Colon cancer, also known as colorectal cancer when it involves the rectum, begins in the inner lining of the colon. It often starts as small, non-cancerous growths called polyps, which may become malignant over time if undetected. Though more common in people over 50, colon cancer rates are steadily rising in individuals under 50, making awareness and early screening essential for all age groups
Colon cancer symptoms often appear in the later stages and may include the following signs:
The American Joint Committee's TNM system is used by medical professionals to stage colon cancer. The five stages of cancer are as follows:
| Stage | Extent of Cancer Spread |
|---|---|
| Stage I | Cancer in the colon wall but not in the lymph nodes or muscle layer. |
| Stage II | Cancer deeper into the colon wall, no lymph node involvement. |
| - IIA | Reached most of the colon wall. |
| - IIB | Penetrated or reached the outer colon wall. |
| - IIC | Spread to the nearby organs, still no lymph nodes involved. |
| Stage III | Lymph nodes involved, not yet distant organs. |
| - IIIA | Affected 1–4 lymph nodes + inner colon wall. |
| - IIIB | Affected ≥4 lymph nodes or deeper colon layers. |
| - IIIC | ≥4 lymph nodes + outer wall or nearby organs affected. |
| Stage IV | Cancer has metastasized to distant parts of the body. |
| - IVA | Spread to 1 distant organ or lymph node group. |
| - IVB | Spread to multiple distant organs or lymph node areas. |
| - IVC | Spread to distant organs, the abdominal lining, and lymph nodes. |
Stage 0: Only the mucosa, the colon's innermost lining, contains abnormal or precancerous cells.
Stage I: The cancer has progressed into the colon wall but has not yet reached the surrounding lymph nodes or the muscle layer.
Stage II: The cancer has not yet reached the lymph nodes, but it has moved farther into the colon wall. It consists of
Stage IIA: The majority of the colon wall has been penetrated by cancer, but not the outermost layer.
Stage IIB: The outer colon wall has been penetrated or reached by the cancer.
Stage IIC: Although lymph nodes have not been affected, cancer has spread to an adjacent organ.
Stage III: Adjacent lymph nodes have been affected by cancer. It consists of
Stage IIIA: One to four lymph nodes and the inner layers of the colon wall are affected by cancer.
Stage IIIB: The cancer has spread to four or more lymph nodes or is in deeper layers.
Stage IIIC: The cancer has spread to four or more lymph nodes and is located in the outer wall of the colon or adjacent organs.
Stage IV: The cancer has metastasized, or spread, to other parts of the body. It includes
Stage IV A: Spread to lymph nodes or a single distant organ that is far from the colon.
Stage IV B: Spread to several distant organs or lymph nodes.
Stage IV C: Spread to lymph nodes, the lining of the abdominal cavity, and distant organs.
Based on your symptoms and medical condition, your healthcare provider can suggest the following tests:
Complete Blood Count test- Checks for anemia (a possible sign of chronic bleeding).
Carcinoembryonic antigen assay— Checks for the level of Carcinoembryonic antigen(CEA) released into the bloodstream by cancer.
X-ray: May detect blockages or abnormal masses in the colon.
Ultrasound: Limited use for colon cancer, but can help detect liver metastasis or guide biopsies.
MRI: Provides detailed images of the colon and surrounding tissues, useful for staging rectal cancer.
CT/PET CT scan- To monitor or check the progression of the cancer.
Note: Colonoscopy is the gold standard for initial detection and biopsy
Surgery is the best option for colon cancer treatment, along with some other treatment therapies that can be used for effective treatment of the disease. These include:
Polypectomy: Removal of malignant polyps.
Partial colectomy: Also known as colon resection surgery. The portion of your colon with the tumor and some surrounding healthy tissue is removed, and the healthy colon sections are connected.
Surgical resection with colostomy: Similar to a colectomy, this procedure involves removing the part of your colon with the tumor and then creating a colostomy. In which your doctor moves the bowel to an opening in your abdominal wall. This lets you collect waste in a bag.
Some treatments can also occur before or after surgery to prevent a recurrence; these are
Chemotherapy- Uses drugs to kill cancerous cells and can be given before or after surgery.
Targeted Therapy— This treatment employs antibodies produced in a lab that bind to particular sites on cancer cells or cells that support the growth of cancer cells. The cancer cells are killed by the antibodies.
Immunotherapy— Immunotherapy helps the immune system identify and kill cancer cells better. It helps some advanced colon cancers. This is true, especially for those with certain genetic traits, like MSI-H or dMMR.
Targeted Therapy- Means it specifically kills cancerous cells.
Fewer side effects- Unlike conventional therapies like chemotherapy and Radiation therapy.
Non-surgical Procedure- Means the patient doesn't have to worry about cuts or stitches.
Enhance Immunity— It enhances immunity by using our immune cells (dendritic cells) that target only cancer cells.
Personalized approach- To suit the patient's needs and provide a personalized cancer treatment plan and care.
Colon Cancer: Global vs. India statistics
| Field | Global (2022) | India (2022) |
|---|---|---|
| New Cases | ~1.9 million new cases (GLOBOCAN); ASIR ~17.8/100k | ~70,038 new cases; ASIR ~4.5/100k (for both sexes) highest in males (~5.7/100k); rising in urban adults |
| Deaths | ~900,000 deaths globally; the third most common cause of cancer death | ~38,367 deaths; increasing trend in men and elderly population |
| Age & Gender | Mostly in adults aged 60+; men have ~20–30% higher risk than women | Mostly diagnosed after age 50; more common in males in the Indian population |
| Hotspots | Highest in developed countries—USA, Europe, Australia, Japan | Urban clusters: Mumbai, Chennai, Mizoram, Bengaluru show higher rates |
| Rural vs Urban | Screening access is better in developed regions. → Early polyp detection | Urban India shows rising cases; rural India is still underdiagnosed. |
| 5-yr Survival | ~64% globally; >90% in stage I3, ~18% in stage IV | ~34% for colon and ~38% for rectal cancer; lower survival due to late diagnosis |
| Key Subtypes | Adenocarcinoma (~95% of cases); mucinous, signet ring cell | Same types found in India; mucinous subtype shows poorer outcomes in some indian studies |
Stages range from 0 (early) to IV (advanced), based on how far the cancer has spread in the colon and to other parts of the body.
When caught early, the prognosis is very good. Your treatment options include surgery, chemotherapy, radiation, and advanced targeted or immunotherapy. Each one helps you gain the upper hand.
Follow a healthy diet. Exercise often. Avoid smoking and heavy drinking. Keep a healthy weight. Get regular checkups.
Start screening at age 45. If you have a family history or other risk factors, begin earlier.
Yes, though it’s less common, colon cancer in people under 50 is rising and can be aggressive.
Researchers link some cases to inherited conditions. These include Lynch syndrome and familial adenomatous polyposis (FAP).
