March is colorectal awareness month. Let’s explore its prevalence and impact on the Canadian and Saudi populations. 

What Is Colorectal Cancer? 

Colorectal cancer refers to the presence of malignant cells in the colon or rectum. Colon cancer and rectal cancer are grouped together because the tissue of the two organs is similar, and there is not a clear demarcation between them. 

Changes within the colon or rectum can result in precancerous conditions, including adenomas and hereditary colorectal syndromes. Cancer most often develops in the mucous glands of the colon and rectum, resulting in adenocarcinoma. In rare cases, small cell carcinoma and squamous cell carcinoma can develop in the colon or rectum. 

Who Is at Risk for Colorectal Cancer? 

Colorectal cancers are quite common. The Canadian Cancer Society estimates that over 24,000 Canadians were diagnosed with colorectal cancer in 2022, and the disease led to 94,000 deaths. It is the fourth most common cancer diagnosis in Canada. 

Colorectal cancer is more common in men than women. One in 14 Canadian men will develop colorectal cancer in their lifetime, compared to 1 in 18 women. 

In Saudi Arabia, colorectal cancer is the most diagnosed cancer in men and the third most common in women.

Age is a risk factor for colorectal cancers. Most cases are diagnosed in people over 40 years old, with incidence numbers rising in every decade of life after that. 

Other risk factors for colorectal cancer include:

• Family history of colorectal cancer or precancerous conditions
• Personal history of cancer such as breast, ovarian, and uterine cancer
• Inflammatory bowel disease
• Diabetes
• Ashkenazi Jewish ancestry
• Lifestyle factors such as excessive weight, a diet high in processed meats, smoking, alcohol consumption, or sedentary behaviour

What Are Current Treatments for Colorectal Cancer? 

Treatment varies by the stage and location of the cancer cells. The most commonly prescribed treatment protocols include:

• Surgery
• Radiofrequency ablation
• Cryosurgery
• Chemotherapy
• Radiation therapy
• Targeted therapy
• Immunotherapy

Surgery is typically the first line of treatment regardless of staging. Excision is often possible with local tumours, with surgery, ablation, or cryosurgery. Resection of the colon with anastomosis is used for larger tumours. In some cases, patients require resection of the colon with colostomy.

Follow-up treatment may be necessary when cancer has spread or surgery cannot remove all tumour cells. Rectal cancer has a higher likelihood of recurrence, so additional treatment and monitoring after surgery are often recommended. 

New and Recent Studies on Colorectal Cancer 

In recent years, research has focused on the screening and prevention of colorectal cancers. New screening methods such as fecal immunochemical tests (FIT), stool DNA testing, and blood tests to detect biomarkers related to colorectal cancer have shown promise. Less invasive imaging tests like CT colonography and capsule endoscopy are alternatives to traditional colonoscopy. 

Researchers have developed immunotherapies such as monoclonal antibodies and immune checkpoint inhibitors that provoke the immune system to attack cancer cells. Investigators are studying whether existing targeted therapy drugs are effective against colorectal cancers. 

Importance of Early Screening 

Colorectal cancer screenings allow doctors to identify precancerous changes and remove the abnormal cells before cancer can develop. Screening can also help identify cancer in earlier, more localized stages when treatment is easier. 

 In Saudi Arabia, the Saudi Cancer Registry found that almost 44.6% of patients diagnosed with colorectal cancer have a chance of five-year survival. In Canada, about 67% of people diagnosed with colorectal cancer will survive for at least 5 years after their diagnosis.

What Are the Early Symptoms and Signs of Colorectal Cancer? 

In the early stages, colorectal cancer may not cause any symptoms. As tumours grow and spread, patients may experience symptoms including:

• Diarrhea
• Constipation
• Rectum not feeling completely empty after a bowel movement
• Blood in the stool
• Rectal bleeding
• Gastrointestinal discomfort such as gas, abdominal cramps, and feeling bloated
• Rectal pain or discomfort
• Mass in the abdomen or rectum
• Fatigue and weakness
• Nausea and vomiting
• Changes in appetite
• Unexplained weight loss
• Bowel obstruction
• Swollen lymph nodes
• Pain in the abdomen, back, buttocks, or legs
• Difficulty breathing

When Should Healthcare Providers Refer Patients for Colorectal Cancer Screenings?

The Canadian Cancer Society recommends that adults ages 50 to 74 and those not at high risk for colorectal cancer should have a stool test every two years. People at higher risk should discuss additional screening options with their doctors.  

In Saudi Arabia, screening for colorectal cancer among asymptomatic persons at average-risk is recommended. The current recommended age to start screening is 45 years, however, further research on the threshold age is required. In most cases screening is not recommended for persons above the age of 70 years. Colonoscopy is recommended to be performed every 10 years, but if unavailable, flexible sigmoidoscopy (FS) every 5 years coupled with annual guaiac fecal occult blood testing (gFOBT) or FIT should be considered.

Patients showing symptoms of colorectal cancer should be referred for additional testing, including bloodwork, CT or MRI, and colonoscopy. Learn more about colorectal cancer by joining OncologyEducation to stay updated on the latest in oncology. 

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