Ovarian cancer is the leading cause of death due to gynecological malignancies in this country. It is the fifth most common cause of cancer death in women. Historically, all ovarian cancers have been grouped together as one disease, though they may actually be a much more diverse disease.
Morphologically, these epithelial ovarian cancers have been separated by histologic cell types:
- High grade serous carcinoma-the most common
- Clear cell carcinoma
- Endometriod carcinoma
- Mucinous carcinoma
- Low grade serous carcinoma
About 70% of epithelial ovarian cancers are of the high grade serous type. In addition, 50% of the high grade serous carcinomas have the BRCA genetic markers.
Malignancies of the fallopian tubes have always been considered very rare. Newer information now suggests a key role for the fallopian tube in the development of ovarian cancer. The distal end of the fallopian tube may be the site of origin for the most common type of ovarian cancer.
This conclusion is derived from the following observations:
- The lifetime risk for ovarian cancer in the general population is approximately 1.6%. If a woman is positive for the BRCA1 gene her risk is increased to 60%. If she is positive for the BRCA2 gene her risk is 30%.
- With this information, women who have been identified with either BRCA gene have been offered prophylactic salpingo-oopherectomy (remove the tubes and ovaries) to reduce this high risk. By doing so, the risk of ovarian cancer in this subset of women has been reduced by 98%.
- In the vast majority of cases, when the pathologist examined the ovaries after removal, NO precursor cancer cells were identified in the ovary. However, serous tubal cancer cells were identified in 5-10% of these cases in the distal fimbriated end of the tube (near the ovary).
- In patients that had the ovaries removed but the fallopian tubes left in the pelvis, there was up to an 11% increased risk of developing Primary Peritoneal cancer ( a form of “ovarian cancer” not requiring the ovary).
- A tubal ligation does not reduce the risk of cancer, however removing the entire fallopian tube (salpingectomy) does reduce the risk.
- Contraceptive pills have been shown to reduce the risk of ovarian cancer. One possible mechanism might be that the pills seem to reduce the inflammation seen at the distal end of the fallopian tube, and this inflammation might be the precursor that initiates the development of ovarian cancer.
A study done with young women identified as being positive for the BRCA1 or BRCA2 gene also offers more insight. The women were divided into two groups. One group waited until the age of 40 and had a bilateral salpingo-oopherectomy done (remove both tubes and ovaries) to help prevent the development of ovarian cancer. The second group had both tubes removed at an earlier age, then returned to the operating room at the age of 40 to remove both ovaries. The reason that the ovaries were not removed until age 40 is in part due to the fact that ovarian cancer seems to peak in the 4th and 7th decades of life and patient’s did not want to be forced into menopause any sooner. The second group however, had finished their family and had the fallopian tubes removed earlier (based on the possible belief that the fallopian tube was the true precursor of ovarian cancer). Results confirmed a significant decline in ovarian cancer in the second group that underwent a two stage procedure of removing their tubes first, the ovaries at a later date.
More studies are being done to help confirm this new evidence that many ovarian cancers might actually be a later stage of fallopian tube cancer. In British Columbia, Canada, a study is ongoing in which doctors are being asked to do a complete salpingectomy-bilateral (remove both tubes) instead of a simple tubal ligation when permanent contraception is desired. In addition, all hysterectomies are including bilateral salpingectomies (remove both tubes) regardless of whether the ovary is to be removed or left in place. In the past, if the ovaries were being left in the pelvis at the time of a hysterectomy, the tube would also be left in place with the ovary. This was done in hopes of not disturbing the blood supply to the ovary so that they would function better post operatively. The hope is that these studies will confirm a significant decline in ovarian cancer and thus offer a new treatment paradigm for this disease.
With all of this new information, one must strongly consider removal of the fallopian tubes at the time of hysterectomy, irregardless of whether the ovaries are to be removed or left in place in hopes of reducing ovarian cancer in the future.
My mum had a hysterectomy back in December, and it wasn’t until a few months later that she discovered that her fallopian tubes were not removed, even though her consultant who she saw numerous times before and performed the operation had told her that they would be removed along with her ovaries, uterus and cervix (Total Laprascopic Hysterectomy Bilateral Salpingoophrectomy). Why would they leave her fallopian tubes in and remove the organs attached at either end? We spoke to a practice nurse about this and she explained that it would be impractical to leave the fallopian tubes in when the ovaries and uterus were removed, as it would involve severing the tissue that connects the fallopian tubes to the ovaries and uterus at both ends, and many other medical professionals have told us they have never heard of a case where the fallopian tubes were the only part of the reproductive system left in.