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Ovarian Cancer Survival Is Higher Than Widely Believed
Ovarian cancer patients have better odds of long-term survival than previously believed, according to a study from the University of California at Davis. Combing data collected on thousands of California women with ovarian cancer, researchers determined that almost one-third survived at least 10 years after diagnosis.
The findings 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.
"The perception that almost all women will die of this disease is not correct," says Rosemary Cress, MPH, PhD, lead author of the paper, published online in the journal Obstetrics and Gynecology.
Cress, an epidemiologist and associate adjunct professor in the university’s Department of Public Health Sciences, used the California Cancer Registry to analyze data reported on all California residents diagnosed with epithelial ovarian cancer between 1994 and 2001. Epithelial ovarian cancer is the most common type of ovarian cancer, occurring in nine out of 10 cases.
Of the 11,541 patients in the registry database, 3,582 (31%) survived more than 10 years, Cress and her colleagues discovered. It was the first time that research has looked at 10-year trajectories for patients; most survival studies have looked only at five-year survival or less.
As expected, the study found that the majority of the long-term survivors were younger, had early-stage disease when they were diagnosed, and had tumors of a lower-risk tissue type. What struck the researchers was that of the 3,582 long-term survivors, 954 had been considered to be at high risk of dying from their disease, either because of their tumor stage, grade, or older age at diagnosis.
"This information is important for patient counseling," says study co-author 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."
Leiserowitz says the next step in the research is to figure out why so many women who are given a poor prognosis eventually beat their odds. "For a disease that is so dangerous, why are so many surviving?" he asks.
Among the theories, Leiserowitz says, are that ovarian cancer patients who carry mutations in the tumor suppressor genes BRCA1 and BRCA2 respond better to chemotherapy than those who don't. He also suggests that other biological differences among patients with advanced ovarian cancer may affect individual outcomes. It's also possible that some patients get more effective treatment than others, boosting their survival odds.
Source: UC Davis Health System; August 5, 2015.