Rectal cancer · Guide
Rectal cancer explorer: guide
What the picture shows, how to use it in an appointment, and what the model assumes.
For patients and families
What the picture shows
A 3D model of the rectum, the last part of the large bowel, and the parts around it: the anal canal and the muscles that keep you continent, the fatty tissue around the bowel, and nearby organs such as the bladder.
It starts with everything as it usually is. Your doctor or nurse then adds what your scan report shows: where the tumour is, how big it is, how deep it has grown, and whether any lymph nodes are affected. If your team has talked about an operation, they can show what it would remove, and whether you would need a stoma.
Things you could ask
“Can you show me where it is?”
“How close is it to the muscles that control my bowel?”
“Can you show me what the operation would take away?”
“Where would the stoma be?”
You can ask them to turn the model, zoom in, cut it open, or show a slice the way it looks on your scan. Bring someone with you if you can.
Words you may hear
Our rectal cancer help and support page explains the words used in clinic, with questions to ask and trusted UK charities.
Afterwards
Ask for a picture sheet: the views you looked at, a summary in plain words, and a page explaining every label. It can carry a QR code that opens the same 3D picture on your phone at home. The code holds only the picture’s settings, never your name, and nothing is stored online.
What it can’t do
The model is simplified. It helps you picture what your team is telling you, but it doesn’t replace your scan or their advice, and it can’t tell you which treatment is right. Your team decides that with you.
For clinicians
Before you start
The explorer opens at normal anatomy: no tumour, operation or stoma. It is often worth starting there, so the patient can get their bearings, and then adding the findings. Press Patient view to hide the set-up panel once you’re ready to talk it through.
Setting it up from the MRI report
| Control | What to set |
|---|---|
| Tumour on the model | Add the tumour. Changing any tumour setting also adds it. |
| Lower edge above the anal opening | Distance from the anal verge, from MRI or endoscopy. Type it to the nearest millimetre (for example 6.7 cm). |
| Length of tumour | Craniocaudal length, to the nearest millimetre. |
| Position and how far round | Clock face with the patient supine: 12 anterior, 6 posterior, 3 the patient’s left. Then how much of the circumference it involves. |
| T stage | T1 to T4b, including T3 sub-stages by depth of extramural spread. T1 and T2 tumours stay within the wall, so the model opens the bowel and turns to the side view to show them. |
| Lymph nodes (N stage) | N0, N1 or N2. Nodes are shown in the mesorectum near the tumour. |
| Response to chemoradiotherapy | Before, partial, good or complete. The tumour shrinks to match; a complete response shows a scar. |
| Pelvis | Male or female, so the nearby organs match. |
Showing a plan
Under Treatment options, tap the operation your team has discussed: local excision, high or low anterior resection, intersphincteric resection, abdominoperineal excision, or watch and wait. The parts it would remove turn teal, the line of division and healthy margin are shown, and the stoma usually needed appears on the body. The tool never suggests which option is right.
Views and layers
Camera buttons show the whole body, abdomen, stoma, side, front, back, from below and angled views. Show / hide turns labels, measurements, the body outline, fatty envelope, muscles, bone, nearby organs and lymph nodes on or off; Clean view removes labels. The slice panel shows an axial cross-section in MRI orientation.
What the model assumes
- Typical adult anatomy. Shapes and sizes are approximate and will differ from the patient.
- Distances are measured along the centre of the bowel from the anal verge.
- “mm to surgical plane” is estimated from the model so the picture is consistent. It is not a measurement of the patient: always quote the report.
- Margins drawn: at least 1 mm to the mesorectal fascia (CRM); at least 1 cm distal margin with total mesorectal excision; about 5 cm of mesorectum below an upper rectal tumour.
Picture sheet and QR code
Set up each view and press Snapshot (up to four). Add optional initials, a key worker and a note, then Preview the A4 sheet to download, open, print or save it. A second page explains each label in plain English. The QR code reopens the same picture on the patient’s phone; it holds the model settings only, never the name or notes. No printer? The preview shows a large QR code the patient can scan there and then.
Between patients
Press Start again or close the tab. Nothing typed or set is kept, not even in the browser.
Spotted something that could be clearer or more accurate? Tell us. Clinician feedback shapes every update.