|
In order to fight it and make intelligent informed decisions about treatment options, you should know what exactly you're up against. Here's a primer....
Tissues, Organs & Building Blocks
Your body is made up of cells, the smallest building blocks that you
can see under a microscope. Cells aggregate or come together in an
orderly fashion and form various tissues, like skin, muscle, bone and
your organs. Just to get an idea of how many cells it takes to make
tissues, a one cubic inch area has approximately one billion cells
connected together. Each cell is composed of a central nucleus
surrounded by cytoplasm (fluid in the cell), all of which is contained
within a cell membrane (outer thin covering). The nucleus contains the
genetic material contained in chromosomes, which harbor many different
genes. Genes, in turn, are composed of deoxyribonucleic acid or  DNA;
the building blocks of life.
Cell Replication & Growth: Normal and Abnormal
Cells normally grow to replace older cells, which continuously die and
are absorbed by the body in a very orderly fashion. That way, in an
adult, most organs and tissues stay more or less the same size. In
order to grow new cells, the DNA is reproduced and chromosomes divide
by an orderly process called mitosis. As you will learn, when Cancer
cells grow, they lose control and replicate and divide very rapidly in
a dis-orderly fashion. Thus they are often said to have a high “mitotic
rate”.
When cancer develops in an organ or tissue, the cells begin growing in
an un-controlled fashion and are unchecked by your body's usual immune
defense mechanisms. The reason they start mis-behaving is based on very
complex interactions between DNA/genes and regulating proteins which
support and interact with genes. Some of these proteins turn genes on
and some turn various genes off, in a highly orchestrated way. When
something goes wrong with this based on environment or other unknown
factors, abnormal cell division and growth begins. Up to 85% of ovarian
cancer cases arise by this mechanism. This is called sporadic ovarian
cancer.
In the remaining 15-20% of cases ovarian cancer occurs as a result of
abnormally coded genes passed on through generations. This is called
familial ovarian cancer. Most of the known abnormal genes for ovarian
cancer risk are located in what are known as the BRCA loci. If genetic
counseling determines that there is a strong family history, BRCA gene
abnormalities can be tested for in the case of ovarian cancer. For other gynecologic cancers there are no additional genetic tests that are highly reliable. However, others do exist and may be considered after appropriate genetic counseling .
Normal cells divide only enough to replace those that die or to repair
injuries, then stop dividing. Cancer cells have lost this restraint due
to the DNA/gene instructions the cell's biochemical machinery gets and
keep dividing and piling up on each other. The mass of cancer cells
will eventually become large enough to cause symptoms and to become
detectable as a lump or a mass on a X-ray or scan. Usually the smallest
lump that can be detected by feeling it or by scan is the size of a
pea, and that already contains about 100 million cells.
Assuming cancer starts as a single abnormal cell, and that cell divides
and each cell that is produced keeps dividing and so on, the amount of
time to get to a pea size mass can take many months to years. At some
point, the cells can grow directly into adjacent tissues and organs, or
break into into tiny blood vessels or lymphatic vessels and spread to
lymph nodes and other parts of the body. These processes are called
invasion and metastasis.
Cancer Blood Vessels & Growth Support
The tiny blood vessels that feed cancerous tumors are usually very
abnormal and leak or rupture easily. Because of this, abnormal bleeding
is one of the signs of cancer in general. In the case of ovarian
cancer, occasionally vaginal bleeding can occur but is not common.
Cancerous tumors can also grow rapidly and outgrow their blood supply,
making the tumors oxygen deficient. When tumors are partly dying
because they are starved for oxygen, the process is called necrosis.
Necrosis, or dead tissue, is one of the reasons cancer can have an odor
if it is exposed to the surface of the body. In addition, cancerous
tumors are more prone to infection, which can also contribute to odor.
Fortunately, ovarian cancer rarely extends to the body's surface, so
odor is not a problem unless the cancer grows into the vagina. This is
rare, but necrosis is still a problem because cancerous ovaries can
become infected and poor blood supply can reduce the effectiveness of
chemotherapy.
Cancer produces factors called angiogenins, which help create new blood
vessels to help the tumor mass grow. Counteracting angiogenesis factors
is one of the newest developments in targeting strategies for fighting
cancer.
Cancer Cell Types
Cancers can arise from many different cell types. In the ovary there
are more than 30 different cell types that can become malignant. Those
which develop from epithelial surfaces which line different organs are
in a group called carcinoma. This is the most common group of cancers.
If the lining is glandular, then the name is extended to
adeno-carcinoma. For example, the cells which line the colon, internal
cervix and uterus, breast tissue, prostate or ovary are in this
grouping. Functional cells which support ovarian eggs can also become
malignant and are called germ cell or stromal cancers. Cancers can also
arise from various cells and structures such as bone, muscle, and fat
and are referred to as sarcomas. These are rare, but can also occur
within some gynecologic organs like the uterus and ovaries. Beyond
these general categories there is a large list of uncategorized,
unusual or rare cancers.
|
Cancer Information: The Basics 
