Colorectal Cancer Management: What to Know

Colorectal cancer is the fourth most commonly diagnosed cancer in the United States, affecting patients of all sexes. While it is generally diagnosed in older adults, it can also occur in younger individuals. Fortunately, diagnosis rates are beginning to decline thanks to reduced risk through lifestyle changes, improved treatments and better screening techniques.

This article provides an overview of colorectal cancer, explains the difference between colon and rectal cancers, briefly outlines diagnostic methods and discusses treatment and management strategies.

What is colorectal cancer?

The term “colorectal cancer” is often used to refer to either colon or rectal cancer, and it will be used interchangeably throughout this article. The key difference between the two is location: colon cancer occurs in the majority of the large intestine, while rectal cancer is diagnosed only when the cancer is found in the last 12 centimeters of the large intestine, known as the rectum. Both types develop in the large intestine, but they differ based on where the cancer is located within the organ.

Colorectal cancer develops when cells in the colon or rectum divide and grow out of control. If left untreated, it can interfere with organ function, impact the digestive and waste systems, spread to nearby lymph nodes and potentially reach other parts of the body such as the bones or other organs. In many cases, colorectal cancer begins as a growth called a polyp, which can be an early indicator of the disease. However, not all polyps are cancerous—many are benign. In fact, only about 5 to 10 percent of polyps become malignant.

Colorectal cancer diagnosis

Ct scan of a patient’s colon

There are several methods used to diagnose colorectal cancer, which are often used in combination with each other based on the individual patient’s symptoms and medical history. Below is a brief overview of these diagnostic techniques.

Blood tests

Certain signs of colorectal cancer may be detected through blood tests analyzed in a laboratory. Physicians often order a complete blood count, among other tests, to evaluate overall body function. Some key indicators they look for include:

Liver enzymes: Advanced colorectal cancer can impact liver function, so this test helps assess how well the liver is working.
Anemia: A lower-than-normal red blood cell count may indicate internal bleeding caused by a tumor in the colon or rectum, which can be a sign of cancer.
Tumor marker tests: Some cancer cells produce substances known as tumor markers. For colorectal cancer, a common example is carcinoembryonic antigen (CEA). Elevated CEA levels in the blood may suggest the presence of cancer.

Stool tests

A variety of stool tests are available to analyze a patient’s feces for signs of colon or rectal cancer. These tests typically look for the presence of blood, DNA or RNA mutations and other abnormalities.

Colonoscopy

One of the most common methods for screening or diagnosing colorectal cancer is a colonoscopy. This procedure involves inserting a thin, flexible tube equipped with a camera and tools (called an endoscope) into the patient’s anus, allowing it to pass through the rectum and colon. During a colonoscopy, the physician looks for polyps, abnormal growths and other signs of colorectal cancer. If a polyp is found, it can often be removed and sent for analysis to check for cancer cells.

Colonoscopies may be diagnostic—performed when a patient shows symptoms of possible cancer—or used for routine screening. As a screening tool, a colonoscopy helps detect colorectal cancer early, when it is most treatable.

Sigmoidoscopy

A sigmoidoscopy is similar to a colonoscopy, using the same type of medical equipment and technique. However, it focuses only on the lower part of the colon and the rectum, rather than the entire large intestine. This makes the procedure quicker and less complex. It is typically used when a physician suspects abnormalities are closer to the rectum rather than deeper within the colon.

Biopsy

One of the most definitive methods for diagnosing colorectal cancer is a biopsy. This typically involves collecting a sample from a polyp or abnormal tissue removed during a colonoscopy. The sample is then analyzed in a laboratory to check for cancer cells, genetic mutations, specific proteins and other markers that can be helpful when determining treatment options.

Diagnostic imaging

Diagnostic imaging plays an essential role in evaluating colorectal cancer. While procedures like colonoscopies and biopsies are vital for confirming or ruling out the disease, imaging helps determine whether the cancer has spread to other parts of the body. Common imaging methods include:

Ultrasound: This technique uses high-frequency sound waves that bounce off internal structures to create real-time images. A handheld device called a transducer generates the sound waves and captures the echoes. It can be moved externally for an abdominal ultrasound or inserted into the rectum for more detailed views, especially in the pelvic region.
CT Scan: Computed tomography (CT) scans use low-dose X-ray radiation to capture multiple cross-sectional images of the body. These slices are compiled into a detailed, three-dimensional image. While traditional X-rays may also be used, CT scans provide far more detail.
MRI Scan: Magnetic resonance imaging (MRI) uses strong magnetic fields and radio waves to produce high-resolution images of organs and tissues. A contrast dye is often injected into the patient’s arm to help highlight specific areas and improve clarity.
PET Scan: Positron emission tomography (PET) scans involve injecting a small amount of a radioactive substance, known as a radiotracer, into the bloodstream. A special camera tracks how the tracer is absorbed by tissues. Since cancer cells typically absorb the tracer at a higher rate than normal tissue, PET scans can help detect whether cancer has spread.

How is colorectal cancer staged?

Staging colorectal cancer is a critical step in understanding how advanced the disease is and determining the most effective treatment approach. The stage reflects how far the cancer has spread within the colon or rectum and to other parts of the body. Below are the main stages to be aware of:

Stage 0: Also called carcinoma in situ, this is when precancerous cells are found in the inner layer of the wall of the colon. It is the easiest stage to treat.
Stage 1: Cancer cells have also moved into the intestinal wall but haven’t spread past the muscular layer or other regions.
Stage 2: Cancer cells have spread deeper into the wall of the intestine, but haven’t spread to the lymph nodes. The subtypes include:
1. Stage IIA: Cancer has spread to the majority of the inner colon wall but hasn’t spread to the outer layer.
2. Stage IIB: Cancer cells have spread into the colon’s outer layer.
3. Stage IIC: Cancer cells have spread to a nearby organ.
Stage 3: Cancer cells have grown and spread to the lymph nodes. Sub-stages include:
1. Stage IIIA: Cancer cells have infiltrated the first or second layers of the colon wall and have also spread to 1–4 lymph nodes.
2. Stage IIIB: The colon wall has multiple cancerous layers, but it has only spread to 1–3 lymph nodes.
3. Stage IIIC: Cancer cells have spread to the outermost layer of the colon and have affected four or more lymph nodes, or it is in one or more lymph nodes as well as a nearby organ.
Stage 4: Colorectal cancer has spread to other areas of the body, such as organs or bones. This is also called metastatic cancer and it is the most challenging to treat. Sub-stages include:
1. Stage IVA: Cancer cells have spread to regions or lymph nodes farther away from the colon.
2. Stage IVB: Cancer cells have spread to additional lymph nodes and multiple organs farther away from the colon.
3. Stage IVC: The cancer has spread to lymph nodes, organs farther from the colon and to abdominal tissues.

Treating colorectal cancer

There are several treatment options available for colorectal cancer, and the approach typically depends on the stage of the disease, the patient’s medical history and personalized recommendations from the care team. Colon cancer treatments are often used in combination, tailored to the specific needs and circumstances of each patient.

Chemotherapy

Chemotherapy involves the use of drugs to kill or shrink cancer cells. These medications are typically administered intravenously, though some forms can be taken orally. If surgery is part of the treatment plan, chemotherapy may be given afterward to eliminate any remaining cancer cells. In some cases, it is used before surgery to shrink tumors or even as an alternative to surgery. Common side effects include fatigue, nausea, temporary hair loss and an increased risk of infection.

Targeted therapy

Some cancers rely on specific proteins or molecules to grow and spread. Targeted therapy uses medications designed to focus on these substances, blocking their activity and effectively cutting off the cancer’s fuel source. This approach can help slow or stop the growth and spread of cancer cells.

Immunotherapy

Immunotherapy involves the use of medications that enhance the patient’s own immune system to fight cancer. Because cancer cells can often evade detection by the immune system, these treatments help the body recognize and target them more effectively, improving its ability to destroy cancer cells.

Radiation

Radiation therapy uses high-energy beams, such as X-rays or protons, to kill cancer cells. It is often used after surgery to help eliminate any remaining cancer cells and reduce the risk of recurrence. By directly targeting affected areas, radiation can be an effective part of a comprehensive treatment plan. Common side effects may include fatigue, inflammation and skin irritation similar to a sunburn.

Ablation

Often used for patients with metastatic colon cancer, ablation involves the use of high temperatures to destroy tumors and cancer cells. As a less invasive alternative to surgery, it is a suitable option for patients with advanced cancers that are more difficult to treat surgically. Ablation typically results in quicker recovery times and fewer complications. This procedure is also referred to as microwave ablation or thermal ablation.

There are variations of ablation techniques as well. Radiofrequency ablation uses radio waves to generate the heat needed to destroy cancer cells. Cryoablation, on the other hand, uses extreme cold instead of heat to target and eliminate cancerous tissue.

Surgical options

Surgery can be a highly effective treatment method for many colorectal cancer cases. Some possible methodologies include:

Polypectomy: Surgically removing a polyp or polyps.
Partial colectomy/colon resection: The part of the colon containing the tumor is removed surgically, along with some of the adjacent tissue that may also contain cancer cells. After the affected portion is removed, the remaining healthy sections of the colon are reattached.
Resection with colostomy: This surgery is similar to a partial resection, but after the tumor removal the healthy sections of the colon are not reconnected. Instead, surgeons make an opening in the abdominal wall, redirecting the bowel through it so that stool can be collected in a bag for removal.

Getting your results

Turnaround times for imaging results can vary widely depending on the facility and your doctor’s availability. Often, patients wait a week or more and receive their results during a follow-up appointment. With PocketHealth, you don’t have to wait as long—your results are securely accessible as soon as the report is available, allowing you to review them often before your follow-up visit.

Your imaging results are interpreted by a radiologist—an expert in medical imaging—who carefully reviews your scans and provides a detailed report of any findings. This report is then sent to your referring doctor, who, with a deeper understanding of your medical history, can offer further insights and recommendations.

To better understand your imaging reports, Report Reader provides clear, straightforward definitions for medical terms. Simply tap or click on any underlined words to reveal their meaning. This is paired with illustrations and highlights of anatomy in your imaging to help you better understand your results and prepare for follow-up appointments.

Frequently asked questions

Here are some commonly asked questions regarding colorectal cancer.

Who is at higher risk for colorectal cancers?

Anyone can potentially develop colon or rectal cancer, but there are some factors that may increase this risk, including:

Eating a diet high in red and processed meat
Being overweight
Smoking
Having type 2 diabetes
Moderate to heavy alcohol use
Family history of colorectal cancer
Personal history of inflammatory bowel disease
Having certain inherited genetic conditions, such as cystic fibrosis

It’s important to remember that having one or more risk factors does not mean you will develop cancer. If you have concerns or would like guidance tailored to your personal health, consider speaking with your medical provider.

What is the recommended age for routine colonoscopies?

The U.S. Preventive Services Task Force recommends that all adults begin screening colonoscopies at age 45 and continue every ten years until age 75. After 75, additional screenings may be considered on a case-by-case basis in consultation with a healthcare provider.

If any non-cancerous findings are detected—such as a benign polyp—follow-up screenings may be scheduled more frequently, often every five years instead of ten. These preventative screenings can be very effective at catching colorectal cancers early, when they are easier to treat.

How long does treatment for colorectal cancer typically last?

Treatment timelines for colorectal cancer can vary widely based on factors such as the stage of the disease, the patient’s overall health and other individual considerations. In early-stage cases, treatment may last from one to six months, depending on the approach used. For more advanced cases, patients may undergo treatment intermittently over a longer period, influenced by factors like recurrence, the extent of spread and the need for surgery.

How common is colorectal cancer?

Colorectal cancer is the fourth most common type of cancer affecting people of all sexes and genders. Approximately 1 in 24 individuals will be diagnosed with it at some point in their lifetime. The good news is that colorectal cancer is highly treatable when detected early. Staying up to date with routine screenings and discussing any symptoms or concerns with your doctor are key steps in protecting your health.

Getting support

For anyone navigating a colorectal cancer diagnosis, it’s understandable to feel overwhelmed. Seeking support—whether emotional, practical or informational—can make a significant difference during treatment and recovery. Your doctor may be able to recommend local support groups and community resources. In addition, here is a list of online support tools that offer guidance on managing transportation, finances and lifestyle changes related to cancer care:

Take control of your health journey

PocketHealth makes it simple to keep track of your colorectal scans. All of your vital imaging is in one secure location and can be accessed online anytime. Reports can also be easily shared with other physicians in your care team, if needed. Additionally, it makes it easy to track health changes over time, such as with repeat imaging. When used in conjunction with your medical provider’s professional advice, it is a powerful tool for organizing and understanding your imaging results and your health.

PocketHealth MyCare Navigator gives personalized insights into your health and identifies any recommended follow-up steps. This feature can also generate individualized questions to ask your doctor based on the findings in your report, ensuring you make the most of your consultation. A colorectal cancer diagnosis may feel overwhelming, but working closely with your providers can give you the best chance of managing your condition and protecting your health.