is significant variation in scan quality and low rates of including all relevant findings in rectal MRI reports in the audit. The authors recommend adoption of routine sequences and template reports in both trial settings and routine practice to improve scan technique and adequacy of reports in rectal cancer MRI staging scans across Australia and New Zealand.