Detect colon cancer


Colon cancer is a malignant (malignant) Tumor (also carcinoma), which is located in the intestine. Mainly the colon is mentioned here, since small bowel carcinoma is a rather rare disease. Regardless of gender, colon cancer is the second most common cancer in Germany. Since over 6% of the population will develop carcinoma of the intestinal tract at some point in their life, it is important to know how to detect colon cancer.

Colon cancer screening

Since the likelihood of developing colon cancer increases with advancing age, preventive examinations have been taken over by health insurance companies since 2002 and thus funded.

Early detection plays an enormous role in the course and in the prognosis and should be taken seriously by everyone. In addition to the examinations carried out by the doctor, there are also opportunities to take care of your own body, to interpret signs correctly and to recognize colon cancer. Preventive measures, which everyone should take care of independently, are also an important point in disease prevention. Of course, none of this replaces going to the doctor.
Read more about this under: Colon cancer screening

You can recognize colon cancer by these typical symptoms

The danger of colon cancer lies in the fact that there are hardly any early symptoms and the tumor disease often remains undetected for too long. The first changes in the colon are usually small polyps or so-called "adenomas". They are neither painful nor hinder digestion, which is why no symptoms or restrictions are to be expected. Even if a malignant carcinoma is already present, it has often been growing for a long time and can spread in the body before the first symptoms appear.

The main indications of colon cancer are constipation and bleeding in the intestine. The latter are often expressed as small, dark spots of blood in the stool. If blockages occur, the tumor must already have filled large parts of the intestine, so that digestion is hindered. In the case of cancer of the rectum, known as "rectal cancer", the symptoms can appear earlier because blockages are easier and more likely to develop here. In this form of colon cancer, the changes can sometimes be seen and felt from the outside at the anus.

Read more on the subject at: Blood in the stool

The so-called "B symptoms" can represent further symptoms of colon cancer. These are not symptoms that are caused locally in the intestine by the growing tumor, but are due to a weakening of the entire body. Advanced cancer is often associated with these general symptoms, which can manifest themselves as poor performance, fatigue, rapid weight loss, a slight fever, and impaired general well-being.

Further information on this topic is available at: B symptoms

This pain indicates colon cancer

Colon cancer rarely manifests itself in pain. If pain occurs, it is usually related to severe bowel movements and digestive disorders. If the cancer largely blocks the inside of the intestine or if it lies unfavorably in the anus, constipation, painful bowel movements or even complete intestinal obstruction can occur. The latter are also referred to as “mechanical ileus” and represent a highly acute, life-threatening clinical picture. This can lead to cramp-like pain with a distended stomach.

The tumor can also cause pain in the abdominal cavity if it becomes so large that it presses on surrounding organs, pain-sensitive structures or against the abdominal wall. However, the pain is not a reliable symptom of colon cancer. On the one hand, many colon tumors occur without pain, and on the other hand, existing abdominal pain is not specific to colon cancer.

Read more on this topic at: Colon cancer pain



In principle, a good feeling for your own body can be helpful in recognizing various diseases.
Colon cancer usually begins with very unspecific symptoms such as decreased performance, increased fatigue, unwanted weight loss, night sweats and fever. The latter three symptoms constitute the B symptoms (applied to B cell tumors, such as the CLL - chronic lymphocytic leukemia), which can often occur with tumor development, but also with infectious diseases such as tuberculosis. The general inspection should be left to a doctor if the signs described apply.

A very reliable early symptom is the admixture of blood in the stool. However, the same applies here: intestinal tumors often lead to blood in the stool, but blood in the stool does not always mean that an intestinal tumor is present. Severe hemorrhoids can also be the cause.
In any case, a colonoscopic examination should be performed as the presence of bleeding hemorrhoids does not rule out colon cancer.

Changes in bowel habits can also alarm. An extremely smelly stool odor and severe flatulence with loss of stool (colloquially "false friend") are not immediately signs of cancer of the bowel, but should be observed if it occurs more frequently and, if necessary, clarified by a doctor. Strongly fluctuating stool irregularities, i.e. a constant change from constipation (Constipation) and diarrhea (Diarrhea) must also be reported to a doctor if these persist for a longer period of time.

If the tumor is in an advanced state, it can be partially palpated through the abdominal wall. But then a complete healing is usually no longer possible. Extreme pain in the abdomen in the context of an intestinal perforation, perforation or tearing of the intestinal wall can also be a sign of a long-standing intestinal tumor. Appendectal cancer manifests itself in many cases with the pain in the right lower abdomen that is typical of appendicitis.

Diagnosis by the doctor:

There are various options available to the doctor to examine the body for cancer or for colon cancer in particular.
At the beginning of every examination there is an anamnesis. In doing so, emphasis should be placed on the documentation of previous illnesses and on familial disease patterns. A precise anamnesis can speed up the following examinations and make them more targeted.

The standard here is a colonoscopy (Colonoscopy). A tube is inserted through the anus into the intestine, at the tip of which a camera and light are mounted. The intestine is systematically drawn from above (proximal) downward (distal) searched for irregularities. The examination is usually carried out under sedation, so the patient does not notice it.
If intestinal polyps or changes in the mucous membrane are discovered, these can be removed directly or biopsied (Take a sample) become. The biopsy (biopsied material) can then be examined under a microscope.

The digital rectal examination (digitum = finger), examining the rectum with a finger, can also provide clues about tumors there.

Laboratory diagnostics can determine so-called biomarkers in the blood of many tumors. These are substances that are associated with cancer and occur more frequently when such a disease is present.
Tumor markers also play a role, although they may be elevated in some but not all tumors. They are used to monitor the progress of therapy.
Stool samples can also be examined in the laboratory using sensitive tests for blood and excreted cell material.

In addition to the examinations by the doctor and the work in the laboratory, imaging procedures can be initiated, such as ultrasound of the abdomen (Abdominal sonography) or a CT (Computed tomography). A colonoscopy check is not bypassed.

Read more about this under How is colon cancer diagnosed?

How can you detect colon cancer without a colonoscopy?

The standard diagnostic procedure for detecting colon cancer is colonoscopy. If this cannot be carried out, however, other methods are available for making the diagnosis and planning therapy.

A first suspected diagnosis can be made by constipation, bleeding in the stool, a positive haemocult test or B symptoms such as weight loss and a drop in performance. An ultrasound examination as an imaging method can also provide information on changes in the intestine and estimate the potential extent of the tumor. The CT examination provides more precise results for this purpose. It makes it possible to recognize the tumor growth in the intestine in several layers, to measure its extent and to diagnose possible settlements in other organs. Therapy planning, for example an operation to remove the colon cancer, can also be carried out with the CT scan.

In the exact diagnosis of cancer, however, a tissue sample of the tumor is urgently necessary in order to be able to examine the malignancy of the cells, as well as the exact nature, origin of the tumor and possible therapy options. If the colonoscopy cannot be performed or if it is refused by the patient, such a biopsy can also be performed through the skin under CT guidance. A tissue sample for diagnostic clarification can also be saved during the operation. The easiest and most comfortable method for the patient to identify the tumor and obtain a tissue sample, however, is a colonoscopy, if possible.

Can you detect colon cancer with ultrasound?

Colon cancer can be detected and examined more closely with an ultrasound scan. During the ultrasound examination, the patient lies on their back while the doctor guides the sound device over the abdomen and the affected organs. The examination is very uncomplicated and quick, but its informative value is limited. In the case of known tumors and metastases, the ultrasound examination can be used to estimate the size of the cancer. In this way, the approximate size can be measured especially in the intestine, as well as the size of potential settlements in organs such as the liver. The ultrasound examination is in contrast to the CT examination, which is often unavoidable in the further course of diagnosis and therapy planning. It is much more meaningful, but is associated with radiation exposure for the patient and significantly higher costs.

You can use these tests to detect colon cancer

The diagnosis of colon cancer plays an extremely important role both in early detection and in therapy planning. In Germany, regular diagnostics are carried out in various preventive programs in order to be able to identify and treat precursors of cancer or early tumors in good time.

A first test that is covered by health insurances from the age of 50 is the so-called "haemoccult test". The test examines the patient's stool and can detect even small amounts of blood. The accuracy of the test is not very high, because a bleeding does not necessarily have to be attributed to a cancer, but on the other hand a cancer does not always bleed either.

The most important diagnostic test in the detection of colon cancer is therefore a colonoscopy. Colonoscopy is also recommended for all adults aged 55 and over and is paid for by health insurances, as early cancer diseases and precursors to tumors can be recognized and treated directly here.

Read more on this topic at: The course of a colonoscopy

Imaging procedures, including ultrasound examinations, computed tomography and PET-CT, can also be used for subsequent diagnostics. In the case of a very deep-seated cancer in the rectum, the doctor can make suspicious diagnoses with the help of a short palpation examination. Malignant tumors and bleeding can be felt at the anus with the finger and recognized.

Which blood values ​​can indicate colon cancer?

It is not possible to make a diagnosis using blood tests. Nevertheless, there are certain values ​​in the blood that change in the presence of colon cancer and make it possible to estimate the course of the disease. These blood values ​​are called tumor markers. In colon cancer, the tumor marker "CEA" plays a role. This cannot be used in diagnostics because an increase in the tumor marker does not have to mean a cancer and not every cancer is associated with an increase in the tumor marker. Nevertheless, the marker is also determined at the beginning of the disease, since its course in the blood is related to the course of the cancer.

The absolute value of the tumor marker is of no significance, but a steady increase in the original value can be related to a progression of the cancer. Even in the follow-up care of a tumor that has been overcome, a renewed rise in the tumor marker CEA can indicate renewed growth and a so-called “relapse” of the tumor.

Further information on this topic can be found at:

  • Can you detect colon cancer in the blood?
  • Tumor markers

Medical check-up

The cost of preventive colonoscopy in Germany has been covered by health insurance companies for high-risk patients since 2002. The group of risk patients includes people aged 55 and over; in special cases, with a family history, also people from the age of 35 years.

If the result of the examination is normal, the next preventive examination in the form of a colonoscopy will be carried out after 10 years at the earliest.
However, if symptoms occur during this period, you should not wait for the next appointment, but contact the doctor directly.

From the age of 50, a blood stool test can be taken and carried out every two years to check it. In order to detect colon cancer in good time, each person should take responsibility for appropriate preventive measures, because the earlier the tumor is discovered, the more likely it is that the cancer will be completely cured.

Read more on the topic:

  • Colonoscopy cost
  • This is how colon polyps are removed

Risk factors

Colon cancer development can be influenced by various factors. If a person is exposed to one or more of these factors, they must pay particular attention to signs of cancer or visit the doctor regularly for check-ups.

One of the most important factors are so-called intestinal polyps, newly formed protrusions in the intestinal wall, which often degenerate into intestinal tumors. It is not possible to recognize this yourself, but you can do so with a colonoscopy (Colonoscopy) are usually easily found and removed.

Chronic diseases such as ulcerative colitis or Crohn's disease also promote the development of colon cancer. These mostly inherited diseases are only part of the risk factors acquired through genetic predisposition. If cancer already exists or was directly related to cancer, offspring are three times more likely to be affected by a corresponding disease than the average citizen.

An improper diet is also a strain on the intestinal tract. A lot of calories, fat and meat as well as little fiber are likely to promote the development of intestinal tumors. Absolute proof has not yet been provided, but there are many parallels between diet and intestinal health.
The lifestyle associated with this plays an important role here - those who eat a lot and with greasy food usually do not exercise and are often overweight, which means that they put a strain on their gastrointestinal tract every day.

Increased alcohol consumption in connection with the lifestyle described can also be an indicator of colon cancer.

Age is an unalterable risk factor that may explain the rising incidence rates: people in industrialized countries are enjoying better and better health care and are therefore getting older - the chances that intestinal tissue will degenerate will increase, and with it new colon cancer.

In order to prevent various types of cancer, including colon tumors, it should be recommended that everyone refrains from smoking. Smoking significantly increases the risk of developing cancer and is a factor that everyone can change and control.

For more information, see: What are the causes of colon cancer?

Further information

For more information on colorectal cancer, visit:

  • Colon cancer metastases
  • Diagnosis and therapy of colon cancer
  • Colon cancer screening
  • What is the Typical Age for Colon Cancer?
  • Colon cancer pain
  • Is Colon Cancer Hereditary?