Colorectal Cancer

Colorectal cancer is cancer that grows in the large intestine (colon) or at the very bottom of the large intestine connected to the anus (rectum). Colorectal cancer can be named colon cancer or rectal cancer, depending on where the cancer grows.

Colorectal cancer usually starts from intestinal polyps or tissue that grows abnormally on the inner wall of the colon or rectum. However, not all polyps develop into cancer. The likelihood of a polyp turning into cancer depends on the type of polyp itself.

The following are three types of polyps that can grow in the large intestine:

Adenoma polyps, which are a type of polyp that sometimes turn into cancer (a precancerous condition)
Hyperplastic polyps, which are the more common type but generally do not become cancerous
Sessile serrated polyps (SSP) and traditional serrated adenomas (TSA), which are types of polyps that are considered adenoma polyps, due to their high risk of turning into colorectal cancer

Regardless of the type of polyp, there are several factors that can increase the likelihood of polyps turning into colorectal cancer, namely:

Polyps are larger than 1 cm
More than 2 polyps in the colon or rectum
Polyps grow over abnormal tissue (dysplasia), usually seen after the polyps are removed

Causes and Risk Factors for Colorectal Cancer

Like all types of cancer, colorectal cancer occurs when cells in the body grow abnormally and form tumors. Over time, these tumors will grow and damage the healthy tissue around it.

Not yet known exactly what causes these cells to grow out of control. However, there are factors that can increase a person's risk of developing colorectal cancer, including:

50 years of age or older
Have a history of cancer or colorectal polyps
Having a family who has had colorectal cancer or polyps
Having a family history of colorectal cancer or breast cancer under the age of 50
Suffering from inflammatory bowel disease, both ulcerative colitis and Crohn's disease
Have diabetes
Suffer from obesity or overweight
Leading an unhealthy lifestyle, for example rarely consuming fiber and fruits, not exercising enough, and having smoking habits and consuming alcoholic beverages
Undergoing radiotherapy (radiation therapy) in the abdominal area

Colorectal Cancer Symptoms

Colorectal cancer usually only causes symptoms when the cancer cells are growing. Symptoms vary, depending on the size and location of the cancer.

Some of the symptoms of colorectal cancer that can appear are:

Diarrhea
Constipation
Defecation feels incomplete
Weight loss for no apparent reason
Bleeding in the rectum (end of the large intestine)
Bloody bowel movements
Nauseous
Vomit
Abdominal pain, cramping, or bloating
The body gets tired easily

When to see a doctor

Colorectal cancer often causes no symptoms when it is in its early stages. Therefore, consult with your doctor about the need for colorectal cancer screening, especially if you are at risk for colorectal cancer.

People over the age of 45 are advised to undergo regular colorectal cancer screening. However, first discuss with your doctor about the right type of screening and the screening schedule.

Colorectal Cancer Diagnosis

Colorectal cancer can be detected as early as possible through screening. That way, the chances of recovering from this disease are getting bigger. There are several types of screening for colorectal cancer, namely:

Stool
examination Stool examination which includes occult blood tests and detection of cancer cells in the stool, can be done for early detection of colorectal cancer. Depending on the type, the doctor may suggest that screening is done every 1–3 years.
Sigmoidoscopy
Sigmoidoscopy is performed by inserting a thin tube with a camera (sigmoidoscope) from the anus into the lower part of the colon. This test is done every 5–10 years, followed by an annual occult blood test.
Colonoscopy Colonoscopy procedure
is almost the same as sigmoidoscopy. The difference is, the tube used in colonoscopy has a longer size. This procedure is recommended to be done every 10 years.
Virtual colonoscopy ( CT colonography )
Virtual colonoscopy is performed using a CT scan machine . This test displays pictures of the entire colon for analysis. Virtual colonoscopy is recommended to be done every 5 years.

In patients who show symptoms of colorectal cancer, the doctor will carry out a number of the following examinations:

Colonoscopy
Colonoscopy is performed to examine all parts of the rectum and colon. If an abnormality is suspected in the rectum or colon area, the doctor will do a biopsy (taking tissue samples) in that area, to then be analyzed in the laboratory.
Examination of the tumor in the biopsied tissue
. This examination aims to detect genes, proteins, or other substances associated with tumor cells. This test can help the doctor determine the method of treatment to be carried out.
Blood
tests Blood tests are performed to calculate the level of red blood cells, so that it is known whether there is bleeding in the rectum or colon. Blood tests are also done to measure levels of carcinoembryonic antigen (CEA), which can be a sign of the development of the cancer's stage.
Scanning
Scanning can be done by ultrasound, CT scan, PET scan, or MRI , to see the location and size of cancer cells, and whether the cancer has spread to other organs of the body.

Colorectal Cancer Stage

After a patient is diagnosed with colorectal cancer, the doctor will perform additional tests to determine the severity (stage) of the cancer that is being experienced. Colorectal cancer stages are divided into four, namely:

Stage 0 – cancer appears on the surface of the inner wall of the rectum or colon, also known as carcinoma in situ
Stage 1 – cancer has penetrated into the muscle layer of the colon or rectum, but has not spread beyond the colon wall
Stage 2 – cancer has spread to the colon wall, beyond the colon wall, or to other nearby organs, but has not spread to the lymph nodes
Stage 3 – the cancer has spread beyond the colon wall, and to one or more lymph nodes
Stage 4 – cancer has penetrated the colon wall and spread to organs far from the large intestine, such as the liver or lungs, with tumor sizes that vary

Colorectal Cancer Treatment

Treatment of colorectal cancer depends on the patient's health condition, as well as the location and stage of the cancer. The following are some methods of treating colorectal cancer:

Operation

Surgery is the main method of dealing with colorectal cancer. There are several types of surgery that doctors can choose from, namely:

Polypectomy, to remove small colorectal polyps through a colonoscopy procedure
Endoscopic mucosal resection , to remove colorectal polyps and the inner lining of the large intestine, via colonoscopy
Laparoscopic surgery , to remove polyps that cannot be treated with a colonoscopy procedure
Partial colectomy , to cut out the part of the colon that is affected by cancer, along with some of the healthy tissue around it

In patients who are undergoing removal of the cancer-affected part of the colon or rectum, the doctor will perform anastomosis, which is the union of each end of the digestive tract that has been cut by means of stitches.

If there is only a small portion of the healthy colon left and it is impossible to connect, the doctor will make a hole in the abdominal wall for stool to exit ( colostomy ) and attach a bag to the outside of the abdominal wall. The patient's stool will come out through the stoma and be accommodated in the bag that is attached.

Colostomy can be temporary or permanent. A temporary colostomy is performed until the part of the colon that was cut recovers. Meanwhile, a permanent colostomy is performed on patients who have undergone a complete removal of the rectum.

Surgical removal of colorectal cancer can be followed by surgical removal of the lymph nodes, to see if the glands have cancer.

Chemotherapy

Chemotherapy is the administration of drugs to kill or destroy cancer cells. Chemotherapy may be done before surgery to reduce the size of the cancer so that it can be easily removed. In addition, chemotherapy can also be done after surgery to reduce the risk of colorectal cancer recurring.

Doctors can prescribe a single drug or a combination of drugs, such as fluorouracil , capecitabine , and oxaliplatin . If needed, doctors can combine chemotherapy drugs with targeted therapy.

Target therapy

Target therapy is the administration of drugs that specifically target genes, proteins or body tissues that contribute to the development of cancer cells. Drugs used in targeted therapy work to inhibit cancer cell growth and prevent further damage to healthy cells.

Drugs used in targeted therapy may be single drugs or combinations. The types of drugs include bevacizumab , regorafenib , and cetuximab .

Immunotherapy

Immunotherapy is the administration of drugs that stimulate the body's resistance to fight cancer cells. This therapy is usually intended for patients with advanced colorectal cancer.

Immunotherapy works in two ways, namely:

Medicines that encourage the immune system to attack cancer cells more effectively
Drugs containing artificial compounds, which mimic how the immune system works

Radiotherapy

Radiotherapy or radiation therapy is a treatment that uses X-rays or protons to kill cancer cells. Radiotherapy can be done by shooting a beam of radiation from a radiotherapy machine to the cancer site, or by placing radioactive material into the patient's body ( brachytherapy ).

Radiotherapy can be done before surgery to reduce the size of the cancer, or after surgery to destroy any cancer cells that may remain. If needed, radiotherapy can be combined with chemotherapy.

Ablation

Ablation is used to destroy cancer that has spread to the liver (liver) or lungs and is less than 4 cm in diameter. There are four ablation techniques that can be used to treat colorectal cancer, namely:

Radiofrequency ablation , which is an ablation technique using high-frequency radio waves
Microwave ablation , which is an ablation technique that utilizes high temperatures from electromagnetic microwaves
Ethanol ablation , which is an ablation technique that is performed by injecting alcohol right into the tumor area, using the help of an ultrasound or CT scan
Cryosurgery or cryotherapy , which is an ablation technique that is performed by freezing the tumor, using liquid nitrogen

Embolization

Embolization is used to destroy colorectal cancer that has spread to the liver and is more than 5 cm in diameter. This technique aims to block the liver arteries that provide nutrients and oxygen to the cancer. Embolization can be done in three ways, namely:

Arterial embolization, which is done by inserting an artery-clogging substance through a catheter
Chemoembolization, which is done by combining arterial embolization with chemotherapy
Radioembolization, which is done by combining arterial embolization with radiotherapy