colon cancer

The most important information about colon cancer

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Colon cancer is the uncontrolled growth of cells in the colon or rectum. Most colorectal cancers begin as a growth on the inner lining of the colon or rectum, called a polyp. Some types of polyps can turn into cancer over time (usually many years).

Colorectal tumors can originate from each of the three layers of the colon: mucosa, muscle, and serous tissue.

This type of cancer is one of the most common in the world and is also one of the easiest to diagnose. The cure rate is high if detected early.

Colon cancer can grow in three ways:

Local growth

In this case tumor deeply attacks all layers of the wall of the digestive tract. The malignant tumor grows from the mucosa, spreads through the serosa and reaches the muscle layers.

Lymph expansion

When the tumor enters deeper into the intestinal wall, it can reach other organs using a network of lymph vessels that allow access to multiple regions of the lymph nodes. One of the characteristics of this diffusion is that it first reaches the nearby ganglia until it reaches the most distant ones.

Hematogenous spread

Here, the tumor spread from the bloodstream to the cancer cells and spread to the liver, lungs, bones and brain.

Frequency

The most commonly misdiagnosed cancer in men is prostate cancer, and in women breast cancer.

Causes

The main risk factors associated with this disease are as follows:

Age

Most cases of colon cancer are found in people between the ages of 65 and 75, and people between the ages of 50 and 65 are at medium risk. Cases diagnosed 35-40 years ago are usually due to the fact that the patient has a genetic predisposition to get cancer.

Nutrition

Colon cancer is associated with a diet high in fat and low in fiber. Numerous scientific studies are underway to study the link between diet and cancer.

The next factor

Genetics play an important role in getting colon cancer, because there is a possibility that it can be inherited and predispose a person to getting cancer.

Medical history

It has been shown that those who have a greater predisposition to suffer from this disease are people who have or have had polyps (benign growth) of the colon or rectum, ulcerative colitis (inflammatory bowel disease), breast cancer , uterus or ovaries.

Lifestyle

There are certain lifestyle-dependent factors that predispose to colon cancer: obesity, inactive lifestyle, smoking and excessive alcohol consumption.

In people who suffer from some type of inflammatory bowel disease, such as ulcerative colitis or Crohn’s disease, the risk of developing the disease increases.

Symptoms

Colon cancer has a long history and its symptoms can vary depending on the location of the tumor in the colon. The symptoms most often appear in the advanced phase of the disease. These symptoms are not exclusive to colon cancer and can occur in other conditions such as hemorrhoids or certain digestive disorders. Specialists recommend going to the doctor as soon as the first symptoms appear in order to facilitate the diagnosis. The most common symptoms are:

Changes in the rhythm of bowel movements

Patients who have colon cancer may have diarrhea or constipation. Patients who had normal bowel function before the disease may have alternating periods of constipation and periods of diarrhea.

Blood in the stool

The most common symptom of this malignant tumor is that the patient has blood in the stool. The color of the blood can be red or black. The presence of red blood occurs when a person has tumors in the most distant part of the colon and rectum. In the case of black blood, this color appears because the blood is digested and comes from nearby parts of the large intestine, which gives black bundles that are known as manes. If this symptom is not diagnosed early, and the patient does not receive adequate treatment, it can worsen and lead to anemia. In these cases, the patient may, among other symptoms, suffer from dizziness, fatigue or a feeling of difficulty breathing. The patient may find that his stool changes in size and is narrower. This happens because the bowel narrows.

If the tumors are located in the distal part of the colon, the patient may also feel that the stool is smaller and that the emptying is incomplete.

Abdominal pain or discomfort

Stomach pains are very common. This is because the tumor partially clogs the intestinal tract and produces pain and a situation similar to that of colic. In some cases, the closure of the intestinal tube can end and intestinal obstruction occurs, in these situations it is necessary for the patient to receive emergency surgical medical care.

Weight loss for no apparent reason, loss of appetite and constant fatigue

Like other diseases related to the stomach, colon cancer, especially when it is in an advanced stage, shows these symptoms.

Studies of colorectal cancer have shown that in some types, tumors start with polyps (small benign nodules). Early detection and removal of these polyps can help prevent disease progression.

Another cause of colon cancer is a genetic predisposition that a person has. This is due to various changes in certain genes, so people with relatives who have or have had this pathology should periodically go for medical examinations.

There are various syndromes that predispose to the appearance of a malignant tumor. The most common are two:

Familial colon polyposis

This syndrome causes only 1% of colon cancer. Familial polyposis of the colon occurs during adolescence, causing multiple polyps in the rectum and colon. The cause is a mutation in the APC gene, which is transmitted from parents to children. Both girls and boys can inherit this gene.

Subsequent non-polyposis colorectal cancer

This type of cancer accounts for between 3 and 5% of tumors of the rectum and colon. The main difference from the previous syndrome is that patients do not have polyps.

Some unhealthy habits can also affect the onset of the disease, so following these tips can be very helpful:

Do not abuse alcohol or tobacco: Tobacco increases the risk of developing polyps that can be a precursor to disease. As for alcohol, its consumption encourages the cells of the mucous membrane of the colon to grow. This growth gives a polyp.

Overweight control: Obesity and excess calories in the diet should be avoided. Regular physical activity strengthens the body and reduces the risk of cancer.

Diet

Specialists advise following a balanced diet and recommend the following guidelines.

Don’t abuse foods high in fat.

Reduce fat intake so that it does not exceed 20 percent of the total calories in the diet, preferably by consuming monounsaturated fats (olive oil) and polyunsaturated (fish oil).

Reduce your red meat intake.

Increase consumption of fish and chicken.

Include foods rich in fiber in your diet, because taking an amount of fiber of at least 25 grams per day, in the form of cereals and whole grain bread, prevents the appearance of tumors.

Increase your intake of fruits and vegetables. Especially cauliflower, broccoli and legumes.

Types of colon cancer

Adenocarcinoma

In 90-95% of cases adenocarcinoma is the most common type of colon cancer. It is located in the mucosa that lines the inside of the colon and rectum.

The rarer types are as follows:

Lymphoma It is a cancer of the defense cells of the intestines and stomach.

Sarcoma This tumor develops in the muscular layer of the digestive tract.

Carcinoid tumors Occur in cells of the digestive system that produce hormones

Melanoma

Diagnosis

One of the main advantages of colon cancer is that it is one of the rare types that can be diagnosed before a person has symptoms, and even before polyps turn into cancer.

The most reliable screening test is the fecal occult blood test, which reveals whether there is blood or not. The patient takes a sample at home and delivers it to his health center for analysis and interpretation by a specialist. This test is recommended every two years after the age of 50. years of age. The next step is a colonoscopy to determine the source of the bleeding. This test is used to detect and remove polyps and to prevent tumor growth.

When it is suspected that a lesion in the colon may occur, the doctor should take a medical history, perform a physical examination and a digital rectal examination. Several techniques are used to detect colon cancer:

Rectal examination

It is a physical examination that the doctor performs by inserting a finger into the anus to detect abnormalities in the lower part of the digestive system, blood, abnormal lumps or if the patient feels pain.

Sigmoidoscopy

It is an examination that consists of introducing a tube that lets light and image through the anus and is called an endoscope. You can use it to examine the rectum and the end of the large intestine (about 60 cm) and detect some of the polyps that may be there.

Colonoscopy

It is an examination similar to sigmoidoscopy, but the tube used is longer and allows an examination of the entire colon. It facilitates the taking of tissue samples (biopsy) at the places where the tumor is suspected, and then a study is performed with a microscope. Sedation is usually done and the risk of complications is very low.

Genetic study

If there is a family history or the possibility of hereditary cancer is suspected, it is recommended to perform a genetic study to detect abnormalities. If there are genetic changes in the family, examination of the colon and rectum should begin at an early age (20 years) and continue periodically.

Double contrast barium enema:

It consists of a series of X-rays of the colon and rectum taken after the patient has received an enema with a chalk-white solution containing barium to radiologically detail the inside of the colon and rectum.

In recent years, a technique known as liquid biopsy, which may be especially useful in colon cancer, has been intensively researched. This is a test performed on a blood sample to look for cancer cells circulating in the blood or DNA fragments of tumor cells circulating in the blood. When its use is standardized, it can be used, among other things, for early detection of cancer and treatment planning.

Treatments

In order to plan the correct treatment, the doctor needs to know at what stage of the disease the patient is. There are currently two systems in use.

Types of scales

TNM classification

Three aspects that affect cancer are measured. T refers to the size of the primary tumor in the intestine; N refers to the presence or absence of lymph nodes, while M refers to the presence of distant metastases. Here’s how the five phases differ:

Stage 0 or carcinoma in situ: In this early stage, the cancer is located in the superficial layer of the mucosa, does not penetrate it and does not affect the lymph nodes.

Stage I: The cancer has spread to the wall of the rectum or colon without penetrating the muscle layer. Lymph nodes are not affected at this stage either.

Stage II: The cancer has spread to the deepest layer of the colon, but not to the lymph nodes, which, spreading throughout the body, produce and store cells capable of fighting infections. At this stage, the tumor can attack the surrounding organs.

Stage III: The cancer has already spread to the nearest lymph nodes and organs.

Stage IV: The cancer has reached other organs of the body (mostly tends to invade the liver, bones and lungs).

Classification of Dukes or Astler and Collera

This scale uses the letters A to D to estimate how deep it enters the wall of the colon:

Stage A: In this phase, there are patients who have a lesion only on the mucosa and do not affect the lymph nodes.

Stage B1: The cancer is located in the part of the wall of the rectum and colon, but it does not pass or affect the nodes.

Stage B2: The tumor spreads along the wall of the colon and rectum without invading the lymph nodes.

Stage C: At this level, the cancer can partially or completely affect the wall, as well as the lymph nodes.

Stage D: The cancer affects the entire wall and spreads to further organs.

Choice of treatment

After performing the tests that determine the diagnosis, the specialist doctor will determine the therapy. As with many other types of cancer, colon cancer requires multidisciplinary therapy to provide the patient with the best possible recovery. Specialists will prescribe therapy based on the patient’s condition, where the tumor is and the stage of the cancer.

The specialist doctor will assess whether the patient suffers from other diseases that may interfere with treatment. All this means that each patient will receive treatment that is tailored to his specific symptoms. The most common treatments are chemotherapy and surgery.

Surgery

The operation in the operating room removes the part affected by the cancer. Surgery is used in all stages of the disease. In phase A, it is the recommended treatment, because in the rest of the phase, specialists advise the use of surgery in combination with other treatments.

In the initial phase, specialists can remove the polyp with a colonoscopy to examine it, and depending on the results, the cancer and the surrounding part of the healthy tissue and nodules in that area will be removed. Another possibility is to make an opening from the colon to the outside (colostomy) after removing a part of the colon, in which case the person will have to use a special bag for external use where the stool will be collected. A colostomy can be transient or permanent.

Radiotherapy

It consists of applying high-energy radiation to the affected area in order to destroy cancer cells. It only affects the area being treated and can be applied before surgery (to reduce tumors and make it easier to remove) or after surgery (to destroy any cancer cells that may remain).

Chemotherapy

It is a treatment in which drugs are given with the aim of destroying cancer cells. This is achieved by inserting a tube into a vein (catheter) through which the drugs will be injected through the pump system. It is usually used after surgery.

Immunotherapy

Immunotherapy , which consists of stimulating or restoring the body’s own immune defenses is of great help in the treatment of various types of cancer. It is still very ineffective in colon cancer: only about 5% of patients with colon cancer can benefit from immunotherapy.

Targeted treatments

There are specific medications for some types of colon or rectal cancer. Drugs developed for advanced tumors that have mutations in the BRAF gene.

Forecast

According to research, approximately 54% of patients with colon cancer survive for more than five years. Although these figures differ depending on the stage. The five-year survival in stage A is between 90 and 92% in phase B between 50 and 75% in stage C from 25 to 55% and in stage D less than 8%.

In recent years, the prognosis of survival in patients with stage C with chemotherapy after surgery has significantly improved.

Consequences

Side effects vary depending on the therapy the patient is receiving, but most of them are temporary. The doctor should inform the patient about possible side effects.

Surgery can cause pain and weakness in the affected area and temporary diarrhea. If the patient had a colostomy, skin irritation around the made opening can occur.

Chemotherapy affects cancer cells and can cause nausea, vomiting, diarrhea and fatigue in patients.

Immunotherapy can cause flu-like symptoms, such as fever, weakness and nausea.

Colon cancer control and monitoring

After treatment, the risk of cancer recurrence decreases over time. During the first three years, it is recommended to perform quarterly examinations. From the fourth and fifth year, these examinations can differ for six months, and from the sixth year they can be performed once a year.

Follow-up tests include careful general physical examination and more precise rectal examination, colonoscopy, and blood tests for tumor markers such as carcinoembryonic antigen (CEA). If symptoms or normal test results indicate a recurrence of the cancer, chest X-rays, CT scans and MRI scans may also be done. If new or persistent symptoms occur, you should see your doctor immediately.

Tumor marker

Carcinoembryonic antigen (CEA) is a substance found in the blood of some people with colon cancer. The blood test for carcinoembryonic antigen is most often used with other tests to monitor patients who have already had cancer and are being treated. This test can provide an early warning of cancer recurrence. Carcinoembryonic antigen may be present in the blood of some people who do not have colon cancer. Smoking can also increase the level of this antigen. Therefore, they cannot be considered a reliable test for detecting colon cancer.

How to reduce discomfort after performing diagnostic tests?

Although tests to diagnose colon cancer are not painful, they can be uncomfortable for the patient and in some cases become difficult to tolerate. Cancer associations make the following recommendations to help the patient with testing:

They recommend that the patient be accompanied, because talking to a close person will make it easier for the patient to be more relaxed.

The patient should ask the doctor for an explanation of what the tests will consist of in order to avoid unforeseen situations.

Before performing the tests, they advise the patient to perform some relaxation exercise. They emphasize that it is important to focus only on what is happening at all times. At the end of the test, they also advise the patient to perform some relaxation exercise.

If you are nervous or anxious, it is advisable to talk to your doctor to prescribe medication if necessary.

Preparations for the immune system

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