Current DateSeptember 19, 2021

Colorectal cancer: causes, symptoms, prevention & treatment

As the name suggests, colorectal cancer starts in the colon or rectum, the last part of the large intestine.

Colorectal cancer is the 4th most common cancer in the United States and according to the CDC, it is the third leading cause of cancer-related deaths in the country. More than 130,000 people are diagnosed each year with the disease. One in 14 men and 1 in 15 women are at risk of developing colorectal cancer in their lifetime.

Colorectal cancer is much more common in industrialized countries. Lifestyle habits, mainly diet, also play a key role in its appearance. This explains, for example, the fact that the Japanese, little affected by colorectal cancer in Japan, become so just as much as their American fellow citizens a few years after having emigrated to the United States and adopted the country’s diet.

Some people can get colorectal cancer because of a hereditary predisposition. But in 75% of cases, inheritance is not involved.

Evolution of colon cancer

Like most cancers, colorectal cancer takes several years to form. It usually does this from polyps, small, fleshy growths found in the wall lining the inside of the colon. There are several kinds polyps. While most often, they are benign, some, however, can become cancerous. It takes an average of 10 years for a polyp to form a cancerous tumor. Polyps (cancerous or not) sometimes cause digestive discomfort.

As soon as the doctor detects polyps in a patient, he or she will perform tests to see if they pose a risk to the patient’s health.

At an advanced stage, colorectal cancer can spread to the lymph nodes, then to the liver, and then to other parts of the body by metastasizing.

Currently, more than half of cases are diagnosed in people aged 65 and over. Health care professionals advise people to get tested regularly, starting at age 50, and earlier in those at risk. The earlier the cancer is detected, the better the chances of recovery.

Symptoms of colorectal cancer

Colorectal cancer usually goes unnoticed in its early stages of growth. The following symptoms may be a sign of colorectal cancer.

  • Changes in stool habits that have lasted for a few weeks (eg constipation or diarrhea).
  • Blood in the stool.
  • Abdominal discomfort, such as stomach gas, cramps, or stomach pain.
  • The feeling that the bowels never empty completely or that you constantly urge to defecate.
  • Great fatigue.
  • Unexplained weight loss.

People at risk

  • People over the age 50 (90% of cases).
  • Personal or family history. The risk increases when you have had colorectal cancer or polyps in the past, or if a close family member (mother, father, brother or sister) has had it. This predisposition is not always of hereditary origin. It can be the result of exposure to the same carcinogen in the environment, or through dietary or lifestyle habits.
  • Certain genetic diseases of the colon increase the risk of colorectal cancer. The 2 most common forms are hereditary nonpolyposis colorectal cancer (or Lynch syndrome), involved in about 5% of colorectal cancer cases, and familial adenomatous polyposis, involved in about 1% of cases. The latter is manifested by the appearance of a very large number of polyps, starting in adolescence.
  • People suffering from inflammatory bowel disease. Having Crohn’s disease or ulcerative colitis increases your risk.
  • People who have diabetes. In epidemiological studies, colorectal cancer has been shown to be more common in people with type 2 diabetes than in those without.
  • People with lack of sun exposure. It appears that the chances of getting colon cancer are higher in areas of the world where people are less exposed to the sun. It is believed that the protective effect is due to vitamin D, produced by the sun’s rays on the skin.

Risk factors

Certain lifestyle habits contribute to colorectal cancer:

  • Smoking and heavy drinking.
  • Overweight or obesity.
  • Sedentary lifestyle.
  • Diet rich in red meat, cold cuts and barbecued meats, and low in fruits and vegetables.
  • Psychological factors

The role of psychological state in the development of cancer is controversial. Certain personality traits have been linked in studies to an increased risk of cancer. However, other studies have contradicted this hypothesis.

Diagnosis

After a detailed medical consultation and a general physical examination, your doctor may perform a digital rectal examination. The last part of the intestine is carefully scanned with one finger, whereby the doctor can assess, among other things, the sphincter and the mucous membrane of the rectum. Changes or tumors close to the anus can be detected. The examination may be perceived as a bit unpleasant, but is generally not painful and lasts only a few minutes.

Another important tool in the diagnosis of intestinal diseases is the implementation of a so-called hemoccult test. This test can detect invisible blood in the stool.

The most important and meaningful examination for the detection and clarification of intestinal tumors is colonoscopy. The entire large intestine can be examined using a thin, flexible hose, at the end of which there is a special camera (endoscope). If conspicuous changes are found during the examination, the doctor can take a tissue sample (biopsy), which is then examined finely (histologically) under the microscope. Only then will it be certain whether or not it is a cancer. Even any polyps that may exist can usually be removed directly and further evaluated. The examination can be carried out on request by light anesthesia or with the administration of sedatives, which means that it is usually not stressful or painful. As part of a general screening, all persons from the age of 50 are recommended to have a first colonoscopy.

Further examinations

If the suspicion has been confirmed and the diagnosis of colorectal cancer has been made, it is important to know what stage of the disease you are in – that is, how large the tumor is, how far it has spread within the intestine and whether other organs or lymph nodes are also affected. The necessary examination steps are summarized under the term staging. It is done so that your doctor can determine the optimal therapy for you individually.

Further examination steps include an ultrasound examination of the abdomen. This is done to determine whether other organs, such as the liver, gallbladder or pancreas, have changes that indicate the spread of cancer cells. An X-ray of the chest is also often taken to detect any existing daughter tumors (metastases) in the lungs.

If the tumor is located in the rectum, a mast or rectum mirroring (proctoscopy) can be performed. The last 20 to 30 centimeters of the intestine are examined. In contrast to colonoscopy, a rigid, non-flexible endoscope is used for this purpose, which allows the location or height of the tumor to be determined more precisely. This is crucial for the choice of optimal therapy or surgical options.

Proctoscopy is often combined with an endoscopic ultrasound. The tumor and the affected intestinal section are examined by means of an ultrasound probe inserted into the intestine. Among other things, the doctor receives information about how far the tumor has spread within the intestinal wall. This, too, is crucial for the planning of the therapy. The examinations usually last only a few minutes and are not painful.

In most cases, an additional CT (computed tomography) of the lungs and abdominal cavity or in rectum cancer an MRI (magnetic resonance imaging) examination of the abdominal cavity and the pelvis is performed. This allows further evaluation of the location and size of the tumor, its relationship to the neighboring structures and any existing daughter tumors. In addition, these examinations provide the doctor with important information on whether the tumor can be surgically removed and how extensive the operation will be. The examinations last about 10 (CT) or 30 (MRI) minutes and are completely painless.

In addition to these imaging procedures, a blood test is one of the necessary steps to assess organ functions and general health status. In this process, so-called tumor markers are usually tested for. Tumor markers are molecules that are often formed by tumors themselves or whose concentration in the blood can be related to tumor diseases. With regular monitoring, they can above all provide information about the course of the disease during therapy or help to detect a recurrence (recurrence of the tumor) at an early stage; however, they are not used as a precautionary measure.

All these tests help to estimate the stage of the disease and determine the optimal form of therapy. If conspicuous changes are found in other organs or lymph nodes, additional tissue samples must occasionally be taken to determine whether these are actually tumor settlements. The exact stage of the disease can often only be determined after that.

Stages of colorectal cancer

Roughly, the individual stages of colorectal cancer can be summarized as follows:

  • Stage I: The tumor is located in the mucous membrane of the intestine and extends no further than the muscle layer of the intestinal wall.
  • Stage II: The tumor has penetrated all wall layers of the intestine or spread locally and crossed the organ boundaries, but the lymph nodes are not affected.
  • Stage III: There are additional settlements in the adjacent lymph nodes.
  • Stage IV: The tumor has formed metastases in other organs.

Prevention of colorectal cancer

Lifestyle habits play an important role in the development of colorectal cancer. Studies show that it is possible to reduce the risk of colorectal cancer by getting more exercise, drinking sensibly, maintaining a healthy weight and eating healthy!

  1. Get tested

There are a number of effective screening tests for colon cancer. Some are easy to do, but need to be done more often. Others are more complicated but need to be done less often. The choice of test depends on your personal preferences and medical history.

Most people should start screening when they are 50 years old. However, some guidelines recommend the age of 45. People with a family history of colon cancer or other significant risk factors may start the test even earlier and get tested more often. Talk to a doctor about the costs and possible benefits of different tests and what is right for you.

  1. Maintain a healthy weight

Besides smoking, nothing increases your overall cancer risk more than being overweight or obese. At least 11 different cancers have been linked to weight gain and obesity, including colon cancer. An ideal goal is to weigh what you did when you were 18. In fact, if you have gained weight, the first goal is to stop gaining weight, which has beneficial effects on your health. Then, for a greater improvement in health, work slowly to shed a few pounds.

  1. Don’t smoke

Smoking is arguably the worst thing you can do for your health. In addition to increasing the risk of serious diseases such as heart disease, stroke and emphysema, smoking is a major cause of at least 14 different cancers, including colon cancer. If you are a smoker, quitting has real benefits, which start soon after your last cigarette.

  1. Be physically active

It’s hard to beat regular physical activity. It lowers the risk of many serious illnesses, including colon cancer, and provides a good mental stimulus. Any amount of physical activity is better than none, but it is good to aim for about 30 minutes or more of moderate physical activity each day. Pick things you like, like brisk walking, biking, dancing, or gardening.

  1. Beware of your alcohol consumption

Alcohol is a strange thing when it comes to health. It is heart healthy in moderation, but can increase the risk of colon cancer and other cancers, even at low levels.

What does that mean ?

If you drink moderately (up to one drink a day for women, two a day for men) you probably have no reason to stop. But if you already do not drink, there’s no reason to start either. Heavy drinkers should try to reduce their intake.

  1. Limit your consumption of red meat

You should limit your consumption of red meat, especially processed meats, and eat a healthy diet. Studies involving large groups of people have shown an association between a typical Western diet and an increased risk of colon cancer. A typical Western diet is high in red meat, animal fat and low in fiber.

When people move from areas where the typical diet is low in fat and high in fiber to areas where the typical Western diet is most common, the risk of colon cancer in these people increases dramatically. It’s not clear why this happens, but researchers are studying whether a diet high in fat and low in fiber affects microbes that live in the colon or causes underlying inflammation that may contribute to cancer risk. This is an area of ​​active investigation and research is ongoing.

Eating too much red meat increases the risk of colon cancer. And processed meats (bacon, sausage, etc.) increase the risk even more. Try to eat no more than three servings per week. Less is even better.

Instead eat a variety of fruits, vegetables, and whole grains. Fruits, vegetables, and whole grains contain vitamins, minerals, fiber, and antioxidants that may play a role in cancer prevention. Choose a variety of fruits and vegetables to get a variety of vitamins and nutrients.

  1. Get enough calcium and vitamin D

Sufficient calcium and vitamin D have been shown to help protect against colon cancer. Shoot for 1,000 to 1,200 milligrams of calcium per day and about 1,000 international units (IU) per day of vitamin D. Some groups recommend screening for vitamin D deficiency, especially in those at increased risk of low vitamin D levels, such as those who live in the north of the country, as well as in the elderly, very obese people, and people with dark skin.

  1. Consider a multivitamin with folate

A daily intake of multivitamins is good nutritional insurance that can also help protect against colon cancer. In addition to calcium and vitamin D, multivitamins contain folate.

Changing some of these lifestyle habits can also reduce the risk of many other types of cancer, as well as other serious illnesses like heart disease and diabetes. The links between diet, weight, exercise, and risk of colorectal cancer are among the strongest for any type of cancer.

Treatment of colorectal cancer

In principle, surgery, radiotherapy and chemotherapy are available for the treatment of colorectal cancer. New molecular biology therapies (so-called “targeted therapies”) may also be used.

The primary goal of any therapy planning is to completely remove the tumor through surgery. If all cancer cells can be removed, this creates the best conditions for a long-term cure. In addition to the tumor, a part of the surrounding intestine must also be removed to ensure that no cancer cells remain, which may already be scattered there but not yet visible. Any metastases that may exist will also be surgically removed if possible.

The operation is often performed via an abdominal incision (open surgical procedure). First, the entire abdominal cavity is examined in detail and tissue samples are taken from conspicuous areas if necessary. The tumor is then removed along with the affected intestinal section and the regional lymph nodes. Subsequently, the remaining darmenden are connected to each other to restore the continuity of the intestine. Depending on the location of the tumor in the large or rectum, different surgical procedures are used.

Chemotherapy is used on a stage-by-stage basis. It can be used before or after surgery or as a sole therapeutic measure and often makes a significant contribution to improving the chances of healing and quality of life. Drugs used for chemotherapy (so-called cytostatics) interfere with the cell division of cancer cells and prevent them from growing further. This can lead to a regression of the tumor and the formation of metastases or a recurrence of the tumor after successful removal can be prevented. Cytostatics are administered in several cycles and mainly attack those cells that divide particularly quickly – primarily damaging the tumor tissue. However, healthy, rapidly growing cells are also attacked, often causing undesirable side effects. Ask your doctor what side effects are likely to happen and the potential ways to alleviate them.

The aim of radiotherapy is also to destroy the cancer cells and to stop their growth. In contrast to chemotherapy, radiotherapy does not work throughout the body, but locally at the site of radiation. In the process, high-energy (ionizing) rays are directed at the tumor, which attack the nucleus of the cancer cells – thus they can no longer divide and then die. In colorectal cancer, radiotherapy is primarily used in tumors of the rectum. On the one hand, it can be used before surgery to reduce the size of the tumor and facilitate surgical removal. On the other hand, after surgery, it can help reduce the risk of recurrence of the tumor. Individual metastases can also be irradiated. The irradiation takes place over a certain period of time in several sessions, with the individual treatments lasting only a few minutes and not painful. Your doctor will inform you about the side effects that may occur and can help you alleviate them.

A relatively new method in the treatment of colorectal cancer is the use of so-called “targeted therapies”. The active ingredients of this group specifically attack certain structures in cancer cells, which are responsible for the formation and growth of a tumor. This can inhibit the growth and propagation of cancer cells and stop the progression of the disease. This form of therapy can be used in advanced stages of colorectal cancer and can be used alone or in combination with chemotherapy. Your doctor will inform you whether this form of therapy is appropriate for you and will inform you about the individual benefits and possible side effects.

In addition, there are some new therapeutic approaches that are currently being tested in clinical trials. Talk to your doctor about the possibility of participating in such a study. This can be an opportunity to benefit from new, promising treatment options.

Which treatment is right for you

Which treatment options are specifically suitable for you depends primarily on whether it is a tumor in the area of the large intestine or rectum. In addition, the choice of optimal therapy depends on the stage of the disease you are in and how well your general health is.

As a rule of thumb, several doctors from different disciplines (e.g. surgery, oncology, radiotherapy) are involved in the planning of the individual therapy strategy. This collaboration between different experts is called a tumor board review. This is to ensure that all important factors are taken into account and that the optimal treatment options are found for you.

A tumor in the area of the large intestine (colon cancer) can usually be completely surgically removed in early stages together with the affected intestinal part. If tumor sieves are present in the lymph nodes (stage III), chemotherapy is performed after the operation. This can destroy any cancer cells that remain in the body and reduce the risk of metastasis. If the tumor has spread only locally (stage II), adjuvant chemotherapy may also be used if certain risk factors are present.

If the tumor sits in the middle or lower third of the rectum (rectal cancel), the surgeon will remove not only the tumor and the affected intestinal part, but also the envelope surrounding the intestine (mesorectum). This tissue contains numerous lymph nodes – if removed, this reduces the risk of recurrence.

If the tumor is very close to the intestinal exit, the sphincter may be removed to ensure complete tumor removal. However, this surgery is extensive and the result usually requires an artificial intestinal exit (stoma, anus praeter). In order to avoid this and facilitate surgery, a combination of radiation and chemotherapy is often performed in rectal cancers before surgery (neoadjuvant radio-chemo therapy). This often reduces the size of the tumor. As with colon cancer, under certain conditions, adjuvant therapy can also be performed in rectal cancer after surgery, depending on the stage, in order to support the long-term healing success.

If metastases are already present in other organs at the time of diagnosis (stage IV), it may still be useful to perform surgery. Often, even at this stage, attempts are made to remove the tumor in the intestine completely or at least partially in order to maintain the continuity of the intestine. Under certain conditions, individual metastases in the lungs or liver can also be surgically removed. If surgery is not possible or if not all tumor deposits can be removed, the focus is on chemotherapy. This can significantly improve the quality of life and extend survival time. In addition or alternatively, active substances from the group of targeted therapies may also be used under certain circumstances. Your doctor will inform you which treatment is best in your case.

In conclusion

Being diagnosed with a serious illness like colon cancer is never an easy thing to swallow and it is quite normal that many questions arise. It is important that you inform yourself well about your illness and ask your doctor any questions that you consider important. Talk to him or her about your fears and wishes and let him or her know the benefits and possible risks of each treatment. This is the only way to make the right decision for you.

Colorectal cancer has a very good chance of a long-term cure, especially in the early stages. In addition, there are now good ways to stop the progression of the disease and to maintain a good quality of life.

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