Medical Oncologist
CION Cancer Clinics
Extended and subtotal colectomy: when more of the colon is removed | CION Cancer Clinics
Most colon cancers are removed with a standard operation that takes one section of the colon. A larger operation is needed in a smaller group: tumours in the middle of the colon, two cancers in different places, an inherited syndrome such as Lynch syndrome or FAP, or an emergency where the bowel upstream is damaged. This page explains each situation and what the trade-off means for daily life. At CION Cancer Clinics, a multidisciplinary team plans colon cancer treatment for your stage, from surgery to chemotherapy and follow-up.
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Medically reviewed by Dr. Muralidhar MuddusettyConsultant Surgical Oncologist · MBBS (AIIMS), MS (Surgery, AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh) · last reviewed October 2026, next review due October 2027
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On this page
- When does colon cancer surgery need to remove more than one section?
- Which situations call for an extended or subtotal colectomy?
- What do the names of these operations mean?
- How does the team decide how much colon to take?
- How does daily life change after a subtotal colectomy?
- What this page cannot tell you
- Common questions about extended and subtotal colectomy
The short answer
When does colon cancer surgery need to remove more than one section?
Only in particular situations. A standard operation removes the part of the colon holding the tumour, together with its blood vessels and lymph nodes. An extended colectomy goes further along the colon, and a subtotal colectomy removes most of it. Surgeons choose these when a smaller operation would leave cancer behind, or would leave a colon likely to cause trouble again.
Why the cut follows the blood supply
Colon cancer usually spreads first to lymph nodes, the small glands that sit along the blood vessels feeding each part of the colon. A safe cancer operation takes the tumour together with those vessels and nodes. A tumour sitting where two blood supplies meet, such as the bends near the liver or the spleen, can drain in two directions. Taking both routes means taking more colon.
Why some people need more than the tumour's section
Sometimes the reason is the rest of the colon. Two cancers far apart, a colon full of polyps, or an inherited fault that keeps producing new growths can all make one larger operation safer than returning for a second one later. The choice of operation for each part of the colon is set out on our page on which operation suits which location.
A bigger operation says more about where the tumour sits, or about the rest of the colon, than about the stage of the cancer.The usual reasons
Which situations call for an extended or subtotal colectomy?
Four situations account for most of these operations. Your surgeon will tell you which one applies to you.
A tumour in the middle of the colon
Cancers at the bend near the liver, called the hepatic flexure, or in the transverse colon across the upper abdomen, usually need an extended right hemicolectomy. This takes the right colon and much of the transverse colon, so every node draining the tumour comes out with it.
For tumours at the bend near the spleen, surgeons differ on how much to take, and the studies comparing the options are limited.Two cancers in different places
A colonoscopy before surgery sometimes finds a second, separate cancer, called a synchronous cancer. When the two sit far apart, one subtotal colectomy with a single join can be safer than two separate operations, each with its own join that could leak.
An inherited syndrome or long-standing colitis
Some people carry a high chance of new cancers forming in whatever colon is left. Removing most or all of it is then discussed as a way of treating this cancer and lowering the chance of the next one.
Usually discussed for
- Lynch syndrome, especially in younger people
- Familial adenomatous polyposis (FAP) and MUTYH polyposis
- Many polyps that a colonoscopy cannot clear
- Ulcerative colitis with cancer or advanced abnormal cells
An emergency with a blocked colon
A cancer blocking the left colon can make the bowel upstream swell badly. If the right side has been stretched thin, damaged or torn, the surgeon may remove most of the colon at once, because joining healthy bowel is safer than leaving damaged bowel behind.
Not sure whether this applies to you?
Ask an oncologistOn your consent form
What do the names of these operations mean?
- Extended right hemicolectomy
- The right colon plus much or all of the transverse colon. The small bowel is joined to the colon that remains on the left side.
- Extended left hemicolectomy
- The left colon plus part of the transverse colon, used for some tumours near the spleen. It is less common than the right-sided version.
- Subtotal colectomy
- Most of the colon is removed, leaving the rectum and sometimes a short piece of the sigmoid colon. The small bowel is joined to what remains.
- Total colectomy with ileorectal anastomosis
- The whole colon is removed and the small bowel is joined straight to the rectum. An anastomosis is simply the join between two ends of bowel.
- Total proctocolectomy
- The colon and rectum are both removed. A pouch is made from small bowel and joined near the anus, or a permanent ileostomy, an opening of small bowel on the abdomen, is formed.
Before the decision
How does the team decide how much colon to take?
The whole colon is examined
A full colonoscopy looks for second cancers and polyps. If the tumour blocks the scope, a CT scan of the colon is used instead. CION arranges these through its diagnostic partners.
The biopsy is tested for an inherited cause
The tumour tissue is checked for MMR or MSI changes, markers that point towards Lynch syndrome. A family history of bowel or womb cancer at young ages is taken at the same visit.
The trade-off is weighed for you
Age, fitness, how well the back passage holds stool, and how much a looser bowel would affect work and travel all count. A strong anal muscle matters more when the rectum must take over the colon's storage job.
The tumour board agrees a plan
CION's surgical oncologists bring the scans and reports to the multidisciplinary tumour board. The agreed operation is carried out at an accredited partner hospital, and the reasons are explained to you before you sign.
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Afterwards
How does daily life change after a subtotal colectomy?
The colon's main job is to take water out of stool and store it until a convenient moment. Without most of it, stool reaches the rectum looser and more often. Most people open their bowels several times a day at first. This usually settles over the following months as the small bowel adapts, though it rarely returns fully to how it was before.
What helps
Regular meals, enough fluid, and thickening foods such as curd rice, bananas and idli help many people. Medicines that slow the bowel are used when needed, on your team's advice. The practical detail is on our page about bowel habits after colectomy.
The rectum still needs checking
When the rectum is kept, it can still grow polyps or cancer, especially in people with an inherited syndrome. Regular checks of the rectum with a short scope become part of follow-up for life. A temporary stoma is sometimes needed after an emergency operation, while most planned extended right hemicolectomies are joined straight away without one.
Being straight with you
What this page cannot tell you
It cannot tell you which operation you need. That depends on the exact position of the tumour on your scans, what the colonoscopy found elsewhere, your biopsy markers and your family history. Only a surgeon who has seen all of them can make that call.
Who this does not apply to
Most people with a single cancer in the right colon or the sigmoid colon need a standard operation, and a larger one would add nothing for them. If your tumour is in the rectum, the last part of the bowel, the operation is planned differently. Our rectal cancer pages cover that.
Where the evidence is thin
For tumours near the spleen, and for whether everyone with Lynch syndrome should have a larger operation, specialists still disagree. A surgeon who explains both options honestly, and why they lean one way, is doing their job well.
If you have been offered a subtotal colectomy and want it reviewed, the CION helpline can arrange a second opinion from the tumour board.Questions we are asked
Common questions about extended and subtotal colectomy
Is an extended right hemicolectomy riskier than a standard one?
It is a longer operation over a wider area, but recovery is usually similar to a standard right hemicolectomy. The join is still between small bowel and colon. Your own risks depend more on your fitness and other illnesses than on the extra length removed, and your surgeon will go through them.
Will I need a stoma after a subtotal colectomy?
Usually not, when the operation is planned. The small bowel is joined to the rectum or the sigmoid colon. A temporary ileostomy is more likely after an emergency, or when the join is under strain, and it is usually reversed in a later, smaller operation.
How often will I need the toilet afterwards?
It varies. Most people go several times a day in the early months, with looser stool than before, and it usually settles as the small bowel adapts. Keeping part of the sigmoid colon tends to mean fewer visits, which is one reason surgeons keep it when it is safe.
I have Lynch syndrome. Must my whole colon be removed?
It is an option to discuss, not a rule. A larger operation lowers the chance of a second colon cancer but brings looser bowels, and the rectum still needs checks. Many people choose a standard operation with close colonoscopy follow-up instead. Age and your own preference weigh heavily.
Does removing more colon mean my cancer is more advanced?
No. The size of the operation reflects where the tumour sits and what the rest of the colon looks like. Stage depends on how deep the tumour has grown and whether lymph nodes are involved, which the pathology report confirms after surgery.
Can these operations be done by keyhole surgery?
Often, yes. Extended and subtotal colectomies can be done laparoscopically in suitable people at the accredited partner hospitals CION works with. Open surgery is more common in an emergency or when the bowel is very swollen. Your surgeon will explain which approach suits you.
Will I need chemotherapy afterwards?
That depends on the stage found in the removed colon, not on how much was taken. If lymph nodes contain cancer, or other high-risk features are found, adjuvant chemotherapy, meaning treatment after surgery to lower the chance of return, is usually discussed. CION gives it at its own centres.
What should I ask my surgeon before agreeing?
Ask why a larger operation is advised, what a standard one would mean for you, whether you might wake up with a stoma, and how your bowel habits are likely to change. Ask what checks the remaining bowel will need. Call the CION helpline if you want a second opinion.
Your Specialists
Meet CION's colon cancer specialists. Bring your colonoscopy, scan or biopsy report.
Our surgical and medical oncologists plan colon cancer care together: which operation, whether chemotherapy is needed, and the follow-up that comes after.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
Surgical Oncologist
Dr. Muralidhar Muddusetty
MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)
Surgical Oncologist
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Sources
- American Cancer Society — Colon Cancer Surgery
- National Cancer Institute — Colon Cancer Treatment
- NHS — Treatment for bowel cancer
- NHS — Ileostomy
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
Which operation for which part of the colonThe standard operation for each tumour position, side by sideHow much colon will be removed?What decides the length of bowel taken in any colon operationLynch syndrome and colon cancerThe inherited condition behind many larger-operation decisionsWill you need a stoma after colon cancer surgery?When a bag is likely, and when it is temporary
Talk to us
Has a surgeon advised removing most of your colon?
Send us the colonoscopy, scan and biopsy reports, and the CION tumour board will review whether a smaller or larger operation suits you. We will explain the reasoning in plain language. One helpline serves every CION centre.