Lindsey A. Torre, MSPH
Ovarian cancer incidence and mortality have declined significantly over the past few decades, but eliminating racial disparities in treatment and improving prevention and early detection could help save even more women, according to an American Cancer Society (ACS) analysis of related statistics.1
From 1985 to 2014, the incidence rate declined 29%, from 16.6 to 11.8 per 100,000 individuals. From 1976 to 2015, ovarian cancer mortality declined by 33%, from 10.0 to 6.7 per 100,000. Despite these gains, “fewer than one-half of women survive beyond 5 years after diagnosis because of the predominance of aggressive high-grade serous carcinomas and the absence of specific early symptoms and effective early detection strategies,” the report said.
Lead author Lindsey A. Torre, MSPH, a Surveillance and Health Services Research scientist with ACS, and her team reviewed population-based data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results registry, the National Center for Health Statistics, and the Centers for Disease Control and Prevention’s National Program of Cancer Registries. Torre et al calculated long-term incidence trends using data representing 9% of the US population.
In an interview, Torre told OncologyLive®
that the drop in mortality was largely due to the decline in incidence. The decreased use of hormone replacement therapy among white women and increased use of birth control, especially among women younger than 65 years, help explain reduced incidence, which has dropped continuously since at least 1975.
Using oral contraceptives for 5 to 9 years was associated with a 35% reduced risk of ovarian cancer. The protective effect diminishes over time but lasts at least 30 years after the final dose. Tubal ligation and oophorectomy also contribute to lower risk. Treatment improvements also have influenced the declines in incidence and mortality but have not been available to all, Torre said. “There are disparities in who has access to those advances, with non-Hispanic blacks having markedly lower survival than non-Hispanic whites,” she said.
Among black women, the 5-year causespecific survival for serous carcinoma, the most common form of ovarian cancer, is 36%, compared with 47% to 48% for non-Hispanic whites, Asians/ Pacific Islanders, and Hispanic women. Torre and her team found that survival was poorest among black women at every stage of the disease.
Furthermore, although 5-year survival for epithelial ovarian cancer improved from 40% for white women who received diagnoses from 1992 to 1994 to 47% for those who received diagnoses from 2007 to 2013, it remained roughly 35% for black women. Comorbidities and inferior access to optimal debulking surgery and intraperitoneal chemotherapy are possible contributors to the worse outcomes.
“Non-Hispanic black women have the secondlowest incidence rate and the second-highest mortality rate. That doesn’t make any sense,” Torre said. “It’s thought to be because of disparities in access to treatment—specifically, in receiving optimal treatment. We’re at an opportunity point. We’re understanding the disease better, and there are effective treatments that just need to be applied more equitably.”
Table. Ovarian Cancer All-stage 5-year Cause-Specific Survival (%) Differs by Race/Ethnicity, Histology1
The ACS estimates that there will be 22,240 new ovarian cancer diagnoses and 14,070 disease-specific deaths in the United States this year. Ovarian cancer represents just 2.5% of all cancers among women but 5% of cancer deaths. For women with local disease, the 5-year relative survival rate is 93%, but many ovarian cancers are diagnosed in hard-to-treat advanced stages, providing hope for improving survival with better prevention and early detection.
Many efforts are under way to improve early detection, and so far in 2018, there have been 2 FDA approvals of oncologic drugs for treatment of ovarian cancer.2
In June, the FDA approved an expanded indication for bevacizumab (Avastin) for epithelial ovarian, fallopian tube, or primary peritoneal cancer. The drug, which starves tumor cells of blood, was approved in combination with carboplatin and paclitaxel, followed by bevacizumab, for stage III or IV disease after initial resection.
In April, the PARP inhibitor rucaparib (Rubraca) was approved for maintenance treatment of recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer. The drug was indicated for patients who have complete or partial response to platinum-based chemotherapy.
On average, the lifetime risk of developing ovarian cancer is 1.3%. Incidence rates were highest among non-Hispanic white women (12.0 per 100,000), 30% greater than for black women (9.4 per 100,000) and Asians/Pacific Islanders (9.2 per 100,000).