Understanding Colorectal Cancer: An Overview and Risks

Introduction

Colorectal cancer, historically known as a disease of the developed world, has been a recognized health concern since the early 1900s. It is a cancer that starts in the colon or the rectum, collectively known as the large intestine. Over the decades, advancements in medical technology and scientific understanding have greatly improved our knowledge of colorectal cancer, its causes, and treatment options. This article aims to provide a comprehensive understanding of colorectal cancer, its progression, statistics, prevalence, and the various risk factors associated with it. In defining colorectal cancer, we can describe it as a malignant growth occurring in the inner wall of the large intestine.

Description of Colorectal Cancer

Colorectal cancer is a type of malignancy that originates from the inner lining of the colon or rectum. The progression of colorectal cancer typically starts with small, noncancerous (benign) clumps of cells known as polyps. Over time, some of these polyps can become cancerous. This transformation process, often spanning several years, offers opportunities for early detection and successful treatment.

Colorectal cancer ranks third in terms of incidence but second in terms of mortality worldwide. According to the World Health Organization, there were nearly 1.8 million new cases and 862,000 deaths from colorectal cancer in 2018. The American Cancer Society estimates that in 2023, there will be over 147,000 new cases and approximately 53,200 deaths from colorectal cancer in the United States alone. Therefore, awareness of the disease, its risk factors, and the importance of regular screening are critical in its prevention and control.

Risk Factors for developing Colorectal Cancer

Lifestyle Risk Factors

Various lifestyle factors can increase the likelihood of developing colorectal cancer. These include physical inactivity, a diet low in fiber and high in fat and calories, overweight and obesity, alcohol consumption, and tobacco use. Processed meats, red meats, and meats cooked at very high temperatures may also contribute to an increased risk.

Medical Risk Factors

Previous history of colorectal polyps or colorectal cancer, a personal or family history of inflammatory bowel disease (such as ulcerative colitis or Crohn’s disease), and certain types of inherited syndromes (like Lynch syndrome or familial adenomatous polyposis) increase the risk of colorectal cancer. Furthermore, individuals with Type 2 diabetes also have an increased risk of colorectal cancer.

Genetic and Age-Related Risk Factors

While colorectal cancer can occur at any age, the majority of people diagnosed are over the age of 50. Genetic factors play a significant role, with about 20% of people who develop colorectal cancer having a family member with the disease. Specific inherited genes can drastically increase the risk of colorectal cancer, but these gene changes are linked to only a small percentage of cases.

Clinical Manifestations

Rectal bleeding

Rectal bleeding, which may be seen as bright red blood in the toilet or on toilet paper, occurs in about 60% of colorectal cancer cases. This symptom often becomes more common as the disease advances and is often accompanied by other symptoms such as changes in bowel habits.

Blood in stool

Approximately 50-60% of individuals with colorectal cancer may observe blood mixed in with their stool, resulting from the tumor in the colon or rectum bleeding. It may appear as dark red or black, tarry stools. This symptom is common in all stages but often becomes more pronounced as the disease progresses.

Change in bowel habits

Changes in bowel habits such as diarrhea, constipation, or narrowing of the stool can occur in about 20-50% of patients. The tumor can interfere with normal bowel movement and function, leading to these changes. This symptom can occur at any stage but is more prevalent in advanced stages of the disease.

Abdominal pain

Abdominal pain, experienced by about 20-30% of patients, can result from a tumor causing blockage or bleeding within the colon. The pain may also be due to the cancer spreading to surrounding tissues or distant organs.

Weight loss

Unexplained weight loss, seen in about 20-30% of patients, occurs when the body’s energy expenditure exceeds caloric intake. This can be due to decreased appetite from a large tumor or the body’s response to a growing cancer.

Fatigue

Many cancer patients, including those with colorectal cancer, report feeling very tired or fatigued. This can occur due to the disease itself, iron deficiency from blood loss, or as a side effect of treatment.

Iron deficiency anemia

Iron deficiency anemia is observed in about 35-45% of colorectal cancer patients. It arises from chronic blood loss from the cancerous tumor in the colon or rectum. Symptoms include fatigue, paleness, and shortness of breath.

Narrow stools

Narrow stools, sometimes described as pencil-thin, can occur in colorectal cancer due to a blockage in the colon. It is estimated that about 20% of patients may experience this symptom.

Diagnostic Evaluation

The diagnosis of colorectal cancer involves a series of tests that help determine whether a person has the disease and, if so, at what stage it is. These tests also assist in determining the best course of treatment. Diagnosis usually involves a physical exam, history taking, and specific diagnostic procedures.

Colonoscopy

A colonoscopy is a test that allows the doctor to examine the entire length of the colon and rectum using a thin, flexible tube with a small camera attached. It is the most accurate test for detecting colorectal cancer and polyps and is usually performed under mild sedation. If a polyp or abnormal tissue is detected, a biopsy can be performed during the procedure. A positive result, indicating the presence of cancer cells, confirms the diagnosis of colorectal cancer.

Flexible sigmoidoscopy

A flexible sigmoidoscopy is similar to a colonoscopy, but it only allows the doctor to examine the rectum and the lower third of the colon. It’s less invasive than a colonoscopy and usually doesn’t require sedation. This test can detect polyps and cancer in the lower colon and rectum but might miss those in the upper colon. Like in a colonoscopy, a positive biopsy result confirms the diagnosis.

Fecal occult blood test (FOBT) and Fecal immunochemical test (FIT)

These tests detect hidden (occult) blood in the stool, which can be an early sign of cancer. However, not all cancers cause blood in the stool and not all blood in the stool is caused by cancer. Therefore, while a positive test may suggest the presence of colorectal cancer, additional tests are required to confirm the diagnosis.

CT colonography (virtual colonoscopy)

Also known as a virtual colonoscopy, a CT colonography uses CT scanning to produce a detailed image of the colon and rectum. It is less invasive than a conventional colonoscopy but also requires bowel prep. If suspicious areas are seen on this test, a conventional colonoscopy may still be needed to biopsy or remove polyps.

Biopsy

A biopsy involves removing a small amount of tissue for examination under a microscope. This is often done during a colonoscopy or sigmoidoscopy. Examination of the biopsy by a pathologist can confirm the diagnosis of colorectal cancer.

Blood tests

While blood tests alone cannot diagnose colorectal cancer, they can provide useful information. A complete blood count can detect anemia, a common sign of colorectal cancer. Measurement of carcinoembryonic antigen (CEA), a protein that can be elevated in colorectal cancer, can be used for monitoring response to treatment and detecting recurrence after treatment, rather than for initial diagnosis.

If all tests come back negative but symptoms persist, it’s crucial not to ignore them. Continue speaking with your healthcare provider about your symptoms. You may need additional testing or be referred to a specialist. Remember, you know your body best, and persistent symptoms warrant further investigation.

Health Conditions with Similar Symptoms to Colorectal cancer

Hemorrhoids

Hemorrhoids are swollen blood vessels in the rectum or anus that can cause discomfort, itching, and bleeding, particularly during bowel movements. Unlike colorectal cancer, hemorrhoids often cause discomfort or pain around the anus and the bleeding is usually bright red and occurs immediately following a bowel movement. A physical exam or an anoscopy can confirm the diagnosis of hemorrhoids.

Inflammatory bowel disease (IBD)

Inflammatory bowel disease, including conditions such as Crohn’s disease and ulcerative colitis, involves chronic inflammation of all or part of your digestive tract. Like colorectal cancer, IBD can cause abdominal pain, changes in bowel habits, and blood in the stool. However, IBD often comes with other symptoms not typically seen in colorectal cancer, such as fever, mouth sores, and skin and joint problems. Diagnosis typically involves a combination of endoscopy, imaging studies, and laboratory tests.

Anal fissures

Anal fissures are small tears in the lining of the anus that can cause pain and bleeding, particularly during or after bowel movements. The pain is often severe and the bleeding is bright red. Physical examination, possibly under anesthesia, is usually sufficient to diagnose anal fissures.

Diverticulosis

Diverticulosis is a condition where small pouches (diverticula) form in the wall of the colon. If these pouches become inflamed or infected, it can cause diverticulitis, which presents with abdominal pain and changes in bowel habits. However, fever and the nature of the abdominal pain (often localized in the lower left side of the abdomen) can help differentiate it from colorectal cancer. Diagnosis is usually confirmed by a CT scan.

Gastrointestinal infections

Gastrointestinal infections can cause symptoms like diarrhea, abdominal pain, and blood in the stool. However, these infections often cause fever and vomiting, symptoms that aren’t typical of colorectal cancer, and the symptoms usually resolve within a few days to a week. Diagnosis usually involves laboratory testing of a stool sample.

Benign polyps

Benign polyps are small, noncancerous growths in the lining of the colon. They can cause similar symptoms to colorectal cancer, but they often don’t cause any symptoms unless they become large. A colonoscopy can help differentiate benign polyps from colorectal cancer.

Irritable bowel syndrome (IBS)

Irritable bowel syndrome is a chronic disorder that affects the large intestine and can cause cramping, abdominal pain, bloating, and changes in bowel habits. Unlike colorectal cancer, IBS does not cause rectal bleeding or weight loss and often comes with periods of remission. A diagnosis of IBS is often made based on symptoms and ruling out other conditions.

Colitis

Colitis, inflammation of the inner lining of the colon, can cause abdominal pain, diarrhea, and blood in the stool. However, other symptoms like fever, joint pain, and, in some cases, symptoms related to liver inflammation can help distinguish it from colorectal cancer. Diagnosis typically involves endoscopy and laboratory tests.

Treatment Options

Medications

Chemotherapy drugs

Chemotherapy drugs, such as 5-fluorouracil and oxaliplatin, are used to kill cancer cells. These drugs are often used after surgery (adjuvant therapy) to kill any remaining cancer cells, or before surgery (neoadjuvant therapy) to shrink tumors. Side effects can include fatigue, nausea, and hair loss.

Targeted therapy drugs

Targeted therapy drugs, such as cetuximab and bevacizumab, are designed to target specific characteristics of cancer cells. They can be used when colorectal cancer is advanced or has come back after treatment. These drugs can help to slow the growth of the tumor and are typically used in combination with chemotherapy.

Immunotherapy drugs

Immunotherapy drugs, like pembrolizumab and nivolumab, work by helping the body’s immune system to recognize and attack cancer cells. They are generally used for advanced colorectal cancer when other treatments aren’t working. Side effects can include fatigue, cough, nausea, itching, skin rash, loss of appetite, constipation, joint pain, and diarrhea.

Anti-diarrheal medications and pain medications

These are used to manage symptoms of colorectal cancer and side effects of its treatment. Anti-diarrheal medications can help manage diarrhea, a common side effect of many cancer treatments. Pain medications can help manage pain, which may be a symptom of the cancer itself or a side effect of treatment.

Procedures

Surgery

Surgery is often the first-line treatment for colorectal cancer, particularly for early-stage cancers. The goal is to remove the tumor, along with a portion of healthy tissue on either side. In some cases, nearby lymph nodes are also removed and tested for cancer.

Chemotherapy

Chemotherapy uses powerful drugs to kill cancer cells throughout the body. It can be used after surgery to kill any remaining cancer cells, before surgery to shrink tumors, or as the main treatment for advanced cancer. Side effects can include fatigue, nausea, and hair loss.

Radiation therapy

Radiation therapy uses high-energy beams to kill cancer cells. It’s often used in combination with chemotherapy before surgery to shrink large tumors, making them easier to remove.

Targeted therapy

Targeted therapy uses drugs that target specific characteristics of cancer cells. It’s often used for advanced or recurrent colorectal cancer, and is typically used in combination with chemotherapy.

Immunotherapy

Immunotherapy uses treatments that boost the body’s natural defenses to fight cancer. It’s often used for advanced colorectal cancer when other treatments aren’t working.

Radiofrequency ablation and cryosurgery

These procedures can be used to treat some small tumors, or to relieve symptoms in cases of advanced cancer. Radiofrequency ablation uses high-energy radio waves to kill cancer cells, while cryosurgery uses extreme cold to freeze and destroy cancer cells.

Improving Colorectal Cancer Outcomes and Seeking Medical Help

Apart from medical treatments, a person’s lifestyle can significantly influence the progression and management of colorectal cancer. These home remedies are not a replacement for medical treatment, but they can support overall health and enhance the effectiveness of cancer treatments.

Living with Colorectal Cancer: Tips for Better Quality of Life

Living with colorectal cancer can be challenging, but there are strategies to manage the condition and maintain quality of life. In addition to the above home remedies, regular check-ups are crucial to monitor the progression of the disease and adjust treatments as needed. Thanks to telemedicine, these appointments can often be conducted from the comfort of your own home, reducing the need for travel and making healthcare more accessible.

Conclusion

Colorectal cancer is a significant health concern, but advances in detection and treatment offer hope. Understanding the disease, its risk factors, symptoms, and available treatments is key to managing the condition effectively. Embracing lifestyle changes can support your overall health and potentially improve cancer outcomes. However, if you experience any concerning symptoms, it’s important to seek medical help promptly. Early detection and treatment of colorectal cancer significantly increase the chances of successful treatment.

Remember, your healthcare team is your best resource for information and support. With the convenience of telemedicine, you can readily access professional care and advice from the comfort of home. Don’t hesitate to reach out to our primary care telemedicine practice for any concerns about colorectal cancer or other health issues.

Brief Legal Disclaimer: This article is for informational purposes only and not intended as medical advice. Always consult a healthcare professional for diagnosis and treatment. Reliance on the information provided here is at your own risk.