The strongest argument for the nature of the primary tumor is malignant metastasis-metastasis in the acquisition of other body parts. The occurrence of metastases tersifat by several separate processes: the penetration of tumor cells into the channels of blood and lymph in and around the primary tumor, hematogenous spread of tumor cells or limfogen (the hematogenous dissemination of tumor cells attached to the capillary wall and prekapiler), penetration of the vessel wall and eventually proliferation of tumor cells outside the vessels in the interstitial tissue stroma with formation fibrovaskuler.
Despite the clear majority of tumors in the beginning mainly held hematogenous metastasis (Kaposi-sarcoma) and others are more often spread limfogen (breast), but both the metastasis is interconnected through the thoracic duct and the relationships limfatiko-venosa.
In aksperimen tumor cells are injected into the blood circulation can also be found in the thoracic duct. In general, tumor cells carried through the lymph vessels of the primary tumor to the lymph nodes first station. Often these glands serve as a filter, but it turns out the function of this filter is not as effective as originally suspected.
Tumor cells can pass through lymph nodes. Filter function seems to decline after radiation and Lymphangiography. Not all tumor cells are caught in the regional lymph nodes can survive and multiply. Experimental studies show that the lymph nodes have a local defense mechanism; immunologic and inflammatory reactions have an important role in this regard (Carier and Gershon).
In some circumstances the tumor cells will multiply and lymph nodes can be completely replaced by tumor tissue, with sometimes results in retrograde lymphatic flow. Of these lymph nodes may occur not only spread further limfogen, but can also occur through hematogenous dissemination limfatiko-venosa relationship as indicated by the Barn.
Problem tumor cells that continue to circulate for some time attracted a lot of attention (Griffiths and Salsburg, Circulating Tumor Cells, 1965). In many cancer patients can be demonstrated tumor cells in venous blood draining the tumor area and sometimes also in the blood that is taken from elsewhere.
Manipulation of the tumor in whom palpation, massage and curettage, increase the likelihood of obtaining these cells in the blood. In patients with low tumor differentiation, is more often found circulating tumor cells can be shown to not always lead to metastasis.
Also based on experimental observations it is likely that most of the cells circulating in the blood is destroyed even though this does not mean that the actions of diagnostic and therapeutic we do not have to prevent the spread.
Although circulating tumor cells can be destroyed by the organism in question most will reach the capillary nets and prekapiler alive and will be stuck here. Investigations conducted by Wood showed that these cells 'attached' to the endothelium and surrounded by a net of fibrin, platelets and leukocytes before they penetrate the wall.
Fibrinolysin and anticoagulants can reduce the number of metastases in humans is unclear. Little is known about how tumor cells penetrate the vessel wall. Should endothelial damage or are we dealing with a process that can be likened to lekodiapedesis on inflammation.
Regarding survival and tumor cell cultures that have penetrated the vessel wall is very dependent on the vascularization area into a new place cells. Tumor fragments were implanted in the camera oculi anterior rabbit eye with minimal vascularity, be destroyed; The same tumors that were grown in the iris area with very good vascularization grow very quickly.
In the course of metastatic human does not always follow a certain pattern. Growth rate may be lowered temporarily or permanently; and spontaneous regression, although very rare it can occur for example in the metastasis of renal carcinoma and melanoma.
On the other hand there are times when metastases become apparent several years after the primary tumor is completely removed (as far as can be determined). There is no information regarding the latent metastasis. Investigations conducted by Breur shows that we may face a tumor with a very long self duplication. Between start-borne tumor cell growth until the tumor nests can be diagnosed lasts a very long time.
The localization of the first hematogenous metastases are often determined by the localization of the first capillary nets reached the tumor cells through the bloodstream. If dissemination occurs through the vena cava system among kidney tumors, testicular and lung, the bones had been the first station of type vena cava.
When circulation through the portal vein among tumors of the stomach, pancreas and colon), the liver is the first localization of type venaporta. Tumor cells through the pulmonary veins into the arterial system tumors metastatic to the lung can make all the organs with a capillary nets.
Frequent localization is the brain, liver, bone and adrenal type pulmonary veins. In the second phase of metastasis formation determine the localization of the first metastasis subsequent dissemination. Although the localization of metastatic mostly according to the place that we expect based on the state of vascularization, as discussed above, we are often faced with the localization of such a nature as to be received by the possibility of other factors.
Anatomic clinical and experimental observations may partly explain this deviant pattern of metastasis. Tumor cells can pass through capillary nets, so it is not caught in the web of first instance found the nets of pulmonary metastasis until finally found in many other organs but not found in the lung.
Metastatic carcinoma of the prostate that is often the first that can be shown there in the lumbar vertebral column. This may be explained by a retrograde blood flow to an increase in intra-abdominal pressure. If this happens, the blood from the prostatic plexus which has an anastomosis with the vertebral plexus venosa can get into the last plexus.
Departing from vascular manner, then in some organs obtained only slightly metastasis. A good example for this is the heart and skeletal muscle. This observation led to the emergence of the theory match the culture medium. The tumor cells more easily 'grow' in one organ than in other organs.
What causes this difference is not clear. In the liver, are more prevalent liver metastases after experiencing mechanical failure or after administration of dextran or giving foods that contain a lot of fat. At the trial of radiation on organs such as the lungs and liver increase the occurrence of metastasis.
Not all malignant tumors metastatic hold. The time and rate of occurrence of this process can be different from each other. Basal cell carcinoma skin metastases almost never make. There is also a very small tumors and has not given the slightest complaint has led to the dissemination of mass, so the first symptoms are caused by metastasis.
On the other hand a very large primary tumors may not give metastases can be diagnosed. Tumors often unpredictable behavior. In general, tumors with low differentiation earlier and more extensive metastases than tumors with a high degree of differentiation.
But even this does not always apply. Tumors of the thyroid and adrenal with structures that still is in accordance with normal thyroid and adrenal tissue, can also make a metastasis. The old observation that tumors are characterized by limfositer infiltrates, plasma cells and macrophages often have a fairly good prognosis becomes clearer after we know that perhaps we are dealing with immunological rejection of the host against the tumor.
The third form of dissemination is, if the primary tumor continues to grow into one of the cavities of the body and the tumor cells make planting metastasis in the pleura and peritoneum. In our efforts to understand the occurrence of metastasis in malignant tumors should always we note that the population of cells in the primary tumor may be very heterogeneous.
Maybe there are big differences regarding the dependence on hormones, antigenicity, kinetic and khromosomal configuration, ie properties that can greatly affect the biological behavior and reaction to radiation, hormones or chemotherapy or immunotherapy. With this prevention and elimination metastasismetastasis got most of the basic biologic approach to replace the anatomic and mechanical ago.
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