Ovarian cancer patients have far better odds of long-term survival than previously thought, according to a new study from the University of California at Davis. Combing data collected on thousands of women with ovarian cancer, which was once thought to be among the deadliest of all cancers, researchers determined that nearly one-third survived at least 10 years after diagnosis.
The findings, published in the journal Obstetrics and Gynecology, challenge the notion that women diagnosed with cancer of the ovary always face a poor chance of survival. And while the study confirmed earlier findings on characteristics associated with ovarian cancer survival—younger age, earlier stage, and lower-grade tumors at diagnosis—it also identified a surprising number of long-term survivors who didn’t meet those criteria at all.
“The perception that almost all women will die of this disease is not correct,” said lead author Rosemary Cress, MPH, PhD, an epidemiologist in the Department of Public Health Sciences at the University of California-Davis (UC Davis).
According to the American Cancer Society, an estimated 21,290 women in the United States will be diagnosed with ovarian cancer this year, and more than 14,000 are projected to die from the disease. The cancer is most common among older women, with more than half of cases diagnosed in women aged 63 or older.
The most recent data from the National Cancer Institute’s Surveillance, Epidemiology and End Results Program (SEER) show that the 5-year survival rate for women diagnosed with ovarian cancer is 45.6%. Long-term survival rates are typically estimated to be poor, though very little research has looked at survival past 5 years after diagnosis.
Nearly a third of ovarian cancer patients survived for 10+ years after diagnosis
In this latest study, the UC-Davis researchers took a longer look, extending their survival analysis to 10 years. The team analyzed data from the California Cancer Registry, identifying 11,541 women who had been diagnosed with epithelial ovarian cancer — the most common form of the disease, accounting for 9 in 10 cases — between 1994 and 2001.
Of these women, 3,582 (31%) survived for more than 10 years following their diagnosis. What’s more, many of these long-term survivors (954 women) had been considered high risk of dying from the cancer because they were an older age at time of diagnosis, had a higher tumor grade or were diagnosed with later-stage cancer.
“This information is important for patient counseling,” said study co-author Dr. Gary Leiserowitz, MD, a professor of gynecologic oncology and interim chair of the university’s Department of Obstetrics and Gynecology. “Many patients and physicians know that ovarian cancer is a dangerous cancer, but they don’t realize that there is significant biological variability among patients. It’s not a uniformly fatal prognosis.”
Dr. Leiserowitz says the next step in the research is to explore the reasons for these encouraging survival trends, especially among women who are given a poor prognosis. “For a disease that is so dangerous, why are so many surviving?” he asks.
It’s possible, says Dr. Leiserowitz, that the increased survival rates could be linked to the BRCA1 and BRCA2 gene mutations present in some patients with the disease; women with these mutations often respond to chemotherapy better than those without. Other biological differences among patients with advanced ovarian cancer may affect individual outcomes, he adds, and some patients may get more effective treatment than others, boosting their survival odds.