The majority of people acknowledge and sympathize with Elizabeth Edwards, wife of the presidential candidate, John Edwards. Hers is the story of successful recovery from the primary breast cancer, only to wake up a few years later to find out the cancer had metastasized to her bone and to her liver. We have additionally learned that although the metastasized cancer can be treated, there no longer is any hope of cure.
How can this be, and what is metastasized cancer? The very word, metastasis comes from the Greek meaning, change of the state. Cancer cells break off the main tumor and travel via the blood stream or lymph system to a secondary site. Usually, the cancer will ‘seed’ in an environment that has similarities to the primary site. For instance, melanomas will spread to the brain, as their basic structure is related to the neural system. Likewise, breast cancer cells which get strength from the calcium in the milk ducts, spread to the bone to continue to obtain the required calcium they need for food.
Unfortunately, we don’t know as much about metastatic cells as the initial tumor. Scientists study cancer in vitro (test tube); however, metastatic cells by their nature are travelers, so the study needs to be done in vivo, or in the bewildering tangle of cells within our bodies.
A direct quote from the New York Times portrays a grim picture of metastitic cancers. “Patients rarely die from the effects of a primary tumor; 90 percent of deaths from cancer are the result of metastases, of malignant cellular outposts proliferating far from the neoplastic mass that spawned them. They are barbarians, the colonist cells, co-opting all nutrients in their adopted organ and starving their normal neighbors of air, sugar and salts, and blocking traffic and clogging conduits, and finally, when their greed exceeds their easy grab, tearing open surrounding cells and feasting like cannibals on the meat of their fellows.”
http://www.nytimes.com/2007/04/03/health/03angi.html?th=&emc=th&pagewanted=print
The real miracle of our bodies is the ability to prevent these voraciously hungry cancers from spreading. Several factors limit the cancers spread:
• Most cancer cells are not streamlined, like our blood cells, and are torn apart through shear forces as they travel through our vessels.
• Some cancer cells do spread; however, millions of them die or remain dormant forever at the secondary site. The mechanisms for exploiting their neighbor cells are non-existent, possibly due to the body’s innate sense to barricade the dangerous intruder.
• New blood vessel growth, or angiogenesis, is always needed to assure the cancer cells are given an adequate supply of nutrients. However, many things, including the foods one eats can prevent this vascular modification. If there is no blood supply, the tumor will not grow.
A study done in mice indicated how very well our defenses work to prevent the spread of cancer. The mice had several bulky tumors containing billions of cancer cells. Each day, a million or more cancer cells were introduced. However, only a very small percentage of the mice had metastatic cancer.
Modern medicine has also developed some knowledge and skills required to support our own defenses that keep the metastatic spread at bay for a while. Primarily, we have learned that when cancer spreads from one organ to the other, it retains all the properties of the original cancer, and needs to be treated as such. For instance, if breast cancer spreads to the lungs, it is still breast cancer, not lung cancer.
Additionally, we now have therapies for cancer that were non-existent in the past. No longer does the patient have to rely on chemotherapy and radiation alone: hormonal, antibodies, and other biological therapies now exist to treat primary, and therefore, metastatic cancers as soon as discovered.
Oncologists are a lot more proactive than in the past, too. It is a standard of practice to use sophisticated X-Rays to scan the patient’s body looking for other tumors which have spread, long before the patient has signs or symptoms. As with primary cancers, it is important to catch metastatic cancers as early as possible.
The National Cancer Institute is always working on newer methods to not only treat, but diagnose and perhaps prevent the spread of cancer cells. So, as difficult as the situation may be, we are very slowly starting to gain a foothold in controlling the aggressive, metastatic invaders.
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