Epithelial Ovarian Cancer - General Information
Contents:
Epithelial ovarian cancer is cancer which originates from a surface
cell of the ovary. It is the most common form of ovarian cancer, and most
cases occur in post-menopausal
women, usually in their 60s or 70s. Unfortunately, the vast majority (65%)
of women with ovarian epithelial cancer are diagnosed with advanced stage
(stage III) disease. In almost all cases, early ovarian cancer is picked
up as incidental findings in someone who is having treatment for an
unrelated problem.
Epithelial cancer tends not to produce any symptoms until the disease
is advanced. It spreads over the surface of the ovary and other organs in
the pelvis
and abdomen.
Eventually, because of the irritation to the peritoneum (the sac inside
the abdomen which holds the intestines, uterus and ovaries) a fluid
accumulates, called ascites. This causes swelling of the abdomen. If the
pressure from the ascites pressing on the diaphragm
is too great, the woman may feel short of breath.
The risk of developing ovarian cancer is about 1% in a lifetime. This
risk increases to 5% if the woman has a close relative who has developed
ovarian cancer.
Studying the Causes
The study of the occurrence and the causes of disease in the population
is called Epidemiology. An epidemiologist studies how common a specified
disease is, who is affected by it, and what are the factors that are
associated with developing that disease, as well as studies aimed at
controlling the disease.
How Common Is Ovarian Cancer?
Ovarian cancer is ranked 5th to 7th most common among cancers occurring
in women, and it will affect 1 to 2% of white women in their
lifetime.
Ovarian Cancer Genetics
Cancerous growth of the cells covering the surface of the ovaries
appear to result from an accumulation of damage to different types of genes
in those surface cells. Factors that increase risk probably act (directly
or indirectly) by increasing the chance that genetic damage occurs in the
cells covering the ovary.
Factors That Increase Risk
 | Age |
The occurrence rate of cancer of the ovary increases with age until menopause,
when rates even out.
| Western European Origin |
Western women have higher rates of ovarian cancer than women of African
or Asian origin.
| Family History |
Women who have a mother or a sister with ovarian cancer have a higher
risk than women who have no immediate family history. Clustering of breast
and ovarian cancer also occurs in a small number of families, and this may
be related to inborn genetic changes.
| Medical Conditions |
Patients with polycystic
ovary syndrome are at increased risk of ovarian cancer.
Reproductive Factors
| Childless Women |
Relative to women who have had one child, childless women are at a
slightly higher risk. Compared with women who have had several children,
childless women are at even higher risk.
| Infertility And Fertility Drugs |
Infertile
women who have had long-term difficulty in becoming pregnant appear to be
at higher risk than other women. Infertile women who have ever used
fertility drugs have been reported to be at approximately double the risk
of ovarian cancer compared with those who are untreated, but this has not
been confirmed.
Weight And Dietary Factors
Ovarian cancer is associated with obesity.
Women in the top range of body weight (adjusted-for-height) have around
twice the risk of women with lower body weights (after taking their age
and number of children into account).
Other External Factors
| Hormone replacement therapy |
There is a suggestion that women who have been long-term users of hormone
replacement therapy have a small increase in risk of developing
ovarian cancer compared to non-users, although results are not consistent.
Oestrogen-only
therapy is associated with the endometrioid
and clear cell subtypes of epithelial ovarian cancer.
| Talc |
Women who have used cosmetic talc in the perineal
region have a small increase in risk of epithelial ovarian cancer.
| Tobacco |
Although the overall evidence does not implicate cigarette smoking in
the causes of ovarian cancer, some studies have shown a positive
association.
Factors That Decrease Risk
| High Parity |
The risk of ovarian cancer decreases with each child a woman has up to
the third. Women with 3 or more children have about half the chance of
developing ovarian cancer compared with women who have never had children.
| Breast-feeding |
Breast-feeding can suppress ovulation
and women who have breast-fed are at lower risk of ovarian cancer for
every month of full lactation.
| Oral contraceptives |
Oral contraceptive use protects against ovarian cancer. The longer they
are used, the lesser the risk.
| Tubal Sterilisation And Hysterectomy |
Tubal
sterilisation and hysterectomy
reduce the chance of developing ovarian cancer by around a third compared
to women who have had neither of these procedures.
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