How does breast cancer get started? How you develop breast cancer?



The first stage of cancer is known as "initiation". This is when the initial damage, or modification of the genetic material of a normal cell, occurs. This damage is caused by a carcinogen, which could be a hormone, a chemical, a virus, radiation, trauma, or a combination of these factors. The result is a permanently altered cell with defective growth controls. Scientists now believe that it usually takes more than on "insult" by carcinogens to DNA before a normal cell is transformed into a cancerous cell. For example, as a teenager you might have been exposed to pesticides or birth control pills during the time when your breasts were developing. In your early twenties you might have used oral contraceptives. A few years later you might paint the inside of your house without adequate ventilation and be exposed to xenoestrogens in the form of solvents. Throughout your life you get chest X rays that expose your breast cells to radiation. In your thirties you fall and hit your breast hard. In your forties you get a mammogram, both squashing the tissue and exposing it to radiation, and then you follow it up every few years with another one. In your fifties you are given an excessive dose of estrogen along with synthetic progestins. This is quite an accumulation of insults, but it's very typical of most postmenopausal women, and most could add a dozen or more incidents to this list. The final insult to breast cell that transforms it into a full-blown cancer cell probably occurs at least 10 to 20 years (depending upon the individual) before the tumor can be recognized by palpation (by hand) or by mammogram.


The second stage of cancer, called "promotion", involves the expansion of the tumor cell population to the point where it begins to interfere with the normal workings of the body. This stage occurs over an extended period of time, as long as 10 to 20 years, and varies depending on many factors. For example, tumor growth rate will depend on whether there's a good blood supply around it for delivering nutrients to its cells, and on growth factors such as estrogens, the hormone prolactin, and the substances called insulin-like growth factors that trigger breast cell division. We'll give you more details on these factors later in the book. Tumor growth will also depend on substances that inhibit growth such as progesterone, thyroid hormone, melatonin, dehydroepiandrosterone (DHEA), and phytochemicals from fruits and vegetables. Let's put the growth rate of a breast cancer in a different kind of perspective. The human body contains approximately 64 trillion cells. A drop of blood contains about 3,000 to 5,000 white blood cells and 5 million red blood cells. If a single healthy cell in a breast becomes a cancer cell, it usually takes 8 to 12 years for this cell to multiply into a detectable tumor. Another way of understanding the rate at which breast cancer tumors grow is that on average, they double in size very two to four months. Assuming 100 days as the doubling rate for the average breast cancer cell, there would be only about 4 to 5 tumor cells the first year, 30 to 50 tumor cells the second year, and so on. Finding a tumor this small would be more challenging than finding a needle in a haystack. Not until the seventh year would there be about a million tumor cells. This may seem like a lot of tumor cells, but if you packaged them into a perfect ball it would measure only about a millimeter across--not much bigger than an average pencil dot. Tumors of these sizes are not detectable by mammography. Only after the tumor grows for another three to four years, or for a total of 10 to 12 years, and contains 1 billion to 10 billion cells is it large enough (about 1 centimeter in diameter; 1 inch equals just about 2.5 centimeters) to be detected by mammography. Of course tumor growth patterns are never this simple. The insitu tumors, or those tumors whose growth is confined to the breast ducts from which they originated, tend to grow more as spheres or tubes because their growth is confined to the inside of the ducts. Invasive tumors, in contrast, don't generally grow as perfect spheres but radiate out in a clawlike pattern--hence the term "crab", or cancer--as they invade normal tissue and SEEK NUTRIENTS FOR GROWTH. This type of spread can make them even more difficult to detec within the confines of the normal breast tissue.


The third stage of cancer, known as the "progressive" stage, is the final stage of the disease. In this stage a distinct tumor grows in size; invades surrounding tissues, blood vessels, and lymphatics; and migrates to (metastasizes) and grows in other tissues of the body. Once a cancer has invaded other parts of the body, stopping its growth becomes much more complicated, but it can be done. The good news is that breast cancer is a disease of long duration, and we have daily opportunities over a lifetime to make decisions that will encourage the body to get rid of cancer. The interval between the initial transformation of a normal cell to a cancer cell and full-blown clinical detection of a tumor the size of a pea, containing as many as a billion cells, may take decades. ...We do know what causes cancer, and there's a lot you can do to help prevent it.

Dr John R Lee

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