Colorectal Cancer: what are the causes and how to prevent

The cancer colorectal is also called rectal or bowel cancer. It is the 4th leading cause of cancer death worldwide, according to the World Cancer Research Fund .

The institution still believes that about 700 thousand deaths due to the disease happen every year in the world.

The National Cancer Institute (INCA) also brings a worrying fact: this cancer led more than 17 thousand people to death in 2017, only in Brazil. And approximately 40,000 people will be diagnosed with this disease by the end of 2020.

For women, in 2020, it will be the 2nd most diagnosed type of cancer, second only to breast cancer .

Men are also not far behind. INCA believes that, soon, the disease will be the 3rd most common. The prostate cancer and lung occupy the first and second place on the podium, respectively.

Healthy Minute believes that medical information and guidance are the best ways for this scenario to be eased. See more about the disease:

What is colorectal cancer?

Colorectal cancer is a disease characterized by tumors present in the intestine, rectum or anus.

As a dangerous disease, bowel cancer can trigger several other complications and, in more severe cases, even lead to death. It can affect people of all ages and genders, although it manifests more frequently in older women (over 50 years old).

Fortunately, it can be treated, increasing the chances of partial recovery or even complete cure.

Its origin is usually in small elevations in the intestinal wall (known as polyps), which grow slowly. Thus, they take a long time to become malignant, which allows them to be identified and removed before causing harm.

The areas of medicine capable of diagnosing and treating this disease are coloproctology, gastroenterology and oncology.

What are the stages of bowel cancer?

The stages of colorectal cancer are classified into 5 categories, with number 0 being the mildest and number 5 being the most advanced. When this disease is grade 5, it means that it has already spread to other parts of the body (metastasis).

Learn a little more about each classification:

  • Stage 0: the diseased cells are only in the internal lining of the organ;
  • Stage 1: the tumor is on the organ wall;
  • Stage 2: the cancer already reaches the outer lining;
  • Stage 3: cancer cells spread to nearby external cells;
  • Stage 4: the tumor is in other parts of the body.

Fortunately, all stages have treatments and chances of cure.

What is metastatic colorectal cancer?

Metastatic colorectal cancer happens when the disease has spread to other parts of the body besides the intestine, rectum or anus. That is, in addition to affecting these regions of the body, the bladder, prostate and uterus can be affected.

When this happens, the chances of a cure are drastically reduced.

What can cause colorectal cancer?

Colorectal cancer, like all other cancers, is caused by genetic mutations in cells. In this specific case, the cells of the intestine and rectum undergo a change in their genes and thus become cancerous. Despite this flaw, they continue to reproduce and generate new diseased cells.

When these cells come together, they form a tumor.

If the tumor is benign, there are no risks, although it is ideal to eliminate it to prevent it from growing. If the exams show a malignant tumor, it is considered cancer, being classified in stages that indicate the severity of the disease.

But what causes this genetic mutation in the cells of the intestine or rectum?

Well, several factors can stimulate this change in the cell’s genes: smoking , obesity , physical inactivity and consumption of unhealthy foods are some examples.

Thus, we can say that these problems mentioned in the paragraph above are not necessarily the cause of colorectal cancer, but they tend to influence the onset or worsening of the disease.

What are the groups and risk factors?

The main risk factors for the development of rectal cancer are:

  • People over 50;
  • Obesity or overweight;
  • Unhealthy diet (with excess fried foods, fats, sweets and sugars);
  • Excessive consumption of red meat (more than 500g per week);
  • Consumption of processed meats (sausage, hams, bacon, sausages, salami and bologna) without moderation;
  • Smoking;
  • Consumption of alcoholic beverages frequently;
  • Family history of bowel cancer;
  • Personal history of bowel, breast, ovarian and uterine cancer;
  • Inflammatory gastrointestinal disorders (such as ulcers, gastritis and Crohn’s disease).

If you are part of one or more of the groups mentioned above, always keep your medical visits up to date and perform the tests requested by the medical professional.

What are the chances of a polyp becoming cancer?

First of all, it is worth saying that the polyp is a benign tumor. The polyps that are most likely to become malignant (cancer) are known as sessile, with a flat shape and more than 1 cm. In general, these tend to become malignant tumors in up to 3 years, if not treated or removed.

The other types of polyp can turn into cancer during the average period that varies between 5 and 10 years, depending on the person and the frequency with which they are exposed to risk factors.

What are the symptoms of colorectal cancer?

First of all, it is important to say that other complications such as hemorrhoids, intestinal ulcers and the presence of worms can also cause the same symptoms as colorectal cancer. Therefore, always consult a coloproctologist.

This professional will be able to correctly assess the situation and request the necessary tests to investigate your condition.

The following signs may indicate the presence of tumors in the intestine:

  • Presence of blood in the stool;
  • Abdominal pain and discomfort (especially at the time of evacuation);
  • Feeling of weakness;
  • Anemia;
  • Weight loss without apparent cause;
  • Diarrhea and constipation interchangeably;
  • Alteration in the shape of the stools that tend to get thinner and longer;
  • Willingness to evacuate, even if the need (tenesmus);
  • Increased abdominal mass.

How is the diagnosis of bowel cancer made?

When presenting symptoms, the person should seek the help of a doctor. This professional tends to ask questions and investigate the patient’s personal and family medical history.

Only from that, clinical and laboratory exams are requested according to each situation.

What exams are needed?

The suspicion of colorectal cancer is raised by presenting the symptoms and by 2 preliminary exams (examination of occult blood in stools and endoscopies) and 1 definitive exam (biopsy).

Learn a little more about each of them:

Fecal occult blood test

The first that can be done is the blood test hidden in the stool.

For this test, it is necessary that the feces be collected for 3 days in a row. This collection should not be done if the person had bleeds in the mouth or nose (because they could have swallowed that blood) or during the menstrual period.

It is necessary to follow a specific diet that should be indicated by the laboratory where the test will be performed. In most cases, the consumption of radishes, beans, beets and broccoli is suspended for a few days.


Only the result of the fecal occult blood test should not be used to diagnose an intestinal disease.

In addition to this, other tests, known as endoscopy, should also be performed.

Endoscopies can be of 2 types: 

  • Colonoscopy: imaging exam that allows you to see the intestine and rectum;
  • Rectosigmoidoscopy: imaging examination that allows the rectum and anus to be seen.

huh? But aren’t rectum and anus the same thing? Well, let’s do a vocabulary review.

The rectum is a chamber that is located at the end of the large intestine, making the connection between the intestine and the anus.

The anus is the orifice through which feces and intestinal gases are released .

That is, going back to the endoscopy exams: the first shows the intestine and this connecting chamber (rectum). The second shows the rectum and the anal canal.


If these 2 exams are evaluated by the coloproctologist and there is still suspicion, a biopsy may be requested.

This examination consists of removing a small piece of tissue from the suspected lesion.

This is done by means of a device called an endoscope, which is introduced through the anus.

Is colorectal cancer curable?

Yes, fortunately, colorectal cancer, in most cases, is curable. Here, it is worth remembering that the sooner the tumor is diagnosed, the greater the chances of a full recovery. For this type of cancer, the chances of cure are up to 95% when the tumor is discovered early.

If the tumor is diagnosed in more advanced or even generalized stages (metastasis), the chances of cure are less than 40%.

The good news is that the disease is considered to grow slowly and therefore takes time to spread to other parts of the body.

The cure for colorectal cancer is achieved through treatment (surgery, radiotherapy and chemotherapy).

What is the treatment?

The type of treatment depends on each case.

This is because factors such as the size and location of the tumor, the age of the patient, the severity of the cancer and the presence of other diseases must be taken into account when choosing one of the forms of treatment.

Find out what are the main ways to treat colorectal cancer:


Surgery is the first option, that is, it is used in milder cases of the disease or in combination with other treatments.

In the surgical procedure, the part of the intestine that is affected by the cancer cells is removed.

Depending on the severity, it may also be necessary to remove some small structures that are part of the abdomen’s immune system (lymph nodes).


Radiotherapy is a form of treatment that uses radiation to combat advances or even destroy a tumor.

Although it looks scary, there is no reason to be afraid. The radiation is not seen with the naked eye and the patient tends not to feel any kind of pain or discomfort during the sessions.

Even so, it is important to follow some precautions and observe some tips:

  • Before the radiotherapy session, clean the area that will receive the radiation. Give preference to water and soap, avoiding using perfumed tissues or toilet paper;
  • Choose comfortable clothes to wear during the procedure;
  • Always keep your skin well hydrated. Drink water and use moisturizing creams;
  • Avoid irritating the area being treated as much as possible. Hair removal, itching and massage should be avoided.


Chemotherapy is the use of drugs that destroy a cancerous tumor.

But how does it work?

In general, when entering the patient’s body, the medicines are broken (digested) and go into the bloodstream.

Once there, they “travel” through the body through the blood until they reach the area where the tumor is located.

This, in addition to killing existing tumors, also prevents cancer cells from spreading to other parts of the body and causing metastasis.

Medicines for colorectal cancer: what to use?

The type of medication indicated for each case varies according to several factors: age of the patient, stage of the disease and use of other medications or other forms of treatment. Therefore, it is essential to always talk to an oncologist or coloproctologist before taking any drug.

The best known drugs for the treatment of colorectal cancer are those that have the following active ingredients (PAs): Capecitabine , Irinotecan Hydrochloride , Fluorouracil and Oxaliplatin .

Know a little more about each one of these substances and know what are the drugs that should of these PAs:


In addition to treating colorectal cancer, this active ingredient is also used in the formula of drugs indicated for breast and gastric cancer.

The remedies that contain Capecitabine in its composition are:

  • Xeloda (reference medicine);
  • Capecitabine Sun Pharma (generic medicine);
  • Capeliv (similar medicine);
  • Capecare (similar interchangeable medicine);
  • Coama (similar interchangeable medicine);
  • Corretal (similar interchangeable medicine).

Irinotecan Hydrochloride

Irinotecan Hydrochloride is used to compose medications indicated to treat tumors in the lung, ovaries, uterus, breasts, skin, intestine and rectum.

The following drugs have a substance like PA:

  • Camptosar (reference medicine);
  • Irinotecan Accord Farm Hydrochloride (generic medicine);
  • Eurofarma Irinotecan Hydrochloride (generic medicine);
  • Glenin Irinotecan Hydrochloride (generic medicine);
  • Irimac (similar medicine);
  • Irnocam (similar medicine);
  • Proto Itecan (similar medicine);
  • Trebyxan (similar medicine);
  • Zotecan (similar medicine);
  • Camptrix (similar interchangeable medicine);
  • Evoterin (similar interchangeable medicine);
  • Tecnotecan (similar interchangeable medicine);
  • Tevairinot (similar interchangeable medicine).


This substance is the most used for the treatment of colorectal cancer, especially if surgery is not possible or has already been done, but without effective results.

In addition to colorectal cancer, other types (breast, gallbladder, bladder, ovaries and uterus) can also be treated with medication based on this AP.

The remedies that contain Fluorouracil in its formula are:

  • Fluoruracil Accord Farma (generic medicine);
  • Fluoruracil Bergamo / Amgen (generic medicine);
  • Fluoruracil Eurofarma (generic medicine);
  • Efurix (similar medicine);
  • Fauldfluor (similar interchangeable medicine);
  • Flusan (similar interchangeable medication);
  • Neugrast (similar interchangeable medicine).


This active ingredient is used to formulate drugs that treat colorectal cancer in more advanced stages (from III A) or even metastatic (IV).

The drugs that contain Oxaliplatin are:

  • Bioezulen (reference medicine);
  • Eloxatin (reference medicine);
  • Oxaliplatin Bergamo / Amgen (generic medicine);
  • Oxaliplatin Blau (generic medicine);
  • Oxaliplatin Eurofarma (generic medicine);
  • Oxaliplatin Glenmark  (generic medicine);
  • Oxaliplatin Mylan (generic medicine);
  • Collectro (similar medicine);
  • Evoxali (similar medicine);
  • Liboxal (similar medicine);
  • O-Plat (similar medicine);
  • Oxalimeiz (similar medicine);
  • Oxalibbs (similar interchangeable medicine);
  • Tevaoxali (similar interchangeable medicine).

Living with the disease

For many people, the positive result for cancer is also a synonym for “death certificate”.

The first thing that needs to be done in this situation is to try to change that thinking. For this, we will give you some tips that can help you have a better quality of life and take care of your physical and emotional health.

Follow medical guidelines

Yes, that phrase will always appear in the Healthy Minute.

We know that medications can be expensive, that chemo and radiotherapy sessions can make the patient unwell and that restrictive diets are sometimes not pleasant to be followed.

Even so, continue medical treatment, as it is the best chance for healing and recovery. And in cases of doubt, seek the guidance of the medical professional who accompanies your case.

Get ready before radio and chemotherapy sessions

In addition to avoiding the use of uncomfortable clothing, you can also plan other issues such as food and transportation to the hospital.

For example, some people feel better eating before the session, while others prefer to eat after treatment, waiting at least 1 hour. Over time, it is possible to observe your preference in this regard.

Another tip is in relation to displacement. Plan your return trip in the way you feel most comfortable and, whenever possible, ask someone you trust to accompany you.

The last piece of advice is to avoid eating strong foods and drinks that can make vomiting easier. Among them are coffee, onion and garlic. Also, do not consume food that is too hot or too cold.

Seek support from friends and family

There’s nothing like being able to count on the people we love, especially in difficult times, isn’t it?

Take advantage of loved ones to talk, vent, laugh, cry, keep company and, if necessary, ask for help to apply medications or recover from the postoperative period.

Do not stop practicing hobbies or physical activities

It doesn’t matter if you like collecting coins, practicing yoga or looking for stamps at the post office while you train for the next half marathon that will take place in your city.

When receiving a diagnosis of cancer, these activities should not be suspended, unless there are medical recommendations to the contrary. 

It is clear that the amount of physical exercises tends to be reduced, since the body is more weakened.

But even so, continue to practice your favorite activity, even if only for a few minutes.

For example, if a person is used to swimming three times a week during the fight against cancer, it may be necessary to reduce that amount to once a week.

Regarding hobbies, this advice is also valid.

Be it playing chess or dominoes, painting pictures, making crafts, taking care of the garden, meditating and even cooking: all these activities are good for emotional health and can help you face this difficult time.

If you don’t have a hobby yet, how about finding one? There are countless things that do us good and help us forget, at least for a moment, the problems.

Share experiences

You can talk about this delicate moment with people who have passed or are going through the same situation.

Search for support groups in hospitals, clinics or even on internet chats.

How long does a person have bowel cancer?

The survival rate is a percentage that estimates the number of people who live for 5 years after the diagnosis of the disease. For someone with bowel cancer, this assumption varies depending on the stage of the disease. Thus, the more advanced the cancerous tumor is, the lower the chances are.

On the other hand, following medical recommendations regarding forms of treatment is an alternative to maintaining hope of survival.

Even if the disease is in an advanced degree, treatment is the best option to increase the survival rate.

The Oncoguia Institute provides relevant data on the survival rate.

To make it easier, we put it in a table that shows the number of patients who remain alive for at least 5 years after the diagnosis (survival rate) compared to the stages of rectal cancer:

phase  Survival rate  
I 88%
II A 81%
II B 50%
III A 83%
III B 72%
III C 58%
IV 13%

Let’s explain it a little better: from the table, for every 100 patients with stage I colorectal cancer, 88 of them will survive for at least 5 years after the discovery of the tumor.

It is important to make it clear that these data are estimates based on the population average.

There is no way to predict exactly what will happen to the individual person, because each organism reacts in a different way in relation to treatments.

So don’t despair. The ideal is to follow your doctor’s recommendations and keep trusting medicine.

Complications: what can colorectal cancer trigger?

Colorectal cancer is a disease that tends to weaken and weaken the organism and the quality of life of the patient. Among the main complications are:

  • Blockage of the rectum and anal canal;
  • Hernias or hemorrhoids (because of the block mentioned above);
  • Reappearance of the disease, even after a period of improvement or cure;
  • Spread of cancer to other parts of the body (metastasis).

One form of treatment is surgery, which can also trigger complications such as nosocomial infections and intestinal perforations.

The other ways of treating the disease (chemotherapy and radiotherapy) can also cause adverse reactions, the most common of which are pain, tiredness , loss of appetite, feeling sick, hair loss, vomiting and diarrhea.

How to prevent bowel problems?

To prevent intestinal problems, especially colorectal cancer, it is necessary to follow a healthy lifestyle. This can be done through a balanced diet, which is rich in fruits, vegetables, legumes and whole grains, avoiding as much as possible the intake of processed meats, fats and sugars.

The consumption of legumes, beans, grains and seeds is also encouraged.

This type of diet described is rich in fiber, which is also positive for the proper functioning of the intestine, aiding in the digestion and elimination of feces.

Frequent physical exercise is also a healthy habit that helps in the loss and maintenance of body weight.

Another factor that helps prevent bowel problems is not to smoke or expose yourself to smoking.

All of these tips are essential to prevent intestinal diseases and can, to a large extent, also help in the prevention of rectal cancer.

But, it is important to emphasize that the sooner the cancer is discovered, the more chances it has of cure.

Therefore, one of the most effective ways to prevent this disease is to do routine medical follow-up and perform tests when requested.