SAN DIEGO -- There's more evidence that the expertise of a gynecologic oncologist gives women with ovarian cancer a survival advantage.
SAN DIEGO, March 7 -- There's more evidence that the expertise of a gynecologic oncologist gives women with ovarian cancer a survival advantage.
In a retrospective study of nearly 1,500 women in northern California, those treated by a gynecologic oncologist had a five year-survival rate of 39%, found John Chan, M.D., of Stanford.
By contrast, women whose treatment was managed by physicians other than gynecologic oncologists had a five-year survival rate of 30% Dr. Chan told a plenary session of the Society of Gynecologic Oncologists meeting here. This difference was statistically significant at P<0.001.
Dr. Chan said there is an extensive literature showing that treatment by specialists improves outcomes, but despite that, "many ovarian cancer patients do not receive care from a gynecologic oncologist."
Dr. Chan based his conclusions on an analysis of 1,491 women with stage Ic to IV ovarian cancer treated in northern California between 1994 and 1996, using data from the California Cancer registry.
During that time, Dr. Chan said, only about a third of women -- 34.1% overall -- were treated by a gynecologic oncologist, although the proportion increased over the three year period from 27.9% to 36.5% to 35.6% (P<0.001).
Women who were treated by a specialist were significantly more likely to be more affluent, live in cities, and be better educated than those who were cared for by doctors with other specialties, he said. Specifically, of women treated by a gynecologic oncologist:
Analysis showed that gynecologic oncologists were significantly more likely to perform primary surgery and to offer chemotherapy, Dr. Chan and colleagues found.
Over the whole cohort, they found, 77% of patients had primary surgery, but among those treated by specialists the rate was 92%, versus 69% for those treated by other doctors.
The same pattern was true for chemotherapy: Overall, 77% of patients were given chemotherapy, compared with 90% of those under the care of gynecologic oncologist and 70% of those under other care. Both differences were significant at P<0.001.
In a multivariate analysis, Dr. Chan said, age, stage, and tumor grade were seen to be negative prognostic factors, while treatment by a gynecologic oncologist was protective, with a hazard ratio of 0.80 that was significant at P<0.001.
In a more detailed analysis including primary surgery and chemotherapy, treatment by a specialist become non-significant, but both primary surgery and chemotherapy were highly protective, with hazard ratios of 0.39 and 0.53, respectively. Both effects were significant at P<0.0005.
"The survival benefit attributed to the gynecologic oncologist is attributed to primary surgery and chemotherapy," Dr. Chan said.
The study was unable to analyze the extent of cytoreductive surgery, a key factor in survival, Dr. Chan said, and also had no information on residual disease after primary surgery. On the other hand, it had relatively large numbers, involved several institutions, and had detailed demographic information, he said.
Dr. Chan joins "a list of researchers who have made important observations about specialty and outcomes in ovarian cancer patients," said Barbara Goff, M.D., of the University of Washington in Seattle, in a formal discussion of the paper.
She said at least 25 published papers have demonstrated that "surgical volume and surgical specialization are key factors in outcomes in ovarian cancer."
Dr. Goff, an officer of the society, said gynecologic oncologists must stop "preaching to the choir" and find ways of ensuring that more women get specialized treatment when they need it.