Assessment Tool Quantifies Risk for Ovarian Cancer

June 13, 2011

More than half of the 600,000 hysterectomies performed in the 1900s involved bilateral salpingo-oophorectomy, and it has been estimated that many of those were performed solely to reduce the risk for ovarian cancer. While there has been increased knowledge in the risk in women with familial history, a knowledge gap still exists for other women, which could lead them down the path of potentially unnecessary surgery

More than half of the 600,000 hysterectomies performed in the 1900s involved bilateral salpingo-oophorectomy, and it has been estimated that many of those were performed solely to reduce the risk for ovarian cancer. While there has been increased knowledge in the risk in women with familial history, a knowledge gap still exists for other women, which could lead them down the path of potentially unnecessary surgery. Thus, Allison F. Vitonis from the department of obstetrics and gynecology and Epidemiology Center at Brigham and Women's Hospital in Boston and colleagues created a risk factor score to further categorize risk for ovarian cancer in women without a personal or family history of cancer and to provide additional guidance to clinicians and their patients regarding elective bilateral salpingo-oophorectomy at the time of hysterectomy.

Data for the analysis of this scale came from a previous case-control study of ovarian cancer in New England. Over the 3 various phases of the study, the researchers looked at 1098 women with ovarian cancer and 1363 control women. To get the best risk snapshot, separate analyses were conducted for those women with cancer who did not have a previous hysterectomy; the researchers felt the information gathered from this group would be relevant to decision-making for “average-risk” women coming to hysterectomy. An analysis of women with a previous hysterectomy was also conducted to determine if risk profiles or reasons for the surgery could have distinguished women who subsequently developed ovarian cancer.

The researchers explored the associations with many risk factors for ovarian cancer. Since the majority of the participants were white, the researchers were unable to conduct an analysis on the impact of race on risk for ovarian cancer. Their analysis showed statistically significant increased odds ratio for women who used oral contraceptives less than a year or not at all, were nulliparous, never breastfed, had no tubal ligation, had painful periods or endometriosis, had polycystic ovarian syndrome or a BMI greater than 30 kg/m2, and used talc in the genital area for more than 10 years (Figure).

Figure. Risk factors associated with invasive ovarian cancer.

The researchers found an increasing risk for ovarian cancer as the conditions associated with risk increased. Thus, they used this information to compile an overall score that summarized the important risk factors. They then translated the overall risk-factor score into absolute risks for the occurrence of ovarian cancer during the remaining years of life from a particular starting age beginning at 40 years until 85 years, broken into 5-year increments. This simple score can then be used by physicians and their patients to determine the best course of action based on their potential overall risks.

While the researchers believe this scoring system will empower women and their clinicians to make the most appropriate treatment decisions for their specific circumstances, they recognize the scoring tool is not quite perfect. “Our risk score does not provide a precise formula for when elective oophorectomy should be recommended because we did not perform a cost–benefit analysis taking into consideration the competing risks from long-term complications of bilateral salpingooophorectomy, including bone fracture and cardiovascular diseases,” Vitonis and colleagues explained. “Although we believe our scoring system is an improvement over existing methods for assessing risk for ovarian cancer in women without a family history, it should be viewed as a prototype until it can be validated in other data sets, especially with prospectively collected data from women including more nonwhites who were underrepresented in our study.”

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Reference

  • Vitonis AF, Titus-Ernstoff L, Cramer DW. Assessing ovarian cancer risk when considering elective oophorectomy at the time of hysterectomy. Obstet Gynecol. 2011;117(5):1042-1050.