Cancer is a malignant tumor disease. Genetic changes cause cells to grow uncontrollably into healthy tissue and damage it. If the resulting mass (the primary tumor) enters the bloodstream, the cancer cells can spread further. In this way, secondary tumors—known as metastases—can develop in other organs.
If cancer is detected early and treated properly, the chances of a cure are often good. A precise diagnosis is therefore crucial. Only then can doctors accurately assess the extent of the disease and its exact nature. Ultimately, the decision on treatment is based on this diagnosis.
Treatment also depends, among other factors, on the patient’s age, condition, and life circumstances. This is referred to as personalized cancer medicine.
There is no single, universal cancer diagnostic test capable of detecting all types of cancer.
Statutory health insurance plans cover the costs of various screening exams. Cancer screening depends on age and gender. It is essential that you take advantage of these screenings. Cancer detected early significantly increases the chances of recovery.
Well-known examples include breast self-examination and the Pap test, which are part of cancer screening for women. They are used for the early detection of breast cancer and cervical cancer. For men, the PSA test is used to rule out prostate cancer.
People with many moles have an increased risk of skin cancer. Screening in this case includes, for example, having suspicious moles examined by a dermatologist using a reflected-light microscope.
In later years, colorectal cancer screening is added. This includes, among other things, the iFOBT stool test, which can detect so-called occult blood in a stool sample. Blood in the stool is a possible sign of colorectal cancer. Colonoscopy is also of great importance. It allows for the detection and easy removal of colorectal polyps. Colorectal polyps are benign growths in the colon that can become malignant over time.
However, tumors are often not detected until they are already causing symptoms. It is also possible for cancer to be discovered incidentally during another examination.
If cancer is suspected, the cancer diagnostic process in the strict sense begins. The goal is to determine
- exactly what type of cancer is present,
- whether it is a primary tumor or metastases (such as liver metastases),
- what stage the tumor is in (tumor staging),
- how far the tumor has spread,
- which tissues, if any, have been damaged, and
- whether the tumor has already metastasized.
Doctors follow a diagnostic protocol when selecting diagnostic methods. This ensures that the most expensive method is not used to search for the tumor as soon as an initial suspicion arises.
The choice of diagnostic procedure also depends on the size and location of the tumor.
An initial cancer finding or suspicion of cancer often arises from a positive physical examination or abnormal blood test results. Imaging techniques are frequently used for more detailed evaluation. These primarily include X-rays and ultrasound (sonography). However, both are rather nonspecific. In addition to requiring some practice on the part of the physician in interpreting such images, they also require the lesions to be of a certain visible size.
Modern imaging techniques from nuclear medicine, such as
These three methods of cancer diagnosis allow for much sharper and more detailed images to be produced.
MRI can detect many tumors © Image Supply Co | AdobeStock
If there are indications of a mass in an organ, a biopsy is usually ordered. A tissue sample taken from the suspected tumor allows for the
- at the molecular level,
- genetically, and
- immunologically
. Using this data, the cancer is individually assessed in the laboratory and its stage of development (“staging”) is determined. Thus, the biopsy is a very important part of cancer diagnosis.
As soon as the test results are available, oncologists meet in an interdisciplinary tumor board to decide on promising treatment options. Patients also have the option of seeking a second opinion.
A tissue sample (biopsy) is used in cancer diagnosis
- to precisely characterize a tumor in terms of its molecular and genetic profile, and
- to distinguish between a benign and a malignant tumor.
The doctor will therefore likely order cancer diagnostic tests if the following findings are present:
- unexplained skin changes,
- abnormal findings on digital rectal examination of the prostate accompanied by an elevated PSA level in the blood,
- lumps in the breast (Note: Men can also get breast cancer!),
- thyroid nodules, or
- changes in the mucous membranes.
It is not always possible to obtain a tissue sample from the tumor. Sometimes a hereditary (germline) component is also suspected.
In such cases, cancer diagnostics rely on the relatively new procedure known as “liquid biopsy.” In this process, physicians attempt to isolate DNA or RNA fragments from the tumor—for example, from the blood—using special molecular biology diagnostic chips. By analyzing these fragments, they can obtain a more accurate picture of the type of tumor.
Similar to the findings from a tissue biopsy, this information is usually relevant to treatment.
Oncology (cancer medicine) is a field of medicine that intersects with many other specialties. For example, prostate cancer is managed by urological oncologists, while breast cancer falls under the scope of gynecology.
Initial cancer diagnosis can usually be performed as part of cancer screening
- by a primary care physician,
- by a gynecologist, or
- urologist
. For more specialized issues, patients are referred to the appropriate specialists. Some of these specialists practice as private-practice oncologists in their respective fields.
However, as cancer diagnostics become more complex, patients must turn to oncology centers. These are often university hospitals or specialized cancer centers.
