Diagnostic methods

Our body is made up of many different types of cells. Therefore, many different types of cancer can occur. Some types grow rather slowly and do not “spread” (they do not form metastases), some grow at great speed and spread a lot, while others do not form solid tumors, such as the blood cancer (leukemia) or lymphatic cancer (lymphoma, Hodgkin’s disease). Once a cancerous disease has been diagnosed, thoughtful action is required.

For this purpose, various diagnostic procedures are used depending on the type and location of the tumour.

Laboratory examinations

The examination of a blood sample in the laboratory provides essential information. Physicians define the immune status by determining the type and number of immune cells in a blood sample. Our immune system reacts to certain tumours, for example, by producing more than the usual count of a special blood cell population. Most tumours also have specific characteristics and reveal themselves through so-called tumour markers. These are substances such as hormones or proteins. These tumour markers are either produced by the tumour itself and released into the blood, or the tumour causes the body to produce them.

Imaging procedures

Imaging procedures are very important in the diagnostics of cancer. X-rays were the first type of imaging technique to be discovered. Classic X-ray technology is still indispensable in many clinical situations today. Equally important nowadays are ultrasound, computed tomography (CT- or CAT-Scan), magnetic resonance imaging (MRI), scintigraphy and positron emission tomography (PET).

Radiographic examination

X-rays enable the radiologist to look inside the body because X-rays can penetrate it. Some organs allow the rays to pass through, while others slow them down to a greater or lesser extent, casting a visible “shadow” on the X-ray image. In cases of suspected cancer, classic radiographic diagnostics have now mostly been replaced by more sophisticated procedures allowing for greater details.

Ultrasound examination

Ultrasound diagnostics, also known as sonography, use sound waves to generate images of the inside of the body. The examining physician can view them directly on a connected monitor and thus detect changes in organs and tissues, such as tumours or metastases. there is no radiation exposure for either doctor or patient while using sonography. Ultrasound examination is therefore used frequently, usually in addition to other methods. However, ultrasound alone is usually not sufficient to fully diagnose a tumour.

Computed tomography

Computed tomography (CT or CAT-Scan) is a modern technique based on X-rays which allows a much more detailed look inside a person’s body, In this way, changes can be detected more precisely than by conventional X-ray imaging. In cancer therapy, computed tomography is used to validate the presence of a tumour or to monitor its progress during treatment.

Magnetic resonance imaging

Magnetic resonance imaging (MRI) uses a combination of a strong magnetic field with radio waves to produce detailed images of the inside of the body. In cancer diagnostics, MRI thus provides information about the location and size of a tumour.

Scintigraphy

In scintigraphy, a low-level radioactive substance can be used to visualize metabolic processes in the body. Before the examination, this radioactive substance is injected into the bloodstream. Metabolic processes cause it to be deposited in the body to varying degrees. Certain tumours and metastases will uptake and store the substance to a greater extent than healthy tissues, but sometimes also less. A special camera and a connected computer calculate images based on the different degrees of radiation emitted by the various body tissues. This way, tumours and metastases can be detected.

Positron emission tomography

Positron emission tomography (PET) can also be used to visualize metabolic processes in the body. For this purpose, radioactively labeled glucose or other substances known as “tracers” are used, which are injected into the bloodstream. Since tumors and metastases often have a different metabolism than healthy tissue, they may accumulate substances to a different degree. A measuring unit and a connected computer calculate PET images from the emitted radiation, producing visualizations on which tumours and metastases are clearly distinguishable.

Biopsy

In most cases, a palpable swelling, changes in lab parameters or a swollen lymph node are the results of benign changes, such as an infection. However, such symptoms can also be signs of tumour disease. In order to rule out the presence of a malignant tumour with certainty, it may be necessary
to examine cells or tissue directly collected from a suspicious area. The process of collecting such a tissue specimen, which usually only involves a minor surgical procedure, is called a biopsy. The specimen is further examined through microscopy by pathologists in a specialized lab, leading to what is called a histological finding. Doctors may advise patients to undergo a biopsy in the following cases:

• Detection of a lump in the chest of unclear dignity
• Changes in the mucous membranes of the digestive tract or the bladder
• Cellular changes in the female cervix
• Conspicuous palpation of the prostate accompanied by an elevated PSA reading
• Nodules of the thyroid
• Skin lesions of unclear dignity

If the tissue changes are small, it may be appropriate to remove the entire suspicious area right away rather than just taking a sample. This applies, for example, to smaller conspicuous moles and other skin changes. Doctors take a similar approach when testing lymph nodes for tumour cells, which are also completely removed and not biopsied. Another example is intestinal polyps, benign precursors of colon cancer, which are also removed completely, if possible immediately, during a colonoscopy.