Editor's Note: Keeping up with the medical literature is hard work. Dr Peter Kovacs has made it a bit easier by summarizing two pivotal studies published in 2014 that are likely to have an impact for years to come.
Can the Lifetime Risk for Ovarian Cancer Be Lowered?
Opportunistic Salpingectomy: Uptake, Risks, and Complications of a Regional Initiative for Ovarian Cancer Prevention
McAlpine JN, Hanley GE, Woo MM, et al
Am J Obstet Gynecol. 2014;210:471.e1-11
Ovarian cancer is the eighth most common cancer among women, with about 22,000 new cases in 2014 and over 14,000 estimated related deaths. A woman has a 1-in-70 chance in her lifetime to be diagnosed with ovarian cancer. Early cancer is associated with nonspecific, vague symptoms, which means that ovarian cancer is typically diagnosed in an advanced stage when treatments are less effective and diagnosis usually carries a poor prognosis.
Various theories have been proposed about the etiology of ovarian cancer. The serous type of cancer of the fallopian tube is often found coexisting with serous ovarian cancer or primary peritoneal cancer. In fact, it is believed that many of these cancers originate in the fimbriated end of the fallopian tube. Furthermore, the tube allows the passage of infectious/inflammatory agents from the lower genital tract, increasing the risk for clear cell and endometrioid ovarian cancer. It has been shown that among those with blocked tubes, the incidence of such cancers is lower. These observations have already led to proposals to have the tubes removed at the completion of reproduction in order to lower the risk for ovarian cancer.
This paper describes how the recommendation to have the tubes removed at the time of gynecologic surgery in order to lower the risk for ovarian cancer has changed the operative practice in British Columbia.
In 2010, all obstetricians and gynecologists were sent information about the potential benefits of salpingectomy for the prevention of ovarian cancer. In this material, recommendations were made to have the tubes removed at the time of hysterectomy, to perform bilateral salpingectomy instead of tubal ligation when surgical sterilization is desired, and to have those diagnosed with the serous type of ovarian cancer screened for BRCA1 and 2 mutations to allow counseling of family members. The authors expect a ~40% decrease in the risk for ovarian cancer in the next 20 years as a result of this change in practice.
This paper assessed how the general surgical approach has changed since the mailing of these recommendations. The number of various types of surgeries was compared from 2008-2010 (before the recommendation) to 2010-2011 (after the recommendation).
Data were available based on 43,931 women who underwent hysterectomy alone, hysterectomy with salpingectomy, hysterectomy with salpingo-oophorectomy, tubal ligation, or salpingectomy alone in the study period. In 2008, out of all of the surgical procedures that involved the removal of the uterus, 55% involved hysterectomy alone; in 5%, the tubes were removed as well; and in 40%, salpingo-oophorectomy was performed too. In 2011, only 21% of procedures involved hysterectomy alone, while the tubes were removed with the uterus in 35% of the cases, and the tubes and ovaries were removed in 44% of the cases. The rate of those procedures where the tubes were removed increased significantly. This trend was seen across all age groups.
In 2008, 99.6% of surgical sterilizations involved tubal ligation. In 2011, in one third of the cases bilateral salpingectomy was performed with the purpose of permanent sterilization. This increase in the number of salpingectomies was also significant.
The mean surgical time was 16 minutes longer for hysterectomies involving salpingectomy and 22 minutes longer when they were combined with salpingo-oophorectomy. The length of the hospital stay was 0.15 days longer in the simple hysterectomy group. The hospital readmission rate was 1.2% higher among those with hysterectomy plus salpingo-oophorectomy.
The mean surgical time of the sterilizing procedure was 10 minutes longer in the bilateral salpingectomy group when compared with tubal ligation. There was no difference in the duration of hospital stay.
Surgical complication rates did not differ in the three hysterectomy groups or in the two tubal sterilization groups.
The authors concluded that the removal of the tubes at the time of hysterectomy or as tubal sterilization did not increase the surgical risk and in most cases could easily be performed by any gynecologist. The impact of this approach on ovarian cancer rates still has to be determined in the future after proper follow-up.
Various etiologies (repetitive surface trauma at ovulation, gonadotropin theory, androgen theory, inflammatory process, etc.) explain the etiology of cancer. An increasing role has been attributed to the fallopian tube as the site of initiation for certain histologic types of cancers and as a transport route of carcinogenic material that can be involved in the induction of ovarian cancer.
Sieh and colleagues have shown in a pooled analysis of case-control studies that tubal ligation is protective against serous, mucinous, endometrioid, and clear cell ovarian cancers. The largest protective effect was seen with endometrioid and clear cell cancers that are likely to be associated with a communication of the endometrium and ovary through an open tube. Lessard-Anderson and colleagues have found a 64% reduction in the risk for serous ovarian cancer and primary peritoneal cancer in women following excisional tubal sterilization. Finally, Madsen and colleagues have observed a significant reduction in both endometriosis and other histologic types of ovarian cancer in women with a history of tubal ligation. The greatest risk reduction (42%) was found in women who had their tubes removed.
There is a logical biological explanation for a lower risk for ovarian cancer following the occlusion of the tube and especially following the removal of the tube. A salpingectomy in most cases is not a technically challenging procedure and therefore could be recommended in a general practice. The study by McAlpine and colleagues has shown that caregivers are open to such recommendations and are willing to make changes in their routine practice. The removal of the tube as part of a hysterectomy or as a way to provide definitive sterilization was associated with only a minimal increase in operating time and was not shown to be associated with increased perioperative risks. It will be important to follow this cohort of patients to prospectively show that ovarian cancer risk can indeed be reduced. If this proves to be the case, then an even more general recommendation for salpingectomy upon completion of the family can be made. This could make a significant impact on a disease that is hard to diagnose early and treat successfully.
It also will be important to see whether any adverse impact of this approach on general health can be seen. Salpingectomy carries the potential risk of affecting ovarian function and may be associated with an earlier menopause through a compromise in the ovarian blood flow. The menopausal hormonal changes could have adverse long-term effects. It also will be important to see whether those women who undergo elective salpingectomy reach menopause at a younger age. If this turns out to be the case, then the overall risks and benefits will need to be balanced when the recommendation is made.
For now, it seems that this is a topic that has to be discussed with patients scheduled for tubal sterilization or hysterectomy.
Medscape Ob/Gyn © 2014 WebMD, LLC
Cite this: Top Ob/Gyn Literature From 2014 - Medscape - Dec 11, 2014.