Diagnostics
Self-diagnosis: In principle, a good feeling for one’s own body can be helpful in the recognition of various diseases. Colon cancer usually begins with very unspecific symptoms such as reduced performance, increased fatigue, unwanted weight loss, night sweat and fever. The three latter symptoms are the B-symptoms (attached to B-cell tumors, such as CLL – chronic lymphocytic leukemia), which are common in tumor development, but also in infectious diseases such as tuberculosis.
The general examination should be left to a physician if the described signs are true. A very reliable early symptom is the admixture of blood in the stool. However, the following also applies here: intestinal tumours often lead to blood in the stool, but blood in the stool does not always mean that an intestinal tumour is present.
Severe haemorrhoids can also be the cause. In any case, a colonoscopic examination should be performed, as the presence of bleeding haemorrhoids does not rule out intestinal cancer. Furthermore, changes in stool habits can be alarming.
Extremely stinky stool smell and strong flatulence with loss of stool (colloquially “false friend”) are not immediate signs of a cancer of the intestine, but should be observed if there is an increased incidence and if necessary be clarified by a doctor. Strongly fluctuating stool irregularities, i.e. a constant alternation between constipation (constipation) and diarrhoea (diarrhoea), must also be reported to a doctor if they persist over a longer period of time. If the tumour is in an advanced state, it can be partially palpated through the abdominal wall.
In this case, however, a complete cure is usually no longer possible. Extreme pain in the abdomen can also be a sign of a long-standing intestinal tumour in the form of a perforation, perforation or tearing of the intestinal wall. Appendicitis often manifests itself with the pain in the right lower abdomen typical of appendicitis.
Diagnosis by the doctor: There are various possibilities available to the doctor to examine the body for cancer, or for intestinal cancer in particular. At the beginning of each examination there is an anamnesis. Here, importance should be attached to the documentation of previous illnesses and to family patterns of disease.
A precise anamnesis can speed up the following examinations and make them more targeted. The standard procedure is a colonoscopy. A tube is inserted through the anus into the intestine, with a camera and light mounted at its tip.
The intestine is systematically searched for irregularities from top (proximal) to bottom (distal). The examination is usually performed under sedation, which means that the patient does not notice anything. If intestinal polyps or changes in the mucous membrane are discovered, they can be removed directly or biopsied (taking a sample).
The biopsy (biopsied material) can then be examined under a microscope. The digital-rectal examination (digitum = finger), the examination of the rectum with the finger, can also provide indications of tumours located there. Laboratory diagnostics can detect so-called biomarkers in the blood of many tumours.
These are substances that are associated with cancer and occur more frequently in the presence of cancer. Tumour markers play a further role, which may be elevated in some, but not all tumours. They are used to monitor the progress of therapy.
Stool samples can also be examined in the laboratory by 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 (computer tomography). A colonoscopy examination is not bypassed.
The standard diagnostic procedure for detecting colorectal cancer is colonoscopy. However, if this cannot be carried out, other methods are available to make the diagnosis and plan a 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 performance kink.
An ultrasound examination, as an imaging procedure, can also provide indications of changes in the bowel and can already estimate the potential extent of the tumour. For this purpose, the CT examination provides more precise results. It enables the tumour tumour tumour in the intestine to be detected in several layers, its extent to be measured and possible metastases in other organs to be diagnosed.
The CT scan can also be used to plan a therapy, for example an operation to remove the colon cancer. However, in the exact diagnosis of a cancerous disease, a tissue sample of the tumor is urgently needed 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 more precisely. If a colonoscopy is not feasible or is rejected by the patient, such a biopsy can also be performed through the skin under CT guidance.
Likewise, a tissue sample can be secured during the ongoing operation for diagnostic clarification. However, the simplest and most convenient method for the patient to identify the tumour and obtain a tissue sample is, if feasible, colonoscopy. Colon cancer can be detected with an ultrasound examination and examined more closely.
In an ultrasound examination, the patient lies on his back while the doctor passes the ultrasound device over the abdomen and the affected organs. The examination is very uncomplicated and quick, but limited in its informative value. In the case of already known tumours and metastases, the ultrasound examination can be used to estimate the size of the cancer.
Especially in the intestine, the approximate size can be measured, as well as the size of potential metastases 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 diagnostics and therapy planning. It is significantly more informative, but is associated with radiation exposure for the patient and significantly higher costs.
The diagnosis of colorectal cancer plays an enormously important role both in early detection and in therapy planning. In Germany, regular diagnostics are carried out in various screening programmes in order to be able to detect precursors of cancer or early tumours in good time and to be able to treat them. A first test, which is covered by health insurance companies from the age of 50, is the so-called “hemoccult test”.
This test examines the patient’s stool and can detect even small amounts of blood. The accuracy of the test is not very high, because bleeding is not necessarily attributed to a cancer, but on the other hand a cancer does not always bleed. The most important diagnostic test in the detection of colorectal cancer is therefore colonoscopy.
Colonoscopy is also recommended for all adults aged 55 and over and is paid for by health insurance companies, as it is a good way of detecting early cancers and precancerous stages of tumours and treating them directly. For subsequent diagnosis, imaging procedures can still be used, including ultrasound, computed tomography and PET-CT. In the case of a very deep-seated cancer of the rectum, suspected diagnoses can already be made by the doctor with the help of a short palpation.
Malignant tumours and bleeding can be palpated with the finger at the rectal exit and detected. A diagnosis based on blood values is not possible. Nevertheless, there are certain values in the blood which change in the presence of colorectal cancer and which make it possible to assess the course of the disease.
These blood values are called tumour markers. The tumour marker “CEA” plays a particularly important role in bowel cancer. It cannot be used in diagnostics, since an increase in the tumour marker does not necessarily mean that the patient has cancer and not every cancer is associated with an increase in the tumour marker.
Nevertheless, the marker is co-determined at the beginning of the disease, since its course in the blood is related to the course of the cancer. Although the absolute value of the tumour marker is not meaningful, a steady increase in the original value can be associated with a progression of the cancer. Even in the follow-up care of a surviving tumour disease, a renewed increase in the tumour marker CEA can indicate renewed growth and so-called “recurrence” of the tumour.
