Medical Oncologist
CION Cancer Clinics
Right, left, sigmoid and total colectomy | CION Cancer Clinics
A colectomy is named after the part of the large bowel that is removed. A right hemicolectomy takes the first section, a left hemicolectomy the descending part, a sigmoid colectomy the S-shaped bend above the rectum, and a total colectomy the whole colon. The surgeon chooses on the basis of where the tumour sits and which artery feeds it. This page explains each operation and what the name does not tell you. CION Cancer Clinics’ surgical oncologists in Hyderabad can talk this through with you.
MI
Medically reviewed by Dr. Mohammed ImaduddinConsultant Surgical Oncologist · MBBS, MS (General Surgery), MCh (Surgical Oncology) · last reviewed September 2026, next review due September 2027
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On this page
- Why does a colectomy have so many different names?
- Which part is removed in each type of colectomy?
- Where the tumour sits, and which operation usually follows
- How does the surgeon decide which type you need?
- Words on the operation note, in plain language
- Four things families ask about the type of operation
- What the name of the operation cannot tell you
- Common questions about the types of colectomy
The short answer
Why does a colectomy have so many different names?
A colectomy is named after the part of the large bowel (the colon) that is removed. Right, left and sigmoid colectomy each take out one section; a total colectomy takes out the whole colon. The name tells you where the cancer sits, not how serious it is.
The colon has four parts
The colon starts on the lower right of the abdomen, climbs the right side (the ascending colon), crosses under the ribs (the transverse colon), comes down the left side (the descending colon) and bends into an S-shape (the sigmoid colon) before the rectum. Each part has its own artery, and that decides how much is removed.
Why the surgeon follows the artery, not the tumour
Cancer cells leave the bowel through the lymph glands that run alongside the artery feeding that section. To take those glands out, the surgeon ties the artery near its root and removes everything that artery supplied. So a small tumour in the right colon still means a right hemicolectomy. Hemicolectomy means removing roughly half the colon.
Your operation note will use one of these names. If it uses a different one, ask your surgeon to show you on a drawing which part was removed.The named operations
Which part is removed in each type of colectomy?
Six names cover almost every planned colon operation. Your surgeon chooses one on the basis of where the tumour sits.
Right hemicolectomy
Removes the last part of the small bowel, the caecum, the ascending colon and the first part of the transverse colon. Used for cancers on the right side. The small bowel is joined to the transverse colon.
Extended right hemicolectomy
The same as a right hemicolectomy but continuing across most of the transverse colon. Used when the tumour sits near the bend under the liver or in the transverse colon itself.
Left hemicolectomy
Removes the descending colon, often with the last part of the transverse colon and the top of the sigmoid. Used for cancers on the left side. The transverse colon is joined to the sigmoid or rectum.
Sigmoid colectomy
Removes only the S-shaped sigmoid colon, just above the rectum. One of the most common colon operations, because many cancers start here. The descending colon is joined to the rectum.
Total colectomy
Removes the whole colon and joins the small bowel directly to the rectum. Used for more than one cancer at once, for some inherited conditions, and occasionally in an emergency.
Sometimes called
- Subtotal colectomy, if a short stump of colon is kept
- Proctocolectomy, if the rectum goes too
Segmental colectomy
A shorter piece taken out, usually from the transverse or descending colon, for some small or early tumours.
Not every surgeon uses this term. Ask what it means in your case.Not sure whether this applies to you?
Ask an oncologistSide by side
Where the tumour sits, and which operation usually follows
Where the colonoscopy found it
Usual operation
Caecum or ascending colon
Right hemicolectomy
Hepatic flexure or transverse colon
Extended right hemicolectomy
Splenic flexure or descending colon
Left hemicolectomy
Sigmoid colon
Sigmoid colectomy, sometimes called an anterior resection
More than one tumour, or an inherited syndrome
Total or subtotal colectomy
Before the date is fixed
How does the surgeon decide which type you need?
The colonoscopy report
It names the part of the colon where the tumour was seen and how far from the anus it sits. Sometimes a small ink tattoo is placed on the bowel wall so the surgeon can find the spot from outside.
The CT scan
A scan of the chest, abdomen and pelvis shows the size of the tumour, whether it touches anything nearby, whether the lymph glands look enlarged, and whether the liver and lungs are clear.
The blood supply
The surgeon works out which artery feeds the tumour. That artery and the glands along it define the operation, which is why two people with tumours a few centimetres apart can have different named operations.
The tumour board
Surgical, medical and radiation oncologists review the reports together and agree the plan. If chemotherapy should come before surgery, this is where that is decided.
The consent conversation
You are told the name of the operation, what will be removed, what the join will be, and whether a stoma is possible. This is the moment to ask everything.
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On your report
Words on the operation note, in plain language
- Caecum
- The pouch at the very start of the colon, where the small bowel joins it and where the appendix hangs. Removed in every right hemicolectomy.
- Flexure
- A bend in the colon. The hepatic flexure sits under the liver on the right; the splenic flexure sits under the spleen on the left.
- Anterior resection
- Removal of the sigmoid colon and the upper rectum through the abdomen. The name overlaps with sigmoid colectomy and surgeons use both.
- Ileocolic
- Describes a join between the small bowel (ileum) and the colon. This is the join made after a right hemicolectomy.
- Mesocolon
- The sheet of fatty tissue that carries the arteries and lymph glands to the colon. It is removed with the bowel, in one piece.
Commonly believed
Four things families ask about the type of operation
"A total colectomy means the cancer is very advanced."
Not usually. The whole colon is removed when there is more than one tumour, when an inherited condition makes new cancers likely, or when the bowel is badly blocked. Stage is decided by the pathology report, not by how much bowel was taken.
"A smaller operation is always safer."
Removing less bowel than the artery supplies leaves lymph glands behind, and those glands are where the cancer spreads first. The named operations exist because that is the amount that clears the glands. Less is not safer if it leaves disease behind.
"Right side or left side makes no difference."
It does. Right-sided operations join small bowel to colon and the join usually heals easily. Left and sigmoid operations join colon to rectum, which is lower and has a poorer blood supply, so a temporary stoma is more often discussed.
"After a total colectomy you cannot live normally."
People live full lives without a colon. Motions are looser and more frequent, especially in the first months, because the colon's job was to absorb water. Diet and medicines settle this for most people, and a stoma nurse helps if a bag is needed.
Being straight with you
What the name of the operation cannot tell you
The name tells you which part of the colon is coming out. It does not tell you the stage, whether the lymph glands are involved, whether you will need a stoma, or whether chemotherapy will follow. Those come from the pathology report after surgery.
When the plan changes on the day
Occasionally the surgeon finds something the scan did not show and removes more bowel than planned, or makes a stoma that was not expected. This is done to keep you safe, and it is explained to you and your family as soon as you are awake. Ask beforehand what might change the plan.
Who these operations may not suit
If the cancer has spread widely, if the bowel is completely blocked, or if the heart and lungs cannot take a long anaesthetic, the team may recommend a different first step, such as chemotherapy, a stent to relieve the blockage, or a smaller operation. Only your treating team can weigh that for you, and this page cannot.
If your report names an operation you do not recognise, call the helpline. A surgical oncologist will explain what it means for you.Questions we are asked
Common questions about the types of colectomy
Which type of colectomy is the most common for cancer?
Sigmoid colectomy and right hemicolectomy are the two most frequent, because the sigmoid and the caecum are where colon cancers most often start. Left and transverse operations are less common. Which one you need depends only on where the tumour sits.
Is a right hemicolectomy a smaller operation than a left?
They remove a similar amount of bowel. The difference is in the join. A right-sided join is between small bowel and colon and tends to heal well. A left-sided join is lower, nearer the rectum, so a temporary stoma is more often considered.
Will I need a stoma with a sigmoid colectomy?
Usually not, when the operation is planned and the bowel has been cleared. A temporary stoma is more likely if the join is very low, if the bowel was blocked or infected, or if you were unwell on the day. Your surgeon will tell you beforehand if it is a real possibility.
Can I live without a colon?
Yes. The colon absorbs water and stores stool; it does not absorb nutrients. Without it, motions are looser and more frequent, particularly in the first months. Most people adjust with diet changes and, where needed, medicines that slow the bowel.
Why is the appendix removed in a right hemicolectomy?
The appendix hangs off the caecum, and the caecum is always part of a right hemicolectomy. It comes out with the rest of the segment. You do not need it, and removing it adds nothing to the recovery.
What is a subtotal colectomy?
Removal of most of the colon, keeping a short stump of the sigmoid or the rectum to join the small bowel to. It is chosen over a total colectomy when keeping that stump is safe and makes bowel function afterwards a little easier to manage.
Is a colectomy the same as surgery for rectal cancer?
No. Rectal cancer sits below the sigmoid, in the pelvis, and is treated with different operations, often after radiotherapy. If your report says rectum or rectal, ask your surgeon which operation is being planned.
Does the type of colectomy change what Aarogyasri covers?
All these operations are covered under Aarogyasri, CGHS, ECHS and EHS, and by most cashless insurers with prior approval. The package name may differ. Call the helpline with your card details and we will check your cover before you travel.
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Sources
- Cancer Research UK — Surgery for bowel cancer
- American Cancer Society — Surgery for Colon Cancer
- National Cancer Institute — Colon Cancer Treatment (PDQ), patient version
- Macmillan Cancer Support — Bowel cancer
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Colectomy: What the Operation InvolvesWhat happens before, during and after, whichever type you haveHow Much Bowel Is Removed and WhyWhy the surgeon follows the artery rather than the tumourWhat an Anastomosis IsThe join that each type of colectomy ends withColectomy for Lynch Syndrome and PolyposisWhen a total colectomy is chosen for an inherited conditionThe Pathology Report After SurgeryThe report that gives the stage, whatever the operation was called
Talk to us
Not sure which operation has been planned?
Send us the colonoscopy and CT reports, or call the helpline. A surgical oncologist will explain which part is being removed and why. One helpline serves every CION centre.