A New Paradigm for Prevention of Ovarian Cancer

A New Paradigm for Prevention of Ovarian Cancer

This article is based on a paper by Nezhat R et al in September, 2015  issue of American Journal of Obstetrics and Gynecology.

• It is estimated by American Cancer society that 21,290 new cases of ovarian cancer will be diagnosed in 2015, and 14,180 deaths from ovarian cancer will occur during that period.

• The incidence of ovarian cancer varies geographically. The incidence is high in the Western world. The age-standardized rate (per 100,000 females) is only 3.8 in China, relatively lower than developed countries such the USA (8.8) and Australia (7.7).

• A woman has a 1:70 lifetime risk of being diagnosed with ovarian cancer, the second most common gynecologic malignancy, with the highest mortality rate.

• The majority of ovarian malignancies are epithelial in origin, and within this group the serous type is the most frequent.

• There is currently no effective screening method available for the detection of this disease, which has an overall five-year survival rate of approximately 45%.

• Apart from the genetics and modifiable risk factors responsible for causation of cancer, a new theory by Nezhat et al holds that serous ovarian cancer begins in the Fallopian tube from where it spreads onto the ovarian surface.

• Nezhat and colleagues classify ovarian cancers on the basis of etiology into two groups. Type I cancers originate from various ovarian pathologies (borderline ovarian tumors, endometriomas). These cancers typically have a more favorable prognosis because they are diagnosed at an earlier stage and metastasize more slowly.

• The more frequent type II tumors originate from the fimbriated end of the Fallopian tube and have a less favorable prognosis because they are often diagnosed at an advanced stage.

• Two large collaborative studies have recently called attention to the role of tubal ligation on reducing the ovarian cancer risk.

• The reduction is the greatest for endometrioid and clear-cell carcinoma, and is thought to be associated with the prevention of retrograde menstruation, ovarian seeding by endometrial cells, and inflammation.

• The Society of Gynecologic Oncology also recommends that for women at average risk of ovarian cancer, risk-reducing salpingectomy should also be discussed and considered in patients at the time of abdominal or pelvic surgery, after completion of child-bearing.

• The interventions called for salpingectomy at the time of hysterectomy, salpingectomy for permanent sterilization instead of tubal ligation, and referral for all patients with high-grade serous cancer for hereditary cancer counseling and genetic testing for BRCA1 and BRCA2 mutations.

• Although still in its infancy, these 3 recommendations are projected to reduce ovarian cancer rates in this province by 40% over the next 20 years.

• These clinical observations and the new recent evidence for the dual pathogenesis of ovarian cancer have set ground for implementing new strategies for screening and prevention programs to reduce the incidence of epithelial ovarian cancer.

• In light of the accumulated data and observations regarding endometriosis and ovarian cancer, Nezhat R. et al propose that it is time to establish criteria for identifying and monitoring women with endometriosis for risk factors and to pursue risk-reducing medical and surgical treatment options in these women.

• At the time of surgical diagnosis and treatment, consideration for complete resection of pelvic endometriosis, salpingectomy, oophorectomy, or hysterectomy should be individualized based on a patient’s age, desire for future fertility, and preoperative consultation with the patient.

• These initiatives, if validated by level 1 evidence, should substantially reduce the risk of ovarian cancer as well as the total mortality risk.

• For now, however, it seems that we may have tools in the future to combat a disease with a high mortality rate.

References:

1. http://www.cancer.org/acs/groups/content/@editorial/documents/document/acspc-044552.pdf

2. Pasalich M, Su D, Binns CW, Lee AH. Reproductive factors for ovarian cancer in southern Chinese women. Journal of Gynecologic Oncology. 2013;24(2):135-140. doi:10.3802/jgo.2013.24.2.135.

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6. http://www.ajog.org/article/S0002-9378%2815%2900325-7/fulltext

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