Endometrial Cancer
for laymen and students
Mario Kopljar, MD
WARNING! This information is for general use only. If you have EC, ask your doctor to explain these facts and how they apply to you.
Introduction
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Endometrial cancer affects predominantly elderly women average age is 55-65. Although the youngest patient was only 3, less than 5% of endometrial cancers are diagnosed in women under 40 years of age. In premenopausal women, the incidence of endometrial cancer (EC) is five times lower than the incidence of the cervical cancer, but after 70 years of age they appear equally frequent.
There are two types of EC - type I and type II. Type I is so called estrogen-dependent, which appears mostly in pre- and perimenopausal women, it is well differentiated and therefore has better prognosis. It is associated with conditions that elevate estrogen levels. Some of the following conditions may result in hyperestrinism: diabetes, liver disease, hypertension, obesity and infertility, menstrual cycle disorders.
Type II of EC is estrogen independent, diagnosed mostly in postmenopausal women, thin and fertile women, or in women with normal menstrual cycles. It is aggressive and has worse prognosis than type I.
There are three locations in the uterus where EC is most commonly begotten: fundus, tubar corners and isthmus. Those are the places of the strongest hormone influence on uterine lining.
There are two major morphological types.
Common sites of EC, two morphological types.
Lateral view of the pelvic organs.
Anatomy and physiology
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Internal female reproductive organs are: uterus, uterine tubes, ovaries and vagina.
Ovaries contain female reproductive cells called eggs. Each egg is surrounded with many other cells that produce hormones and provide nourishment for the egg. One part of the brain called pituitary gland secretes substances that control hormonal synthesis in the ovaries. Under their influence reproductive cells grow and mature, and ovaries secrete female hormone estrogen. When the egg is mature, it is surrounded with liquid and cells that provide nourishment form the wall of the follicle called Graaf follicle.
Then, the ovulation occurs. This is when the follicle breaks and the egg enters uterine tube (left or right, depending from which ovary it came from). Under the influence of pituitary substances mentioned earlier (called FSH - follicle stimulating hormone), many eggs are maturing, but at different speeds, so that one is always the most mature. The most mature egg is also the most sensitive to the influence of FSH, so it grows faster and faster (positive feedback).
After the ovulation, cells that were nourishing the egg begin to produce another female hormone called progesterone. This production is time limited and only lasts for two weeks on average. If the egg is not fertilized (joined with a spermatozoid - the male reproductive cell), it will not get buried into the endometrium (see later) and will not support further production of progesterone.
Normal endometrium
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Uterine void is covered with cells that form a layer called endometrium. The thickness of endometrium changes during the menstrual cycle. Just after the menstrual bleeding has finished, endometrium is very thin and consists only of few layers of cells called basal endometrium. In the first 14 days of a menstrual cycle, ovaries produce more and more estrogen, which causes endometrial cells to grow (proliferate). At day 14 on average, ovulation occurs. Ovaries begin to produce progesterone and under its influence endometrium changes; its cells become filled with glycogen bubbles. Glycogen is a complex sugar and its role is to be secreted on the surface of the endometrium and provide energy for the fertilized egg (blastocysta).
If the blastocysta (already multiplied fertilized cells) does not get implanted (buried) into the endometrium, ovaries will stop producing progesterone after about two weeks (14 days on average). This will cause sudden drop in progesterone level and as a result, blood wessels that provide blood for the endometrium will contract. As a result of such contraction, not enough blood will be available for the endometrium, and it will shed off, mixed with blood to produce menstrual discharge.
This explains how predominance of estrogen over progesterone may cause the uncontrolled growth of the endometrium.
Mario Kopljar, MD
Department of Surgery
University Hospital Sestre milosrdnice
Vinogradska 29
10000 Zagreb, Croatia
http://www.mef.unizg.hr
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