Most patients with localised colon cancer have surgery first. The operation removes the affected part of the colon and nearby lymph nodes. The final pathology then helps determine whether chemotherapy is needed to reduce the risk of recurrence. For metastatic colon cancer, treatment usually starts with medicines selected using the tumour’s biomarkers and the sites of spread, although some patients with limited liver or lung metastases may still be treated with the aim of cure. [1–3]
By Dr Raman Narang, Consultant Medical & Hemato-Oncologist, New Delhi
Two people can both have stage II colon cancer and receive different advice after surgery. One may need scheduled follow-up alone. The other may be offered chemotherapy because the tumour grew through the bowel wall or caused a blockage. If you are seeking colon cancer treatment in Delhi, ask which findings in your own report determine the next step. This page focuses on cancers that start in the colon. Rectal cancer has its own treatment pathway, and the exact location matters when a tumour is near the junction between the sigmoid colon and rectum. [1, 2]
1. What are the symptoms and risk factors for colon cancer?
Colon cancer can develop without obvious symptoms. When symptoms occur, they can include blood in the stool, a persistent change in bowel habits, abdominal pain, unexplained weight loss, or iron-deficiency anaemia. A tumour on the right side of the colon may cause slow blood loss and fatigue without visible bleeding. A tumour on the left side may present with a change in bowel habits or a blockage. [1]
Age, a personal history of certain colon polyps, a family history of colorectal cancer, and long-standing inflammatory bowel disease can increase risk. Inherited conditions such as Lynch syndrome can also raise the risk. Colon cancer can occur in younger adults, so persistent bleeding or unexplained iron-deficiency anaemia deserves evaluation at any age. [1, 2]
Severe abdominal pain with vomiting, increasing swelling of the abdomen, or an inability to pass stool or gas needs urgent assessment. These symptoms can occur with a bowel blockage. [1]
2. How is colon cancer diagnosed and staged?
A colonoscopy with biopsy usually confirms the diagnosis. The procedure also allows the doctor to examine the rest of the colon for other lesions when the scope can pass safely. Most colon cancers are adenocarcinomas. A contrast CT of the chest, abdomen, and pelvis helps assess whether cancer has spread. Liver MRI may be useful when a finding on CT needs clarification or when liver surgery is being considered. [1, 3]
A blood test called CEA is often measured before treatment. It can help establish a baseline for follow-up. Some patients have a normal CEA even when cancer is present, so it is interpreted alongside the scans and pathology. [1]
The tumour should also be tested for mismatch repair deficiency (dMMR) or high microsatellite instability (MSI-high). These results can affect treatment decisions and may prompt further testing for Lynch syndrome. A tumour result alone does not establish an inherited diagnosis. [1–3]
3. How are early-stage and locally advanced colon cancers treated?
For most removable colon cancers, the first treatment is a colectomy, which removes the affected segment of bowel and nearby lymph nodes. The pathologist checks how deeply the tumour grew, whether it reached the surgical margins, and whether any lymph nodes contain cancer. These findings guide the decision about treatment after surgery. [1, 2]
| Stage or clinical situation | What the team usually discusses |
|---|---|
| Stage I | Surgery is usually sufficient. Selected very early cancers found in a removed polyp may be managed with endoscopic removal alone if the pathology shows that it was completely removed and has favourable features. |
| Stage II | The cancer has grown beyond the inner muscle layer or through the bowel wall, with no cancer found in the regional lymph nodes. Many patients need surgery and follow-up alone. Chemotherapy is discussed when the risk of recurrence is higher. |
| Stage III | Cancer is present in regional lymph nodes or has formed certain nearby tumour deposits. Chemotherapy after surgery is generally recommended for patients fit enough to receive it. |
| Selected bulky or locally advanced tumours | If the tumour appears to involve nearby organs or may be difficult to remove completely, a multidisciplinary team may consider treatment before surgery. The plan depends on the anatomy, symptoms, and tumour biology. |
When does stage II colon cancer need chemotherapy?
The decision depends on the likelihood of recurrence and how much chemotherapy could reduce it. A T4 tumour, meaning it has reached the outer surface of the colon or grown into a nearby structure, is an important reason to offer chemotherapy. Other findings that can influence the discussion include a bowel blockage or perforation, fewer than 12 lymph nodes examined, and cancer cells found in small vessels or around nerves. [2]
MMR status matters. For most patients with stage II dMMR or MSI-high colon cancer, chemotherapy is not routinely recommended. If high-risk features lead the team to recommend chemotherapy despite dMMR, the choice of regimen needs individual review. [2]
What chemotherapy is used after surgery for stage III colon cancer?
Two common options are CAPOX, which combines capecitabine tablets with intravenous oxaliplatin, and FOLFOX, which combines intravenous fluorouracil and leucovorin with oxaliplatin. The choice and duration depend on the extent of tumour and lymph node involvement, the regimen, and the balance between benefit and side effects. For some patients, three months is reasonable. Others are advised to have six months. One reason duration matters is that oxaliplatin can cause tingling, numbness, or other nerve symptoms that may persist. [1]
For stage III dMMR colon cancer, the phase III ATOMIC trial found that adding atezolizumab to postoperative chemotherapy improved disease-free survival. The US FDA approved an atezolizumab-based postoperative regimen for this group in October 2026. In Delhi, the team should verify the applicable Indian prescribing indication, access, and individual suitability before recommending it. [4, 5]
4. How is metastatic colon cancer treated?
When colon cancer has spread to the liver, lungs, abdominal lining, or another distant site, the first question is whether all known sites of disease can be treated locally. Selected patients with limited liver or lung metastases may be considered for surgery or, in some cases, ablation. Some can proceed to a local treatment early. Others start with systemic treatment and have repeat scans to see whether surgery has become feasible. [1, 3]
When the disease cannot be removed completely, treatment usually starts with medicines. Common chemotherapy combinations include FOLFOX, CAPOX, and FOLFIRI. The team may add a targeted drug or choose immunotherapy based on the tumour’s biology. If the primary tumour is causing a blockage, perforation, or significant bleeding, a procedure may need to come first. [1, 3]
| Finding | How it may change treatment |
|---|---|
| MSI-high or dMMR | Immunotherapy can be a first-line option in metastatic disease. Pembrolizumab is one established example. |
| KRAS and NRAS without a relevant mutation | For eligible patients with a left-sided primary tumour, chemotherapy with an EGFR-targeted drug such as cetuximab or panitumumab may be considered. Tumour sidedness matters when selecting first-line treatment. |
| BRAF V600E mutation | A regimen containing encorafenib and cetuximab may be appropriate. The treatment line, combination, and locally applicable prescribing indication guide use. |
Supportive care can begin alongside cancer treatment. Pain, diarrhoea, poor intake, fatigue, or bowel symptoms can affect day-to-day life and whether a patient can continue treatment as planned. [1, 3, 6]
What I look for clinically before recommending treatment
After surgery, I review the pathology for tumour depth, lymph nodes, margins, and MMR status. If the report says stage II, I look for the specific finding that would make chemotherapy worth considering. If cancer has spread and the scans show only a few liver lesions, I want those images reviewed with a liver surgeon before committing to a treatment sequence. That review can change both the first treatment and its goal.
How the next step is decided
| If the reports show… | The next discussion is about… |
|---|---|
| A completely removed stage I cancer | The follow-up plan after surgery |
| Stage II disease | Which pathology findings and MMR results affect the value of chemotherapy |
| Stage III disease | The postoperative regimen, duration, and whether dMMR changes the options |
| Limited liver or lung metastases | Whether surgery or ablation is feasible now or after systemic treatment |
| Metastases that cannot all be treated locally | Biomarker-guided systemic treatment and symptom control |
What to bring to a colon cancer consultation in Delhi
- Colonoscopy report, including the exact tumour location and biopsy findings.
- Surgical pathology report, including tumour depth, margins, and the number of lymph nodes examined and involved.
- CT, MRI, or other imaging reports and the original scan images.
- CEA results with dates, including the result before surgery if available.
- MMR/MSI, KRAS, NRAS, and BRAF reports, if already performed.
- A summary of previous treatment and any family history of colorectal, endometrial, or other relevant cancers.
Frequently asked questions
Does a positive lymph node mean stage IV colon cancer?
Cancer in a regional lymph node usually means stage III if there is no distant spread. Stage III colon cancer is commonly treated with the aim of cure. [1]
Will I need a permanent stoma after colon cancer surgery?
Many patients can have the bowel reconnected without a permanent stoma. The chance of needing one depends on the tumour location, whether surgery is urgent, and whether the bowel can be safely reconnected. [1]
Can stage IV colon cancer be cured?
Some patients with limited metastases, especially when all known disease can be removed, may be treated with the aim of cure. For more widespread disease, the usual goals are to control the cancer, relieve symptoms, and extend life where possible. [1, 3]
Do I still need follow-up if I do not need chemotherapy?
Yes. The follow-up schedule depends on the stage and treatment received. It can include colonoscopy, clinic visits, and, when appropriate, CEA testing and scans. [1]
At your consultation, ask for the exact stage, MMR result, and the finding driving the next decision. If chemotherapy is recommended after surgery, ask how much benefit is expected in your situation and what determines whether a shorter or longer course is appropriate.
This page is for general education. Individual treatment decisions require review of your pathology, imaging, symptoms, and overall health by your treating team.
Clinical references
- National Cancer Grid, India. Management of Colorectal Cancer. Colon adenocarcinoma pathways.
- American Society of Clinical Oncology. Adjuvant Therapy for Stage II Colon Cancer: ASCO Guideline Update.
- American Society of Clinical Oncology. Treatment of Metastatic Colorectal Cancer: ASCO Guideline.
- ATOMIC phase III trial. Atezolizumab Plus FOLFOX for Stage III Mismatch Repair–Deficient Colon Cancer. New England Journal of Medicine, 2026.
- US Food and Drug Administration. FDA Approves Atezolizumab in Combination with Chemotherapy for Stage III Mismatch Repair Deficient Colon Cancer. October 2026.
- US Food and Drug Administration. FDA Grants Traditional Approval to Encorafenib for Metastatic Colorectal Cancer with a BRAF V600E Mutation. February 2026.