A lady asked : I have a cystic ovarian endometriosis ; do I have an increased riks of ovarian cancer ?

The association between cystic ovarian endometriosis and ovarian cancer remains problematic and disturbing. Too often this soo called association is highlighted ; it creates fear  in many patients and is often an alibi not to perform  laparoscopic surgery but a laparotomy instead.
To read the original review article by Van Holsbeke et al
Fact 1 In large series there is some statistical association demonstrating that ovarian cancer is slightly more frequent in women with cystic ovarian endometriosis dan in women without. The association however is so weak that it can be considered as  clinically irrelevant.   Then there is a lot of speculation  to explain this.
Fact 2 In large series of ultrasound diagnosis of cystic ovarian endometriosis ovarian cancer is found in some 3% of women, almost all of them in women after menopause though.

Comments

Statistical associations cannot demonstrate a cause and effect relationship and should be interpreted carefully.

Most important is the strength of the association. The association of cystic  ovarian endometriosis and ovarian cancer is much weaker than the association between the use of oral contraception and tubal sterilisation and a decrease in ovarian cancer. The latter has been used to suggest that some ascending viral infections might be related to the onset of ovarian cancer, but has never been used as an argument to perform mass sterilisations or for the use of oral contraception.

Associations should be interpreted clinically. With the data we have today, it is important for the patients to know that

If you have a cystic ovarian endometriosis and are less than 45 years

there is almost no (never say never in medecine) real risk of cancer, and a cystectomie can safely be performed.
this will not increase your risk of developing ovarian cancer later.

If you have a cystic ovarian endometriosis and are older than  45 years or after menopause

normally the ovary will be removed, since this is technically easier and out of prudence in a bad so there is no spilling
In addition an larger ovarian cyst many years after menopause is alwyas suspect since endometriosis becomes rare.
This definitively is not an indication for a systematic laparotomy. If you are over 50 and the ovarian cyst is large, making the removal in a bag difficult the surgeon should have the skills to do this without spilling, otherwise it is better to perform a laparotomy.

This is an example of the statement on the home page that scientific data can be difficult to translate to the patient. Too often data are overstretched or misused to induce fear and/or to jsutify a laparotomy, especially by those non familiar with laparoscopic surgery.

P.R. Koninckx