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  • Early Detection Matters: How to Diagnose Colon Cancer Accurately
Illustration highlighting the importance of early detection for colon cancer, featuring diagnostic tests and support group symbols.

Colon cancer is the third most commonly diagnosed cancer in the United States, making early detection and prevention crucial to saving lives. When caught early, colon cancer is treatable, and understanding the risk factors, symptoms, and available diagnostic procedures can make a significant difference in effectively managing the disease. This comprehensive guide will provide you with essential knowledge on how to diagnose colon cancer, from understanding its causes to exploring various diagnostic and treatment options, ultimately empowering you to take control of your health.

Throughout this blog post, we will delve into the various aspects of colon cancer, including risk factors, types of colorectal cancers, initial assessment and screening methods, advanced diagnostic techniques, staging, and treatment options based on diagnosis. We will also discuss coping strategies and support systems for patients, as well as preventive measures and early detection strategies. So, let’s embark on this journey to better understand colon cancer and how to diagnose colon cancer effectively.

Key Takeaways

  • Colon cancer is the 3rd most common form of cancer worldwide, and early detection strategies are key to prevention.

  • Initial assessment and screening involve a variety of tests such as FOBT, colonoscopies, virtual colonoscopy etc., which can help detect precancerous polyps.

  • Treatment options vary depending on the stage & location of tumor. Coping & support includes finding confidants or joining support groups for emotional assistance.

Understanding Colon Cancer

Illustration of colon cancer cells

Colon cancer, also known as colorectal cancer, is a disease that develops when abnormal cells in the colon or rectum begin to grow uncontrollably. These cells can eventually form tumors and invade nearby tissues, causing significant health complications. Age, family history, and lifestyle factors contribute significantly to the risk of developing colon cancer, making it necessary to comprehend these risks and the different types of colon cancers and colorectal cancers that might arise.

Detecting the cancer in its early stages, when treatment is most effective, becomes increasingly crucial as the disease progresses. The prognosis for colon cancer patients varies depending on the stage of the disease.

  • Stage 0, I, II and III colon cancer is usually treatable.

  • However, the chances of curing higher stages are lower.

  • Stage IV cancer is generally not curable, with a few exceptions.

Early detection and removal of noncancerous polyps in the colon and rectum can help prevent colon cancer from developing, emphasizing the importance of regular screening and early intervention.

Risk Factors

Comprehending the risk factors linked to colon cancer is pivotal for undertaking proactive steps to lessen the probability of disease development. Age is a significant risk factor, with studies indicating that by age 50, one in four individuals have polyps (abnormal tissue growths) that can develop into colon cancer. The proportion of patients diagnosed with colorectal cancer under the age of 50 has been increasing.

Multiple factors contribute to the development of colon cancer, such as family history, lifestyle choices, and certain inherited diseases like Lynch syndrome. Having a family history of colon cancer, as well as a history of adenomatous polyps (which can become cancerous), is linked to a higher risk of colon cancer.

Unhealthy lifestyle choices that are associated with an increased risk of colon cancer include:

  • Being overweight or obese

  • Lack of physical activity

  • Consuming diets high in red and processed meats

  • Smoking

  • Excessive alcohol consumption

Types of Colorectal Cancers

Colorectal cancers encompass various types, including:

  • Adenocarcinomas: the most prevalent type, accounting for more than 90% of cases. They develop in the cells lining the colon and rectum.

  • Carcinoid tumors: rare tumors that can exhibit aggressive behavior and have the potential to metastasize.

  • Lymphomas: cancers that develop in the lymphatic system.

Globally, colorectal cancer is the third most widespread form of cancer, constituting roughly 10% of all cancer cases. In 2018, there were an estimated 1,096,000 new cases of colon cancer and 704,000 new cases of rectal cancer. The overall incidence rate of colorectal cancer has decreased over the years, yet early detection and understanding of the various types of colorectal cancers remain essential for effective diagnosis and treatment.

Initial Assessment and Screening

Illustration of colonoscopy procedure

The initial step towards detecting and diagnosing colon cancer involves preliminary assessment and screening. Methods employed to screen for colorectal cancer include:

  • Fecal occult blood tests (FOBT)

  • Colonoscopies

  • Other imaging tests like virtual colonoscopies

  • Stool DNA tests (newly developed)

Health insurance typically covers the cost of colorectal cancer screening tests, making regular screening more accessible for individuals.

If an abnormality is detected during a colorectal cancer screening test, additional tests or a colonoscopy might be suggested to confirm the presence of cancer. Colorectal cancer screening guidelines suggest that individuals at average risk should begin screening at age 50 and continue until age 75. Deciding which colorectal cancer screening test to utilize depends on factors such as age, risk factors, and personal preferences, which can be discussed with a healthcare provider.

Fecal Occult Blood Test (FOBT)

The Fecal Occult Blood Test (FOBT) is a diagnostic tool used to detect the presence of hidden blood in the stool, which can be an early indication of colon cancer. It is a non-invasive and cost-effective screening method that can be conveniently performed at home. The steps involved in an FOBT include:

  1. Collecting a small amount of stool using an applicator stick provided in the testing kit.

  2. Applying the stool sample onto a special card or slide.

  3. Sending the sample to a laboratory for analysis.

Despite its advantages, the FOBT does have some drawbacks. These include:

  • The possibility of false positives and false negatives

  • Limited sensitivity in detecting early-stage cancer

  • Dietary restrictions prior to the test

  • The requirement of invasive follow-up tests if results are positive

The sensitivity of an FOBT in detecting colon cancer ranges from 25.5% to 86.3%, while its specificity ranges from 21.6% to 98.6%.


A colonoscopy is a more comprehensive screening method for detecting colon cancer and removing polyps. This procedure involves the following steps:

  1. Insertion of a long, flexible tube known as a colonoscope into the rectum to examine the colon.

  2. The colonoscope is fitted with a light and camera at the end, enabling the physician to visualize the colon and search for any irregularities, such as polyps or tumors.

  3. Special instruments can be passed through the colonoscope to biopsy or remove suspicious areas if necessary.

This makes a colonoscopy an effective way to detect colon cancer and precancerous polyps.

During a colonoscopy, the following steps are taken:

  1. A tube equipped with a tool is inserted into the rectum to extract polyps.

  2. The tool is utilized to cut the polyps out, particularly in the early stages when they are smaller.

  3. This procedure, referred to as a polypectomy, assists in the removal of polyps from the colon.

It is recommended to receive a colonoscopy for colon cancer screening every 10 years.

Advanced Diagnostic Techniques

MRI scan for colon cancer diagnosis

In certain instances, if the initial screening tests show abnormalities, advanced diagnostic techniques might be needed to confirm a diagnosis of colon cancer. These advanced techniques include:

  • Biopsies

  • Various imaging tests such as colonoscopy, angiography, MRI scans, and tumor marker tests

  • Blood tests, CEA blood tests, and other laboratory examinations conducted on biopsy samples

These techniques are employed to diagnose colorectal cancer.

The selection of a diagnostic technique is influenced by factors like the cancer stage, tumor location, and the patient’s overall health. Further tests may be suggested if a biopsy is not feasible.

Diagnostic colonoscopies, along with other imaging tests such as angiography and MRI scans, are vital for determining the cancer’s extent and whether it has metastasized to other body areas.


A biopsy is an essential diagnostic tool for verifying the existence of cancer cells in the colon. It involves the removal of a small piece of tissue using a specialized instrument passed through a scope. The tissue sample is then sent to a laboratory for analysis. There are various types of biopsies used to diagnose colon cancer, including needle biopsy, endoscopic biopsy, and punch biopsy.

The type of biopsy chosen is influenced by factors like the cancer stage, tumor location, and the patient’s overall health. Some common types of biopsies include:

  • CT-guided needle biopsy: This procedure uses a CT scan to guide a biopsy needle into a mass to obtain a tissue sample for assessment.

  • Fine needle aspiration (FNA) biopsy: This technique utilizes a thin slender needle to extract cell samples from an area of concern for further analysis.

  • Core needle biopsy: This method uses a thicker needle to extract a core tissue sample for detailed examination.

  • Surgical biopsy: This involves the removal of a larger sample of tissue through surgery.

Biopsies are instrumental in confirming the existence of cancer cells, which is crucial for devising the most suitable treatment plan.

Imaging Tests

Imaging tests, such as CT scans, MRI scans, and ultrasounds, are used to detect the extent of colon cancer and its spread. A CT scan creates detailed cross-sectional images of the body and can help determine if colorectal cancer has spread to adjacent lymph nodes or other organs. An MRI scan utilizes radio waves and strong magnets to produce detailed images of soft tissues within the body.

Endorectal ultrasound is a test that uses a specific transducer inserted into the rectum to ascertain the extent to which a cancer has infiltrated the rectal wall and whether it has extended to adjacent organs or lymph nodes. The choice of imaging test depends on factors such as the stage of the cancer, the location of the tumor, and the overall health of the patient.

These imaging tests are crucial in deciding the most appropriate treatment plan for colon cancer patients.

Staging Colon Cancer

Illustration of TNM staging system

The staging of colon cancer is a critical step in assessing the severity and extent of the disease. The American Joint Committee on Cancer (AJCC) TNM system is used for colon cancer staging and is based on three key factors: Tumor (T), Node (N), and Metastasis (M). The staging process evaluates the size and extent of the primary tumor, the involvement of nearby lymph nodes, and the presence of distant metastasis, which helps guide treatment decisions.

Comprehending the stage of colon cancer is pivotal in formulating an appropriate treatment plan, as treatments can differ based on the disease stage. Cancer stages range from 0 to 4, with stage 0 being the earliest stage and stage 4 being the most advanced. Higher stages are less likely to be cured, and stage IV cancer is generally not curable, though there are exceptions.

TNM Staging System

The TNM staging system for colon cancer is based on three key factors:

  • Tumor (T): describes the size and extent of the primary tumor

  • Node (N): describes the involvement of nearby lymph nodes

  • Metastasis (M): describes the presence of distant metastasis

This system, endorsed by the National Cancer Institute, is utilized to ascertain the stage of colon cancer and guide treatment decisions accordingly.

The T stage is indicative of the size of the tumor and whether it has infiltrated neighboring tissues or organs. The N stage is based on the quantity of metastatic lymph nodes, with a numerical value following the N indicating the number of lymph nodes containing cancer. The M stage assesses the presence of distant metastasis, such as cancer spreading to the liver or lungs.

Stage 0-4

Colon cancer stages range from 0 to 4, with stage 0 being the earliest stage and stage 4 being the most advanced. Here is a breakdown of each stage:

  1. Stage 0 colon cancer: This is a very early cancer, often referred to as carcinoma in situ. The cancer cells are confined to the innermost lining of the colon or rectum.

  2. Stage I colon cancer: The cancer has grown into the muscular layer of the colon but has not spread to the lymph nodes or other organs.

  3. Stage II colon cancer: The cancer has grown through the wall of the colon or rectum but has not yet spread to the lymph nodes or other organs.

  4. Stage III colon cancer: The cancer has spread to nearby lymph nodes but not to other parts of the body.

  5. Stage IV colon cancer: The cancer has metastasized to distant organs, such as the liver, lungs, or peritoneum.

The stage of colon cancer is instrumental in deciding the appropriate treatment options. Treatment for colon cancer can include:

  • Surgery

  • Chemotherapy

  • Radiation

  • Other therapies

The precise treatment plan is determined based on the stage of the cancer.

Treatment Options Based on Diagnosis

Chemotherapy treatment for colon cancer

Once colon cancer has been diagnosed and staged, a treatment plan can be formulated based on the individual’s specific diagnosis. Treatment options for colon cancer include:

  • Surgery

  • Chemotherapy

  • Radiation therapy

  • Targeted therapy

  • Immunotherapy

Surgery is the primary treatment for colon cancer, with options varying depending on the stage and location of the tumor.

Chemotherapy and radiation therapy are also utilized in colon cancer treatment, with chemotherapy targeting and destroying rapidly dividing cells in the body and radiation therapy directing powerful energy beams at cancer cells to destroy them. Targeted therapy and immunotherapy are newer treatment options for advanced colon cancer, focusing on specific cancer cell characteristics and augmenting the immune system.


Surgery is the primary treatment for colon cancer, and the type of surgery chosen depends on the cancer stage, tumor location, and the patient’s overall health. Various surgical options for colon cancer include:

  • Hemicolectomy

  • Partial colectomy

  • Segmental resection

  • Open surgery

  • Laparoscopic surgery

  • Robotic surgery

  • Polypectomy

Following colon cancer surgery, the recovery process typically involves getting up and walking within 24 hours, with bowel functions returning within 2 to 3 days. The hospital stay usually lasts a few days, and full recovery may take up to 6 weeks. During this time, it is advised to avoid strenuous activities, heavy lifting, and contact sports.

Chemotherapy and Radiation Therapy

Chemotherapy and radiation therapy, which aim to kill cancer cells, shrink tumors, and prevent recurrence, are employed in treating colon cancer patients. Chemotherapy utilizes potent medications to eradicate cancer cells, targeting and destroying rapidly dividing cells in the body. However, it can also impact healthy cells that divide quickly, resulting in adverse effects. Common chemotherapy protocols for colon cancer treatment include 5-Fluorouracil (5-FU), Capecitabine, and Oxaliplatin, often used in combination regimens such as FOLFOX (5-FU, leucovorin, and oxaliplatin) or CAPOX (capecitabine and oxaliplatin).

Radiation therapy is a powerful way to battle cancer cells. It uses beams of energy to destroy them. This treatment can facilitate the complete removal of the tumor and aid in preventing the recurrence of the disease. Researchers have found that inhibiting a specific protein located in cancer cells can make radiation therapy more successful for colon cancer. The energy employed in radiation therapy can be derived from X-rays, protons, or other sources.

Targeted Therapy and Immunotherapy

Targeted therapy and immunotherapy are recent treatment options for advanced colon cancer. Targeted therapy is a type of treatment that utilizes medicines to specifically target certain chemicals in cancer cells, such as:

  • Bevacizumab (Avastin)

  • Ramucirumab (Cyramza)

  • Ziv-aflibercept (Zaltrap)

  • Cetuximab (Erbitux)

  • Panitumumab

This form of treatment focuses on specific cancer cell characteristics, making it a more precise approach compared to traditional chemotherapy.

Immunotherapy, on the other hand, is a treatment utilizing medicine that assists the body’s immune system in eliminating cancer cells. Colon cancer that has progressed to an advanced stage is usually treated with immunotherapy. Other cancer treatments may also be used depending on the individual’s case. By boosting the immune system, immunotherapy helps the body recognize and attack cancer cells, providing a potentially effective treatment option for patients with advanced colon cancer.

Coping and Support

Dealing with a colon cancer diagnosis can be tough, but there are available strategies to offer support and aid patients during this difficult period. Identifying a reliable confidant, such as a friend or family member, to discuss feelings and concerns can provide emotional support and help alleviate stress. Consulting with a mental health professional, such as a counselor or therapist, can also provide valuable guidance and coping strategies for dealing with the emotional impact of a cancer diagnosis.

Joining a support group for colon cancer patients can provide multiple benefits, including:

  • Improved quality of life

  • Increased survival rates

  • Emotional assistance

  • A feeling of inclusion

  • A network of people who comprehend the difficulties of living with colon cancer

  • Educational resources and information to assist patients in managing their cancer experience

Prevention and Early Detection Strategies

Preventing colon cancer and early detection are pivotal to lessen the risk of disease development and enhance treatment outcomes. Regular screening, maintaining a healthy lifestyle, and being aware of risk factors associated with colon cancer are key prevention strategies. It is recommended that adults begin colon cancer screening at the age of 45 and above, with certain risk factors, such as a family history of colon cancer or a personal history of colorectal polyps or inflammatory bowel disease, necessitating earlier or more frequent testing.

Adopting a healthy lifestyle may assist in reducing the risk of colon cancer. This includes:

  • Sustaining a healthy weight

  • Engaging in regular exercise

  • Consuming a nutritious diet comprising vegetables, fruits, and whole grains

  • Restraining alcohol consumption

  • Refraining from smoking

  • Emphasizing fruits, vegetables, unprocessed cereals

  • Decreasing red meat consumption

These practices are recommended for lowering the risk of colon cancer.


In summary, understanding colon cancer, its risk factors, diagnostic procedures, and treatment options is essential for effectively managing the disease and improving patient outcomes. Early detection and prevention through regular screening, maintaining a healthy lifestyle, and being aware of risk factors can make a significant difference in the prognosis and quality of life for colon cancer patients.

As we conclude this comprehensive guide, remember that knowledge is power in the fight against colon cancer. By staying informed and taking proactive measures, you can take control of your health and contribute to the ongoing battle against this prevalent disease.

Frequently Asked Questions

How do they diagnose colon cancer?

Colon cancer is usually diagnosed through a colonoscopy, during which the doctor examines the rectum and colon using an endoscope. A biopsy may also be taken to confirm the diagnosis, in which tissue samples are collected for laboratory analysis by a pathologist.

Can you have stage 4 colon cancer and not know it?

It is possible to have stage 4 colon cancer and not know it, as early stages often don’t have symptoms and some people may not experience any symptoms when the cancer has metastasized. Early detection is therefore key in order to give the best chance of successful treatment.

What is the survival rate for colon cancer?

The five-year survival rate for localized colon cancer is 90%, while the five-year survival rate for distant colon cancer is 74%, and 17% if the cancer has spread to distant parts of the body.

How treatable is colon cancer?

Colon cancer is highly treatable and often curable when caught early, with the five-year survival rate being 90 percent. Surgery is the primary form of treatment and can result in a cure for approximately 50 percent of patients. However, recurrence after surgery is a major concern and can be the ultimate cause of death.

At what age should I begin colon cancer screening?

It is recommended that adults begin colon cancer screening at the age of 45 and above.

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