symptoms

Colorectal cancer has a long evolution and its symptoms can vary depending on the location of the tumor in the large intestine. The most common complaints are in the advanced stage of the disease. However, these symptoms are not unique colon cancer and may occur in other diseases such as hemorrhoids or certain gastrointestinal disorders. Experts recommend seeing a doctor as they appear to facilitate the diagnosis is made properly. The most common are:

Changes in the intestinal rhythm

Patients with colon cancer may, in some cases, have diarrhea and, in others constipation. The second option is common in people who previously had a normal intestinal rhythm. However, the most common option is that the patient suffers bouts of constipation combined with periods when suffering from diarrhea.

Blood in the stool

The most frequent 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 mainly when the person presents tumors of the distal part of the colon and rectum. In the case of black blood, this color appears because the blood is digested and comes from sections closer to the colon, giving rise to black beams known as manes. If this symptom is not diagnosed early and the patient does not receive the appropriate treatment, it may become worse and lead to the appearance of anemia. In these cases, the patient may suffer dizziness, fatigue or have the sensation of lack of air, among other symptoms.

On the other hand, the patient can detect that their stools change in size and are narrower . This occurs because the intestine is narrowing.

If the tumors are located in the distal part of the colon, the patient may also have the feeling that the deposition is not complete and that the evacuation is incomplete.

Abdominal pain or discomfort

Abdominal discomfort and pain are very common. This is because the tumor partly obstructs the intestinal tube and pain and a situation similar to colic occurs. In some cases the closure of the tube can be completed and an intestinal obstruction occurs, in these situations it is necessary that the patient receives urgent surgical medical attention.

Loss of weight without apparent cause, loss of appetite and constant tiredness

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

Prevention

In all types of cancer there are risk factors that make people who are exposed to them more likely to develop a malignant tumor.

Research in colorectal cancer has shown that in some types, tumors originate from polyps (small benign lumps). Early detection and extraction of these polyps can help prevent the onset of the disease .

Another cause of the appearance of colon cancer is the genetic predisposition that the person has. This is due to various alterations in certain genes therefore, individuals with family members who have or have had this pathology should attend medical examinations periodically.

There are different syndromes that predispose the malignant tumor to appear. The most common are two:

Familial colonic polyposis

This syndrome only causes 1 percent of colon cancers. Familial colonic polyposis appears during adolescence, causing multiple polyps in the rectum and colon. The cause of the appearance is the mutation of the APC gene, which is transmitted from parents who are children. This gene can be inherited by both girls and boys.

Hereditary nonpolyposis colorectal cancer

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

Some unhealthy habits could also be the cause of the onset of the disease, so that following the following tips can be very beneficial:

• Do not abuse alcohol or tobacco : Tobacco increases the risk of developing polyps that can be precursors of the disease. Regarding alcohol, its consumption promotes the growth of colon mucosal cells. This growth gives rise to polyps.
• Control overweight : Avoid obesity and excess calories in the diet. Performing physical exercise regularly contributes to a sedentary lifestyle and favors the appearance of the disease.
• Food : The specialists advise to follow a balanced diet and recommend the following guidelines.
  • Do not abuse high fat foods.
  • Reduce the consumption of fats so that they do not exceed 20 percent of the total calories in the diet, preferably consume monounsaturated fats (olive oil) and polyunsaturated fats (fish oil).
  • Reduce the intake of red meat.
  • Increase the fish and chicken consumption.
  • Incorporate foods rich in fiber into the diet since taking a fiber quantity of at least 25 grams a day, in the form of cereals and wholemeal bread, prevents the appearance of the tumor.
  • Increase the intake of fruits and vegetables. Especially cauliflower, Brussels sprouts, broccoli and legumes.
• Age : This type of cancer usually appears after the age of 40 and its incidence increases as years go by.

Finally, if the person has some type of inflammatory bowel disease, such as ulcerative colitis or Crohn’s disease , the risk of suffering from the disease increases.

Types

In 90-95 percent of cases, adenocarcinoma is the most common type of colon cancer . This is located in the mucosa that lines the inside of the colon and rectum. Although this is the most common there are other less frequent types:

• Lymphoma : It is the cancer of the cells of the defense of the intestine and the stomach.
• Sarcoma : This tumor arises in the muscular layer of the digestive tract.
• Carcinoid tumors : It occurs in the hormone-producing cells of the digestive system.
• Melanoma .

Diagnosis

One of the main advantages of colon cancer is that it is one of the few types that can be diagnosed before the person has symptoms .

The most reliable test is a hidden blood test in the stool that finds out if there is blood or not. If it is positive, then a colonoscopy will be done to see the origin of bleeding. This test is used to detect and remove the polyps to prevent the tumor from developing. The test can be performed by the patient at home and must be interpreted by a specialist. This test is recommended, as a general rule, every two years starting at age 50 .

Once there is a suspicion that there may be a possible problem or injury to the colon, the doctor must prepare a medical history, perform a physical examination and a digital rectal examination. To detect colon cancer, several techniques are used:

• Rectal examination : This 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, such as blood, abnormal lumps, or if the patient feels pain.
• Sigmoidoscopia : It is an exploration that consists in introducing through the anus a tube that transmits light and image, and that is called endoscope. With it you can examine the rectum and the final part of the colon (about 60 cm), and detect some of the polyps that might be there.
• Colonoscopy : It is a scan similar to sigmoidoscopy, but the tube used is longer and allows to travel the entire colon. It facilitates the taking of tissue samples (biopsy) in areas where there is a suspicion that there may be a tumor, and then a microscopic study is performed. It is usually done with sedation and the risk of complications arising is very low.
• Genetic study : If there is a family history or the possibility of hereditary cancer is suspected, it is advisable to carry out a genetic study to detect anomalies . In case of genetic alterations in the family, the colon and rectum should be started at an early age (20 years) and continued periodically.
• Barium enema with double contrast : It consists of a series of x-rays of the colon and rectum that are taken after the patient has been given an enema (enema) with a white, calcareous solution containing barium to show the interior with detail of the colon and rectum.

Treatments

To plan the right treatment, the doctor needs to know at what stage of the disease the patient is. Currently there are two systems that are used with the same frequency.

Types of scale

TNM classification

In this, the three aspects that affect cancer are measured. First, T refers to the size of the primary tumor in the intestine; N refers to the presence or absence of lymph nodes, whereas M refers to the presence of distant metastases. This distinguishes five stadiums:

• Stage 0 or carcinoma in situ : At this early stage the cancer is in the most superficial layer of the mucosa, does not pass it and does not affect the lymph nodes.
• Stage I : Cancer has spread to the wall of the rectum or colon without passing through the muscle layer. In this stage the lymph nodes are not affected either.
• Stage II : The cancer has spread to the deepest layer of the colon, but not to the lymph nodes, which, spread throughout the body, produce and store cells capable of fighting infections. At this stage the tumor can invade the surrounding organs.
• Stage III : The cancer has already spread to the lymph nodes and to the nearest organs.
• Stage IV : The cancer has reached other organs of the body (mainly tends to invade the liver, bones and lungs).

Classification of Dukes or Astler and Coller

This scale uses the letters from A to D, assessing how deep it goes into the colon wall :

• Stage A : In this stage are patients who have a lesion only in the mucosa and does not affect the lymph nodes.
• Stage B1 : The cancer is in part of the wall of the rectum and colon but does not pass through it, nor does it affect the lymph nodes.
• Stage B2 : The tumor spreads throughout the wall of the colon and rectum without invading the lymph nodes.
• Stage C : At this level the cancer can partially or totally affect the wall and also the lymph nodes.
• Stage D : Cancer affects the entire wall and extends to organs further away.

Choice of treatment

After performing the tests that confirm the diagnosis, the specialist will determine the treatment. As in many other types of cancer, colon cancer requires a multidisciplinary therapy to offer the patient the highest recovery rates . The specialists will decide what is the appropriate treatment depending on the patient’s condition, where the tumor is located and the stage in which the cancer is found.

In addition, the specialist will assess whether the patient suffers from other diseases that may hinder the treatment. All this implies that each patient will receive a treatment that suits their particular circumstances. The most common treatments are chemotherapy and surgery.

Surgery

Through an operation in the operating room, the part affected by the cancer is removed . Surgery is used in all stages of the disease. In fact, in stage A, it is the recommended treatment since in the rest of the stadiums the specialists advise to apply the surgery in combination with other treatments.

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

Radiotherapy

It consists of applying high energy radiation on the affected area in order to destroy the cancer cells. It only affects the area under treatment and can be applied before surgery (to reduce the tumor and be able to remove it more easily) or after surgery (to finish destroying the cancer cells that may have been left).

Chemotherapy

It is the treatment by which drugs are administered with the objective of destroying cancer cells. It is done by inserting a tube into a vein (catheter) through which the drugs will be injected through a pump system. It is usually administered after the surgical operation.

Immunotherapy

It consists of stimulating or restoring the body’s own immune defenses . For this purpose, natural products or products manufactured in the laboratory are used.

Other data

Forecast

According to data from the Spanish Association Against Cancer , approximately 54 percent of patients with colon cancer survive more than five years. Although these figures vary depending on the stadium. Thus, survival at five years in stage A is between 90 and 92 percent; in stage B, between 50 and 75 percent; in stage C from 25 to 55 percent and in stage D is less than 8 percent.

In addition, in recent years, the prognosis of survival for patients with stage C chemotherapy after surgery has improved a lot.

Side effects

Side effects vary according to the treatment the patient receives , but most are temporary. The doctor must inform the patient about any that may appear.

• The surgery can cause pain and weakness in the affected area and temporary diarrhea . In addition, if the patient has had a colostomy, irritation of the skin around the opening can occur . 
• The Chemotherapy affects both cancer cells as normal and may cause nausea, vomiting, hair loss (although it always grows back), diarrhea and fatigue.
• Finally, immunotherapy can cause symptoms similar to the flu , such as fever, chills, weakness and nausea .

Control and monitoring of colon cancer

After the treatment is finished, the risk of the cancer reappearing decreases with the passage of time . During the first three years it is advisable to carry out quarterly reviews. From the fourth and fifth year these revisions can be extended to six months and from the sixth year they can be carried out annually.

Follow-up tests include a careful general physical exam and a more specific rectal exam, colonoscopy, and blood tests for tumor markers such as carcinoembryonic antigen (CEA). If symptoms or common test results suggest a reappearance of the cancer, chest x-rays, CT scans, and magnetic resonance imaging may also be done. For any new or persistent symptoms, you should consult your doctor immediately.

Tumor markers

Carcinoembryonic antigen (CEA) is a substance found in the blood of some people with colon cancer. The blood test for carcinoembryonic antigen is used more often with other tests to monitor patients who have already had cancer and have received treatment. This test can alert early of the reappearance of a cancer. Carcinoembryonic antigen may be present in the blood of some people who do not have colon cancer. Smoking can also increase the levels of this antigen. Therefore, it can not be considered as a specific test to detect colon cancer.

How to reduce discomfort after performing diagnostic tests?

Although tests to diagnose colon cancer are not painful, they can be bothersome to the patient and become difficult to tolerate in some cases. From the Spanish Association Against Cancer give these recommendations to help the patient to pass the tests:

• First of all, they recommend that the patient be accompanied, since talking to a close person will make the patient more relaxed.
• They then point out that the user asks the doctor to explain to them what the tests will consist of to prevent them from imagining situations.
• Before carrying out the tests, advise that the patient perform some relaxation exercise. In addition, they emphasize that it is important to focus only on what is happening at each moment. After finishing the test they also advise that the patient perform some relaxation exercise.
• Finally, if you are nervous or have anxiety, it is advisable to talk with the doctor to tell them about it and to prescribe medication that can improve that situation if you think it is convenient.