1. Due to instability of colon cells, more tumor suppressor cells are inactivated. This leads to growth of aggressive tumors that can metastasize.
2. Pathophysiology/Ethiology
2.1. Colon epithelial cells suffer from accumulating genetic modifications that cause cancer and inhibit tumor suppressor genes.
2.2. The cell that originated the tumor is called a"stem cell" and is crucial to initiate and maintain the tumor.
2.3. Polyps are sometimes benign, but can grow and turn into ademonas (larger than 1 cm) and possible metastasize to other organs and tissues.
2.4. Cancer cells are able to produce new blood vessels, resist cell death and start remodeling, invasions and metastasis.
2.5. The human body contains tumor suppressor genes and defenses against cancer genes. When the DNA of these genes modify, there is a production of cancer.
2.6. (Kuipers et al., 2015)
3. Causative Factors
3.1. Cancers can be caused by genetic factors or lifestyle behaviors
3.1.1. Most common hereditary colorectal cancer is due to Lynch syndrome (mutation from a DNA mismatch gene).
3.1.2. Second most common colorectal cancer is "familial adenomatous polyposis".
3.2. (Kuipers et al., 2015)
3.3. Tobbaco use
3.4. Alcohol comsumption
3.5. Lack of physical activity
3.6. Air pollution
3.7. Ionizing radiation
3.8. Obesity
3.9. Infections, such as Human Papillomaviruses
3.10. Chronic colitis due to inflammatory bowel disease (IBD) - found in only 1% of colorectal cancers
3.11. Toxic chemicals such as fumes, gases, pesticides or drug abuse
3.12. (Rote, 2019)
4. Pathophysiologic Factors
4.1. Injury
4.1.1. When colon cells lose stability, injury to cells occurs, causing neoplasmic lesions (polyps and adenomas).
4.1.2. (Kuipers et al., 2015)
4.2. Inflammation
4.2.1. Cancer triggers a systemic inflammatory response.
4.2.2. This causes modifications in many systems of the body.
4.2.3. Systemic inflammatory response causes the liver to produce proteins such as CRP (c-reactive protein: produced to protect body tissues).
4.2.4. Many symptoms of cancer are caused by the inflammatory response: fever, weakness, anemia, lack of appetite.
4.2.5. (Tuomisto et al., 2019)
5. Risk factors
5.1. Family history of colorectal cancer
5.2. Low levels of physical activity
5.3. Being overweight
5.4. Drinking
5.5. Older age
5.6. Smoking
5.7. Poor dietary habits
5.7.1. (Kuipers et al., 2015)
6. Treatments
6.1. Surgery
6.1.1. Main treatment for cancers that are usually not metastasized
6.2. Chemotherapy
6.2.1. Targeted therapies that address the environment of the tumor
6.3. Radiation
6.3.1. Tumor Staging
6.4. (Kuipers et al., 2015)
6.5. Immunotherapy
6.5.1. This therapy trains the person's immune system to recognize and destroy cancer cells
7. Diagnostics
7.1. Screening colonoscopy
7.1.1. Detailed imaging of mucosa of gastric system
7.1.2. Gold standard for diagnosis
7.1.3. Doctors can diagnostic and treat adenomas if found
7.2. Capsule endoscopy
7.2.1. Involves swallowing a small capsule for video images
7.3. CT colonography
7.3.1. Virtual colonoscopy with x-rays and computers
7.4. (Kuipers et al., 2015)
7.5. Tumor Markers
7.5.1. Utilizes high-energy rays (such as x-rays) or particles to destroy cancer cells
7.5.2. Histology findings: size of tumor, where it is located in the body and extent of damage.
7.5.2.1. (Rote, 2019)
7.5.3. Biologic substances that represent cancer.
7.5.3.1. Most common are carcinoembryonic antigen (CEA) and CA 19-9
7.5.3.1.1. (Lech et al., 2016)