Ovarian cancer is the most deadly of the gynecologic cancers. This is mainly due to the fact that, for the vast majority of women, by the time the tumor has been discovered, it has spread beyond the ovary.
So far, screening strategies to detect ovarian cancer at its earliest stages, when it can be curable, have not been proven beneficial. In some groups of women, routine screening for ovarian cancer may actually be harmful, because women may undergo unnecessary operations for harmless conditions.
For most women, the risk of ovarian cancer will be about 1.6% in their lifetime. For women who are members of families with multiple cases of breast and/or ovarian cancer, the lifetime risk may be as high as 44%. For these high-risk women, the ovaries and fallopian tubes may be removed to prevent the disease.
But while this strategy may be beneficial for women who are at high risk to develop the disease, it is generally not acceptable for women who are at average risk. This is because the ovaries produce important levels of estrogens and androgens up to the age of 65. The routine removal of the ovaries may significantly increase the risk for cardiac disease, the leading cause of death in women. It is generally accepted amongst clinicians, that if a woman has a 10% or greater lifetime risk to develop ovarian cancer she is a reasonable candidate for prophylactic removal of the ovaries and fallopian tubes. However, the vast majority of women with ovarian cancer have no family history of the disease or no identifiable risk factors that put them at high risk for the disease.
About five years ago, the origins of what we call “ovarian cancer” were called into question. After looking at many ovaries and fallopian tubes removed from women at high risk for ovarian cancer, researchers began to notice that early “ovarian cancer” might by be originating from the portion of the fallopian tube nearest to the ovary. This finding has been supported by a number of additional pathologic observations. A 2009 study of women with mutations in genes that predispose them to ovarian cancer revealed that all cancers found at the time of surgery actually were arising from the portion of fallopian tube nearest the ovary. This is an important discovery because the fallopian tube does not produce important hormones, indeed it serves only as a passage for an egg to reach the uterus. We can now ask: Does removal of the fallopian tube alone allow a woman to maintain her ovarian function and prevent “ovarian cancer?”
Hysterectomy and tubal ligation (“tying” the tubes, or BTL), are two of the most common operations performed for women in the United States. Both of them offer an opportunity to prevent ovarian cancer in the average-risk woman. Traditionally, when a tubal ligation is performed the tubes are either tied or burned but left in place. When ovaries are left in place at the time of hysterectomy, the standard has been to also leave the fallopian tubes attached to the ovaries.
This new hypothesis concerning the origins of ovarian cancer should change the views on these common practices. It has been estimated that if the fallopian tubes are entirely removed at the time of tubal ligation and hysterectomy, a significant portion of ovarian cancer could be prevented. In North America, up to 15 – 20% of women diagnosed with ovarian cancer have had a hysterectomy prior to the diagnosis. Estimates from a large Canadian research group have concluded that up to 30% of ovarian cancer deaths could be prevented by routine removal of the fallopian tubes at the time of hysterectomy and tubal ligation. Questions concerning the routine removal of the entire tube at the time of tubal ligation include whether this will cause any compromise to ovarian function because the procedure may disrupt a larger portion of the blood supply to the ovary.
The take-home message: if you are considering a hysterectomy or tubal ligation, discuss with your surgeon the removal of the entire fallopian tube at the time of the procedure. Although there is not enough data yet to support widespread changes of medical practice, certainly the risks, benefits, and alternatives should be reviewed with your surgeon.