About Me

Colorectal Cancer

Black Panther's King T'Challa, Chadwick Boseman, died at the age of 43. His family said Chadwick died of colorectal cancer. It is known, Chadwick had colon cancer since four years ago. So what is colorectal cancer?

Definition

Colorectal cancer (Colorectal Carcinoma or colon cancer) is aimed at malignant tumors found in the colon and rectum. More than 95% of colorectal carcinomas are adenocarcinomas. This cancer originates from the glandular cells found in the lining of the colon and rectum walls.

Basically, cancer is a cell proliferation without following the standard rules of proliferation (abnormal proliferation). This proliferation is divided into non-neoplastic and neoplastic, non-neoplastic divided into:

a. Hyperplasia is excessive cell proliferation. Hyperplasia can be normal because it aims to improve in certain physiological conditions such as pregnancy.
b. Hypertrophy is an increase in cell size, which results in enlargement of the organ without increasing the number of cells.
c. Metaplasia is the change from one type of dividing cell type to another, usually in the same class but less specialized.
d. Dysplasia is a disorder of cellular development, the production of abnormal cells that accompany hyperplasia and metaplasia. The changes included in this consist of increased mitosis, the production of many abnormal cells, and a tendency to become disorganized.


Epidemiology

Who is at high risk for colon cancer? 

Epidemiologically, colorectal cancer ranks 4th in terms of incidence in the world, with a slightly higher number of males than females at a ratio of 19.4 and 15.3 per 100,000 population, and a mortality rate of 655,000 per year worldwide.

This cancer is mostly found in North America, Australia, New Zealand, and parts of Europe. Its incidence varies among different ethnic, racial, or multiethnic / multi-racial populations. In general, colorectal cancer incidence increases sharply after the age of 50 years—a phenomenon associated with exposure to various carcinogens and lifestyle.

Colorectal cancer is the second leading cause of death of all cancer patients in the United States. More than 150,000 new cases are diagnosed each year in the US, with an annual death rate approaching 60,000. The average colorectal cancer patient is 67 years, and more than 50% of deaths occur in those over 50 years of age.

The distribution of colorectal cancer in parts of the colon is as follows: Caecum 1.9%; Ascendent colon 8,7%; Transverse colon 6.8%; Descending colon 11,7%; Sigmoid 9.7%, Rectosigmoid 9.7% and Rectum 51.5%.

However, in recent years, there has been a marked shift in its distribution. The incidence of cancer in the sigmoid & rectal area has decreased, while the ascending and descending colon incidence has increased. More than 156,000 people are diagnosed each year, about half of which die each year, although nearly three in four patients can be saved with early diagnosis and prompt action. The under five-year survival rate is 40–50%, mainly because of late diagnosis and the presence of metastases.

Most people have no complaints or asymptomatic for a long time. They seek medical assistance only when they notice a change in bowel habits or rectal bleeding. Survivals around the world vary widely depending on the facilities and available drugs. Five years survival rates in the US are more than 60% but less than 40% in developing countries.


Etiology

What are the risk factors and causes of colorectal cancer?

In general, cancer is always associated with: chemicals, radioactive materials, and viruses. Generally, colon cancer occurs related to genetic and environmental factors. Colon cancer arises through a complex interaction between genetic and environmental factors. And it is also associated with predisposing factors for a low fiber diet, weight gain, alcohol consumption. 

1. Genetic Factors: Genetic factors predominate in other cases of hereditary syndromes such as Familial Adenomatous Polyposis (FAP) and Hereditary Nonpolyposis Colorectal Cancer (HNPCC). A family history of colorectal cancer, if a close family member is affected (parent, sibling, sister, or child), the risk of growing this cancer is greater, especially if the affected family developed this cancer at a young age.

2. Age: Colorectal cancer generally attacks more often in old age. More than 90 percent of this disease afflicts people over the age of 50. Even at an age younger than 50 years, it can be affected. About 3% of these cancers attack patients under 40 years of age.

3. Colon polyps, some of which are adenomatous polyps, are among the risk factors for colorectal cancer. Often occurs at 50 years old. Most of these polyps are benign tumors, but some can turn into cancer. Finding and removing these polyps can lower the risk of developing colorectal cancer.

4. Diet: Research shows that the diet high in red meat and fat and low in fruit, vegetables, and fish increases the risk of developing colorectal cancer. The content of macronutrients and micronutrients associated with colorectal cancer. Research shows that animal fat, especially from red meat sources, affects the incidence of colorectal cancer.

5. Alcohol: Frequent consumption of alcohol increases 2-3 times the incidence of Colorectal Cancer. People who consume alcohol more than 30 grams per day show a high-risk factor for developing colorectal cancer.

6. Inflammatory Bowel Disease: Approximately 1% of patients with colorectal cancer have a history of colitis ulcers. Patients with Crohn's disease have a significant risk of developing colorectal cancer.

7. Environmental factors: some evidence shows that the environment plays an important role in developing colorectal cancer. Industrial countries have increased relatively more than in developing countries. This is related to traditional diets that tend to be high in fiber and low in fat.

8. Viral infection: Exposure to some viruses (such as Human Papillomavirus) can be associated with Colorectal Cancer incidence.

9. Physical activity: People who have more physical activity have a lower risk of developing colorectal cancer.

10. Smoking, selenium deficiency, and low vitamin B6 intake are associated with the risk of colorectal cancer.


Pathophysiology

How can colorectal cancer occur?

The pathogenesis of colorectal cancer originates from the mucosal epithelium along the colon and rectum in the gastrointestinal tract due to cell mutation. Some mutations are inherited, and others are acquired disorders. The most common mutation in colorectal cancer is the APC gene (Adenomatous Polyposis Coli), which produces the APC protein. APC protein is a "brake" of protein β-catenin. Without APC, β -catenin is translocated (enters) into the nucleus, binds to DNA and activates more proteins. 

The transition of adenoma to carcinoma is the result of mutations in the p53 tumor suppressor gene. Under normal circumstances, the p53 gene's protein will inhibit the proliferation of cells that have DNA damage. The mutation of the p53 gene causes cells with DNA damage to continue to undergo replication, which results in cells with more severe DNA damage. Cells replicate by losing some segments on the chromosome containing multiple alleles (e.g., loss of heterozygote). This leads to the loss of other tumor suppressor genes such as DCC (Deleted in Colon Cancer), which is the final stage of malignancy transformation.


Clinical Manifestations

What are the signs and symptoms of colorectal cancer?

Symptoms depend on the location, type of malignancy, spread, and complications (perforation, obstruction, bleeding). Colorectal Adenocarcinoma tends to be slow-growing. It is estimated at around 620 days. Therefore, Colorectal cancer is usually asymptomatic before it reaches a certain magnitude. For early diagnosis, a careful history and examination are helpful. Most colorectal cancer's symptoms also occur in various other diseases. Hence there are no specific symptoms for Colorectal Cancer. Symptoms and signs are divided into local, constitutional, and metastatic.

1. Local
a. Ascendent Colon
The ascending colon lumen is relatively large, thin-walled, and the stool's consistency is liquid. Therefore, before cancer has enlarged, it will not have any apparent symptoms. The patient appears lethargic and emaciated due to anemia (microcytic hypochromic). There may be no blood in the stool, but occult bleeding can be found.

The patient complains of discomfort in the right side of the stomach, especially after eating. It is often confused with abnormalities in the gallbladder and gastroduodenal disease. Change of bowel habits and obstruction symptoms are usually absent—about 10% of cases with a palpable tumor mass.

b. Descending colon
The descending colon lumen is relatively narrow, and the stool consistency is semisolid. The tumor grows around the intestinal wall, and there is a change of bowel habit (constipation and defecation more frequently).

Total or partial obstruction may occur. Complete obstruction can occur without preceded symptoms or early symptoms in the form of increased constipation, reduced stool size, and a feeling of fullness in the stomach accompanied by pain becomes more pronounced. There was bleeding, but not massive. Often, stool mixed with fresh or old blood and mucus with blood, or blood clots.

c. Rectum
The main complaint is bloody and slimy bowel movements. There was a change in defecation pattern, namely diarrhea for a few days, followed by constipation for several days (alternating diarrhea and constipation). The size of the stool is small, like goat feces. Patients complain dyspepsia intermittent, resulting in anorexia, and weight will decrease rapidly. Besides that, there are complaints of tenesmus (feeling dissatisfied with defecation) and aches.

In contrast to the colon, the rectum mucosal lining is not covered by serous tunica. The bleeding comes from Superior artery hemorrhoids (branches of the inferior mesenteric artery), and inferior and media hemorrhoids arteries. The bleeding that occurs is usually more.

2. Constitutional
Cancer causes chronic bleeding, iron deficiency anemia can occur, and symptoms such as weakness, palpitations, and pallor may appear. Colorectal cancer also causes weight loss and decreased appetite. There may also be febrile and/or paraneoplastic syndromes that often are thrombosis, usually deep vein thrombosis.

Post a Comment

3 Comments

  1. I loved the article, very explanatory and accessible.
    It is so strange to think about the death of someone famous, it is almost unbelievable. Even more because it is such a disease, and we know that we cannot avoid it.
    https://www.dearlytay.com.br/

    ReplyDelete
  2. Duh bahaya juga ya diet bisa memicu kanker. Khususnya diet yang dilakukan tidak secara sehat :3

    ReplyDelete
  3. Do any patients recover from this disease? how long does it take to heal?

    ReplyDelete