What is Colon Cancer? Symptoms and Treatment

Colon cancer is a common type of cancer that occurs when cells in the large intestine—the final part of your digestive system—multiply uncontrollably. It usually begins as harmless polyps on the inner lining of the bowel, which can change in structure over the years. Although the disease progresses silently in its early stages, timely screenings can detect and remove these polyps before they turn into cancer.

• It develops when polyps on the inner lining of the large intestine become cancerous.
• It often causes no symptoms in its early stages.
• Regular screening tests are recommended starting at age 45.
• A colonoscopy allows for both diagnosis and cancer prevention through the removal of polyps.
• Treatment involves methods such as surgery, chemotherapy, and radiotherapy.

What is Colon Cancer?

Also known as bowel or colorectal cancer, this disease begins in the final section of the digestive tract, which is about 1.5 metres long. Mutations in the DNA of healthy cells cause them to divide faster than normal and continue living when they should naturally die. This accumulation primarily manifests as small, fleshy growths called polyps.

While the vast majority of polyps remain benign (non-cancerous), certain types can grow over time and transform into malignant tumours. Cancer cells can spread from the inner wall of the bowel to the muscle layers, then to the lymph nodes, and in advanced cases, to distant organs like the liver or lungs. The slow-progressing nature of the disease offers a highly valuable window of time for early diagnosis. Even if you feel perfectly healthy and have no complaints, getting your bowel health checked after a certain age is vital.

Causes and Risk Factors

Although the exact cause of the disease is not always fully understood, it is scientifically proven that certain factors increase the risk. Age is one of the most prominent risk factors; the vast majority of cases are seen in individuals aged 45-50 and older. Family history also plays a critical role. If you have a first-degree relative with a history of colon cancer or bowel polyps, your likelihood of developing the disease increases due to genetic predisposition.

Dietary habits directly affect bowel health. Frequently consuming processed meats like sucuk (traditional Turkish sausage), salami, and hot dogs, eating a diet heavy in red meat, and lacking dietary fibre all raise the risk. Furthermore, obesity, a sedentary lifestyle, and heavy smoking or alcohol consumption cause damage at the cellular level, paving the way for cancer development. Individuals previously diagnosed with inflammatory bowel diseases (such as Crohn's disease or ulcerative colitis) must also be monitored regularly due to chronic inflammation in their bowel cells.

What Are the Symptoms of Colon Cancer?

In the initial stages of the disease, there are usually no noticeable symptoms. However, as the tumour grows or causes narrowing within the bowel, your body begins to send out warning signals. The most common symptoms of colon cancer include sudden and unexplained changes in your bowel habits. Diarrhoea, constipation, or a feeling that your bowel hasn't completely emptied, lasting longer than two or three weeks, should be taken seriously.

Seeing bright red or very dark blood in your stool is one of the most serious warnings. You might also experience persistent cramps, gas pains, and a feeling of bloating in your abdomen. It is important not to dismiss such pains as a simple digestive issue; you can also read our article titled do not underestimate abdominal pain to learn about different causes of stomach aches. Additionally, losing weight suddenly without dieting, feeling constantly fatigued, and developing anaemia due to blood loss are other significant signs that the disease is progressing.

Stages of Colon Cancer

Determining the stage of the disease is the most fundamental factor in shaping the treatment plan. Stage 0 is the very early phase where cancer cells are only found in the innermost layer (mucosa) of the bowel and have not yet grown deeper. In Stage 1, the cancer has grown through the inner lining but has not spread beyond the muscle wall.

By Stage 2, the tumour has reached the outer wall of the bowel or begun pressing against neighbouring tissues, but it has not spread to the lymph nodes. In Stage 3, cancer cells have spread to the nearby lymph nodes. At this point, the disease is considered regionally advanced. Stage 4 is the most advanced phase; the cancer has spread (metastasised) beyond the large intestine to distant organs such as the liver, lungs, abdominal lining, or ovaries. The stage of the disease determines the extent of surgical intervention and whether additional treatments like chemotherapy will be needed.

Diagnosis: How Is It Diagnosed at the Hospital?

When you visit the hospital with bowel complaints, your doctor will first listen to your medical history and perform a detailed physical examination. The gold standard method for diagnosis is a colonoscopy. Using a flexible tube with a lighted camera at the tip, the entire large intestine is examined in detail. If any suspicious tissue or polyp is spotted during this procedure, a biopsy (tissue sample) can be taken immediately, or the polyp can be removed entirely.

The collected samples are examined at the cellular level in a pathology laboratory to make a definitive diagnosis. The faecal occult blood test is also frequently used for screening purposes; this test detects microscopic, invisible bleeding in the stool and, if positive, directs the patient to a colonoscopy. Once a cancer diagnosis is confirmed, advanced imaging methods such as computed tomography (CT), magnetic resonance imaging (MRI), or PET-CT are used to determine the spread (stage) of the disease in the body. Blood tests are also conducted to monitor the course of the disease by checking tumour markers (such as CEA).

Colon Cancer Treatment

The treatment process is planned with a multidisciplinary approach based on the stage of the disease, the patient's general health, and the location of the tumour. In early stages, simply removing polyps during a colonoscopy can be a sufficient treatment on its own. However, if the tumour has progressed into the deeper layers of the bowel, the primary treatment for colon cancer is surgery.

During surgery, the cancerous section of the bowel, a margin of surrounding healthy tissue, and nearby lymph nodes are removed. The remaining healthy ends of the bowel are then stitched together to maintain the integrity of the digestive system. In advanced stages, chemotherapy (drug therapy) and radiotherapy (radiation therapy) are introduced alongside surgery. Chemotherapy is used to destroy any microscopic cancer cells that might remain after surgery or to shrink the tumour beforehand. Newly developed smart drugs (targeted therapies) and immunotherapy methods also significantly increase the life expectancy and quality of life for advanced-stage patients by stopping the growth of cancer cells.

How to Prevent It?

Protecting yourself from bowel cancer is largely possible through lasting, healthy changes in your daily life. Focusing on high-fibre foods in your diet regulates bowel movements, shortening the time carcinogenic substances remain in the intestine. Consuming plenty of vegetables, fruits, whole grains, and legumes is one of your strongest defence mechanisms. For more information on balancing your fruit intake, you can browse our guide titled the art of balance in fruit consumption.

Limiting red meat consumption to 1-2 portions a week and completely avoiding processed meats (like sausages and salami) significantly reduces your risk. Engaging in regular physical activity, maintaining your ideal weight, and quitting smoking and alcohol support your cellular health. Beyond all this, the most effective prevention method is participating in regular screening programmes. Having a colonoscopy at intervals recommended by your doctor after the age of 45, even if you have no complaints, allows you to stop the disease while it is still in the polyp stage.

When to See a Doctor?

Changes in your bowel habits lasting more than a few days may not always be a cause for concern, but certain signs require immediate medical evaluation. If you see a noticeable amount of blood in your stool, if your stool is tar-black, or if you are experiencing unexplained, persistent abdominal pain, you should see a specialist without delay. Unintentional weight loss, constant fatigue, and signs of severe anaemia are also signals that must be taken seriously.

Sudden, stabbing, severe pain in the abdominal area, extreme swelling of the abdomen, or the inability to pass gas or stool may indicate a bowel obstruction. Such situations carry a life-threatening risk and may require emergency surgical intervention. If you encounter such a situation, you should immediately go to the nearest emergency department or call 112 for medical assistance.

The Process at BHT CLINIC

At BHT CLINIC İstanbul Tema Hastanesi, the diagnosis and treatment of digestive system diseases are carried out meticulously by our team of expert physicians. Our hospital's General Surgery, Gastroenterology, and Oncology departments work with a multidisciplinary council approach for our patients suspected of having bowel cancer.

In our advanced technology endoscopy units, colonoscopy procedures are performed under anaesthesia, painlessly and with high comfort. For our patients diagnosed with cancer, surgical interventions, chemotherapy, and radiotherapy processes are planned seamlessly under one roof. In emergencies, we are always by your side with our 24/7 emergency department and fully equipped operating theatres. To avoid postponing your health and to get your bowel screenings done, you can consult our expert physicians by booking an appointment.

Frequently Asked Questions

Is colon cancer fatal?

When diagnosed in its early stages, colon cancer is highly treatable, and patients can recover completely. However, the risk to life increases when the disease reaches advanced stages and spreads to other organs. Therefore, regular screening for early diagnosis is of vital importance.

How long does a colonoscopy take?

A colonoscopy procedure usually takes between 20 and 30 minutes to complete. Including pre-procedure preparation and post-procedure recovery time, the total time spent at the hospital can be around 2-3 hours. Since the procedure is performed under light anaesthesia (sedation), no pain is felt.

Can colon cancer be detected in a blood test?

A definitive diagnosis of colon cancer cannot be made with standard blood tests alone. Anaemia detected in blood tests or elevated tumour markers like CEA may raise suspicion, but a colonoscopy and biopsy are absolutely necessary for a definitive diagnosis.

What is the recovery process like after bowel cancer surgery?

Depending on whether the surgery is performed open or closed (laparoscopically), patients are generally discharged within 4 to 7 days. Returning to normal daily activities takes 2-4 weeks. The recovery process is faster and less painful with laparoscopic surgeries.

Do haemorrhoids turn into colon cancer?

Haemorrhoids are benign enlarged blood vessels and do not turn into cancer over time. However, because bleeding from haemorrhoids can be confused with bleeding from cancer, any rectal bleeding must be evaluated by a specialist.

This article is for informational purposes only; please consult your physician for diagnosis and treatment.