Skip to main contentLast updated: 27-Oct-2026
Dr Harsh Shah
MS, MCh (Surgical Gastroenterology), DrNB (Surgical Gastroenterology)
Registered with Gujarat Medical Council, Reg. No. G-38738
Gastro & Cancer Surgeon
Apollo Hospital, Bhat, Gandhinagar · Gota OPD, Ahmedabad · 18 years of experience
★★★★★ Google: 4.89 from 216 reviews (Gota clinic) · 4.94 from 18 reviews (Apollo, Bhat)
In short
Rectal cancer is confirmed by a biopsy taken at a scope. Its extent is then mapped with an MRI of the pelvis and a CT scan of the chest and belly.
The rectal MRI matters most. It shows how deep the growth goes, how close it lies to the wall of the pelvis, and whether the muscle of the back passage is involved.
A finger examination, a blood test called CEA and a check on the tumour’s repair genes complete the set. One team then reads all of it together.
Once the tests are done, the plan of care is on the middle rectal cancer surgery page. This post explains the tests that come before it.
A full set has seven parts. Each answers a different question, and none can stand in for another.
| Test | What it tells us | Why it matters |
|---|---|---|
| Finger examination | How far the growth is from the anal opening, and whether it moves | Decides if the muscle of the back passage can be kept |
| Scope with biopsy | That it is cancer, and what type | Nothing is planned without a biopsy |
| Full colonoscopy | Whether the rest of the large bowel has another growth or polyp | A second growth would change the operation |
| MRI of the pelvis | Depth of the growth, nearby glands, the margin around it | Chooses between radiation first or surgery first |
| CT of chest, belly and pelvis | Whether it has spread to the liver or lungs | Separates a plan to remove it for good from a long-term one |
| CEA blood test | A marker that some rectal cancers release | A baseline to compare with later |
| Repair-gene test (MMR or MSI) | Whether the tumour has a repair fault | Can open a different line of treatment |
The order can change a little with each patient. The list stays the same.
A gentle finger examination gives the one number the surgeon needs first: the distance of the growth from the anal opening.
It takes a minute. A report that says only “growth seen” without a distance is not enough for planning, and the measure is often repeated with a short rigid scope.
The MRI shows the layers of the rectal wall and the fat around it. It is the test that guides whether radiation or chemotherapy should come before the operation.
Not every MRI report says all five of these. If yours does not, ask for it to be read again by a radiologist who reports rectal scans often. Outside scans are sometimes taken in the wrong planes. In that case we may repeat it, because every later decision depends on it.
The CT scan looks for spread. It covers the chest, belly and pelvis, usually with dye injected into a vein.
If the scope could not reach the top of the bowel, a CT scan of the colon can clear the rest before treatment starts.
Routine bloods check fitness and anaemia. CEA gives a baseline, and a gene test on the biopsy can change the treatment.
Genetic counselling is advised when rectal cancer appears under fifty, when several family members have had bowel or womb cancer, or when the tumour test points to an inherited fault.
Before any treatment we note how your bowel, bladder and sexual function work, and how fit you are. These notes shape the plan.
Planning a stoma site before surgery does not mean one will be made. It means that if one is needed, it sits where you can manage it.
A rectal cancer should be discussed by a team before treatment starts. The surgeon, radiation specialist, cancer physician, pathologist and a rectal radiologist read the same file.
Then the plan is explained to you in plain words. For how stage guides the first step, see lower rectal cancer: sphincter preservation or stoma.
Yes. Treatment is not planned on a scan or a scope picture alone. A biopsy confirms the cancer and its type.
A CT scan looks for spread. An MRI of the pelvis shows the wall of the rectum and the margin around it, which a CT cannot show well.
Not usually. It is added when other scans are unclear or when spread is suspected. It is not a routine part of rectal cancer tests.
A normal CEA does not rule out cancer, because some rectal cancers do not release it. It is mainly a baseline to compare with later.
It depends on how soon the MRI can be booked. Many patients complete the set in about two weeks. Tell us if the bleeding is heavy or the bowel is blocked.
Often yes, if the rectal MRI is complete. If a key detail is missing, we may ask for it to be read again or repeated.
The full range of rectal cancer care starts at the middle rectal cancer page. For questions before you travel, call +91-63555-64601.
Shah’s Gastro, Cancer & Robotic Surgery Centre, Gota, Ahmedabad
Consultation, review of endoscopy, biopsy and scan reports, second opinions and follow-up.
Apollo Hospital, Bhat, Gandhinagar
Apollo Hospital International Limited, GIDC Bhat Industrial Estate, Bhat, Gandhinagar. Endoscopy and biopsy, CT scans, surgery for stomach and duodenal disorders, and inpatient care.
A biopsy has shown a growth in the rectum, or a scope has found something you cannot name. The tests that come next set the whole plan, so each one has to be done well. Send us your reports, or book a visit. Dr Harsh Shah goes through them with you. Call +91-63555-64601 Ask for a report review on WhatsApp
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