What is metastasis?
Metastasis are in oncology malignant tumors that occur at a different place than the original location of the first ("primary") tumor. It can occur metastasis is one of the main characteristics of a malignant tumor (cancer).
Metastasis usually start from a single cell that settles somewhere and grows into a new tumor. Because here a fairly long period of silence exists in which the metastasis is still too small to detect by eg X-ray or physical examination, be many cancer patients after treatment of the main tumor for years in uncertainty. Even if their operation was successful and "all the results were good" may best one, ten or even hundreds of metastasis undetected and untraceable in silence to grow.
Therefore often after surgery yet given chemotherapy or radiation. However, that usually provides no guarantee against recurrence.
In most malignant tumors, if no relapse occurred after five years the chance that this will happen is still very small; for breast cancer that period is significantly longer, up to ten years.
Dissemination forms
Metastasis may occur by diffusion of malignant cells in several ways:
- Through the blood (hematogenous metastasis)
- Through the lymphatic vessels (lymph node metastasis)
- By direct diffusion in a cavity (cavitary metastasis), for example, the abdominal cavity.
- By carry during an examination or treatment, eg after diagnostic puncture (entmetastase).
By haematogenous metastasis are the metastasis are often in the next flowed organ. For the intestine, this is the liver, other organs usually the lungs. Other organs which are often affected are the bone, usually with multiple metastasis, and the brains, which are difficult to treat by chemotherapeutic agents.
When lymph node metastasis metastasis arise mainly in the lymph nodes located downstream of the tumor - in breast cancer under the armpit.
The third group are especially ovarian tumors a good example. Also, tumors of the gastrointestinal tract can cavitair (ie in the abdominal cavity) spread.
Graft metastasis may occur, for example on the skin surface after a biopsy because of malignant tumor growth in the liver.
Metastasis symptoms
Metastasis usually occur only at a late stage of cancer, but can also occur early. The timing of the onset of symptoms can vary. The symptoms are always the result of a reduced functionality of the affected organ, but not necessarily cause pain. The problems one can encounter In other words, depending on the organ in which the metastasis is located and the extent to which these metastasis has supplanted the normal tissue.
A good example is a metastasis in the bone. Due to the growth of the metastasis displaces the normal bone tissue, and thus interferes with the strength of the bone. This leads to breaks in situations where this is not normally the case, for example, by a slight fall. These breaks can, however, also occur spontaneously. In medicine, this is called a "pathologic fracture". This rupture obviously causes pain, but it is not directly caused by the presence of secondary tumor there. Moreover, the symptoms of the primary tumor is usually paramount.
Consequences
For most types of cancer is that if there are distant metastasis once found, the prognosis (chance of survival) fell seriously but cure is still possible in some cases. This applies mainly to types of cancer that are very sensitive to chemotherapy, such as testicular cancer. Also, a single liver or lung metastasis can sometimes still be surgically removed. In the presence of multiple metastasis, surgery is often excluded. Radiation therapy has been in that situation for the same reason no curative option. This is called palliative treatment where cure is not possible, but in which symptoms and sometimes inhibition of tumor growth are the target.
Other types of metastasis
Also infections may arise incidentally metastasis - metastatic abscesses. Another, less confusing term for this is multiple abscesses. Instead of metastasis is called more frequently in infections of dissemination.