Frederick R. Jelovsek MD
Do you have a family history of ovarian cancer? Is a family
history of breast, colon or endometrial cancer important in
predicting risk to ovarian cancer? Yes it is.
If one of your relatives has had ovarian cancer, this can
raise your chance over the baseline risk:
-
the average woman has a 1% (1 in 70) lifetime risk of
ovarian cancer
-
having one first degree relative with ovarian cancer
(mother, sister or daughter) gives a 5% lifetime risk for
ovarian cancer
-
having two first degree relatives increases the
lifetime risk to 20-30%.
Randall TC, Rubin SC: Assessing a patient's risk for
hereditary ovarian cancer. OBG Management 1998;Oct:37-
46, have examined the different risk factors for using
a woman's family history of any cancer to determine if she
is at risk for ovarian cancer. They report the general
classification of hereditary ovarian cancer syndromes.
-
breast-ovarian cancer syndrome
-
Lynch syndrome in which family members may develop non
polyposis-related colon or rectal carcinoma, endometrial
carcinoma and in some cases, ovarian carcinoma
-
site-specific ovarian cancer
In the breast-ovarian cancer syndrome, about 90% of cases
can be explained by mutation in two genes, BRCA1 and BRCA2.
These are the two breast/ovarian cancer genes that have been
identified to date. Women who have these inherited genetic
mutatations have as high as a 40-45% risk of ovarian cancer and
as high as an 85% risk for breast cancer. If their relatives
with breast or ovarian cancer have their disease onset
at less than 50 years of age, or if they are of Ashkenazi
Jewish heritage, that is even more suspicion that the family
members carried the gene mutation.
In order to differentiate women who have a risk of an
hereditary ovarian cancer syndrome (only about 5-10% of all
ovarian cancers) versus just having relatives with cancer
but no increased genetic risk, the following questions
should be asked.
| Family history of | Increased ovarian cancer risk
if... |
| ovarian cancer | 1st degree relative (mother,
daughter, sister) with ovarian cancer especially if age onset is
less than 50
|
| breast cancer | 1st degree relative (mother,
daughter, sister) with ovarian cancer especially if age onset is
less than 50
|
| any 1st or 2nd degree relative with a bilateral
breast cancer
|
| endometrial (uterine) cancer | 1st degree relative (mother,
daughter, sister) with ovarian cancer especially if age onset is
less than 50 |
| colon or rectal cancer | if not arising in a polyp
(nonpolyposis); this represents about 10-20% of all colorectal
cancer
|
| prostate cancer | a 1st or 2nd degree relative
with prostrate cancer, especially at an early age, can sometimes
have BRCA1 or BRCA2 gene mutations
|
Well now that we've asked the questions and determined there is
an increased risk for ovarian cancer, what are the next steps?
With any increased risk due to family history, these authors
reccomend:
-
establish a complete family history with medical records if
possible
- try to get genetic testing done on the family member with the
cancer history if they are still alive
-
armed with all the information possible, obtain good genetic
counseling
-
screen for early lesions using ultrasound and CA-125 starting at
least 5 years before the earliest age of cancer onset in the
family member
- consider chemoprevention such as oral contraceptives which
can reduce the risk of hereditary cancer by 50% or more
- consider prophylactic removal of ovarian tissue only if the
risk is proved to be substantial
|
