Literature review
Two of the organising members (DL, MM) in consensus searched current literature to identify newly available indexed scientific evidence regarding rectal cancer imaging, published following the 2012 meeting, which was used to update the questionnaires used for the 2012 consensus meeting by addition of topics not discussed previously.
Update of the questionnaires
Updated questionnaires were constructed by two organising members (DL, MM), in consultation with two others (SB, RB). The original 2012 questionnaire comprised 236 items. Seventeen new items were added, which mainly concerned the current use of tumour node metastasis (TNM) staging systems [6 , 7 ], the staging of tumours extending into the anal canal, criteria for nodal staging, use of structured reporting, and protocols for acquisition and evaluation of DWI. The questionnaire was divided into part A and part B. Part A included items reaching consensus in the 2012 meeting. Panellists were asked to indicate for each item whether they still agreed with the consensus statement reached previously or whether the item should be re-discussed. Part B combined items that did not reach consensus in 2012 with the additional 17 items derived from the updated literature review. All items were scored binomial (YES/NO; still valid or to be rediscussed) or ordinal (e.g. not recommended, recommended, mandatory), according to the individual item in question. Panellists were instructed to select ‘Mandatory’ for items that they considered were mandatory, ‘Recommended’ for items that they believed to be of additional benefit but that were not mandatory, and ‘Not recommended’ for items that they believed were not required and of no additional value.
Panel selection
The panel consisted of the same 14 panellists (BB, LC-S, HF, MG, SG, SH, CH, SHK, AL, AM, SR, JS, ST, MT) who participated in the 2012 consensus meeting. All were leading abdominal radiologists and members of ESGAR with recognised expertise and a publication track record within the field of rectal cancer imaging. The panel also included two non-voting Chairs (LB, RB) and three non-voting organising members (DL, MM, SB).
Questionnaire completion before the face-to-face meeting
Questionnaires were emailed to panellists on 11 May 2016. Panellists rated items independently with no interaction amongst each other and returned completed questionnaires by email.
Data analysis from questionnaire round
For each rated item from the electronic questionnaire round, two non-voting members (DL,MM) assessed whether or not consensus (defined as ≥ 80 % agreement) was reached.
Face-to-face panel meeting
A face-to-face panel meeting took place during the annual ESGAR meeting, Prague, 15 June 2016. Twelve of the 14 panellists attended. The meeting was moderated by two non-voting Chairs, RB and LB. Two non-contributing (non-voting) observers (DL, MM) documented key points of discussion and outcomes from the voting rounds. The results from the electronic questionnaire round formed the basis for discussion. Discussion included all items from the part A questionnaire selected for re-discussion by at least 20 % of the panellists in addition to all items from questionnaire part B that failed to reach consensus after the email round. Some items were rephrased or merged after face-to-face panel discussion (to reduce ambiguity or overlap) and as a result seven previously included items were discarded. After each item was discussed, panellists were asked to vote (using the same scoring systems as in the electronic round). Thirty items were not discussed face-to-face due to time constraints and were voted on by email subsequently.
Data analysis and reporting
Data from both electronic and face-to-face rounds were collected and descriptive metrics calculated by DL and MM. Each item was ultimately classified as: (1) ‘Appropriate’ with ≥ 80 % agreement, (2)’ Inappropriate’ with ≥ 80 % agreement or (3; Uncertain (no consensus, i.e. < 80 % agreement).
