Skip to main contentLast updated: 28-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
The report names the type of cancer, how it looks, how far it has gone, and which genes are changed. Each part guides a step in treatment.
Most rectal cancers are one common type. The gene test for mismatch repair matters most, because it can change the first treatment.
A good report also gives the margin, the nodes and the quality of the operation. Ask for any item that is missing.
The full plan of care is on the middle rectal cancer surgery page. This post explains the pathology behind that plan, in plain words.
A pathologist studies the tissue under a microscope. The report describes what the cells are, how they behave, and what tests show inside them.
The first report comes from the biopsy. A second, fuller report comes after surgery. The tests we order are listed in our post on the tests you need before treatment.
Nearly all rectal cancers are adenocarcinoma. The other types are rare, and some of them need a different plan.
| Type | How often | What it means for you |
|---|---|---|
| Adenocarcinoma | The usual type | Standard plan. Cells may look well, moderately or poorly formed |
| Mucinous adenocarcinoma | Uncommon | Pools of mucus in the tumour. It may respond less to radiation |
| Signet-ring cell | Rare | Behaves more aggressively. It can spread along the lining of the belly |
| Squamous cell | Very rare | Acts like anal canal cancer, and is usually treated with radiation and chemotherapy |
| Neuroendocrine carcinoma | Very rare | Fast growing. It is treated like a small-cell cancer |
Tiny growths such as lymphoma or a stromal tumour can also arise here. These are different diseases and are not covered in this post.
The same panel is used as for colon cancer. It is ideal to send it all with the first biopsy, so that no time is lost later.
| Test | What it checks | Why it matters |
|---|---|---|
| Mismatch repair (MMR or MSI) | Whether the cells can fix errors in their genes | Shows who may get immunotherapy first. Also screens for an inherited syndrome |
| RAS (KRAS, NRAS) | A change that keeps growth signals switched on | Decides if certain drugs can work, if the cancer has spread |
| BRAF | A change linked to a harder-to-treat cancer | Guides targeted drugs and gives a hint of outlook |
| HER2 | Extra copies of a growth gene | Opens the way to certain targeted drugs |
| NTRK and others | Rare gene fusions | A few patients can use special drugs |
For cancer that stays in the bowel, RAS and BRAF do not yet change the first plan. They matter more if the cancer has spread.
A small group of rectal cancers has lost mismatch repair. These tumours can respond very well to immunotherapy.
If the growth fully clears, some patients can avoid surgery with close checks. This is covered in our post on the trials behind rectal cancer care.
These items show how close the cancer sits to the edge of the specimen, and how likely it is to return.
| Item | What it is | Why it matters |
|---|---|---|
| Circumferential margin | Distance from the tumour to the cut edge around the rectum, in millimetres | The key item. A cancer at the edge is more likely to return in the pelvis |
| Distal margin | Distance to the lower cut end | Needs to be clear. A short margin can be safe in a low tumour that shrank well |
| Vein invasion outside the wall | Cancer seen in veins beyond the rectal wall | Raises the chance of spread to other organs |
| Nerve and vessel invasion | Cancer cells along small nerves or vessels | Shows more aggressive behaviour |
| Tumour budding | Small clusters of cells at the tumour edge | Hints at spread to nodes. It guides the choice of local removal |
| Lymph nodes | The number removed and the number with cancer | Sets the stage and the need for chemotherapy |
The circumferential margin is the most important of these. See our post on what the main guidelines agree on for how it guides care.
The pathologist also grades the removed rectum and its fat. This is a direct check of the surgeon’s work.
A whole, smooth specimen goes with a lower chance of the cancer returning. Ask for this grade in your report.
After radiation or chemotherapy, the report also describes how much of the tumour is left. This is called the regression grade.
Adenocarcinoma. It starts in the gland cells that line the rectum, and nearly all rectal cancers are of this type. The other types are rare and are treated differently.
It tells us if the tumour cells can fix mistakes in their own genes. A tumour that has lost this ability is called mismatch-repair deficient. It may respond to immunotherapy, so the test is needed.
The rectum sits in a narrow pelvis. The wall of tissue around it is thin. If cancer reaches that wall, it can come back in the pelvis, so surgeons and pathologists measure it with care.
Yes, in some cases. The mismatch-repair result can change the first treatment. RAS, BRAF and HER2 results guide drug choice if the cancer has spread.
Ask for a fresh review by the pathologist. These items guide decisions, and a report without them is incomplete. Bring the slides and blocks to a second opinion if you need one.
No. The report is read together with your MRI, your scope findings and your general health. A team then decides the plan.
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.
Got a biopsy or surgery report that is full of unfamiliar words? A pathology report is the map that guides your plan. Send a photo of it on WhatsApp, or book a visit. Dr Harsh Shah will go through each line with you. Call +91-63555-64601 Send your report on WhatsApp
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