What is meant by metastasis? What are the common sites for metastasis?
What is meant by metastasis?
Metastasis is the ability of the tumor cells to spread to other parts of the body and establish secondary tumors. Malignant tumors break loose from the mass and spread to other parts of the body through lymphatic system and blood stream. Extra cellular matrix will be present between the surrounding cells, tumour cells release the protease enzyme whose function is to digest the extra cellular matrix between the surrounding cells and thus enhances its metatstatic property.
A malignant tumor also promotes angiogenesis by producing growth factors. These growth factors stimulate the formation of new blood vessels, which in turn support the rapid growth of tumour cells.
Certain organs such as lungs are the primary location for the formation of the metastases because of the abundant blood flow they receive from the body. The liver is the common site of metastasis of tumors originating in the gastrointestinal tract because the blood draining the intestines first passes through the liver via hepatic portal system.
What are the common sites for metastasis?
Common sites of metastasis for several specific cancers:
- Breast cancer-bones, brain, and axillary lymph nodes
- Lung cancer- liver, brain, bone and many other organs
- Prostate cancer-bones, lungs, liver, endocrine glands
- Colon cancer-liver
- Testicular cancer-liver, lungs
- Ovarian cancer-peritoneum, lungs, liver, diaphragm
Also you may be interested in knowing about Cachexia
What is meant by Cachexia?
Cachexia is a complex syndrome that is characterized by weight loss, anorexia and muscle wasting (lean body) seen in some patients suffering with cancer and AIDS.The patients with cachexia exhibit a number of metabolic abnormalities which results in poor utilization of nutrients and overall malnutrition.
Key factor in cachexia is the production of cytokines like tumor necrosis factor and interleukins in response to presence of cancer. Many cells produce these substances within the body and are protective against bacterial infections, viral infections and malignant cells. Although these substances are useful, they also produce effects of cachexia including anorexia and lean body wasting.