Colon cancer symptoms


The symptoms of colon cancer are generally very uncharacteristic. Unfortunately, especially in the early stages, there are no reliable symptoms that can be used to make a diagnosis easily.

General symptoms in colon cancer

A symptom of colon cancer can be blood in the stool. This is most common with rectal cancer. Here the blood is often (bright-) red and easy to see. The motto is often that the higher the cancer is in the intestinal tract, the darker or black the blood in the stool. However, this statement does not always apply in all cases! It should also be noted that no blood in the stool is also not a sign that nothing is present, as the addition of blood is not mandatory.

Sudden changes in bowel habits over the age of 40 are also noticeable. Such changes can include switching between diarrhea (Diarrhea) and blockages (Constipations) be. An increased urge to defecate and flatulence, which can lead to defecation at the same time, can also occur.
Abdominal pain can also occur in the context of colon cancer, but is also not mandatory.Also a warning sign are changes in bowel movements that lead to a putrid, purulent smell of the stool.

Read more on the subject at: Blood in the stool such as Black bowel movements

Early-stage signs of colon cancer

One of the reasons colorectal cancer is such an important and common cancer today is the fact that colorectal cancer unfortunately presents in its early stages with no specific symptoms. The signs do not make many people think of colon cancer so quickly. It is therefore important to take part in preventive examinations and to consult a doctor if you suspect it.

Signs of colon cancer in the early stages can be general symptoms such as fever, fatigue or decreased performance with increased paleness of the skin. There may be an unconscious decrease in weight.

Changes in bowel movements are also common. The bowel movements may become more frequent or appear in what is called a "pencil-thin" form. Occasionally, foul-smelling stools occur early on. Flatulence and loud bowel noises can also occur in early-stage colon cancer.

Read more on the subject at:

  • How do you recognize colon cancer?
  • Colon cancer screening

Typical symptoms of colon cancer

The following symptoms are typical symptoms of colon cancer:

  • Constipation or diarrhea

  • Pencil-thin, frequent, or foul-smelling bowel movements

  • Blood in the stool

  • Mucus in the stool

  • Abdominal pain up to intestinal cramps

  • Flatulence

  • Weight loss

  • Loss of appetite

  • Loss of performance, tiredness, paleness

Symptoms of rectal cancer

If the colon cancer is in the rectum, i.e. the last section of the intestine, separate symptoms can occur. This includes not only blood in the stool but also mucus deposits.

What is important is that blood in the stool can also come from hemorrhoids. However, such blood admixtures must not be dismissed, but examined for colon cancer despite the presence of hemorroids at the same time. It is also important that the blood is not always visible in the stool with the naked eye. There are special tests for this, such as the stool occult blood test, which tests for blood in the stool.

Read about this too Blood in the stool from hemorrhoids

Another symptom that can speak for colon cancer in the rectum is the so-called "pencil chair". The narrowing of the intestinal lumen caused by the cancer results in a thinner stool. Frequent and involuntary movements of stool and wind also occur in this context. Especially in the case of rectal cancer, hardening and the displacement of the lumen of the intestine may even be palpated during a digital rectal examination.

Read more on the topic: Cancer of the rectum

More symptoms

Other unspecific symptoms can also include general decreased performance and fatigue. The so-called B symptoms, which can occur in various types of cancer, can also occur in colon cancer.
These include:

  • severe weight loss in a relatively short period of time (which is not self-induced)
  • Fever and
  • nocturnal sweating during which even the bed linen or bed linen is changed at night.
  • A general paleness as part of anemia (anemia) and possibly a slight fever can also occur. The anemia can occur in the context of blood loss during bowel movements.

The problem is that these symptoms are very uncharacteristic and can appear with different diseases. As a result, these symptoms are often not recognized as warning signals in good time or are not properly assessed.

Pain as a symptom of colon cancer

Colon cancer usually only leads to pain in the later stages. These are mostly localized in the abdominal area and can occur there in a small area as well as in the entire area. The pain is usually expressed with a dull character. In the advanced stage, however, narrowing of the intestine can lead to sharp pain. If metastases already exist, these can also cause local pain. A typical place in the body is the spine.

Read more on the subject at:

  • Colon cancer pain
  • Stages of colon cancer and their prognosis

Flatulence as a symptom of colon cancer

Colon cancer changes the intestinal mucosa and intestinal flora. The intestine is naturally colonized with bacteria that do not harm the intestine and support the absorption of certain components from food. Colon cancer can lead to an imbalance between the bacteria and the intestine. As a result, more gas is released and flatulence occurs. These can also be expressed as loud bowel noises and often occur at the same time as mucus and blood deposits in the stool.

Phlegm as a symptom of colon cancer

Mucus in the stool can occur as a symptom of colon cancer, but is not an obligatory (compelling) Signs of illness. A healthy intestine also produces mucus to make the stool smoother. However, these small amounts of mucus are usually not visible in the toilet after a bowel movement. Large amounts of mucus can indicate various diseases of the intestine. It is not always a malignant disease.

In the case of colon cancer, different types of cancer can also be distinguished. Depending on which original cell degenerates and further develops into a tumor, the tumor shows different properties. Accordingly, not all types of cancer lead to increased mucus production.

In bowel cancer, there is often not only mucus but also blood in the stool. The mucus does not only come off during bowel movements, but also in between. This is very uncomfortable for those affected. If unusually large mucus secretions are noticed, a visit to a doctor is advisable in order to clarify the exact cause of this symptom.

Vomiting as a symptom of colon cancer

In the more advanced stages of colon cancer, nausea and vomiting can occur. The tumorous growths lead to increased disturbances of the intestinal passage. The food accumulates over a longer period of time because it is only pushed slowly forward through the intestine. Depending on the fullness of the intestines, this can lead to nausea and resulting vomiting.

Night sweats as a symptom of colon cancer

In addition to fever and unwanted weight loss, night sweats are part of the so-called B symptoms. One speaks of night sweats when the person sweats so heavily at night that they have to change their completely soaked top or even have to freshly make the bed.

Night sweats can occur as a symptom of all malignant diseases, including colon cancer. It comes about through a disruption of normal temperature regulation, for example through the release of certain messenger substances by tumors.

Night sweats, however, also occur without disease value or in the context of other diseases, for example in the case of infections or autoimmune diseases. If the night sweat persists suddenly and over a longer period of time, a medical examination is recommended. This is especially true if other symptoms are added to the night sweats, for example unwanted weight loss or - in relation to colon cancer - blood in the stool, changing stool habits or mucus.

Read more on the subject at: Sweating at night - harmless or dangerous?

Back pain as a symptom of colon cancer

At an advanced stage, colon cancer can also lead to back pain. This is most often the case when bone metastases have formed, i.e. the cancer has spread to the spine.

Depending on where exactly the metastasis is located, this can lead to more or less severe pain and restricted mobility. Very large tumors also compress their surroundings and can press on nerves and neighboring organs. Depending on the location, this can also cause back pain. Basically, back pain is not one of the common symptoms of colon cancer.

Much more common are blood and mucus in the stool, as well as changing stool habits. Back pain is much more often caused by poor posture and wear and tear and is therefore more likely to be caused by the musculoskeletal system.

However, you cannot rule out that a malignant disease is behind the symptoms without a thorough medical examination.

Read more on the subject at: Back pain as a symptom of colon cancer

End-stage symptoms

If the disease is more advanced, the infestation can be so great that the intestinal lumen is completely blocked and it leads to an intestinal obstruction (Ileus) is coming. In the later stages, vomiting with faeces can occur. This can also lead to severe and seizure-like cramps and pain.

In the advanced stages and especially in the final stages of the disease, pain is also generally more common. These pains come depending on the location of the colon cancer in the abdominal area (Colon cancer) or in the lumbar spine area (Cancer of the rectum) in front. The latter pains thus dominate as back pain and are often not initially associated with colon cancer.

If the colon cancer is already spreading in other organs (Metastases), further symptoms may occur depending on the organ and extent.

It is important that during the early stage of the disease there are usually no clear symptoms, especially then that more symptoms and complaints occur in the final stage. Unfortunately, this is often too late and the colon cancer has progressed too far. Because of these early warning signals, which are often missing, it is important to be aware of early detection examinations in good time and, above all, to have early and uncharacteristic signs clarified in good time.

Read more on this topic at: End-stage colon cancer


Colon cancer often remains completely without symptoms for a long time and develops few characteristic signs of a disease in the further course. The most characteristic symptom is blood in the stool, which is caused by ulceration of the tumor surface. The blood can be deposited on the stool or mixed with the stool, but in most cases it occurs in the form of so-called hidden (occult) blood. This hidden blood can be diagnosed with a special test (Haemoccult test) during the preventive medical check-up.

Changes in bowel movements may occur as the disease progresses. Frequently, diarrhea (diarrhea) and constipation (constipation) alternate. Stool shape changes such as "pencil stools" and "goat droppings" are less common due to the strong tumor constriction of the intestine. If the tumor shows a steady loss of blood, it can lead to anemia in the long term, which is manifested by tiredness and poor performance.

As with almost every tumor disease, an immense weight loss (Tumor cachexia), high temperature (Tumor fever) and pain in the area of ​​the tumor occurs. Has tumor colonization already occurred in the liver (Liver metastasesliver swelling and loss of function, which results in yellowing of the skin (Jaundice) shows. If there is a tumor settlement in the skeletal system (Skeletal metastases), bone pain occurs, which is accompanied by a particularly strong, devastating pain character. Metastases in the lungs sometimes cause shortness of breath (Dyspnea), Coughing up blood (Hematemesis) and pneumonia (pneumonia).

Further information

Further information on colorectal cancer can be found at the link:

  • Diagnosis and therapy of colon cancer
  • Colon cancer screening
  • What is the Typical Age for Colon Cancer?
  • Colon cancer pain
  • Detect colon cancer
  • Blood in the stool
  • Tests for suspected colon cancer
  • Appendix cancer