Colorectal cancer

Last updated date: 13-Mar-2023

Originally Written in English

Colorectal Cancer

Colorectal Cancer

Healthy cells in the lining of the colon or rectum alter and grow uncontrollably to form a mass known as a tumor, which is how colorectal cancer develops. A tumor may be benign or malignant. Malignant refers to the ability of a cancerous tumor to proliferate and metastasize to different body areas.


What is Colorectal Cancer?

digestive system

The digestive system ends with the large intestine. The colon, which makes up the first 6 feet of the large intestine (colon), and the rectum, which makes up the final six inches and terminates in the anus, are its two parts. Colorectal cancer is a term that is frequently used to describe cancers of the colon and rectum.

When colon or rectum cells divide inappropriately, colorectal cancers develop. The majority of colorectal cancers begin as polyps, which are tiny tissue overgrowths in the colon's lining. The majority of polyps are benign (non-cancerous), but some might enlarge uncontrollably and develop into cancer.

More precisely, adenocarcinomas make up the majority of colorectal cancer cases. Cancers known as adenocarcinomas start in the cells that line the colon and produce mucus. Within polyps, these glandular cells can be discovered. While there are a few additional forms of colon cancer, they are uncommon and require special care.

It is crucial to undergo routine colon cancer screenings because the majority of precancerous polyps exhibit few, if any, symptoms. Your physician can locate and remove polyps before they develop into cancer thanks to colorectal cancer screenings.


Colorectal Cancer Risk Factors

Colorectal Cancer Risk Factors

A risk factor is anything that raises your likelihood of developing colorectal cancer. Risk factors for colorectal cancer include:

  • Age.  The most common age range for colorectal cancer diagnoses is 65 to 74. 67 is the average age at diagnosis.
  • Race. Of all racial groupings in the US, African Americans have the highest prevalence of colon cancer.
  • Family history of polyps or colorectal cancer.
  • Inflammatory bowel diseases (Crohn's disease or ulcerative colitis).
  • Personal history of polyps or colorectal cancer.
  • Hereditary cancer syndromes. Some genetic alterations can be passed down through families and put you at higher risk for developing specific cancers. You may be more susceptible to getting colon cancer if you have inherited syndromes such as familial adenomatous polyposis (FAP) or hereditary nonpolyposis colorectal cancer (HNPCC syndrome).

Many doctors provide cutting-edge genetic testing and counseling to individuals who are worried about inherited familial disorders that lead to colorectal cancer to better understand your risk.

Your risk of colorectal cancer is increased by the following lifestyle factors:

  • Obesity
  • Inadequate exercise
  • Diet. Consuming large amounts of red meat, processed meats, or meats cooked at extremely high heat may increase your risk of developing colon cancer.
  • Sedentary lifestyle
  • Smoking
  • Binging on alcohol


Colorectal Cancer Symptoms

Colorectal Cancer Symptoms

Usually, colorectal cancer begins as a tiny polyp (tissue overgrowth) in the colon or rectum. In their early stages, these polyps may not show any symptoms. There may be an increase in symptoms as the condition worsens. Colorectal cancer symptoms can include:

  • Constipation or diarrhea that doesn't go away
  • Changes in the size, form, and frequency of one's regular bowel movements
  • Discomfort or the urge to defecate despite not having stool
  • Lower stomach ache or cramps in the abdomen
  • Feeling bloated or overstuffed
  • Change in appetite
  • Rectal hemorrhage
  • Blood after a bowel movement in the toilet on the stool
  • Excessive fatigue
  • Loss of weight without dieting

The polyp may metastasize (travel) to other parts of the body in the advanced stages of colorectal cancer. Depending on where cancer has spread, this can result in other symptoms.

Typically, these symptoms do not indicate colorectal cancer. However, never assume unexplained alterations will disappear if you see them and they last for longer than two weeks. Go to the doctor.


How Colon Cancer is Diagnosed?

colorectal cancer Diagnosis

 Routine screening can detect colorectal cancer. Other times, doctors will request more testing after speaking with a patient about their concerns.

The tests listed below can be used to identify colorectal cancer or determine whether it has spread. Tests may also be conducted to determine whether the treatment has harmed any nearby tissues or organs.


Colorectal Cancer Screening

Starting at age 45, it is advised that you begin routine colorectal cancer screenings if you have an average risk of the disease. There are various at-home non-invasive colon cancer screening tests available. These tests cannot provide a conclusive diagnosis of colon cancer, but they can suggest the need for other, more precise diagnostics. At-home screening tests come in a variety of forms:

  • Fecal DNA test (FDNA). This at-home test detects DNA alterations in the cells of a feces sample.
  • Fecal immunochemical test (FIT). This at-home test detects the presence of blood proteins in stools.
  • Fecal occult blood test (FOBT). This at-home test detects the presence of blood in the stool.

Endoscopic examinations are other, more invasive colorectal cancer screening techniques. To ensure your comfort, these procedures are typically carried out while you are sedated. Your doctor can view the inside of your colon thanks to endoscopic procedures. Endoscopic examinations may involve:

  • Colonoscopy.  A colonoscope, or small camera, is introduced into the rectum and moved through the colon. As a result, the doctor can see the whole colon. To check for tumor cells, tissue or polyps can be collected (biopsied) and examined under a microscope.
  • Sigmoidoscopy. Similar to a colonoscopy but just examines the lower colon and rectum.


Diagnostic Tests

Your doctor could suggest further tests if you have colorectal cancer symptoms or have had abnormal screening test results to get a more definitive diagnosis and follow the disease's course. These tests could consist of:

  • Blood tests. While no blood test can accurately identify colon cancer, they can give your doctor additional details about your health, such as how well your kidneys and liver are functioning. Additionally, a carcinoembryonic (CEA) antigen test can be performed on your blood. Some malignant tumors produce CEA, a protein that serves as a tumor marker. This test can also be used to determine whether the tumor is spreading, responding to therapy, or recurring after therapy.
  • Imaging tests. Imaging tests can be used to assess if colorectal cancer has metastasized to other parts of the body and to offer precise information about the extent or location of the disease. The following imaging procedures are frequently used: CT or CAT scans (computed axial tomography), MRI scans (including specialized rectal cancer MRIs), and PET/CT scans (positron emission tomography scans).


Other Imaging Tests

  • CT (computed tomography) or virtual colonoscopy.  A targeted CT scan of your abdomen and pelvis is used during a colonoscopy to produce three-dimensional images that can reveal polyps and other irregularities in your colon and rectum. Patients who have health issues that make conventional colonoscopies riskier, such as bleeding disorders, can use this test.
  • Endoscopic ultrasound (EUS). It involves inserting a flexible tube with an ultrasound device at the tip through the rectum into the colon. Images of the colon and the surrounding tissue are produced by the device using ultrasonic waves. With the aid of this technique, a doctor can assess the extent of a tumor's colonic wall invasion. Additionally, it can be used to check for cancer spread in surrounding lymph nodes.
  • Double-contrast barium enema (DCBE). Using a substance called barium, a procedure known as a double contrast barium enema makes the gut lining visible on an X-ray. After administering a barium solution via enema, many X-rays are taken.


Colorectal Cancer Staging

The stage of the disease will be determined by your doctor if you are given a colorectal cancer diagnosis. When cancer is discovered, it is staged according to how much of the disease is present in the body and where it has spread. This aids the doctor's planning of the most effective cancer treatment. Before starting treatment, staging should be carried out.

  • Stage 0. The inner lining of the colon tissue contains abnormal cells. These aberrant cells could develop into cancer and metastasize to surrounding healthy tissue. Cancer in situ is another name for stage 0.
  • Stage one. Cancer developed and spread in the first or second layers of the intestinal wall. It hasn't gotten past the bowel.
  • Stage two. Cancer has moved outside the rectal walls and into the adjacent fat or tissue. The lymph nodes have not been affected by it. Depending on the degree of local tumor involvement, it is categorized into stages IIA, IIB, or IIC.
  • Stage three. Cancer has reached the surrounding lymph nodes. Other body parts have not been affected by its spread. Depending on the number of lymph nodes that have cancer and the degree of the local tumor involvement, it is classified as stage IIIA, IIIB, or IIIC.
  • Stage four. Cancer has gone to the liver, lungs, or ovaries, among other organs. Depending on how many more body parts or locations cancer has gone to, it is categorized into stages IVA, IVB, and IVC.


Colorectal Cancer Treatment

Colorectal Cancer Treatment

The minimally invasive procedures the surgeons employ to speed up your recovery and improve your quality of life. One or more of the following treatments may be used during your colorectal cancer therapy.


colorectal cancer surgery

The most frequent course of action for colorectal cancer is surgery, particularly if it has not metastasized. Similar to many other diseases, colorectal cancer surgery is most effective when carried out by a surgeon with extensive experience in the technique. Colorectal cancer resection is conducted by surgeons who have specialized in the procedure and are thought experts in their fields on a national and international scale.

Depending on the tumor's stage and location, different types of surgery may be performed, including:

  • Polypectomy. The polyp is detected with a colonoscope, a long tube with a camera at one end, which is put into the rectum. The polyp is removed using tiny instruments or a wire loop. For stage 0 and isolated polyps, a polypectomy is suitable. If a polyp is too large to be removed by a conventional polypectomy, an endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) may be done. To do a precise operation from inside the colon, your doctor will utilize tiny instruments introduced through a colonoscope. Doctors will cut out the polyp and some of the surrounding tissue. Major surgery can occasionally be avoided with this kind of advanced endoscopic technique.
  • Colectomy. During a colectomy, the diseased portion of the colon is removed along with some healthy surrounding tissue and all of the lymph nodes that are connected to it. To find out if cancer has spread elsewhere, a microscope will be used to inspect the lymph nodes. The surgeon then connects the colon's remaining segments back together. Hemicolectomy and partial colectomy are other names for this procedure. Generally speaking, a minimally invasive technique can be used to execute it.
  • Proctectomy. When rectal cancer is present, your doctor will remove a portion of the rectum along with the tissue that surrounds it and contains lymph nodes. Typically, the colon can be lowered and connected to the residual rectum or the anus directly. This type of procedure, known as sphincter preservation surgery, enables you to maintain total control over your bowel movements. 
  • Pelvic exenteration. Rectal cancer may occasionally invade nearby pelvic structures through exenteration. If that has been done, it is crucial that the tumor and any other structures it has affected are thoroughly removed during surgery. A pelvic exenteration is a highly specialized procedure that entails the removal of any cancerous structures, including the rectum, a portion of the colon, the reproductive system, or the bladder. Your surgical team will subsequently perform reconstructive surgery following the removal of these structures. This can entail making new channels for waste to exit your body. Life-altering pelvic exenteration demands skilled health care.
  • Robotic or laparoscopic surgery. With minimally invasive surgery, small incisions are made in the belly to insert a tiny camera and surgical instruments. The surgery is then carried out by the surgeon using high-definition video imaging, including 3D. The doctors performing this are most skilled in performing robotic colorectal surgery.

Patients who undergo minimally invasive surgery can recover more quickly and with less discomfort. Your doctor will determine if minimally invasive robotic, laparoscopic, or open surgery is appropriate.

As with many cancers, colorectal cancer resection is most effective when carried out by a surgeon with extensive experience in the process. Colorectal cancer surgery is conducted by surgeons who have specialized in the procedure and are thought experts in their fields on a national and international scale.


Adjuvant and Neoadjuvant Therapy

Surgery, chemotherapy, or surgery, chemotherapy, and radiotherapy are all options for treating colorectal cancer. Radiation or chemotherapy may be administered as:

  • Neoadjuvant treatment is used before surgery.
  • Adjuvant treatment is used after surgery.

Neoadjuvant therapy typically aims to reduce the size of the tumor and make the patient more comfortable during surgery and recovery. Adjuvant therapy is used to eliminate any cancer cells that may have missed detection after surgery and to stop the disease from returning.



Chemotherapy employs potent medications to stop or slow the growth of cancer cells. It is a systemic therapy, which means it kills cancer cells everywhere in your body. For colorectal cancer, doctors provide the most recent and efficient chemotherapy options. Chemotherapy medications are administered intravenously (injected into a vein) or orally as pills. Chemotherapy could benefit:

  • Reduce tumor size before surgery
  • Prevent cancer after surgery
  • Prolonging life in the absence of surgery




To kill cancer cells, radiotherapy uses focused, high-energy photon beams. The most cutting-edge radiation therapies offered by hospitals include:

  • 3D-conformal radiation therapy. Multiple radiation beams are delivered in precisely the shape of the tumor during 3-dimensional conformal radiation therapy.
  • Intensity-modulated radiotherapy (IMRT). To minimize injury to healthy tissue, treatment is tailored to the unique shape of the tumor.
  • Proton therapy. It is a form of radiation treatment that targets cancer while minimizing damage to healthy tissues.
  • Brachytherapy. The tumor is treated with tiny radioactive seeds injected into the body.
  • Intraoperative radiation therapy (IORT). It is utilized during cancer surgery to treat an exposed tumor. Lead shields are used to screen nearby healthy organs and tissues from radiation or they are moved away from it.



Immunotherapy combats cancer by utilizing the body's built-in defenses. Specially formulated medications can activate the immune system's white blood cells (T cells), which can identify and kill cancer cells.

Immunotherapy was first utilized to strengthen the body's immunological response against cancer cells. More recently, as science has progressed, it has been found that T cells have several proteins on their surface that function as a brake, or checkpoint, blocking them from targeting cancer cells.


Colorectal Cancer Survival Rate

Colorectal Cancer Survival Rate

The prognosis is highly stage-dependent. The 5-year survival rate for cancer that has only spread to the mucosa is close to 90%; for cancer that has spread to the intestinal wall, it is 70% to 80%; for cancer that has positive lymph nodes, it is 30% to 50%; and for metastatic disease, it is 20%.



A considerable proportion of deaths are brought on by the prevalent malignancy known as colorectal cancer. When detected early enough, it is highly treatable with surgery alone and might be prevented by screening. Patients with more advanced stages of the disease continue to have better survival due to modern chemotherapy.