Metastasis has two definitions. It is either the process by which cancer spreads from the primary organ to other organs or tissues or the type of cancer that results from this process. Metastasis happens when cancer cells break away from the primary tumor and travel through the bloodstream or through the lymphatic system. Practically all types of cancer have the ability to metastasize, and this possibility depends on factors such as the type of primary cancer, the stage of the cancer and the original location of the cancer.
Where cancers metastasize
Cancer cells may spread in three ways:
- by local extension from the primary tumor to neighboring cells and tissues;
- to lymph nodes near or surrounding the primary tumor; or,
- through the bloodstream or the lymphatic system, settling in organs and lymph nodes far from the location of the primary tumor.
The most common organs for metastasis are the lungs, bones, liver and brain. Although there are common areas certain types of cancers metastasize to. For instance, breast cancer often spreads to the lungs, liver, bones, or brain while lung cancer commonly spreads to the brain or bones. On the other hand, prostate cancer usually spreads to the bones while colon cancer often spreads to the liver.
Leukemia, multiple myeloma and lymphoma cells may be found in various lymph nodes and organs within the body but this is not considered metastatic since blood flows and travels in all parts of the body, thus allowing these particular cancer cells to easily spread to several organs and tissues.
Metastatic tumors may be easily differentiated from primary tumors as it retains the characteristic of the cells from which it originated. As such, breast cancer cells that have spread to the lungs will form a metastatic breast tumor, not a lung tumor. When examined under a microscope, the cells of the metastatic breast tumor found in the lung would look like breast cancer cells, not lung cancer cells.
There are cases wherein the metastatic cancer is detected ahead of the primary cancer. Identifying the metastatic cancer cell would determine where the primary tumor is. In rare cases, the primary tumor is not found, thus the metastatic cancer is identified as cancer of unknown primary origin.
Signs and symptoms
Symptoms of metastasis are similar, if not the same, to that of primary cancers. Some people with metastatic cancer do not exhibit any sign or symptom, though. The signs are dependent on where the metastasis is and at which stage the cancer is at. For example, a patient with metastatic cancer in the brain would experience severe headaches, seizures, or loss of balance.
There are also cases wherein the patient experiences symptoms from the metastasis ahead of the primary cancer. For example, a male patient suddenly suffers pain in the hips later found to be caused by metastasis from prostate cancer which has remained asymptomatic until then.
Treatment of metastatic cancer largely depends on its origin. The metastasis may be treated in the same manner as the primary cancer. In some situations, however, the metastatic cancer may be treated in specific ways independent of the procedure for the primary cancer.
Cancer control programs in the Philippines
There is still not enough accurate and relevant information on the relationship between various cancer agents, both natural and man-made, and the Filipinos’ predisposition to cancer. As such, the search for ways of effectively preventing cancer is still a work in progress. The more effective program, therefore, is the early detection of cancer among patients. The Department of Health (DOH) has launched campaigns to promote ways to detect cancer even at the onset, such as self-assessment (for breast cancer) and routine screening (such as rectal examinations for prostatic or colorectal malignancy in males).
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- Metastatic Cancer. Cancer Supportive Care Programs. (Accessed 09 January 2011)
- Definition of Metastasis. MedicineNet.com (Accessed 09 January 2011)
- Metastasis. Medline Plus (Accessed 09 January 2011)
- Cancer or Malignant Neoplasams. Department of Health (Accessed 09 January 2011)