colon cancer symptoms, causes, diagnosis, treatment

Colon Cancer

Overview

Colon cancer starts from polyps, which are growths that form on the inner lining of the colon. Doctors have screening tests that can find and remove these polyps before they turn into cancer. If colon cancer is not treated, it can spread to other parts of the body. Because of these screening tests, early treatment, and new types of treatments, the number of people dying from colon cancer has gone down.

What is Colon Cancer?

What is Colon Cancer?

Colon cancer is a disease that begins when abnormal cells grow in the colon, which is the first and longest part of the large intestine. The large intestine is the final section of the digestive system, which is responsible for breaking down food so the body can absorb nutrients. Colon cancer often starts as small growths called polyps on the inner lining of the colon. While most polyps are harmless, some can slowly turn into cancer over time if they are not removed.

This type of cancer usually affects older adults but can occur at any age. Polyps often do not cause noticeable symptoms, so regular screening is important to find and remove them early. Early detection can help stop colon cancer before it starts. If cancer does develop, several treatment options are available. These include surgery to remove the cancer, radiation therapy, and various types of medicine like chemotherapy, targeted therapy, and immunotherapy. When colon cancer affects the rectum as well, it is sometimes referred to as colorectal cancer.

Types of Colon Cancer

Most colorectal cancers are adenocarcinomas. These cancers begin in the cells that produce mucus to keep the inside of the colon and rectum moist. When doctors refer to colorectal cancer, they usually refer to this type. Some forms of adenocarcinoma, like signet ring and mucinous subtypes, may lead to a more serious outlook than others.

Other, less common types of tumors can develop in the colon and rectum. These include:

  • Carcinoid tumors:

    These start in special cells in the intestine that make hormones.
  • Gastrointestinal stromal tumors (GISTs):

    These form from nerve-related cells in the wall of the digestive tract. Some GISTs are not cancerous. While they are more often found in the stomach or small intestine, they rarely appear in the colon or rectum.
  • Lymphomas:

    These are cancers that start in immune system cells. While they most often begin in the lymph nodes, they can also form in the colon, rectum, or other organs in the digestive system.
  • Sarcomas:

    These tumors begin in connective tissues like muscles or blood vessels in the colon and rectum. Sarcomas in this area are very rare.

Risk Factors

Colon cancer can affect anyone, but some people are more likely to develop it than others. Several factors, including age, lifestyle habits, medical conditions, and family history, can raise the chances of getting colon cancer. Understanding these risks can help with early detection and prevention.

Here are the main factors that may increase the risk of colon cancer:

  • Older age: Although colon cancer can occur at any age, most people diagnosed with it are over the age of 50. In recent years, the number of younger individuals being diagnosed has increased, but the reason for this shift is still unknown.
  • Black race: In the United States, Black individuals have a higher risk of developing colon cancer compared to people of other races.
  • Personal history of colorectal cancer or polyps: If someone has had colon cancer or certain types of polyps before, their chances of developing colon cancer again are higher.
  • Inflammatory bowel diseases: Chronic conditions that cause inflammation in the digestive tract, such as ulcerative colitis and Crohn’s disease, can increase the risk of colon cancer over time.
  • Inherited syndromes: Some people inherit genetic conditions that make them more likely to develop colon cancer. Two of the most common inherited syndromes are familial adenomatous polyposis and Lynch syndrome.
  • Family history of colon cancer: Having a close relative, such as a parent or sibling, with colon cancer raises the risk. If more than one family member has had colon or rectal cancer, the risk goes up even more.
  • Low-fiber, high-fat diet: Some research suggests that eating a diet low in fiber and high in fat and calories may be linked to a higher risk of colon cancer. Eating large amounts of red meat and processed meat may also play a role, though studies have shown mixed results.
  • Lack of physical activity: People who do not get regular exercise have a higher risk of colon cancer. Staying physically active may help lower that risk.
  • Diabetes: Having diabetes or resistance to insulin, a condition that often comes with diabetes has been linked to a higher chance of getting colon cancer.
  • Obesity: Being overweight or obese increases the risk of colon cancer. It can also raise the chances of dying from the disease.
  • Smoking: Long-term cigarette smoking may increase the risk of developing colon cancer.
  • Alcohol use: Drinking large amounts of alcohol regularly has been linked to an increased risk of colon cancer.
  • Radiation therapy: People who have had radiation treatments to the abdomen for other cancers may have a higher chance of developing colon cancer later on.

Understanding these risk factors can help with prevention and early diagnosis. Making healthy lifestyle changes, staying up to date with screenings, and talking to a doctor about personal and family health history can all play a role in reducing risk.

Symptoms

Colon cancer can sometimes grow without causing any symptoms, especially in the early stages. That’s why regular screening is so important. When symptoms do show up, they can often be mistaken for signs of less serious problems. Still, any ongoing or unusual changes in your body should be taken seriously. Paying attention to these warning signs can help with early detection and better outcomes.

Here are some common symptoms of colon cancer to look out for:

  • Blood in or on your stool: If you notice blood when you wipe, see it in the toilet bowl, or your stool appears dark or bright red, it’s time to talk to a healthcare provider. While the presence of blood does not always mean cancer, it could be from hemorrhoids, small tears, or even certain foods, it’s still important to get checked.
  • Changes in bowel habits: If you experience ongoing constipation, diarrhea, or feel like your bowel movements aren’t empty, it may be a sign that something isn’t right. These changes, especially if they last more than a few days, should be discussed with a healthcare provider.
  • Unexplained abdominal pain: Pain or discomfort in the belly that doesn’t go away or has no clear cause can sometimes be linked to colon cancer. Even though belly pain can have many causes, frequent or lasting discomfort should not be ignored.
  • Bloating: Feeling bloated is common and can happen for many reasons. But if the bloating lasts more than a week, gets worse, or comes with other symptoms such as vomiting or blood in your stool, it’s worth checking in with a healthcare provider.
  • Unexplained weight loss: Losing weight without trying, especially if the weight loss is significant, can be a sign of a more serious condition like colon cancer.
  • Vomiting: Throwing up from time to time might not be a cause for alarm, but vomiting without a known reason, especially if it happens often or is severe, needs medical attention.
  • Fatigue or shortness of breath: Feeling constantly tired or weak, or noticing that you’re short of breath during normal activities, may be due to several things. In some cases, it could be linked to internal bleeding or anemia, which are sometimes caused by colon cancer.

Even if these symptoms turn out to be from something less serious, it’s always best to talk with a healthcare provider when your body doesn’t feel right. Early diagnosis can make a big difference in treatment and recovery.

colon cancer symptoms and causes
colon cancer symptoms and causes

Causes

The exact cause of most colon cancers is still not known. While certain risk factors can increase the chances of getting colon cancer, doctors cannot always say why one person gets it and another does not.

Colon cancer begins when cells in the colon develop changes in their DNA. DNA is the instruction manual inside each cell that tells it how to grow, function, and die. When changes, also called mutations, occur in the DNA, they can make the cells grow out of control.

These abnormal cells start to multiply rapidly. Unlike healthy cells, which die off at the right time, these cells keep living. Over time, they can build up and form a lump called a tumor. This tumor can grow and damage surrounding healthy tissue.

In some cases, the cancer cells may break away from the tumor and travel to other parts of the body. This spread is called metastasis. Once cancer has spread, it can be harder to treat and may affect how well treatment works.

Diagnosis

Diagnosing colon cancer involves a series of tests and procedures that help doctors confirm if cancer is present, understand how far it may have spread, and decide on the best treatment plan. These tests also help rule out other conditions that might cause similar symptoms. Below are the most common methods used to detect colon cancer.

01
colon cancer diagnosis colonoscopy

Colonoscopy To View The Colon

Colonoscopy is often the first step in diagnosing colon cancer. It uses a long, flexible tube with a camera on the end to look at the inside of the colon and rectum. The doctor can see the entire length of the colon and identify any abnormal areas, such as growths or polyps. During the procedure, tools can be passed through the tube to take tissue samples or remove polyps if needed.
02
Biopsy for Colon Cancer Diagnosis

Biopsy To Examine Tissue Samples

A biopsy involves removing a small piece of tissue so it can be tested in a laboratory. In most cases, this is done during a colonoscopy when the doctor finds something unusual. If the tissue can’t be reached during a colonoscopy, surgery might be needed to collect it. Lab tests can confirm if the tissue contains cancer cells and shows how fast the cancer might be growing. This information helps guide treatment decisions.
03
Blood Tests for Colon Cancer

Blood Tests To Check Overall Health

Blood tests are not used to confirm colon cancer, but they provide useful information about a person’s general health. These tests can check how well the liver and kidneys are working, and they might show if someone has anemia, which could be a sign of bleeding inside the colon.
04
CEA Test for Cancer Monitoring

CEA Test To Monitor Cancer Activity

Some colon cancers produce a substance called a carcinoembryonic antigen, or CEA. A blood test can measure the amount of CEA in the body. High levels might suggest the presence of cancer. Doctors may use this test during and after treatment to see if the cancer is responding or if it has returned.
Colon Cancer Treatment

Treatments

Treatment for Colon cancer depends on several factors, including where the cancer is located, how far it has spread, your overall health, and your personal treatment goals. Surgery is often the first and most common step, but your healthcare team might also recommend chemotherapy, radiation therapy, targeted therapy, immunotherapy, or palliative care.

The goal of treatment can be to remove the cancer completely, slow its growth, or ease symptoms and improve quality of life.

If colon cancer is found at an early stage, surgery alone may be enough to remove it. Several minimally invasive procedures may be used:

  • Polypectomy during colonoscopy: If the cancer is contained within a polyp, the entire polyp may be removed during a colonoscopy. This procedure is known as a polypectomy.
  • Endoscopic mucosal resection: Larger polyps may be removed along with a small section of the colon lining during a colonoscopy using special tools.
  • Laparoscopic surgery: If the polyp cannot be removed during a colonoscopy, a surgeon may use laparoscopic surgery. This involves making several small cuts in the abdomen and using instruments with cameras to remove the cancer and possibly nearby lymph nodes.

If the cancer has spread beyond a polyp or into the wall of the colon, more extensive surgery may be needed:

  • Partial colectomy: The surgeon removes the part of the colon that contains cancer along with some healthy tissue on both sides. In many cases, the healthy ends of the colon or rectum can be reconnected. This procedure is sometimes done using laparoscopic surgery.
  • Ostomy creation: If the healthy parts of the colon or rectum can’t be reconnected, the surgeon creates an opening in the abdominal wall. This allows the stool to exit the body into a bag placed over the opening. Sometimes the ostomy is temporary and reversed after healing; other times, it’s permanent.
  • Lymph node removal: Lymph nodes near the tumor are usually removed during surgery and tested to see if the cancer has spread.

If surgery cannot fully remove the cancer, it may still help reduce symptoms such as pain or blockage in the colon. In some cases where cancer has only spread to areas like the liver or lungs and the patient is otherwise healthy, surgery or other local treatments may be used. Chemotherapy might also be included before or after the procedure to improve outcomes.

  • Chemotherapy: Chemotherapy uses strong drugs to kill cancer cells. It may be used after surgery to destroy any remaining cancer cells and lower the risk of the cancer coming back. It may also be given before surgery to shrink large tumors, or to ease symptoms in cases where surgery isn’t possible. Sometimes chemotherapy is combined with other treatments, including radiation therapy.
  • Radiation Therapy: Radiation therapy uses high-energy beams like X-rays or protons to kill cancer cells. It may be used before surgery to shrink tumors, or after surgery to reduce the chance of the cancer returning. When surgery isn't an option, radiation may be used to relieve symptoms such as pain or bleeding. Radiation therapy can also be given at the same time as chemotherapy for a stronger effect.
  • Targeted Therapy: Targeted therapy uses drugs that focus on specific changes or markers in cancer cells. These medicines work by blocking the signals that help cancer cells grow and survive. This type of treatment is usually given with chemotherapy and is more common in cases of advanced colon cancer.
  • Immunotherapy: Immunotherapy helps the body’s immune system recognize and attack cancer cells. Some colon cancers avoid detection by the immune system. Immunotherapy can boost the body's natural defenses to help find and destroy these cells. It’s typically used in cases where the cancer is advanced and other treatments are no longer working well.
  • Palliative Care: Palliative care focuses on relieving pain, stress, and other symptoms of serious illness. It’s provided by a team of healthcare professionals who work alongside your main treatment team. This support helps improve quality of life during and after treatment. Palliative care can be offered at any stage of illness and may help patients feel better and live longer when used along with other treatments.

Side Effects of Treatment

Each type of colorectal cancer treatment can cause its own set of side effects. Not everyone will experience them in the same way. While some people may only deal with mild fatigue or nausea, others may face more intense reactions depending on their overall health, age, and how their body responds to treatment. Personalized care and regular communication with your doctor make a big difference in managing side effects effectively.

  • Dehydration: Not drinking enough fluids can lead to dizziness, weakness, and confusion. Keep sipping water, try electrolyte drinks, and eat water-rich foods like fruits or popsicles.
  • Skin Rash and Irritation: Some treatments can make your skin red, bumpy, itchy, or sensitive. Use mild skincare products and talk to your doctor about creams or medications that can help.
  • Nausea and Vomiting: If you feel sick or are throwing up, ask your doctor about anti-nausea medicines. Natural remedies like ginger or peppermint might also provide relief. Early treatment is key.
  • Diarrhea: Frequent loose stools can leave you dehydrated and drained. Medication, changes in diet, and staying hydrated can ease this. After colon surgery, it may take time for your digestive system to adjust.
  • Fatigue: Feeling tired all the time is one of the most common side effects. Get plenty of rest, space out your daily activities, and ask for help when needed. Always mention fatigue to your doctor.
  • Peripheral Neuropathy: This nerve damage causes tingling, pain, or cold sensitivity. Keep your doctor updated on any new symptoms. Medications, acupuncture, and creams may reduce discomfort. In many cases, symptoms improve after treatment ends.
  • Mucositis: This condition causes inflammation in the lining of your digestive tract. Rinse with saltwater, avoiding spicy foods, and using special mouthwashes can bring relief. Your doctor may recommend coating agents or pain medicine.
  • Hand and Foot Syndrome: This can cause blisters, peeling skin, and sensitivity on your hands and feet. Use gentle lotions, avoid hot water, and wear soft cotton clothing. Stay hydrated and keep your nails trimmed short.
  • Anemia: A drop in red blood cells can make you feel weak or short of breath. Your care team may suggest iron supplements, dietary changes, or in some cases, a blood transfusion.
  • Loss of Appetite: When eating becomes difficult or unappealing, try smaller meals more often or add nutritional shakes to your routine. Let your care team know if you’re losing weight or can’t eat.
  • Managing Skin Toxicity: Targeted therapies can cause dry skin, rashes, or acne-like breakouts. Gentle skin care, sunscreen, and staying moisturized can help you feel more comfortable. Talk to your doctor about treatment options if skin problems become severe.

Going through treatment for colorectal cancer is never easy but knowing what to expect and how to manage side effects can help you stay strong and supported throughout the process. Keep the conversation open with your care team and take one step at a time.

Colon Cancer Support Area

Support

A colon cancer diagnosis can turn life upside down. From physical symptoms to emotional stress, many challenges come with it. But no one has to face them alone. Support both emotional and practical can make a real difference. Whether it's from healthcare professionals, loved ones, or others who’ve walked a similar path, the right support system can help make the journey feel less overwhelming.

Emotional and Mental Health Support

Emotional and Mental Health Support

Hearing the words “you have colon cancer” often brings fear, sadness, anger, or confusion. It’s completely normal to feel overwhelmed. Talking to a mental health professional can be helpful. Therapists and counselors who specialize in cancer care understand how to support people through the ups and downs.
Support from Family and Friends

Support from Family and Friends

Having loved ones close by can ease stress. Even small acts, like cooking a meal, helping with transportation, or just listening can help someone feel cared for. Open conversations with family and friends can also clear up misunderstandings and let others know how to help in ways that matter.
Medical and Professional Support

Medical and Professional Support

Doctors, nurses, social workers, and patient navigators are there to help guide you through the treatment process. They can explain test results, discuss treatment plans, and help manage side effects. Many hospitals and clinics also offer access to nutritionists, financial counselors, and physical therapists to support your overall well-being.
Practical Help and Daily Life

Practical Help and Daily Life

Colon cancer treatment often affects daily routines. Help may be needed for things like driving to appointments, managing meals, or handling work and finances. Accepting help, or asking for it, does not mean weakness. It’s a smart and healthy way to manage life during treatment.
Nutritional Support

Nutritional Support

Good nutrition supports the body during cancer treatment. Eating may be hard during certain stages, especially with side effects like nausea or changes in appetite. A registered dietitian can provide guidance based on your treatment and needs, helping you stay strong and avoid further health problems.
Spiritual and Personal Support

Spiritual and Personal Support

For many people, faith or personal beliefs play a big role in healing. Spiritual leaders, faith communities, or personal practices like prayer or meditation can offer strength, peace, and comfort during difficult times. It’s okay to lean on the sources of support that feel meaningful to you.
Support for Caregivers

Support for Caregivers

Caregivers also need support. Taking care of someone with colon cancer can be emotionally and physically draining. Caregivers should make time for their well-being, rest, and mental health. Connecting with others who are also caregiving can offer valuable tips and emotional support.
Long-Term Support and Survivorship

Long-Term Support and Survivorship

Support does not end when treatment ends. After treatment, many people face a mix of emotions, from relief to anxiety about the future. Regular check-ins with your care team, follow-up screenings, and access to survivorship resources can help you stay healthy and feel supported in the years ahead.

Research

Colon cancer continues to be a major area of focus for researchers and medical experts around the world. Studies aim to better understand how the disease starts, how it spreads, and how to treat it more effectively. With discoveries every year, researchers are working to improve detection, develop safer and more effective treatments, and raise survival rates. This ongoing research gives hope to patients, families, and healthcare providers.

01

Early Detection and Screening Improvements

Early detection is one of the most effective ways to fight colon cancer. Researchers are studying how to improve screening tests so cancer can be found earlier, sometimes even before symptoms appear. This includes work on less invasive tests, such as stool-based tests, blood tests, and advanced imaging methods that can spot warning signs more accurately.
02

Genetics and Personalized Medicine

One of the most promising areas of colon cancer research is personalized medicine. Scientists are studying how a person’s genes can affect their chances of developing colon cancer and how their cancer responds to treatment. This research includes identifying genetic mutations in tumor cells that can be targeted with specific drugs.
03

Immunotherapy

Immunotherapy uses the body’s immune system to fight cancer. While this type of treatment has shown success in certain cancers, researchers are working to find out how it can be used more effectively in colon cancer, especially in advanced cases. Some studies are exploring immune checkpoint inhibitors, which help the immune system recognize and attack cancer cells more easily.
04

Targeted Therapy

Targeted therapies focus on specific features of cancer cells that make them different from healthy cells. Researchers are studying how drugs can block the growth and spread of these cells while leaving normal cells alone. This includes work on anti-angiogenesis drugs that stop tumors from forming new blood vessels and monoclonal antibodies that attach to cancer cells and interfere with their ability to grow.
05

Improving Chemotherapy & Radiation

Even though chemotherapy and radiation are standard treatments, researchers continue to study how to make them more effective and less harmful. This includes finding the best combinations of drugs, new methods of delivery, and ways to reduce side effects.
06

Lifestyle and Prevention Studies

Research is also being done on how lifestyle factors such as diet, exercise, and smoking, affect colon cancer risk. Some studies are looking at how specific foods or nutrients may play a role in prevention. Others are examining how physical activity and maintaining a healthy weight might reduce the risk of cancer returning after treatment.
07

Survivorship and Quality of Life

As more people survive colon cancer, researchers are also focusing on life after treatment. This includes looking at long-term side effects, emotional well-being, and ways to support recovery. Survivorship studies help patients, and their care teams prepare for life beyond treatment and manage any lasting effects of the disease.
08

Future Directions

The future of colon cancer research holds promise. With advancements in technology, including artificial intelligence and big data, scientists can analyze large amounts of information quickly to find patterns and new treatment possibilities. Clinical trials continue to test new drugs and treatment approaches, bringing hope for safer and more effective care.
Colon Cancer Prevention

Prevention

While colon cancer cannot always be prevented, there are steps you can take to reduce your chances of developing it. Making healthier choices and staying informed about your health history can help you take more control over your long-term well-being. Here are some practical ways to manage your risk factors and stay on top of your health.

Using tobacco is linked to many types of cancer, including colon cancer. If you smoke, consider making a plan to quit. Giving up tobacco may lower your cancer risk and improve your overall health.

Drinking too much alcohol can raise your chances of developing colon cancer. Try to drink in moderation, if at all. Choosing water, herbal tea, or other non-alcoholic options more often can help support your long-term health.

Being overweight or obese can increase your risk. Staying active, making smart food choices, and keeping your weight within a healthy range may lower your chances of developing colon cancer and other chronic illnesses.

What you eat plays a role in your overall health. To reduce your risk of colon cancer, try to eat more fruits, vegetables, and whole grains. Limit your intake of red meat, processed meats, and foods that are high in fat or calories. Some research also suggests that drinking coffee might help lower your risk.

Colon cancer can sometimes occur in families. If your biological parents, siblings, or children have been diagnosed with colon cancer or had an advanced polyp, share this with your healthcare provider. This is especially important if any relatives were diagnosed before the age of 45. Knowing your family’s history can help you and your doctor decide when to begin screening and what steps to take for early detection.

Colon cancer often begins with no symptoms. That’s why regular screening is one of the best tools for early detection and prevention. Talk to your healthcare provider about when you should begin screening. For many people, screening starts around age 45. If you have a family history of colon cancer or live with chronic conditions such as inflammatory bowel disease, your doctor might recommend earlier or more frequent testing.
Questions to Ask your Healthcare Provider about Colon Cancer

Learning that you have colon cancer can bring a lot of emotions and uncertainty. Asking the right questions can help you better understand your diagnosis and feel more confident in the steps ahead. It’s important to speak openly with your healthcare provider so you can make informed decisions about your care. Here are some questions you might consider asking during your appointment.

  • Q1. Which part of my colon is affected by the cancer?
  • Q2. What stage is cancer, and what does that mean for me?
  • Q3. Can you walk me through the details of my lab report?
  • Q4. Is it possible to get a copy of my lab results?
  • Q5. Has the cancer spread beyond my colon? If so, where?
  • Q6. Will I need any additional tests before we move forward?
  • Q7. What treatment options are available for my situation?
  • Q8. Is there a possibility of curing this cancer?
Questions to Ask your Healthcare Provider about Colon Cancer